Tamoxifen induces cellular stress in the nervous system by inhibiting cholesterol synthesis
Open accessAbstract
BACKGROUND: Tamoxifen (TAM) is an important cancer therapeutic and an experimental tool for effecting genetic recombination using the inducible Cre-Lox technique. Despite its widespread use in the clinic and laboratory, we know little about its effects on the nervous system. This is of significant concern because TAM, via unknown mechanisms, induces cognitive impairment in humans. A hallmark of cellular stress is induction of Activating Transcription Factor 3 (Atf3), and so to determine whether TAM induces cellular stress in the adult nervous system, we generated a knock-in mouse in which Atf3 promoter activity drives transcription of TAM-dependent Cre recombinase (Cre-ERT2); when crossed with tdtomato reporter mice, Atf3 induction results in robust and permanent genetic labeling of cells in which it is up-regulated even transiently. RESULTS: We found that granular neurons of the olfactory bulb and dentate gyrus, vascular cells and ependymal cells throughout the brain, and peripheral sensory neurons expressed tdtomato in response to TAM treatment. We also show that TAM induced Atf3 up-regulation through inhibition of cholesterol epoxide hydrolase (ChEH): reporter expression was mitigated by delivery in vitamin E-rich wheat germ oil (vitamin E depletes ChEH substrates), and was partially mimicked by a ChEH-specific inhibitor. CONCLUSIONS: This work demonstrates that TAM stresses cells of the adult central and peripheral nervous systems and highlights concerns about clinical and experimental use of TAM. We propose TAM administration in vitamin E-rich vehicles such as wheat germ oil as a simple remedy.
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Written from the paper’s full text.
TL;DR
Tamoxifen (TAM) induces cellular stress in the adult mouse nervous system, marked by Atf3-driven reporter recombination in central and peripheral neurons, vasculature, and ependyma. The effect is mediated by inhibition of cholesterol epoxide hydrolase (ChEH), and delivery in vitamin E-rich wheat germ oil reduces TAM-induced Atf3 up-regulation.
Key findings
- A single 75 mg/kg i.p. TAM dose induced tdtomato reporter expression in granular neurons of the olfactory bulb and dentate gyrus, vascular endothelial and smooth muscle cells, ependymal cells throughout the brain and spinal cord, and dorsal root ganglion (DRG) sensory neurons; more than 20% of DRG neurons were affected after one dose.
- In DRG, recombination occurred preferentially in large-diameter NF200-positive neurons, with a small percentage in non-peptidergic IB4-positive nociceptors; repeated daily TAM did not increase the proportion of recombined DRG neurons, but ATF3-positive neuronal nuclei were noticeably increased 24 h after a third daily injection.
- TAM-induced Atf3 up-regulation was linked to ChEH inhibition: TAM in vitamin E-rich wheat germ oil drastically reduced recombination (P < 0.0001, one-way ANOVA), and the selective ChEH ligand DPPE significantly increased recombination in DRG (12.33 ± 2.33 saline vs 26.00 ± 3.21 DPPE, p = 0.026), dentate gyrus (1.17 ± 0.44 vs 8 ± 0.58, p = 0.001), and olfactory bulb (2 ± 0.58 vs 12.33 ± 1.45, p = 0.003).
- ERα and sigma 1/2 receptor drugs (ICI 182,780, PPT, DTG) did not significantly alter TAM-induced recombination, and recombined neurons did not express the pro-apoptotic marker activated caspase 3.
Methods
- Generated an ATF3-CreERT2 knock-in mouse in which CreERT2 is driven by the native Atf3 promoter, crossed with a floxed stop ROSA-tdtomato reporter; also used an advillin-CreERT2 reporter line for DRG studies.
- TAM was given at 75 mg/kg i.p. in sunflower oil, wheat germ oil, or sunflower oil supplemented with vitamin E; additional drugs included ICI 182,780, PPT, DTG, and DPPE, with saline or oil controls.
- Quantification used confocal imaging of brain sections and DRG whole-mounts, immunohistochemistry for NeuN, calbindin D28k, NF200, CGRP, IB4, TH, and ATF3, recursive translation for DRG cell-size distributions, and statistics including Student’s t-test, one-way ANOVA with Holm-Sidak post-hoc, and Kolmogorov-Smirnov tests.
Limitations
- The paper states that whether Atf3 induction is due to accumulation of cholesterol epoxides or reduction in cholestane-3β,5α,6β-triol synthesis remains unknown.
- The paper notes that DPPE cannot induce active nuclear translocation of the ERT2 construct, so DPPE-induced tdtomato expression relies on leaky nuclear translocation and produces far less recombination than TAM; the ATF3-CreERT2 construct also displays TAM-independent leakiness.
- Evident from the text: vitamin E delivered directly in sunflower oil was less successful at preventing TAM-induced Atf3 expression, likely due to uneven dissolution and increased variability; the study did not directly measure ChEH substrates/products or assess behavioral/cognitive outcomes.
Model-written summary. Check it against the paper before relying on it.
Integrity signals
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Cites
Statistics
Claims the paper makes
19 of 40 cited sources checked · 12 supported · 0 flagged · accuracy not yet measured
- Premisecitation
TAM binds cholesterol epoxide hydrolase (ChEH), an enzyme complex involved in cholesterol biosynthesis.
“Furthermore, TAM binds other endogenous molecules, including sigma 1 and 2 receptors on the endoplasmic reticulum [10], and cholesterol epoxide hydrolase (ChEH) – an enzyme complex involved in cholesterol biosynthesis [11].”
Quote in the paperSubstantial claim1 of 1 sources checked- cites [11] de Medina P, Paillasse MR, Segala G, Poirot M, Silvente-Poirot S. Identification and pharmacological characterization of cholesterol-5,6-epoxide hydrolase as a target for tamoxifen and AEBS ligands. Proc Natl Acad Sci U S A. 2010;107:13520–5. doi: 10.1073/pnas.1002922107 . source
- Premisecitation
A small number of uninjured sensory neurons express Atf3.
“We and others have found that a small number of uninjured sensory neurons express Atf3 [23]”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [23] Averill S, Davis DR, Shortland PJ, Priestley JV, Hunt SP. Dynamic pattern of reg-2 expression in rat sensory neurons after peripheral nerve injury. J Neurosci. 2002;22:7493–501. source
- Premisecitation
A subpopulation of TAM-treated patients experience cognitive disturbances such as confusion, deterioration of verbal memory, and executive dysfunction (often called "TAM brain fog").
“TAM, via unknown mechanisms, induces cognitive impairment in humans.”
- Also stated in: § Introduction · plain
“there is accumulating evidence that a subpopulation of TAM-treated patients experience cognitive disturbances such as confusion, deterioration of verbal memory, and executive function such as decision-making, symptoms often referred to as “TAM brain fog” [1–4].”
Quote in the paperSubstantial claim2 of 4 sources checked- cites [1] Bender CM, Paraska KK, Sereika SM, Ryan CM, Berga SL. Cognitive function and reproductive hormones in adjuvant therapy for breast cancer. J Pain Symptom Manage. 2001;21:407–24. doi: 10.1016/S0885-3924(01)00268-8 . source
The review’s “Mechanisms of Changes in Cognitive Function with Adjuvant Chemotherapy” section (page unavailable) reports tamoxifen-related CNS toxicities, including confusion, and says their mechanism is unclear. It does not specifically attribute verbal-memory deterioration or executive dysfunction to tamoxifen; the cognitive-domain findings in the breast-cancer section concern women receiving chemotherapy, some of whom also received tamoxifen. (LLM, conf=0.86)
Experimental — accuracy not yet measured - cites [2] Chen X, Li J, Chen J, Li D, Ye R, Zhang J, et al. Decision-making impairments in breast cancer patients treated with tamoxifen. Horm Behav. 2014;66:449–56. doi: 10.1016/j.yhbeh.2014.07.005 . source
- cites [3] Espeland MA, Shumaker SA, Limacher M, Rapp SR, Bevers TB, Barad DH, et al. Relative effects of tamoxifen, raloxifene, and conjugated equine estrogens on cognition. J Womens Health. 2010;19:371–9. doi: 10.1089/jwh.2009.1605 . source
The Discussion (page not available) reports possible small adverse effects of tamoxifen on global cognition, particularly among older women with lower baseline cognitive scores; it also cites studies suggesting memory effects. But the paper hedges the effect rather than establishing that tamoxifen induces impairment, and it does not identify confusion, executive dysfunction, or “TAM brain fog” as effects in a subpopulation of treated patients. (LLM, conf=0.87)
Experimental — accuracy not yet measured - cites [4] Palmer JL, Trotter T, Joy AA, Carlson LE. Cognitive effects of tamoxifen in pre-menopausal women with breast cancer compared to healthy controls. J Cancer Surviv. 2008;2:275–82. doi: 10.1007/s11764-008-0070-1 . source
- Also stated in: § Introduction · plain
- Premisecitation
Under normal circumstances, Atf3 is expressed in very few regions of the adult nervous system.
“Under normal circumstances, Atf3 is expressed in very few regions of the adult nervous system [12].”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [12] Hunt D, Raivich G, Anderson PN. Activating transcription factor 3 and the nervous system. Front Mol Neurosci. 2012;5:7. doi: 10.3389/fnmol.2012.00007 . source
- Premisecitation
TAM's affinity for ChEH is second only to its affinity for ERα.
“In fact, the affinity of TAM for ChEH is second only to that for ERα, which may underlie its counter-intuitive efficacy in ER-negative breast cancers [11].”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [11] de Medina P, Paillasse MR, Segala G, Poirot M, Silvente-Poirot S. Identification and pharmacological characterization of cholesterol-5,6-epoxide hydrolase as a target for tamoxifen and AEBS ligands. Proc Natl Acad Sci U S A. 2010;107:13520–5. doi: 10.1073/pnas.1002922107 . source
- Interpretationcitation
TAM-induced recombination in dentate gyrus and olfactory bulb, particularly when dependent upon Arc expression, was remarkably similar to what we show here, in number of neurons recombined and dorso-ventral distribution in granular cell layer of dentate gyrus.
“TAM-induced recombination in the dentate gyrus and olfactory bulb, particularly when recombination was dependent upon Arc expression, was remarkably similar to what we show here (Figs. 5 and 7), both in terms of number of neurons recombined and dorso-ventral distribution in the granular cell layer of the dentate gyrus.”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [9] Guenthner C, Miyamichi K, Yang H, Heller H, Luo L. Permanent genetic access to transiently active neurons via TRAP: Targeted recombination in active populations. Neuron. 2013;78:773–84. doi: 10.1016/j.neuron.2013.03.025 . source
Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.
Experimental — accuracy not yet measured
- Premisecitation
Some primary afferent neurons express ERα as well as the sigma-1 receptor.
