USP22 deficiency leads to myeloid leukemia upon oncogenic Kras activation through a PU.1-dependent mechanism

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

USP22 functions involve remodeling chromatin by removing ubiquitin from histones H2B and H2A and activation/stabilization of transcription factors.

“USP22 functions involve the remodeling of chromatin by removing ubiquitin from histones (H2B and H2A) and activation/stabilization transcription factors.14,15”

• cites [14] Zhang, 2008, The putative cancer stem cell marker USP22 is a subunit of the human SAGA complex required for activated transcription and cell-cycle progression, Mol Cell sourceNot checked — no full text of the source
• cites [15] Schrecengost, 2014, USP22 regulates oncogenic signaling pathways to drive lethal cancer progression, Cancer Res sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Somatic Ras mutations are recurrent in acute lymphoblastic leukemia and myeloid leukemias.

“Somatic mutations in Ras have been found recurrently in acute lymphophastic leukemia and myeloid leukemias.1”

• cites [1] Braun, 2008, Targeting Ras in myeloid leukemias, Clin Cancer Res sourcePartly supported

  The Background reports that RAS mutations are common in myeloid malignancies, including about 20% of acute myeloid leukemia specimens. It does not address recurrent Ras mutations in acute lymphoblastic leukemia, so that part of the citing sentence is unsupported. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Ras pathway mutations are associated with initiating events necessary for early leukemia development and cooperative events necessary for continuous growth.

“Mutations in the Ras pathway have been associated with initiating events in which these mutations are necessary for early stages of leukemia development, as well as cooperative events necessary for continuous growth. 2”

• cites [2] Knight, 2014, Ras/Raf/MEK/ERK pathway activation in childhood acute lymphoblastic leukemia and its therapeutic targeting, Front Oncol sourcePartly supported

  The section “Are Ras Pathway Mutations an Initiating or Secondary Event?” (page not provided) says Ras pathway mutations may be early initiating events or later cooperative events. It does not establish that these mutations are necessary for early leukemia development or continuous growth; its statement of necessity concerns additional cooperating genetic events for full-blown leukemia. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

Human AML samples with FLT3-ITD show higher USP22 expression than samples without FLT3 mutations.

“analysis of human acute myeloid leukemia (AML) samples with an FLT3-ITD mutation showed higher expression of USP22 than did samples without FLT3 mutations.16”

• cites [16] Li, 2014, SIRT1 activation by a c-MYC oncogenic network promotes the maintenance and drug resistance of human FLT3-ITD acute myeloid leukemia stem cells, Cell Stem Cell sourcePartly supported

  The Results section (“USP22 Interacts with SIRT1 and Maintains Its Protein Expression,” Figure 7A) reports significantly higher USP22 mRNA in FLT3-ITD than FLT3-WT AML CD34+ cells. The citing sentence omits that the comparison was specifically of CD34+ cells and mRNA expression, making its reference to AML samples more general than the reported finding. (LLM, conf=0.82)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

USP22 hypomorphic mice have defects in brain and small intestine.

“USP22hypomorphic mice have defects in the brain and small intestine.10”

• cites [10] Kosinsky, 2015, Usp22 deficiency impairs intestinal epithelial lineage specification in vivo, Oncotarget sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing).

Elevated expression of BMI1 signature is associated with cancer development and chemotherapy resistance in different cancers including hematological malignancies.

“Elevated expression of this signature is associated with cancer development and chemotherapy resistance in different types of cancer, including hematological malignancies.11”

• cites [11] Glinsky, 2005, Microarray analysis identifies a death-from-cancer signature predicting therapy failure in patients with multiple types of cancer, J Clin Invest sourcePartly supported

  The Discussion (page unavailable) associates a stem cell-like expression profile of the 11-gene signature with disease progression and a high likelihood of therapy failure. The validation section (page unavailable) reports this association in cancers including lymphoma and acute myeloid leukemia. The paper does not establish that the signature is uniformly elevated, or specifically link it to cancer development or chemotherapy resistance rather than progression and therapy failure more broadly. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

USP22 controls cell growth by activating transcription and inhibiting apoptotic pathways.