“Since some primary afferent neurons express ERα as well as the sigma-1 receptor [27, 28]”
Quote in the paperSubstantial claim1 of 2 sources checked- cites [27] Bangaru ML, Weihrauch D, Tang Q-B, Zoga V, Hogan Q, Wu H-E. Sigma-1 receptor expression in sensory neurons and the effect of painful peripheral nerve injury. Mol Pain. 2013;9:47. doi: 10.1186/1744-8069-9-47 . source
- cites [28] Chaban VV, Micevych PE. Estrogen receptor-alpha mediates estradiol attenuation of atp-induced ca2+ signaling in mouse dorsal root ganglion neurons. J Neurosci Res. 2005;81:31–7. doi: 10.1002/jnr.20524 . source
- Premisecitation
Previous investigation revealed loss of OPCs in corpus callosum at therapeutic TAM doses.
“A previous investigation of TAM-induced toxicity at therapeutic doses in the brain revealed a loss of oligodendrocyte progenitor cells (OPCs) in the corpus callosum [7].”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [7] Chen H-Y, Yang YM, Han R, Noble M. MEK1/2 inhibition suppresses tamoxifen toxicity on CNS glial progenitor cells. J Neurosci. 2013;33:15069–74. doi: 10.1523/JNEUROSCI.2729-13.2013 . source
- Premisecitation
ChEH inhibition is complete even at lower (therapeutic) doses of TAM.
“ChEH inhibition, which is complete even at lower (therapeutic) doses of TAM [11]”
Quote in the paperSubstantial claim1 of 1 sources checked- cites [11] de Medina P, Paillasse MR, Segala G, Poirot M, Silvente-Poirot S. Identification and pharmacological characterization of cholesterol-5,6-epoxide hydrolase as a target for tamoxifen and AEBS ligands. Proc Natl Acad Sci U S A. 2010;107:13520–5. doi: 10.1073/pnas.1002922107 . source
- Findingreasoning
In naïve ATF3-CreERT2:stopfl/fltdtomato mice, occasional reporter-expressing neurons are found in the olfactory bulb and dentate gyrus.
“and accordingly, in naïve ATF3-CreERT2:stopfl/fltdtomato mice, occasional reporter-expressing neurons were found in both of these regions (Fig. 1d).”
Quote in the paperNot a substantial claim - Findingown data
Spontaneous recombination events in DRG increase with age, from 3-5 cells per DRG in 8-week-old mice to 10-20 cells in 7-month-old mice.
“As would be expected in the case of spontaneous Atf3 activation, recombination events increased with age, ranging from 3 to 5 cells per DRG in 8 week old mice to 10–20 cells in 7 month old mice (data not shown).”
Quote in the paperNot a substantial claim - Findingown data
Reporter expression in response to TAM was mitigated by delivery in vitamin E-rich wheat germ oil.
“reporter expression was mitigated by delivery in vitamin E-rich wheat germ oil (vitamin E depletes ChEH substrates)”
Quote in the paperSubstantial claim - Findingown data
TAM treatment induces tdtomato reporter expression in peripheral sensory neurons.
“We found that granular neurons of the olfactory bulb and dentate gyrus, vascular cells and ependymal cells throughout the brain, and peripheral sensory neurons expressed tdtomato in response to TAM treatment.”
- Also stated in: § TAM-induced Atf3 induction in primary afferent neurons · plain
“TAM also induced high levels of tdtomato expression in the DRG (Fig. 4).”
Quote in the paperSubstantial claim - Also stated in: § TAM-induced Atf3 induction in primary afferent neurons · plain
- Findingown data
TAM treatment induces tdtomato reporter expression in vascular cells and ependymal cells throughout the brain.
“We found that granular neurons of the olfactory bulb and dentate gyrus, vascular cells and ependymal cells throughout the brain, and peripheral sensory neurons expressed tdtomato in response to TAM treatment.”
- Also stated in: § TAM-induced Atf3 induction in cortical regions · plain
“Recombination also occurred throughout the brain and spinal cord in vascular endothelial, smooth muscle and ependymal cells (Fig. 2e), but not in tanycytes lining the ventral part of the 3rd ventricle (data not shown).”
Quote in the paperSubstantial claim - Also stated in: § TAM-induced Atf3 induction in cortical regions · plain
- Findingown data
Reporter expression in response to TAM was partially mimicked by a ChEH-specific inhibitor.
“and was partially mimicked by a ChEH-specific inhibitor.”
Quote in the paperSubstantial claim - Findingown data
TAM treatment induces tdtomato reporter expression in granular neurons of the olfactory bulb and dentate gyrus.
“We found that granular neurons of the olfactory bulb and dentate gyrus, vascular cells and ependymal cells throughout the brain, and peripheral sensory neurons expressed tdtomato in response to TAM treatment.”
- Also stated in: § TAM-induced Atf3 induction in cortical regions · plain
“TAM administration resulted in wide-spread recombination in granular neurons of the olfactory bulb and dentate gyrus (Fig. 2b-d).”
Quote in the paperSubstantial claim - Also stated in: § TAM-induced Atf3 induction in cortical regions · plain
- Findingown data
In naïve mice, occasional clusters (probably clonal) of microglia and vascular endothelial cells are found throughout the brain.
“We also found occasional clusters (probably clones) of microglia and vascular endothelial cells throughout the brain (Fig. 1e).”
Quote in the paperNot a substantial claim - Findingown data
Ependymal cells are particularly prone to TAM-induced Atf3 upregulation.
“Our data show that ependymal cells are particularly prone to TAM-induced Atf3 upregulation.”
Quote in the paperSubstantial claim - Findingown data
The number of ATF3-positive neuronal nuclei is noticeably increased 24 h after a third daily TAM injection.
“although the number of ATF3-positive neuronal nuclei was noticeably increased 24 h after a third daily injection, indicating that TAM repeatedly stresses otherwise healthy neurons.”
Quote in the paperSubstantial claim - Findingown data
Mesencephalic trigeminal proprioceptive neurons undergo recombination with TAM treatment.
“Other cell populations found to be preferentially affected by TAM treatment were mesencephalic trigeminal neurons that convey proprioceptive information from the masseter (Fig. 5f), as well as vascular endothelial, smooth muscle and ependymal cells (Fig. 5g).”
Quote in the paperNot a substantial claim - Findingreasoning
The overall density of recombined cells in DPPE-treated mice was far less than that of TAM (in SFO)-treated animals.
“The overall density of recombined cells in DPPE-treated mice was far less than that of TAM (in SFO)-treated animals.”
Quote in the paperNot a substantial claim - Findingown data
TAM-induced tdtomato expression occurs preferentially in large diameter DRG neurons.
“TAM-induced tdtomato expression occurred preferentially in large diameter neurons, indicating that they may be more vulnerable to cellular stress.”
Quote in the paperSubstantial claim - Findingown data
The mean recombination frequency was consistently decreased in all tissues examined (dentate gyrus, olfactory bulb, and DRG).
“Nevertheless, we found that the mean recombination frequency was consistently decreased in all tissues examined (dentate gyrus, olfactory bulb, and DRG, data not shown).”
Quote in the paperNot a substantial claim- Rests on an assumption: α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.
- Findingown data
Reduced recombination was particularly striking in the dentate gyrus of the hippocampus.
“Reduced recombination was particularly striking in the dentate gyrus of the hippocampus (Fig. 7a, b).”
Quote in the paperNot a substantial claim - Findingown data
With either WGO schedule there was a drastic and statistically significant reduction in the number of recombined neurons in the DRG.
“With either WGO schedule there was a drastic and statistically significant reduction in the number of recombined neurons in the DRG (Fig. 6a, b).”
Quote in the paperSubstantial claim- Rests on an assumption: α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.
- Findingown data
Vitamin E delivered directly in SFO was less successful at preventing TAM-induced Atf3 expression.
“We also attempted to deliver vitamin E directly in SFO, which was less successful at preventing TAM-induced Atf3 expression (Fig. 6c).”
Quote in the paperNot a substantial claim- Rests on an assumption: α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.
- Findingown data
None of ICI 182,780, PPT, or DTG significantly altered the proportion of DRG neurons which underwent recombination.
“none significantly altered the proportion of DRG neurons which underwent recombination (Fig. 6b)”
Quote in the paperSubstantial claim - Findingown data
More than 20% of DRG neurons are affected by TAM-induced tdtomato expression after a single intraperitoneal dose of 75 mg/kg.
“More than 20 % of neurons were affected, even after a single intraperitoneal dose of TAM at 75 mg/kg.”
Quote in the paperSubstantial claim - Findingown data
TAM-induced elevated nuclear ATF3 expression in DRG is transient.
“Using an antibody to stain for Atf3, we could show that noticeably elevated nuclear expression was transient (Fig. 4a).”
Quote in the paperNot a substantial claim - Findingown data
A single intraperitoneal dose of DPPE (50 mg/kg) significantly increased tdtomato positive cells compared to saline in naïve ATF3-CreERT2:stopfl/fltdtomato mice.
“A significant increase in tdtomato positive cells occurred (Fig. 6d and Table 2)”
Quote in the paperSubstantial claim - Findingown data
None of ICI 182,780, PPT, or DTG induced recombination if given alone.
“None of these compounds induced recombination if given alone (data not shown)”
Quote in the paperNot a substantial claim - Findingown data
A single tamoxifen dose induced ATF3 expression, albeit transiently, in several populations of neurons.
“We found that a single tamoxifen dose induced ATF3 expression, albeit transiently, in several populations of neurons.”
Quote in the paperSubstantial claim - Findingown data
ATF3 expression can be maintained in susceptible neurons with repeated daily dosing.
“Our data show that ATF3 expression can be maintained in susceptible neurons with repeated daily dosing (Fig. 4)”
Quote in the paperSubstantial claim - Findingown data
Repeated dosing of mice with TAM does not increase the number of recombined neurons in the DRG beyond that after a single 75 mg/kg i.p. injection.
“Repeated dosing of mice with TAM did not increase the number of recombined neurons in the DRG beyond that which occurred after a single 75 mg/kg i.p. injection (Fig. 4b)”
Quote in the paperNot a substantial claim - Findingown data
Administration of TAM in WGO considerably decreased the ATF3 expression induced by TAM across most affected cell types and brain regions.
“As was observed in the DRG, administration of TAM in WGO considerably decreased the ATF3 expression induced by the compound across most affected cell types and brain regions.”
Quote in the paperNot a substantial claim- Rests on an assumption: α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.
- Findingown data
We found no evidence of TAM-induced recombination in OPCs or in the deeper neurogenic regions of the dentate gyrus or subventricular zone.
“In contrast, we found no evidence of TAM-induced recombination in OPCs or in the deeper neurogenic regions of the dentate gyrus or subventricular zone.”
Quote in the paperSubstantial claim - Findingown data
TAM does not induce Atf3 via estrogen receptors or sigma 1/2 receptors in these cells.
“In addition, we show that TAM does not induce Atf3 via estrogen receptors or sigma 1/2 receptors in these cells.”
Quote in the paperSubstantial claim - Findingown data
DPPE partially mimicked the effects of TAM in the dentate gyrus.
“Again, DPPE partially mimicked the effects of TAM in this area (Fig. 7c)”
Quote in the paperSubstantial claim - Findingown data
A single 75 mg/kg dose of TAM induces Atf3 upregulation in granular neurons of the olfactory bulb and dentate gyrus, a subpopulation of sensory neurons, ependymal cells, and endothelial and vascular smooth muscle cells.
“We show that granular neurons of the olfactory bulb and dentate gyrus, a subpopulation of sensory neurons, ependymal cells and endothelial and vascular smooth muscle cells upregulate Atf3 in response to a single 75 mg/kg dose of TAM.”
Quote in the paperSubstantial claim - Findingown data
Our study does not support a role for Atf3 in this process (neurogenesis).
“it does not support a role for Atf3 in this process.”
Quote in the paperSubstantial claim - Findingown data
Direct activation of ChEH using selective ligand DPPE upregulates Atf3.
“direct activation of ChEH using the selective ligand DPPE upregulates Atf3.”
Quote in the paperSubstantial claim - Findingown data
Vitamin E prevents TAM-induced cellular stress.
“Our finding that vitamin E prevents TAM-induced cellular stress represents a solution to this previously unappreciated experimental confound.”
Quote in the paperSubstantial claim- Rests on an assumption: α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.
- Study design and conductown data
The ATF3-CreERT2 construct displays a small degree of TAM-independent leakiness.
“When examining the resulting mice for tdtomato signal, it became clear that the ATF3-CreERT2 construct displays a small degree of TAM-independent “leakiness”.”
Quote in the paperNot a substantial claim - Premisecitation
Allen Brain Atlas in situ hybridization data show ATF3 expression only in granular neurons of the olfactory bulb and dentate gyrus.
“Allen Brain Atlas in situ hybridization data [24] show ATF3 expression only in granular neurons of the olfactory bulb and dentate gyrus”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [24] Lein ES, Hawrylycz MJ, Ao N, Ayres M, Bensinger A, Bernard A, et al. Genome-wide atlas of gene expression in the adult mouse brain. Nature. 2007;445:168–76. doi: 10.1038/nature05453 . source
- Premisecitation
There has been little preclinical work in animal models on TAM-induced changes in nervous system structure or function.
“Despite its widespread use in the clinic and laboratory, we know little about its effects on the nervous system.”
- Also stated in: § Introduction · plain
“Yet, there has been surprisingly little work done in animal models to identify TAM-induced changes in structure or function of the nervous system (either central or peripheral) [6]”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [6] Buwalda B, Schagen SB. Is basic research providing answers if adjuvant anti-estrogen treatment of breast cancer can induce cognitive impairment? Life Sci. 2013;93:581–8. doi: 10.1016/j.lfs.2012.12.012 . source
- Also stated in: § Introduction · plain
- Premisecitation
TAM binds sigma 1 and 2 receptors on the endoplasmic reticulum.
“Furthermore, TAM binds other endogenous molecules, including sigma 1 and 2 receptors on the endoplasmic reticulum [10], and cholesterol epoxide hydrolase (ChEH) – an enzyme complex involved in cholesterol biosynthesis [11].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [10] Kedjouar B, Daunes S, Vilner BJ, Bowen WD, Klaebe A, Faye JC, et al. Structural similitudes between cytotoxic antiestrogen-binding site (AEBS) ligands and cytotoxic sigma receptor ligands. Evidence for a relationship between cytotoxicity and affinity for AEBS or sigma-2 receptor but not for sigma-1 receptor. Biochem Pharmacol. 1999;58:1927–39. source
- Study design and conductreasoning
The ATF3-CreERT2 reporter mouse permanently labels cells in which Atf3 is upregulated even transiently.
“when crossed with tdtomato reporter mice, Atf3 induction results in robust and permanent genetic labeling of cells in which it is up-regulated even transiently.”
- Also stated in: § Introduction · plain
“Crossing the ATF3-CreERT2 line with floxed stop ROSA-tdtomato line, when combined with TAM treatment, allows for permanent labelling of cells even transiently stressed by TAM.”
Quote in the paperSubstantial claim - Also stated in: § Introduction · plain
- Interpretationown data
TAM stresses cells of the adult central and peripheral nervous systems.
“This work demonstrates that TAM stresses cells of the adult central and peripheral nervous systems and highlights concerns about clinical and experimental use of TAM.”
Quote in the paperSubstantial claim - Interpretationown data
TAM-induced Atf3 up-regulation occurs through inhibition of ChEH.
“We also show that TAM induced Atf3 up-regulation through inhibition of cholesterol epoxide hydrolase (ChEH): reporter expression was mitigated by delivery in vitamin E-rich wheat germ oil (vitamin E depletes ChEH substrates), and was partially mimicked by a ChEH-specific inhibitor.”
Quote in the paperSubstantial claim- Rests on an assumption: Vitamin E depletes ChEH substrates.
- Interpretationown data
TAM repeatedly stresses otherwise healthy neurons.
“although the number of ATF3-positive neuronal nuclei was noticeably increased 24 h after a third daily injection, indicating that TAM repeatedly stresses otherwise healthy neurons.”
Quote in the paperSubstantial claim - Study design and conductown data
The ATF3-CreERT2 mice, even in a homozygous state, appear phenotypically normal and outwardly indistinguishable from wild-type littermates.
“The resulting mice, even in a homozygous state, which effectively constitutes an Atf3 knock-out, appear phenotypically normal and outwardly indistinguishable from their wild-type littermates.”
Quote in the paperNot a substantial claim - Interpretationown data
Based on our results, TAM treatment would (repeatedly) induce cellular stress in older neurons.
“Based on our results, TAM treatment would (repeatedly) induce cellular stress in older neurons”
Quote in the paperSubstantial claim - Premisecitation
Dentate granule neurons are born in an outside-out manner during development and adulthood.
“Both during development and in adulthood, dentate granule neurons are born in an outside-out manner [8, 30]”
Quote in the paperSubstantial claim0 of 2 sources checked- cites [8] Imayoshi I, Sakamoto M, Ohtsuka T, Takao K, Miyakawa T, Yamaguchi M, et al. Roles of continuous neurogenesis in the structural and functional integrity of the adult forebrain. Nat Neurosci. 2008;11:1153–61. doi: 10.1038/nn.2185 . source
- cites [30] Stanfield BB, Cowan WM. The development of the hippocampus and dentate gyrus in normal and reeler mice. J Comp Neurol. 1979;185:423–59. doi: 10.1002/cne.901850303 . source
- Interpretationreasoning
In each of these examples, the use of TAM to induce recombination may have profound consequences on interpretation of the data.
“In each of these examples, the use of TAM to induce recombination may have profound consequences on interpretation of the data.”
Quote in the paperSubstantial claim - Interpretationreasoning
Recombined neurons in the dentate gyrus occupy relatively superficial positions in the granular cell layer.
“Taking previous findings and our results at face value, they would suggest that recombined neurons in the dentate gyrus occupy relatively superficial positions in the granular cell layer.”
Quote in the paperNot a substantial claim - Interpretationown data
Large diameter DRG neurons may be more vulnerable to cellular stress.
“TAM-induced tdtomato expression occurred preferentially in large diameter neurons, indicating that they may be more vulnerable to cellular stress.”
Quote in the paperSubstantial claim - Interpretationown data
Reporter expression after TAM is not simply due to TAM-induced nuclear translocation of the ATF3-CreERT2 construct in cells expressing Atf3, because the density of tdtomato-expressing neurons is far higher than expected from Atf3 in situ hybridization data.
“Reporter expression was not simply due to TAM-induced nuclear translocation of the ATF3-CreERT2 construct in cells expressing Atf3 as the density of tdtomato-expressing neurons was far higher than would be expected based on Atf3 in situ hybridization data.”
Quote in the paperSubstantial claim - Interpretationreasoning
Those which are most susceptible to TAM-induced Atf3 upregulation are more mature cells.
“implying that those which are most susceptible to TAM-induced Atf3 upregulation are more mature cells.”
Quote in the paperNot a substantial claim - Interpretationown data
ChEH inhibition is responsible for TAM-induced Atf3 upregulation.
“supporting the idea that ChEH inhibition is responsible for TAM-induced Atf3 upregulation.”
- Also stated in: § ChEH inhibition accounts for Atf3 induction by TAM · hedged
“suggesting an important role for ChEH inhibition in Atf3 activation.”
- Also stated in: § Discussion · hedged
“Instead, our results indicate that ChEH is the responsible TAM-binding entity”
Quote in the paperSubstantial claim- Rests on an assumption: TAM binds not only mutated ERT2, but also endogenous ERα, ChEH enzyme complex and sigma1/2 receptors.
- Rests on an assumption: α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.
- Rests on an assumption: DPPE cannot induce active nuclear translocation of the ERT2 construct and tdtomato induction is therefore entirely reliant on leaky nuclear translocation of CreERT2.
- Also stated in: § ChEH inhibition accounts for Atf3 induction by TAM · hedged
- Interpretationcitation
ChEH inhibition is likely to have contributed significantly to the observed effects in those studies.
“is thus likely to have contributed significantly to the observed effects.”
Quote in the paperSubstantial claim- Rests on an assumption: In all three above studies, TAM was delivered in corn oil, which has a vitamin E content of ~14.3 mg/100 g, compared to ~40 mg/100 g in SFO and ~150 mg/100 g in WGO.
- Interpretationown data
The ATF3-CreERT2 mice we have generated have allowed the first glimpse into the cellular stress pathway elicited in CNS by TAM.
“The ATF3-CreERT2 mice we have generated have allowed the first glimpse into the cellular stress pathway elicited in the central nervous system by TAM.”
Quote in the paperSubstantial claim- Rests on an assumption: This is the first study to directly assess the effects of TAM on cellular stress-induced Atf3 expression in the nervous system.
- Interpretationown data
TAM induces Atf3 expression in CNS and PNS neurons, vasculature and ependyma by interfering with cholesterol biosynthesis.
“They have revealed that TAM induces Atf3 expression in CNS and PNS neurons, vasculature and ependyma by interfering with cholesterol biosynthesis”
Quote in the paperSubstantial claim- Rests on an assumption: TAM binds not only mutated ERT2, but also endogenous ERα, ChEH enzyme complex and sigma1/2 receptors.
- Rests on an assumption: α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.
- Rests on an assumption: DPPE cannot induce active nuclear translocation of the ERT2 construct and tdtomato induction is therefore entirely reliant on leaky nuclear translocation of CreERT2.
- Classified as probably not a substantial claim. 19
- May combine two claims. 16
Classified as probably not a substantial claim.
PremisecitationAtf3 is one of a number of transcription factors upregulated by cellular stress, including the unfolded protein response, tyrosine kinase receptor activation, glutamate receptor hyperactivation, and cellular injury.
“We generated a knock-in mouse expressing CreERT2 driven by the native promoter for activating transcription factor 3 (Atf3), one of a number of transcription factors upregulated by cellular stress, such as the unfolded protein response, tyrosine kinase receptor activation, glutamate receptor hyperactivation, and cellular injury [12].”