“USP22 controls cell growth by activating transcription 12,13 and inhibiting apoptotic pathways.9”

• cites [12] Henry, 2003, Transcriptional activation via sequential histone H2B ubiquitylation and deubiquitylation, mediated by SAGA-associated Ubp8, Genes Dev sourcePartly supported

  The section “Ubp8 is required for optimal gene activation” (page unavailable) reports that loss of yeast Ubp8 reduced GAL1 and ADH2 transcription and slightly impaired growth. That supports a role for Ubp8 in transcription and growth, but the paper does not establish the stated role for USP22. The apoptosis clause is attached to citation 9, not to this source. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [13] Zhao, 2008, A TFTC/STAGA module mediates histone H2A and H2B deubiquitination, coactivates nuclear receptors, and counteracts heterochromatin silencing, Mol Cell sourceNot checked — no full text of the source
• cites [9] Lin, 2012, USP22 antagonizes p53 transcriptional activation by deubiquitinating Sirt1 to suppress cell apoptosis and is required for mouse embryonic development, Mol Cell sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

H2B monoubiquitylation induced by RNF20 was necessary for leukemic cell growth in MLL-AF9 leukemia.

“Moreover, H2B monoubiquitylation induced by the ubiquitin ligase RNF20 was necessary for leukemic cell growth in MLL-AF9 leukemia.47”

• cites [47] Wang, 2013, Histone H2B ubiquitin ligase RNF20 is required for MLL-rearranged leukemia, Proc Natl Acad Sci USA sourcePartly supported

  The section “Rnf20 Is Required for Proliferation of MLL-Fusion Leukemia Cells” reports that RNF20 knockdown inhibited proliferation of MLL-AF9 leukemia cells. The paper also shows that Rnf20 knockdown reduced H2B monoubiquitylation, but its Discussion proposes a mechanism linking that modification to leukemia growth; it does not establish that the modification itself was necessary. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

H2B monoubiquitylation stimulates DOT1L activity, and DOT1L is required for leukemia initiation and maintenance.

“H2B monoubiquitylation has been shown to stimulate the activity of DOT1L, a methyltransferase required for leukemia initiation and maintenance.46”

• cites [46] McGinty, 2008, Chemically ubiquitylated histone H2B stimulates hDot1L-mediated intranucleosomal methylation, Nature sourcePartly supported

  The Abstract reports that ubiquitylated H2B directly stimulates hDot1L-mediated H3 K79 methylation in nucleosomes. Our copy does not address whether DOT1L is required for leukemia initiation or maintenance; searches for those terms found no supporting passage. (LLM, conf=0.90)

  Experimental — accuracy not yet measured

Probably not a substantial claim: may not pass S3 (load-bearing).

USP22-hypomorphic mice showed differentiation defects in the small intestine and brain.

“Moreover, USP22-hypomorphic mice showed differentiation defects in the small intestine and the brain.10”

• cites [10] Kosinsky, 2015, Usp22 deficiency impairs intestinal epithelial lineage specification in vivo, Oncotarget sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Irradiation-induced myeloid leukemias in mice had low PU.1 levels and mutations affecting its DNA binding.

“Likewise, irradiationinduced myeloid leukemias in mice had low PU.1 levels and mutations that affected its binding to the DNA.41,42”

• cites [41] Cook, 2004, PU.1 is a suppressor of myeloid leukemia, inactivated in mice by gene deletion and mutation of its DNA binding domain, Blood sourcePartly supported

  The Discussion reports that, in 87% of γ-radiation-induced tumors with one PU.1 allele deleted, the remaining allele was mutated; the mutations were expected to impair or abolish DNA binding. It does not establish that those tumors had low PU.1 levels. The low-expression finding in the “Roles of PU.1” section concerns a separate enhancer-deletion mouse model. (LLM, conf=0.85)

  Experimental — accuracy not yet measured
• cites [42] Suraweera, 2005, Mutations of the PU.1 Ets domain are specifically associated with murine radiation-induced, but not human therapy-related, acute myeloid leukaemia, Oncogene sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

A reduction in PU.1 expression and activity is commonly seen in mouse and human AML.