Quote in the paperSubstantial claim1 of 1 sources checked- cites [12] Hunt D, Raivich G, Anderson PN. Activating transcription factor 3 and the nervous system. Front Mol Neurosci. 2012;5:7. doi: 10.3389/fnmol.2012.00007 . source
Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
PremisecitationIn one study, TAM was associated with loss of glial progenitor cells in the corpus callosum and with reduced cell division in neurogenic regions of the CNS.
“although in one study it was associated with a loss of glial progenitor cells in the corpus callosum and with reduced cell division in neurogenic regions of the CNS [7].”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [7] Chen H-Y, Yang YM, Han R, Noble M. MEK1/2 inhibition suppresses tamoxifen toxicity on CNS glial progenitor cells. J Neurosci. 2013;33:15069–74. doi: 10.1523/JNEUROSCI.2729-13.2013 . source
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationTAM's affinity for ChEH may underlie its counter-intuitive efficacy in ER-negative breast cancers.
“In fact, the affinity of TAM for ChEH is second only to that for ERα, which may underlie its counter-intuitive efficacy in ER-negative breast cancers [11].”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [11] de Medina P, Paillasse MR, Segala G, Poirot M, Silvente-Poirot S. Identification and pharmacological characterization of cholesterol-5,6-epoxide hydrolase as a target for tamoxifen and AEBS ligands. Proc Natl Acad Sci U S A. 2010;107:13520–5. doi: 10.1073/pnas.1002922107 . source
The paper’s opening section says that, after the estrogen receptor, AEBS is tamoxifen’s highest-affinity target; the Discussion links ChEH inhibition to possible anticancer effects. But the paper does not address tamoxifen’s efficacy in ER-negative breast cancers or propose ChEH affinity as an explanation for it. Page numbers are unavailable in our copy. (LLM, conf=0.86)
Experimental — accuracy not yet measured
Classified as probably not a substantial claim.
PremisecitationOPC loss was prevented both in vitro and in vivo by MEK1/2 inhibition.
“OPC loss was prevented both in vitro and in vivo by MEK1/2 inhibition”
Quote in the paperSubstantial claim1 of 1 sources checked- cites [7] Chen H-Y, Yang YM, Han R, Noble M. MEK1/2 inhibition suppresses tamoxifen toxicity on CNS glial progenitor cells. J Neurosci. 2013;33:15069–74. doi: 10.1523/JNEUROSCI.2729-13.2013 . source
May combine two claims.
PremisecitationThe Guenthner study used a genetic labeling technique nearly identical to ours, but recombination was driven by promoters for immediate-early genes Fos and Arc, upregulated as part of excitation-transcription neuronal response to synaptic activity initiated by CREB phosphorylation.
“The Guenthner study [9] used a genetic labeling technique nearly identical to ours, but recombination was driven by promoters for the immediate-early genes Fos and Arc, upregulated as part of the “excitation-transcription” neuronal response to synaptic activity initiated by CREB phosphorylation [40].”
Quote in the paperSubstantial claim2 of 2 sources checked- cites [9] Guenthner C, Miyamichi K, Yang H, Heller H, Luo L. Permanent genetic access to transiently active neurons via TRAP: Targeted recombination in active populations. Neuron. 2013;78:773–84. doi: 10.1016/j.neuron.2013.03.025 . source
- cites [40] Ma H, Groth RD, Wheeler DG, Barrett CF, Tsien RW. Excitation-transcription coupling in sympathetic neurons and the molecular mechanism of its initiation. Neurosci Res. 2011;70:2–8. doi: 10.1016/j.neures.2011.02.004 . source
Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.
Experimental — accuracy not yet measured
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationMEK1/2 inhibition is one of a number of intracellular messengers that can activate Atf3 expression.
“one of a number of intracellular messengers that can activate Atf3 expression [12].”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [12] Hunt D, Raivich G, Anderson PN. Activating transcription factor 3 and the nervous system. Front Mol Neurosci. 2012;5:7. doi: 10.3389/fnmol.2012.00007 . source
The ATF3 Induction and Regulation section says several intracellular signaling pathways affect or induce ATF3 expression, supporting the general point. It does not say that MEK1/2 inhibition activates ATF3; its examples instead describe induction through p38 or JNK activation. No page number is available in our copy. (LLM, conf=0.84)
Experimental — accuracy not yet measured
Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
PremisecitationThis was accompanied by reduction in their proliferation, and that of neural progenitors in SVZ and dentate gyrus.
“This was accompanied by a reduction in their proliferation, and that of neural progenitors in the subventricular zone and dentate gyrus”
Quote in the paperNot a substantial claim1 of 1 sources checked- cites [7] Chen H-Y, Yang YM, Han R, Noble M. MEK1/2 inhibition suppresses tamoxifen toxicity on CNS glial progenitor cells. J Neurosci. 2013;33:15069–74. doi: 10.1523/JNEUROSCI.2729-13.2013 . source
The Results section on systemic tamoxifen treatment reports reduced O-2A/OPC division in vitro and significantly suppressed cell division in the mouse subventricular zone and dentate gyrus. It does not identify the dividing cells in those two regions as neural progenitors; the Discussion says the affected precursor populations remain to be defined. Page numbers are not available in our copy. (LLM, conf=0.84)
Experimental — accuracy not yet measured
May combine two claims.
PremisecitationTAM has been exploited experimentally to induce permanent reporter expression in newly-born neurons in olfactory bulb and dentate gyrus, in physiologically-active neurons throughout the brain, and in progeny of ependymal cells of intact and injured murine spinal cord.
“TAM has been exploited experimentally to induce permanent reporter expression in, for example, newly-born neurons in the olfactory bulb and dentate gyrus [8], in physiologically-active neurons throughout the brain [9], and in progeny of ependymal cells of the intact and injured murine spinal cord [39].”
Quote in the paperSubstantial claim1 of 3 sources checked- cites [8] Imayoshi I, Sakamoto M, Ohtsuka T, Takao K, Miyakawa T, Yamaguchi M, et al. Roles of continuous neurogenesis in the structural and functional integrity of the adult forebrain. Nat Neurosci. 2008;11:1153–61. doi: 10.1038/nn.2185 . source
- cites [9] Guenthner C, Miyamichi K, Yang H, Heller H, Luo L. Permanent genetic access to transiently active neurons via TRAP: Targeted recombination in active populations. Neuron. 2013;78:773–84. doi: 10.1016/j.neuron.2013.03.025 . source
- cites [39] Barnabé-Heider F, Göritz C, Sabelström H, Takebayashi H, Pfrieger FW, Meletis K, et al. Origin of new glial cells in intact and injured adult spinal cord. Cell Stem Cell. 2010;7:470–82. doi: 10.1016/j.stem.2010.07.014 . source
May combine two claims.
Findingown dataTAM induces recombination in granular neurons of the dentate gyrus of the hippocampus and olfactory bulb, as well as in vascular and ependymal cells.
“In the cortex, we found TAM to induce recombination in granular neurons of the dentate gyrus of the hippocampus and olfactory bulb, as well as in vascular and ependymal cells.”
Quote in the paperNot a substantial claimMay combine two claims.
Findingown dataTAM induced Atf3 upregulation in sensory neurons, particularly marked in large proprioceptive NF200 positive cells in trigeminal mesencephalic nucleus and in those projecting to Clarke's column in spinal cord, and to a much lesser extent in non-peptidergic IB4 positive neurons.
“TAM also induced Atf3 upregulation in sensory neurons, which was particularly marked in large proprioceptive NF200 positive cells in the trigeminal mesencephalic nucleus and in those projecting to Clarke’s column in the spinal cord, and to a much lesser extent in non-peptidergic IB4 positive neurons.”
Quote in the paperSubstantial claimMay combine two claims.
Findingown dataThe vast majority of recombined DRG neurons express NF200, with a small percentage also in non-peptidergic IB4 positive nociceptors.
“The vast majority of recombination occurred in NF200 positive neurons, with a small percentage also in non-peptidergic IB4 positive nociceptors (Fig. 5e).”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
Findingown dataIn the spinal cord, primary afferent projections of recombined neurons are particularly dense in Clarke's column.
“In the spinal cord, primary afferent projections to Clarke’s column (a proprioceptive relay to the cerebellum) were particularly dense.”
Quote in the paperNot a substantial claimMay combine two claims.
InterpretationreasoningTAM has the potential to alter neurophysiology via ERα, sigma 1/2 receptors, or ChEH.
“TAM thus has the potential to alter neurophysiology via any one of these avenues.”
Quote in the paperSubstantial claim- Rests on an assumption: TAM acts at the endogenous estrogen receptor α (ERα).
May combine two claims.
Interpretationown dataTAM's induction of Atf3 expression occurs via ChEH binding and not via ERα or sigma 1/2 receptors.
“We also provide evidence that TAM’s induction of Atf3 expression occurs via ChEH binding, and not via ERα or sigma 1/2 receptors.”
Quote in the paperSubstantial claim- Rests on an assumption: TAM acts at the endogenous estrogen receptor α (ERα).
- Rests on an assumption: DTG is a sigma-1 and -2 receptor agonist.
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationICI 182,780 is a pure anti-estrogen.
“we treated mice with either the anti-estrogen ICI 182,780 (ICI), a “pure” anti-estrogen [17], 4,4′,4″-(4-Propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT), a potent ERα agonist [18], or ditolylguanidine (DTG), a sigma-1 and −2 receptor agonist.”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [17] Dauvois S, White R, Parker MG. The antiestrogen ICI 182780 disrupts estrogen receptor nucleocytoplasmic shuttling. J Cell Sci. 1993;106(Pt 4):1377–88. source
May combine two claims.
PremisecitationSunflower oil contains approximately 40 mg/100 g α-tocopherol, while wheat germ oil contains ~150 mg/100 g, nearly four times as much.
“Sunflower oil (SFO) contains approximately 40 mg/100 g α-tocopherol, while wheat germ oil (WGO) contains ~150 mg/100 g, nearly four times as much [15].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [15] United States Department of Agriculture. Agricultural Research Service. National Nutrient Database for Standard Reference Release 27. http://ndb.nal.usda.gov/ndb/foods . Accessed 06 October 2015.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationPPT is a potent ERα agonist.
“we treated mice with either the anti-estrogen ICI 182,780 (ICI), a “pure” anti-estrogen [17], 4,4′,4″-(4-Propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT), a potent ERα agonist [18], or ditolylguanidine (DTG), a sigma-1 and −2 receptor agonist.”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [18] Harris HA, Katzenellenbogen JA, Katzenellenbogen BS. Characterization of the biological roles of the estrogen receptors, eralpha and erbeta, in estrogen target tissues in vivo through the use of an eralpha-selective ligand. Endocrinology. 2002;143:4172–7. doi: 10.1210/en.2002-220403 . source
May combine two claims.
InterpretationreasoningTogether these data indicate pleiotropic effects of TAM on dentate granule neurons, one involving MEK1/2 activation in immature neural cells (neuronal and glial progenitors), the other reliant upon Atf3 upregulation induced by ChEH inhibition in older adult-born neurons.
“Together these data indicate pleiotropic effects of TAM on dentate granule neurons, one involving MEK1/2 activation in immature neural cells (neuronal and glial progenitors), the other reliant upon Atf3 upregulation induced by ChEH inhibition in older adult-born neurons.”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
PremisecitationThe in vitro studies showed that 3 days after cessation of TAM treatment, recombined ependyma could give rise to neurospheres with cells expressing markers for neurons, astrocytes and oligodendrocyte-lineage cells.
“The in vitro studies showed that 3 days after cessation of TAM treatment, recombined ependyma could indeed give rise to neurospheres with cells expressing markers for neurons, astrocytes and oligodendrocyte-lineage cells.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [39] Barnabé-Heider F, Göritz C, Sabelström H, Takebayashi H, Pfrieger FW, Meletis K, et al. Origin of new glial cells in intact and injured adult spinal cord. Cell Stem Cell. 2010;7:470–82. doi: 10.1016/j.stem.2010.07.014 . source
Probably not a substantial claim: may not pass S3 (load-bearing).
Study design and conductnone givenMice in treatment and control groups were sex and age-matched.
“For all experiments, mice in treatment and control groups were sex and age-matched.”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationDPPE is a selective ChEH ligand.
“The selective ChEG ligand N,N-Diethyl-2-[4-(phenylmethyl) phenoxy]ethanamine hydrochloride (DPPE, also known as tesmilifene) was administered at a one-time dose of 50 mg/kg i.p. in saline [21].”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [21] Hiramatsu H, Kikuchi Y, Kudoh K, Kita T, Tode T, Nagata I. Growth-inhibitory effects of N, n-diethyl-2-[4-(phenylmethyl)phenoxy]-ethanamine-hcl combined with cisplatin on human ovarian cancer cells inoculated into nude mice. Jpn J Cancer Res. 1997;88:1003–8. source
Classified as probably not a substantial claim.
PremisecitationWhat is absent in anatomical and behavioural experiments assessing role of newly-generated hippocampal neurons in memory formation/retention is a TAM-only control in wild-type mice.
“What is absent, however, both in anatomical and behavioural experiments assessing the role of newly-generated hippocampal neurons in memory formation/retention, is a TAM-only control in wild-type mice.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [8] Imayoshi I, Sakamoto M, Ohtsuka T, Takao K, Miyakawa T, Yamaguchi M, et al. Roles of continuous neurogenesis in the structural and functional integrity of the adult forebrain. Nat Neurosci. 2008;11:1153–61. doi: 10.1038/nn.2185 . source
Probably not a substantial claim: may not pass S3 (load-bearing).
Study design and conductown dataOur study does not rule out effects of TAM on neurogenesis.
“although our study does not rule out effects of TAM on neurogenesis”
Quote in the paperNot a substantial claimClassified as probably not a substantial claim. May combine two claims.
PremisecitationIn Barnabé-Heider et al., five daily treatments of TAM (80 mg/kg) were used to induce recombination in ependymal cells in FoxJ1-CreER mice to determine whether ependymal cells are multipotential in vitro, and in vivo following spinal cord injury.
“Here, five daily treatments of TAM (80 mg/kg) were used to induce recombination in ependymal cells in FoxJ1-CreER mice in order to determine whether ependymal cells are multipotential in vitro, and in vivo following a spinal cord injury.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [39] Barnabé-Heider F, Göritz C, Sabelström H, Takebayashi H, Pfrieger FW, Meletis K, et al. Origin of new glial cells in intact and injured adult spinal cord. Cell Stem Cell. 2010;7:470–82. doi: 10.1016/j.stem.2010.07.014 . source
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationIn vivo, reporter-expressing ependyma self-renewed and produced astrocytes and oligodendrocyte-lineage cells 5 days following last TAM dose.
“In vivo, reporter-expressing ependyma self-renewed and produced astrocytes and oligodendrocyte-lineage cells 5 days following the last TAM dose.”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [39] Barnabé-Heider F, Göritz C, Sabelström H, Takebayashi H, Pfrieger FW, Meletis K, et al. Origin of new glial cells in intact and injured adult spinal cord. Cell Stem Cell. 2010;7:470–82. doi: 10.1016/j.stem.2010.07.014 . source
Classified as probably not a substantial claim. May combine two claims.
PremisecitationIn the Imayoshi study, very large doses (400 mg/kg) were administered daily for 4 days, a regimen repeated twice more in some experiments.
“In the Imayoshi study [8], very large doses (400 mg/kg) were administered daily for 4 days, a regimen that was repeated twice more in some experiments.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [8] Imayoshi I, Sakamoto M, Ohtsuka T, Takao K, Miyakawa T, Yamaguchi M, et al. Roles of continuous neurogenesis in the structural and functional integrity of the adult forebrain. Nat Neurosci. 2008;11:1153–61. doi: 10.1038/nn.2185 . source
Classified as probably not a substantial claim. May combine two claims.
PremisecitationSunflower oil is relatively low in vitamin E (40 mg/100 g) and wheat germ oil is relatively rich in vitamin E (~150 mg/100 g).
“Sunflower oil (SFO), which is relatively low in vitamin E (40 mg/100 g), was used as a TAM vehicle and compared with wheat germ oil (WGO), which is relatively rich in vitamin E (~150 mg/100 g) [15].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [15] United States Department of Agriculture. Agricultural Research Service. National Nutrient Database for Standard Reference Release 27. http://ndb.nal.usda.gov/ndb/foods . Accessed 06 October 2015.
Couldn’t be matched to a paper in Crossref, so it can’t be checked.
May combine two claims.
PremisecitationTAM binding to ChEH inhibits the enzyme's activity, resulting in the accumulation of cholesterol-5,6-epoxides and the inhibition of cholestane-3β,5α,6β-triol production.
“TAM binding to ChEH inhibits the enzyme’s activity, resulting in the accumulation of cholesterol-5,6-epoxides and the inhibition of cholestane-3β,5α,6β-triol production [26].”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [26] Silvente-Poirot S, Poirot M. Cholesterol epoxide hydrolase and cancer. Curr Opin Pharmacol. 2012;12:696–703. doi: 10.1016/j.coph.2012.07.007 . source
- Rests on an assumption: TAM binds not only mutated ERT2, but also endogenous ERα, ChEH enzyme complex and sigma1/2 receptors.
Probably not a substantial claim: may not pass S3 (load-bearing).
InterpretationreasoningThe less successful prevention by vitamin E in SFO was likely due to increased variability as a result of difficulties dissolving vitamin E evenly in SFO.
“This was likely due to increased variability as a result of the difficulties encountered when attempting to dissolve vitamin E evenly in SFO.”
Quote in the paperNot a substantial claim- Rests on an assumption: α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.
May combine two claims.
Study design and conductown dataTAM-induced recombination in the olfactory bulb and dentate gyrus occurs in neurons, as confirmed by colocalization of tdtomato with NeuN and NeuN/calbindin D28k.
“In the olfactory bulb and dentate gyrus, neuronal expression of reporter was confirmed by colocolization of tdtomato with NeuN (olfactory bulb) and NeuN/calbindin D28k (dentate gyrus) (Fig. 3a, b).”
Quote in the paperNot a substantial claim
The paper relies on this without support.
TAM is widely used as an experimental tool for manipulating gene expression in vivo via the inducible Cre-Lox technique.
“Tamoxifen (TAM) is an important cancer therapeutic and an experimental tool for effecting genetic recombination using the inducible Cre-Lox technique.”
“TAM is a widely-used tool for manipulating gene expression in vivo via the inducible Cre-Lox technique.”
The paper relies on this without support.
TAM acts at the endogenous estrogen receptor α (ERα).
“What remains little-acknowledged in studies using the Cre-ERT2 system is that TAM acts at the endogenous estrogen receptor α (ERα), hence its clinical use in cancer.”
The paper relies on this without support.
Vitamin E depletes ChEH substrates.
“reporter expression was mitigated by delivery in vitamin E-rich wheat germ oil (vitamin E depletes ChEH substrates)”
The paper relies on this without support.
DTG is a sigma-1 and -2 receptor agonist.
“or ditolylguanidine (DTG), a sigma-1 and −2 receptor agonist.”
The paper relies on this without support.
TAM binds not only mutated ERT2, but also endogenous ERα, ChEH enzyme complex and sigma1/2 receptors.
“TAM binds not only the mutated estrogen receptor (ERT2), but also endogenous ERα, the ChEH enzyme complex and the sigma1/2 receptors.”
The paper relies on this without support.
α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.
“we took advantage of the fact that α-tocopherol (vitamin E) prevents the accumulation of cholesterol epoxides.”
The paper relies on this without support.
DPPE cannot induce active nuclear translocation of the ERT2 construct and tdtomato induction is therefore entirely reliant on leaky nuclear translocation of CreERT2.
“This was expected, since DPPE cannot induce active nuclear translocation of the ERT2 construct and tdtomato induction is therefore entirely reliant on leaky nuclear translocation of CreERT2.”
The paper relies on this without support.
This is the first study to directly assess the effects of TAM on cellular stress-induced Atf3 expression in the nervous system.
“This is the first study to directly assess the effects of TAM on cellular stress-induced Atf3 expression in the nervous system.”
The paper relies on this without support.
Patients prescribed tamoxifen take the medication on a daily basis.
“patients prescribed tamoxifen take the medication on a daily basis.”
The paper relies on this without support.
In all three above studies, TAM was delivered in corn oil, which has a vitamin E content of ~14.3 mg/100 g, compared to ~40 mg/100 g in SFO and ~150 mg/100 g in WGO.
“In all three of the above studies, TAM was delivered in corn oil, which has a vitamin E content of ~14.3 mg/100 g, compared to ~40 mg/100 g in SFO and ~150 mg/100 g in WGO.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Tamoxifen is known to be toxic to humans and rodents at high doses.
“Tamoxifen is known to be toxic to humans and rodents at high doses [72–74]; therefore, it is possible that giving tamoxifen at 300 mg/kg, compared to 1 mg/kg [39, 55], was toxic and induced neuronal cell death.”
From Delayed short-term tamoxifen treatment does not promote remyelination or neuron sparing after spinal cord injury (2020) · cites this paper as [72]
The Results report that 75 mg/kg tamoxifen repeatedly stressed otherwise healthy mouse neurons, and the Introduction reports cognitive disturbances in some treated patients. But the paper does not establish toxicity in humans specifically at high doses; its Discussion says the consequences of a very-high-dose mouse regimen remain unknown. (LLM, conf=0.87)
Experimental — accuracy not yet measured
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
Each contradiction between two passages listed here was confirmed by an independent check.
DPPE is described as both inhibiting and activating ChEH
MinorThe abstract calls DPPE a ChEH-specific inhibitor, but the discussion says it directly activates ChEH. This reverses the proposed mechanism used to interpret its effect on Atf3.
“and was partially mimicked by a ChEH-specific inhibitor.”
“direct activation of ChEH using the selective ligand DPPE upregulates Atf3.”
Cites
A robust and high-throughput Cre reporting and characterization system for the whole mouse brain
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“crossed with a floxed stop ROSA-tdtomato line (AI14, Jackson Labs) [13] for characterization of expression.”