“A reduction in PU.1 expression and activity is commonly seen in mouse and human cases of AML.[28][29][30]”

• cites [28] Rosenbauer, 2004, Acute myeloid leukemia induced by graded reduction of a lineage-specific transcription factor, PU.1, Nat Genet sourceNot checked — no full text of the source
• cites [29] Metcalf, 2006, Inactivation of PU.1 in adult mice leads to the development of myeloid leukemia, Proc Natl Acad Sci USA sourcePartly supported

  The Abstract reports that reduced PU.1 expression was associated with frequent AML in a mouse model. It also says PU.1’s role in human AML remains uncertain, so it does not support the claim that reduced PU.1 expression or activity is commonly seen in human AML. (LLM, conf=0.87)

  Experimental — accuracy not yet measured
• cites [30] Will, 2015, Minimal PU.1 reduction induces a preleukemic state and promotes development of acute myeloid leukemia, Nat Med sourcePartly supported

  The Introduction and Discussion (pages not provided) say that modest impairment of PU.1 expression or activity is common in human AML. The Results show that experimentally reduced PU.1 expression led to AML in a mouse model, but do not establish that reduced PU.1 is commonly seen across mouse AML cases. (LLM, conf=0.86)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Prior in vitro studies show USP22 acts as an oncogene by promoting cell growth and proliferation.

“Previous studies in vitro have shown that USP22 behaves as an oncogene by promoting cell growth and proliferation.14,17,19”

• cites [14] Zhang, 2008, The putative cancer stem cell marker USP22 is a subunit of the human SAGA complex required for activated transcription and cell-cycle progression, Mol Cell sourceNot checked — no full text of the source
• cites [17] Atanassov, 2011, USP22 regulates cell proliferation by deubiquitinating the transcriptional regulator FBP1, EMBO Rep sourceSupported
• cites [19] Lin, 2015, Ubiquitin-specific protease 22 is a deubiquitinase of CCNB1, Cell Discov sourceSupported

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

USP22 interacts with different cell cycle regulators, and its decrease impairs proliferation in vitro.

“USP22 interacts with different cell cycle regulators, and its decrease impairs proliferation in vitro.14,17,19”

• cites [14] Zhang, 2008, The putative cancer stem cell marker USP22 is a subunit of the human SAGA complex required for activated transcription and cell-cycle progression, Mol Cell sourceNot checked — no full text of the source
• cites [17] Atanassov, 2011, USP22 regulates cell proliferation by deubiquitinating the transcriptional regulator FBP1, EMBO Rep sourcePartly supported

  The FBP1 interaction experiments report that USP22 coprecipitates with FBP1, and the ‘Impaired proliferation of USP22-depleted cells’ section reports reduced proliferation after USP22 depletion in MCF7 and H1299 cells. The paper does not establish interactions with different cell-cycle regulators: it identifies FBP1 and says additional substrates remain to be confirmed. Page numbers are unavailable in our copy. (LLM, conf=0.86)

  Experimental — accuracy not yet measured
• cites [19] Lin, 2015, Ubiquitin-specific protease 22 is a deubiquitinase of CCNB1, Cell Discov sourceSupported

May combine two claims.

Mice receiving KMUKO cells had decreased neutrophil and lymphocyte counts, severe anemia, and thrombocytopenia.

“In addition, mice receiving KMUKO cells had decreased neutrophil and lymphocyte counts and presented severe anemia and thrombocytopenia (Figure 3C).”

May combine two claims.

Further analysis showed increase in immature myelomonocytic cells and decrease in Ly6G+ mature cells in KMUKO mice.

“Further analysis using Ly6G and Ly6C antibodies showed an increase in immature myelomonocytic cells and a decrease in Ly6G 1 mature cells in KMUKO mice (Figure 2D).”

May combine two claims.

Absence of USP22 did not affect body weight or organ weight.

“The absence of USP22 did not affect body weight or the weight of organs (supplemental Figure 1E).”

May combine two claims.

Mice receiving KMUKO cells died 4-7 weeks after transplant, whereas mice transplanted with KM cells survived >10 weeks.

“Mice receiving KMUKO cells died 4-7 weeks after transplant, whereas mice transplanted with KM cells survived for .10weeks (Figure 3A).”

May combine two claims.

PU.1 protein expression was modestly decreased in KMUKO cells compared with KM cells, but similar between WT and UKO cells.

“Expression of PU.1 protein was modestly decreased in KMUKO cells compared with KM cells, but it was similar between WT and UKO cells (Figure 5B; supplemental Figure 8).”

May combine two claims.

GSEA showed Myc target genes were overrepresented in KMUKO myeloid progenitors, while PU.1 targets were underrepresented.

“GSEA showed that Myc target genes were overrepresented in KMUKO myeloid progenitors; in contrast, targets of PU.1 were underrepresented (Figure 4F-H; supplemental Figure 7).”

May combine two claims.

KMUKO cells had slightly lower levels of phosphorylated ERK and S6 compared with KM cells, indicating absence of USP22 did not enhance MEK/ERK signaling.

“Our results show that KMUKO cells had slightly lower levels of phosphorylated ERK and S6 compared with KM cells (supplemental Figure 4), indicating that the absence of USP22 did not enhance MEK/ERK signaling.”

May combine two claims.

KMUKO mice showed higher frequency of GMPs, decrease in mature myeloid cells (CD11b+Gr1hi), and accumulation of immature myeloid cells (CD11b+Gr1-/low) compared with KM.

“KMUKO mice showed a higher frequency of GMPs, a dramatic decrease in mature myeloid cells (CD11b 1 Gr1 hi ), and accumulation of immature myeloid cells (CD11b 1 Gr1 2/low ) compared with KM mice (Figure 2B-C).”

The quote only partly states this claim.

Hematopoietic recovery kinetics after 5-FU were similar in UKO and WT mice.

“Our results showed similar kinetics of hematopoietic recovery of myeloid cells in UKO mice compared with WT mice (supplemental Figure 2E).”

May combine two claims.

KMUKO immature myeloid cells were not apoptotic, no differences vs KM.

“We also determined whether KMUKO immature myeloid cells were apoptotic, but we found no differences compared with KM mice (supplemental Figure 3D).”

May combine two claims.

CMPs and GMPs from KMUKO mice were slightly more proliferative than KM cells, showing USP22 is dispensable for their proliferation.

“CMPs and GMPs from KMUKO mice were slightly more proliferative than cells from KM mice, showing that USP22 is dispensable for their proliferation.”

May combine two claims.

Usp22 alleles were deleted and USP22 protein was not expressed in UKO mice after pIpC.

“Usp22 alleles were deleted and USP22 protein was not expressed in UKO mice after receiving polyinosinicpolycytidylic acid (pIpC) (supplemental Figure 1C-D).”

May combine two claims.

Most KMUKO mice died 1-2 days after first pIpC injection, whereas KM mice were alive.

“Unexpectedly, most KMUKO mice died 1-2 days after the first injection, whereas KM mice were still alive (supplemental Table 1).”

May combine two claims.

The difference in bone marrow cell numbers was due to decreased body weight, as normalization to body weight showed no differences.

“This difference was due to the decreased body weight seen in these mice, because normalization of cell counts to body weight showed no differences among the groups (Figures 1D and 2A).”

May combine two claims.

Blood cell counts and bone marrow population frequencies in UKO mice were comparable to WT mice.

“Blood cell counts and the frequency of different bone marrow populations in UKO mice were comparable to those in young and 1.5-year-old WT mice (supplemental Figures 1F-H and 2A-C).”

May combine two claims.

Bone marrow cells from Kras-induced MPN mice showed increased USP22 protein but not mRNA.

“Analysis of bone marrow cells from mice with a Kras-induced MPN (Kras G12D/1 Mx1-Cre mice [KM]) showed a dramatic increase in USP22 protein levels but not mRNA levels (supplemental Figure 3A-B).”

May combine two claims.

Bone marrow cytospins confirmed increased proportion of myeloblasts/immature myeloid cells and decrease in mature forms in KMUKO mice.

“Accordingly, bone marrow cytospins confirmed the increased proportion of myeloblasts/immature myeloid cells and a decrease in mature forms in KMUKO mice (Figure 2E).”

May combine two claims.

KMUKO mice had shorter survival and smaller size compared with other groups.

“KMUKO mice had a shorter survival time and were smaller in size compared with the other groups (Figure 1C-D).”

May combine two claims.

Usp22 is highly expressed in LSK, CMP, GMP, and CLP cells, but not MEPs.

“Usp22 was highly expressed in all of these cell subsets, with the exception of MEPs (supplemental Figure 1B).”

May combine two claims.

CD11b+ cells showed mild decrease in BrdU+ cells, not statistically significant.