Genome-wide atlas of gene expression in the adult mouse brain
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“Allen Brain Atlas in situ hybridization data [24] show ATF3 expression only in granular neurons of the olfactory bulb and dentate gyrus, and accordingly, in naïve ATF3-CreERT2:stoptdtomato mice, occasional reporter-expressing neurons were found in both of these regions (Fig.”
InfluentialThe United States Department of Agriculture
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Unbiased classification of sensory neuron types by large-scale single-cell RNA sequencing
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“Beyond its therapeutic use in breast cancer, TAM has been exploited experimentally to induce permanent reporter expression in, for example, newly-born neurons in the olfactory bulb and dentate gyrus [8], in physiologicallyactive neurons throughout the brain [9], and in progeny of ependymal cells of the intact and inju…”
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“Atf3 is among the earliest genes to be upregulated after axonal injury [34], and is associated with successful regeneration: it is robustly induced in regeneration-competent sensory neurons by peripheral nerve injury [35] but not by injury to centrally-projecting dorsal roots [36].”
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Origin of New Glial Cells in Intact and Injured Adult Spinal Cord
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“Beyond its therapeutic use in breast cancer, TAM has been exploited experimentally to induce permanent reporter expression in, for example, newly-born neurons in the olfactory bulb and dentate gyrus [8], in physiologicallyactive neurons throughout the brain [9], and in progeny of ependymal cells of the intact and inju…”
The antiestrogen ICI 182780 disrupts estrogen receptor nucleocytoplasmic shuttling
Dauvois, S., White, R., & Parker, M. G. (1993) · Journal of Cell Science · doi:10.1242/jcs.106.4.1377 · Cited by 522 · see citing works
ATF3 Increases the Intrinsic Growth State of DRG Neurons to Enhance Peripheral Nerve Regeneration
Seijffers, R., Mills, C. D., & Woolf, C. J. (2007) · Journal of Neuroscience · doi:10.1523/jneurosci.5313-06.2007 · Cited by 425 · cited 1× · see citing works
“Furthermore, genetic overexpression of Atf3 in sensory neurons improves the regenerative response to peripheral nerve injury [37, 38].”
Harris, H. A., Katzenellenbogen, J. A., & Katzenellenbogen, B. S. (2002) · Endocrinology · doi:10.1210/en.2002-220403 · Cited by 357 · see citing works
The development of the hippocampus and dentate gyrus in normal and reeler mice
Stanfield, B. B., & Cowan, W. M. (1979) · Journal of Comparative Neurology · doi:10.1002/cne.901850303 · Cited by 241 · cited 1× · see citing works
“outside-out manner [8, 30], implying that those which”
The transcription factor ATF-3 promotes neurite outgrowth
Seijffers, R., Allchorne, A. J., & Woolf, C. J. (2006) · Molecular and Cellular Neuroscience · doi:10.1016/j.mcn.2006.03.005 · Cited by 232 · cited 1× · see citing works
“Furthermore, genetic overexpression of Atf3 in sensory neurons improves the regenerative response to peripheral nerve injury [37, 38].”
Estrogen- and tamoxifen-associated effects on brain structure and function
Eberling, J. L., Wu, C. C., Tong-Turnbeaugh, R., & Jagust, W. (2003) · NeuroImage · doi:10.1016/j.neuroimage.2003.08.037 · Cited by 211 · cited 1× · see citing works
“Changes in human brain structure and metabolism with TAM treatment have also been reported [5].”
Activating Transcription Factor 3 and the Nervous System
Hunt, D., Raivich, G., & Anderson, P. N. (2012) · Frontiers in Molecular Neuroscience · doi:10.3389/fnmol.2012.00007 · Cited by 162 · cited 3× · see citing works
“We generated a knock-in mouse expressing CreERT2 driven by the native promoter for activating transcription factor 3 (Atf3), one of a number of transcription factors upregulated by cellular stress, such as the unfolded protein response, tyrosine kinase receptor activation, glutamate receptor hyperactivation, and cellu…”
Influentialde Medina, P., Paillasse, M. R., Segala, G., Poirot, M., & Silvente-Poirot, S. (2010) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1002922107 · Cited by 128 · cited 4× · see citing works
“Furthermore, TAM binds other endogenous molecules, including sigma 1 and 2 receptors on the endoplasmic reticulum [10], and cholesterol epoxide hydrolase (ChEH) – an enzyme complex involved in cholesterol biosynthesis [11].”
InfluentialCognitive Function and Reproductive Hormones in Adjuvant Therapy for Breast Cancer
Bender, C. M., Paraska, K. K., Sereika, S. M., Ryan, C. M., & Berga, S. L. (2001) · Journal of Pain and Symptom Management · doi:10.1016/s0885-3924(01)00268-8 · Cited by 118 · see citing works
Papaconstantinou, A. D. (2000) · Toxicological Sciences · doi:10.1093/toxsci/56.2.332 · Cited by 113 · cited 1× · see citing works
“ICI 182,780 in SFO (20 μg) [19] or SFO only was administered to nerve-injured mice by gavage the day before, the day of, and the day following TAM (or oil only) treatment.”
Lau, M. J., Minett, M. S., Zhao, J., Dennehy, U., Wang, F., Wood, J. N., & Bogdanov, Y. D. (2011) · Molecular Pain · doi:10.1186/1744-8069-7-100 · Cited by 100 · cited 1× · see citing works
“We also used a BAC transgenic mouse in which the promoter for advillin, expressed in all dorsal root ganglion (DRG) neurons, drives CreERT2 [14], and crossed it with the same reporter line as above.”
Self-citationCounting sectioned cells via mathematical reconstruction
Rose, R. D., & Rohrlich, D. (1987) · The Journal of Comparative Neurology · doi:10.1002/cne.902630305 · Cited by 94 · cited 1× · see citing works
“In the DRG we traced recombined profiles and used recursive translation [22] to convert profile distributions (in which large profiles are numerically overrepresented and lead to overestimations of the number of small diameter profiles) to cell distributions.”
Palmer, J. L., Trotter, T., Joy, A. A., & Carlson, L. E. (2008) · Journal of Cancer Survivorship · doi:10.1007/s11764-008-0070-1 · Cited by 89 · see citing works
Cholesterol epoxide hydrolase and cancer
Silvente-Poirot, S., & Poirot, M. (2012) · Current Opinion in Pharmacology · doi:10.1016/j.coph.2012.07.007 · Cited by 82 · cited 2× · see citing works
“ligands) or reduction in the synthesis of cholestane3β,5α,6β-triol remains unknown, although the anti-cancer effects of TAM in estrogen-insensitive breast tumors are thought to be attributable to the former [11, 26, 29].”
Chaban, V. V., & Micevych, P. E. (2005) · Journal of Neuroscience Research · doi:10.1002/jnr.20524 · Cited by 78 · see citing works
Sigma-1 Receptor Expression in Sensory Neurons and the Effect of Painful Peripheral Nerve Injury
Bangaru, M. L., Weihrauch, D., Tang, Q.-B., Zoga, V., Hogan, Q., & Wu, H.-E. (2013) · Molecular Pain · doi:10.1186/1744-8069-9-47 · Cited by 62 · cited 1× · see citing works
“Since some primary afferent neurons express ERα as well as the sigma-1 receptor [27, 28], we also assessed their putative roles in this context.”
Activating Transcription Factor 3, a Useful Marker for Regenerative Response after Nerve Root Injury
Lindå, H., Sköld, M. K., & Ochsmann, T. (2011) · Frontiers in Neurology · doi:10.3389/fneur.2011.00030 · Cited by 62 · cited 1× · see citing works
“Atf3 is among the earliest genes to be upregulated after axonal injury [34], and is associated with successful regeneration: it is robustly induced in regeneration-competent sensory neurons by peripheral nerve injury [35] but not by injury to centrally-projecting dorsal roots [36].”
de Médina, P., Paillasse, M. R., Segala, G., Khallouki, F., Brillouet, S., Dalenc, F., Courbon, F., Record, M., Poirot, M., & Silvente‐Poirot, S. (2011) · Chemistry and Physics of Lipids · doi:10.1016/j.chemphyslip.2011.05.005 · Cited by 61 · cited 1× · see citing works
“ligands) or reduction in the synthesis of cholestane3β,5α,6β-triol remains unknown, although the anti-cancer effects of TAM in estrogen-insensitive breast tumors are thought to be attributable to the former [11, 26, 29].”
Dynamic Pattern of Reg-2 Expression in Rat Sensory Neurons after Peripheral Nerve Injury
Averill, S., Davis, D. R., Shortland, P. J., Priestley, J. V., & Hunt, S. P. (2002) · The Journal of Neuroscience · doi:10.1523/jneurosci.22-17-07493.2002 · Cited by 60 · cited 1× · see citing works
“We and others have found that a small number of uninjured sensory neurons express Atf3 [23], and evidence of rare spontaneous recombination was found in reporterexpressing trigeminal and spinal sensory neurons, and their terminals in the spinal trigeminal nucleus and spinal cord (Fig.”
安永, 敏., Kato, H., Ohgaki, K., et al. (1982) · Journal of Nutrition · doi:10.1093/jn/112.6.1075 · Cited by 55 · cited 2× · see citing works
“47 mg/ml, to match the dose contained in WGO, chosen based on previous efficacy and toxicity studies of vitamin E in mice [16].”
Clinically Important Ocular Reactions to Systemic Drug Therapy
Rennie, I. G. (1993) · Drug Safety · doi:10.2165/00002018-199309030-00005 · Cited by 45 · cited 1× · see citing works
“However, with the exception of rare optic neuropathies [32, 33], we can find no evidence in the literature that”
Decision-making impairments in breast cancer patients treated with tamoxifen
Chen, X., Li, J., Chen, J., Li, D., Ye, R., Zhang, J., Zhu, C., Tian, Y., & Wang, K. (2014) · Hormones and Behavior · doi:10.1016/j.yhbeh.2014.07.005 · Cited by 44 · see citing works
Buwalda, B., & Schagen, S. B. (2013) · Life Sciences · doi:10.1016/j.lfs.2012.12.012 · Cited by 43 · cited 1× · see citing works
“Yet, there has been surprisingly little work done in animal models to identify TAMinduced changes in structure or function of the nervous system (either central or peripheral) [6], although in one study it was associated with a loss of glial progenitor cells in the corpus callosum and with reduced cell division in neu…”
Ma, H., Groth, R. D., Wheeler, D. G., Barrett, C. F., & Tsien, R. W. (2011) · Neuroscience Research · doi:10.1016/j.neures.2011.02.004 · Cited by 42 · cited 1× · see citing works
“The Guenthner study [9] used a genetic labeling technique nearly identical to ours, but recombination was driven by promoters for the immediate-early genes Fos and Arc, upregulated as part of the “excitation-transcription” neuronal response to synaptic activity initiated by CREB phosphorylation [40].”
Relative Effects of Tamoxifen, Raloxifene, and Conjugated Equine Estrogens on Cognition
Espeland, M. A., Shumaker, S. A., Limacher, M., Rapp, S. R., Bevers, T. B., Barad, D. H., Coker, L. H., Gaussoin, S. A., Stefanick, M. L., Lane, D. S., et al. (2010) · Journal of Women's Health · doi:10.1089/jwh.2009.1605 · Cited by 30 · see citing works
Reid, A. J., Welin, D., Wiberg, M., Terenghi, G., & Novikov, L. N. (2009) · Brain Research · doi:10.1016/j.brainres.2009.11.011 · Cited by 28 · cited 1× · see citing works
“Atf3 is among the earliest genes to be upregulated after axonal injury [34], and is associated with successful regeneration: it is robustly induced in regeneration-competent sensory neurons by peripheral nerve injury [35] but not by injury to centrally-projecting dorsal roots [36].”
Kedjouar, B., Daunes, S., Vilner, B. J., Bowen, W. D., Klaebe, A., Faye, J.-C., & Poirot, M. (1999) · Biochemical Pharmacology · doi:10.1016/s0006-2952(99)00285-3 · Cited by 27 · cited 1× · see citing works
“Furthermore, TAM binds other endogenous molecules, including sigma 1 and 2 receptors on the endoplasmic reticulum [10], and cholesterol epoxide hydrolase (ChEH) – an enzyme complex involved in cholesterol biosynthesis [11].”
Lack of cocaine-like discriminative-stimulus effects of σ-receptor agonists in rats
Hiranita, T., Soto, P. L., Tanda, G., et al. (2011) · Behavioural Pharmacology · doi:10.1097/fbp.0b013e328349ab22 · Cited by 22 · cited 1× · see citing works
“The sigma receptor agonist 1,3-di-o-tolylguanidine (DTG) was prepared as previously described [20] and delivered by i.”
MEK1/2 Inhibition Suppresses Tamoxifen Toxicity on CNS Glial Progenitor Cells
Chen, H.-Y., Yang, Y. M., Han, R., & Noble, M. (2013) · The Journal of Neuroscience · doi:10.1523/jneurosci.2729-13.2013 · Cited by 18 · cited 3× · see citing works
“Yet, there has been surprisingly little work done in animal models to identify TAMinduced changes in structure or function of the nervous system (either central or peripheral) [6], although in one study it was associated with a loss of glial progenitor cells in the corpus callosum and with reduced cell division in neu…”
Tamoxifen associated bilateral optic neuropathy
Zvorničanin, J., Sinanović, O., Zukić, S., et al. (2014) · Acta Neurologica Belgica · doi:10.1007/s13760-014-0327-6 · Cited by 7 · cited 1× · see citing works
“However, with the exception of rare optic neuropathies [32, 33], we can find no evidence in the literature that”
Hiramatsu, H., Kikuchi, Y., Kudoh, K., Kita, T., Tode, T., & Nagata, I. (1997) · Japanese Journal of Cancer Research · doi:10.1111/j.1349-7006.1997.tb00321.x · Cited by 5 · cited 1× · see citing works
“We injected animals with a single intraperitoneal dose of the selective ChEH ligand DPPE (50 mg/kg) [21], and compared recombination to saline treated animals.”
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Ryu, A. H., Eckalbar, W. L., Kreimer, A., Yosef, N., & Ahituv, N. (2017) · Scientific Reports · doi:10.1038/s41598-017-07757-w · Cited by 139 · see citing works
“…genes, is ATF3 , a transcriptional repressor that is known to play a role in cell differentiation and proliferation 33–36 , the unfolded protein response 37 , inflammation and immune response 38–40 , hepatic gluconeogenesis and insulin resistance 41–45 , as well as drug response 4, 10–16 .”
BackgroundMyelin regulatory factor drives remyelination in multiple sclerosis
Duncan, G. J., Plemel, J. R., Assinck, P., Manesh, S. B., Muir, F. G. W., Hirata, R., Berson, M., Liu, J., Wegner, M., Emery, B., et al. (2017) · Acta Neuropathologica · doi:10.1007/s00401-017-1741-7 · Cited by 115 · see citing works
“0 mg/kg) [22] and results in cellular stress at high doses (75 mg/kg) indicated by the upregulation of the Atf3 transcription factor [9].”
BackgroundEstrogens and SERMS as adjunctive treatments for schizophrenia
Kulkarni, J., Butler, S., & Riecher‐Rössler, A. (2019) · Frontiers in Neuroendocrinology · doi:10.1016/j.yfrne.2019.03.002 · Cited by 88 · see citing works
Large Scale In Vivo Recording of Sensory Neuron Activity with GCaMP6
Chisholm, K. I., Khovanov, N., Lopes, D. M., Russa, F. L., & McMahon, S. B. (2018) · eNeuro · doi:10.1523/eneuro.0417-17.2018 · Cited by 81 · see citing works
“Tamoxifen (T5648; Sigma-Aldrich) was dissolved in 100% ethanol to a concentration of 97.5 (cid:2) g/ (cid:2) l and further dissolved to a working concentration of 7.8 (cid:2) g/ (cid:2) l in wheat germ oil (Denk et al., 2015).”
MethodInfluentialSelf-citationTamoxifen Provides Structural and Functional Rescue in Murine Models of Photoreceptor Degeneration
Wang, X., Zhao, L., Zhang, Y., Ma, W., Gonzalez, S. R., Fan, J., Kretschmer, F., Badea, T. C., Qian, H., & Wong, W. T. (2017) · Journal of Neuroscience · doi:10.1523/jneurosci.2717-16.2017 · Cited by 63 · see citing works
“, 2016), investigation of the appropriate dose ranges and delivery routes for tamoxifen may be necessary to find experimental parameters at which CreER(T) activation can be induced without incurring other CreER(T)-independent biological effects (Denk et al., 2015).”
BackgroundSeralini, G.-E., & Jungers, G. (2021) · Toxicology Reports · doi:10.1016/j.toxrep.2021.07.014 · Cited by 57 · see citing works
Hippocampal neurons respond to brain activity with functional hypoxia
Butt, U. J., Steixner-Kumar, A. A., Depp, C., Sun, T., Hassouna, I. A., Wüstefeld, L., Arinrad, S., Zillmann, M. R., Schopf, N., Garcia‐Agudo, L. F., et al. (2021) · Molecular Psychiatry · doi:10.1038/s41380-020-00988-w · Cited by 53 · see citing works
Leignadier, J., Dalenc, F., Poirot, M., & Silvente‐Poirot, S. (2017) · Biochemical Pharmacology · doi:10.1016/j.bcp.2017.06.120 · Cited by 52 · see citing works
Patel, S. H., O’Hara, L., Atanassova, N. N., et al. (2017) · Scientific Reports · doi:10.1038/s41598-017-09016-4 · Cited by 48 · see citing works
Kilani, B., Gourdou‐Latyszenok, V., Guy, A., Bats, M., Peghaire, C. R., Parrens, M., Renault, M., Duplàa, C., Villeval, J., Rautou, P., et al. (2019) · Journal of Thrombosis and Haemostasis · doi:10.1111/jth.14417 · Cited by 49 · see citing works
Mice lacking Kcns1 in peripheral neurons show increased basal and neuropathic pain sensitivity
Tsantoulas, C., Denk, F., Signore, M., Nassar, M. A., Futai, K., & McMahon, S. B. (2018) · Pain · doi:10.1097/j.pain.0000000000001255 · Cited by 39 · see citing works
“This result agrees with recent work highlighting transient toxicity of tamoxifen 4 days after single administration, resulting in cellular stress and induction of nerve injury markers in DRG neurons, particularly proprioceptors.(8) Although we accessed pain phenotypes 10 days post-treatment, it is possible that some t…”
ResultSelf-citationAtf3 defines a population of pulmonary endothelial cells essential for lung regeneration
Niethamer, T. K., Levin, L. I., Morley, M. P., Babu, A., Zhou, S., & Morrisey, E. E. (2023) · eLife · doi:10.7554/elife.83835 · Cited by 39 · see citing works
Zhang, W.-B., Huang, Y. M., Guo, X., Zhang, M.-Q., Yuan, X.-S., & Zu, H. (2023) · Acta Neuropathologica Communications · doi:10.1186/s40478-023-01593-y · Cited by 34 · see citing works
“What’s more, Tamoxifen, which induced cognitive impairment in cancer therapy, was also found lead to cellular stress via inhibiting cholesterol synthesis [17].”
BackgroundEstrogen receptor alpha in the brain mediates tamoxifen-induced changes in physiology in mice
Zhang, Z., Park, J. W., Ahn, I. S., Diamante, G., Sivakumar, N., Arneson, D. V., Yang, X., van Veen, J. E., & Correa, S. M. (2021) · eLife · doi:10.7554/elife.63333 · Cited by 34 · see citing works
Recent Advances in the Synthesis of Tamoxifen and Analogues in Medicinal Chemistry
Tandon, N., Luxami, V., Tandon, R., & Paul, K. (2020) · Asian Journal of Organic Chemistry · doi:10.1002/ajoc.202000308 · Cited by 30 · see citing works
Liu, Y., Zhang, Z., Zhao, Z., Xu, Y., Duan, X., Zhao, Y., Ma, W., Yang, Y., Yang, Y., & Liu, Z. (2024) · Advanced Functional Materials · doi:10.1002/adfm.202407411 · Cited by 31 · see citing works
An ATF3-CreERT2 Knock-In Mouse for Axotomy-Induced Genetic Editing: Proof of Principle
Holland, S. D., Ramer, L. M., McMahon, S. B., Denk, F., & Ramer, M. S. (2019) · eNeuro · doi:10.1523/eneuro.0025-19.2019 · Cited by 29 · see citing works
“Tamoxifen (Sigma) was dissolved in wheat germ oil (Denk et al., 2015) and injected at a concentration of 75 mg/kg at the time of injury.”
MethodInfluentialSelf-citationPeripheral nerve injury results in a biased loss of sensory neuron subpopulations
Cooper, A. H., Barry, A. M., Chrysostomidou, P., Lolignier, R., Wang, J., Canales, M. R., Titterton, H. F., Bennett, D., & Weir, G. A. (2024) · Pain · doi:10.1097/j.pain.0000000000003321 · Cited by 19 · see citing works
“All experimental cohorts contained a mix of male and female mice, apart from the cohort of Mrgprd CreERT2 ;Ai32 mice that underwent SNI crush surgery, which was exclusively female.”
Translational Significance of Selective Estrogen Receptor Modulators in Psychiatric Disorders
Khan, M. M. (2018) · International Journal of Endocrinology · doi:10.1155/2018/9516592 · Cited by 16 · see citing works
“While both tamoxifen and raloxifene have been shown to reduce oxidative stress by increasing expression of various proteins and enzymes involved in antioxidant defense [152–157], tamoxifen under certain conditions may in fact increase oxidative stress, although, by different mechanisms [158].”
BackgroundAdult‐onset depletion of sulfatide leads to axonal degeneration with relative myelin sparing
Dustin, E., McQuiston, A. R., Honke, K., Palavicini, J. P., Han, X., & Dupree, J. L. (2023) · Glia · doi:10.1002/glia.24423 · Cited by 12 · see citing works
“Tamoxifen treated PLPCreERT / ;Cstfl/fl mice were used to control for potential side effects of tamoxifen treatment (Denk et al., 2015; Valny et al., 2016; Barratt et al., 2016).”