“CD11b 1 cells showed a mild decrease in the percentage of BrdU 1 cells, although the differences were not statistically significant (Figure 2F).”

May combine two claims.

Transcriptome profile of USP22-deficient Kras G12D/+ progenitors resembled leukemic stem cells and was highly correlated with genes associated with poor prognosis in AML.

“The transcriptome profile of USP22-deficient Kras G12D/1 progenitors resembled leukemic stem cells and was highly correlated with genes associated with poor prognosis in AML.”

May combine two claims.

USP22 is necessary for myeloid cell differentiation under oncogenic Kras conditions but not under normal conditions.

“We further demonstrated that USP22 was necessary for the differentiation of myeloid cells under oncogenic Kras conditions but not under normal conditions.”

• Also stated in: § Discussion · plain

  “In our model, USP22 was dispensable for myeloid development under normal conditions; however, it was necessary for myeloid differentiation upon Kras activation.”

May combine two claims.

Spleen sections from KMUKO mice showed complete effacement of normal architecture by neoplastic cells and reduction of white pulp.

“Spleen sections from KMUKO mice showed complete effacement of normal architecture by neoplastic cells and reduction of the white pulp.”

May combine two claims.

KMUKO-recipient mice had increased numbers of myeloblasts and decreased numbers of segmented mature neutrophils, indicating a block at the myeloblast stage of maturation.

“KMUKO-recipient mice had increased numbers of myeloblasts (CD34 1 cKit 1 fractions 1 and 2) and decreased numbers of segmented mature neutrophils (CD34 2 cKit 2 fraction 6), indicating a block at the myeloblast stage of maturation.”

May combine two claims.

WT USP22, but not catalytically inactive mutant C185A, decreased PU.1 ubiquitylation.

“We then performed ubiquitylation assays and found that WT USP22, but not its catalytically inactive mutant (C185A), decreased PU.1 ubiquitylation (Figure 5E).”

May combine two claims.

Western blotting confirmed ectopic PU.1 protein expression and restoration of PU.1 target gene expression in KMUKO cells.

“Western blotting confirmed the ectopic PU.1 protein expression and, as a consequence, the expression of PU.1 target genes in KMUKO cells was restored (supplemental Figure 9A-B).”

May combine two claims.

Mutant Kras led to a dramatic increase in USP22 protein levels, but not mRNA levels, in myeloid progenitors.

“We found that mutant Kras, by an unknown mechanism, led to a dramatic increase in USP22 protein levels (but not mRNA levels) in myeloid progenitors.”

May combine two claims.

Targets of Myc oncogene were highly enriched in KMUKO progenitors, whereas PU.1 target genes were inversely correlated.

“Targets of the Myc oncogene were highly enriched in KMUKO progenitors (F), whereas PU.1 target genes were inversely correlated (G).”

May combine two claims.

Liver sections from KMUKO mice were severely infiltrated by nonlymphoid cells with congestion of central veins.

“Liver sections from KMUKO mice were severely infiltrated by nonlymphoid cells that occurred with congestion of central veins.”

May combine two claims.

USP22-deficient mice monitored for 2 years did not develop myeloid abnormalities or hematopoietic malignancies.

“We monitored USP22-deficient mice for 2 years and we did not find myeloid abnormalities; these mice did not develop hematopoietic malignancies, and their survival was comparable to WT mice.”

May combine two claims.

USP22 deficiency under Kras-oncogenic conditions led to generation of myeloid leukemia by increasing Myc target genes and reducing PU.1 target genes.

“These results indicate that USP22 deficiency under Kras-oncogenic conditions led to the generation of myeloid leukemia by increasing the expression of Myc target genes and reducing the expression of PU.1 target genes.”

May combine two claims.

Under Kras-oncogenic conditions, absence of USP22 specifically resulted in acute myeloid disease and reduced generation of T-ALL/lymphoma.

“Therefore, our data show that, under Kras-oncogenic conditions, the absence of USP22 specifically resulted in an acute myeloid disease and reduced the generation of T-ALL/lymphoma.”

May combine two claims.

USP22 functions as a PU.1 deubiquitylase by positively regulating its protein stability and promoting the expression of PU.1 target genes.

“USP22 functions as a PU.1 deubiquitylase by positively regulating its protein stability and promoting the expression of PU.1 target genes.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Activation of RAS signaling leads to multiple intracellular changes including deregulation of transcriptional programs.