MethodDevelop an efficient and specific AAV-based labeling system for Muller glia in mice
Gao, Y., Fang, K., Yan, Z., Zhang, H., Geng, G., Wu, W., Ding, X., Zhang, H., Zhong, N., Wang, Q., et al. (2022) · Scientific Reports · doi:10.1038/s41598-022-27013-0 · Cited by 13 · see citing works
“Additionally, tamoxifen administration reportedly impairs neurogenesis (C. M. Lee et al., 2020) and can adversely affect the activity and specificity of promoters driving Cre (Denk et al., 2015; Donocoff, Teteloshvili, Chung, Shoulson, & Creusot, 2020).”
BackgroundRyu, A. H., Eckalbar, W. L., Kreimer, A., Yosef, N., & Ahituv, N. (2017) · doi:10.1101/130484 · Cited by 139 · see citing works
Pukos, N., & McTigue, D. M. (2020) · PLOS ONE · doi:10.1371/journal.pone.0235232 · Cited by 9 · see citing works
Small molecules targeting mitochondria as an innovative approach to cancer therapy
Kamble, O., Chatterjee, R., Abishek, K. G., Chandra, J., Alsayari, A., Wahab, S., Sahebkar, A., Kesharwani, P., & Dandela, R. (2024) · Cellular Signalling · doi:10.1016/j.cellsig.2024.111396 · Cited by 8 · see citing works
Transfer of nuclear and ribosomal material from Sox10-lineage cells to neurons in the mouse brain
Mayrhofer, F., Hanson, A. M., Navedo, M. F., Xiang, Y. K., Soulika, A. M., Deng, W., & Chechneva, O. V. (2023) · The Journal of Experimental Medicine · doi:10.1084/jem.20221632 · Cited by 7 · see citing works
Vorobyov, V., Деев, А. Д., Morozova, O., et al. (2023) · Biomedicines · doi:10.3390/biomedicines11123282 · Cited by 6 · see citing works
“On the other hand, TAM has been shown to affect many brain structures and functions [24] seemingly in part via TAM-induced neuronal stress evoked by inhibiting the cholesterol synthesis [25].”
BackgroundA method for TAT-Cre recombinase-mediated floxed allele modification in ex vivo tissue slices
Cheong, S., Luis, T. C., Stewart, M. E., Hillier, R., Hind, M. D., & Dean, C. H. (2023) · Disease Models & Mechanisms · doi:10.1242/dmm.050267 · Cited by 6 · see citing works
“…in vivo (Fuhrmann-Benzakein et al., 2000), costly and laborious breeding strategies, risk of toxicity caused by Cre-inducing agents such as 4OH-T (Denk et al., 2015; Savery et al., 2020), low transfection efficiencies of Cre plasmids or mRNA resulting in low recombination, instability of mRNA…”
Merchant, W., Tinajero, A., KHAN, A. R., Chu, Y., Saleh, S., Tasabehji, D., Morgan, D. A., Williams, K. W., Rahmouni, K., Mokadem, M., et al. (2025) · American Journal of Physiology-Endocrinology and Metabolism · doi:10.1152/ajpendo.00452.2025 · Cited by 5 · see citing works
Effects of tamoxifen therapy on sciatic nerve crush injury: An experimental study in rats
Akar, E., Emon, S. T., Efendioğlu, M., et al. (2021) · Acta Orthopaedica et Traumatologica Turcica · doi:10.5152/j.aott.2021.19183 · Cited by 5 · see citing works
“The most common side effects in its long-term use include visual impairment, toxic neuropathy, cataract, and thromboembolic events (39, 40).”
BackgroundOligodendroglia-to-pericyte conversion after lipopolysaccharide exposure is gender-dependent
Yu, Q., Zhang, L., Xu, T., Shao, J., Yuan, F., Yang, Z., Wu, Y., & Lyu, H. (2024) · PLoS ONE · doi:10.1371/journal.pone.0308132 · Cited by 4 · see citing works
AEBS inhibition in macrophages: Augmenting reality for SERMs repurposing against infections
Sfogliarini, C., Tran, L. H., Cesta, C. M., Allegretti, M., Locati, M., & Vegeto, E. (2024) · Biochemical Pharmacology · doi:10.1016/j.bcp.2024.116544 · Cited by 5 · see citing works
Repurposing Tamoxifen for Tumor Microenvironment Priming and Enhanced Tumor‐Targeted Drug Delivery
Biancacci, I., Santis, D. D., Rama, E., Benderski, K., Momoh, J., Pohlberger, R. F., Moeckel, D., Kaps, L., Rijcken, C. J. F., Prakash, J., et al. (2023) · Advanced Therapeutics · doi:10.1002/adtp.202300098 · Cited by 3 · see citing works
Wang, S., Barry, A. M., Lee, Y. K., Young, N., Shim, S. W., Wang, X., Kim, H., Stirling-Barros, L., González‐Cano, R., Costigan, M., et al. (2025) · Journal of Neuroinflammation · doi:10.1186/s12974-025-03675-1 · Cited by 3 · see citing works
Skin inflammation and itch response are independently regulated by distinct nociceptor subsets
Voisin, T., Ghéziel, N., Samrout, C. E., et al. (2026) · Immunity · doi:10.1016/j.immuni.2026.03.020 · Cited by 2 · see citing works
Yang, K., Xu, T., Lin, C., et al. (2025) · Acta Histochemica · doi:10.1016/j.acthis.2025.152269 · Cited by 1 · see citing works
Oligodendroglia Generate Vascular Mural Cells and Neurons in the Adult Mouse Brain
Xu, T., Yu, Q., Huang, M., Yang, K., Yang, Z., He, X., & Yuan, F. (2025) · Biological and Pharmaceutical Bulletin · doi:10.1248/bpb.b25-00335 · Cited by 1 · see citing works
Neuronal stress promotes Cre recombinase transfer from oligodendroglia to neurons
Xu, T., Yang, K., Feng, Y., Wu, Y., Zhang, L., Yang, Z., Yuan, F., & Lyu, H. (2025) · Acta Histochemica · doi:10.1016/j.acthis.2025.152300 · Cited by 1 · see citing works
Problems with Technologies of Genomic Editing and Transgenesis
Bolshakov, A. P. (2021) · Neurochemical Journal · doi:10.1134/s1819712421040036 · Cited by 1 · see citing works
Oligodendroglia generate vascular mural cells and neurons in the adult mouse brainPreprint
Yu, Q., Yang, K., Fan, Z., Huang, M., Xu, T., Yang, Y., Yang, Z., He, X., & Yuan, F. (2023) · bioRxiv (Cold Spring Harbor Laboratory) · doi:10.1101/2023.09.12.549127 · Cited by 1 · see citing works
Postnatal β1 Integrin Deficiency in Pancreatic Beta-Cells Impairs Function and Survival
Peart, J. N. (2017) · Scholarship@Western (Western University)
Sex Hormones as Risk Factors for Dementia
Mante, P. K., & Adomako, N. O. (2022) · Springer eBooks · doi:10.1007/978-981-16-7606-2_4
Zhang, W.-B., Huang, Y., Guo, X.-R., Zhang, M.-Q., 袁向山, & Zu, H.-B. (2024) · Figshare · doi:10.6084/m9.figshare.26598869
Zhang, W.-B., Huang, Y., Guo, X.-R., Zhang, M.-Q., 袁向山, & Zu, H.-B. (2024) · Figshare · doi:10.6084/m9.figshare.26598866
Li, G., Yang, M., Zhang, L., Li, X., Wu, X., Peng, F., & Liu, Y. (2026) · Frontiers in Pharmacology · doi:10.3389/fphar.2026.1731849 · Cited by 1 · see citing works
“…in Pharmacology frontiersin.org 11 Li et al. 10.3389/fphar.2026.1731849 cross the blood-brain barrier and affect dopaminergic pathways; previous animal studies and cognitive research have suggested potential neurological effects (Chen et al., 2002; 2014; Denk et al., 2015; Novick et al., 2020).”
InfluentialSfogliarini, C., Bernardinelli, C., Tran, L. H., Corsetto, P. A., Rizzo, A. M., Cattani, F., Cesta, M. C., Allegretti, M., Torre, S. D., Locati, M., et al. (2026) · Biomedicine & Pharmacotherapy · doi:10.1016/j.biopha.2026.119708
- Authors
- Denk, F., Ramer, L. M., Erskine, E. L. K. S., Nassar, M. A., Bogdanov, Y., Signore, M., Wood, J. N., McMahon, S. B., & Ramer, M. S.
- Affiliations
- King's College London (GB)
- University of British Columbia (CA)
- University of Sheffield (GB)
- University College London (GB)
- Corresponding author
- Ramer, Matt S.
- Venue
- Acta Neuropathologica Communications
- Published
- 2015-11-26
- Volume
- 3
- Issue
- 1
- Pages
- 74-74
- ISSN
- 2051-5960 (ISSN-L)
- PMC
- PMC4660723
- OpenAlex
- W2177532767
- Cited by
- 44
- References
- 40
- Citations by year
- 2026: 3 · 2025: 5 · 2024: 7 · 2023: 8 · 2022: 2 · 2021: 5 · 2020: 2 · 2019: 3 · 2018: 3 · 2017: 6
- FWCI
- 2.15
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- cc-by
- Locations
- Acta Neuropathologica Communications (publishedVersion, cc-by)
- PubMed (publishedVersion)
- White Rose Research Online (University of Leeds, The University of Sheffield, University of York) (acceptedVersion)
- Europe PMC (PubMed Central) (submittedVersion, cc-by)
- PubMed Central (submittedVersion, cc-by)
- ePrints Soton (University of Southampton) (submittedVersion)
- UCL Discovery (University College London) (submittedVersion)
- Funders
- Wellcome Trust (PNWRAQR)
- Natural Sciences and Engineering Research Council of Canada (RGPIN 250355-1)
- Topics
- Health Sciences › Medicine › Pulmonary and Respiratory Medicine › Cancer-related cognitive impairment studies
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Estrogen and related hormone effects
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Endoplasmic Reticulum Stress and Disease
- Keywords
- tamoxifen, cellular stress, ATF3, cholesterol synthesis inhibition, dentate gyrus, ependymal cells, vascular cells, sensory neurons, Cre-loxP recombination, CreERT2, tdTomato reporter, wheat germ oil, vitamin E, cognitive impairment, neurotoxicity
- MeSH terms
- Animals, Cholesterol, Dose-Response Relationship, Drug, Epoxide Hydrolases, Mice, Inbred C57BL, Mice, Transgenic, Mutation, Nerve Tissue Proteins, Nervous System, Neurons, Plant Oils, Promoter Regions, Genetic, Tamoxifen, Vitamin E, Calcitonin Gene-Related Peptide, Up-Regulation, Selective Estrogen Receptor Modulators, Plant Lectins, Mice, Activating Transcription Factor 3
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
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