“Activation of the RAS signaling pathway leads to multiple intracellular changes, including the deregulation of transcriptional programs.3”

• cites [3] Schäfer, 2011, RAS oncogene-mediated deregulation of the transcriptome: from molecular signature to function, Adv Enzyme Regul sourceNot checked — no full text of the source

May combine two claims.

USP22 deficiency in KM mice blocked myeloid differentiation and was dispensable for proliferation of myeloid progenitors.

“Collectively, our data show that USP22 deficiency in KM mice blocked myeloid differentiation and was dispensable for the proliferation of myeloid progenitors.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Germ line deletion of USP22 is lethal in mice.

“its germ line deletion is lethal in mice.9”

• cites [9] Lin, 2012, USP22 antagonizes p53 transcriptional activation by deubiquitinating Sirt1 to suppress cell apoptosis and is required for mouse embryonic development, Mol Cell sourceNot checked — no full text of the source

May combine two claims.

The effect was cell autonomous because mice transplanted with USP22-deficient Kras G12D/+ cells developed an aggressive disease and died rapidly.

“This effect was cell autonomous because mice transplanted with USP22-deficient Kras G12D/1 cells developed an aggressive disease and died rapidly.”

May combine two claims.

KMUKO-recipient mice presented similar phenotype to primary mice, and transplantation resulted in rapid death.

“These data show that KMUKO-recipient mice presented a similar phenotype to primary mice, and transplantation of these cells resulted in a rapid death of recipient mice.”

Probably not a substantial claim: may not pass S3 (load-bearing).

USP22 is important for differentiation of embryonic stem cells in vitro.

“USP22 is important for the differentiation of embryonic stem cells in vitro, 8”

• cites [8] Sussman, 2013, The epigenetic modifier ubiquitin-specific protease 22 (USP22) regulates embryonic stem cell differentiation via transcriptional repression of sex-determining region Y-box 2 (SOX2), J Biol Chem sourceNot checked — no full text of the source

May combine two claims.

USP22 deficiency in Ras-driven myeloproliferative neoplasm blocks myeloid differentiation and promotes acute myeloid leukemia.

“USP22 deficiency inRas-driven myeloproliferative neoplasm blocks myeloid differentiation promoting acute myeloid leukemia.”

May combine two claims.

USP22 is a PU.1 deubiquitylase that positively regulates PU.1 stability and the expression of myeloid differentiation genes.

“USP22 is a PU.1 deubiquitylase that positively regulates PU.1 stability and the expression of myeloiddifferentiation genes.”

May combine two claims.

KMUKO cells undergoing spontaneous recombination became majority in bone marrow, suggesting selective advantage over nonrecombined cells.

“The fact that KMUKO cells undergoing spontaneous recombination (resulting in the deletion of USP22) became the majority of the cells present in the bone marrow suggests that KMUKO cells had a selective advantage over the nonrecombined cells.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

NRAS or KRAS mutations are found in ~20-40% of myeloid malignancies and 10-15% of acute lymphoblastic leukemia.

“NRAS or KRAS mutations are found in ;20-40% of myeloid malignancies and in 10-15% of acute lymphoblastic leukemia.4,5”

• cites [4] Schubbert, 2007, Hyperactive Ras in developmental disorders and cancer, Nat Rev Cancer sourceNot checked — no full text of the source
• cites [5] Lauchle, 2006, Inherited predispositions and hyperactive Ras in myeloid leukemogenesis, Pediatr Blood Cancer sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

In cultured embryonic stem cells, USP22 is necessary for the transition from self-renewal to differentiation.

“Previous reports have shown that USP22 was necessary for the transition from self-renewal to differentiation in cultured embryonic stem cells.”

• cites [8] Sussman, 2013, The epigenetic modifier ubiquitin-specific protease 22 (USP22) regulates embryonic stem cell differentiation via transcriptional repression of sex-determining region Y-box 2 (SOX2), J Biol Chem sourceNot checked — no full text of the source

May combine two claims.

USP22 interacts with and deubiquitylates PU.1, increasing its protein stability.

“At the molecular level, USP22 interacts and deubiquitylates PU.1, increasing its protein stability.”

Probably not a substantial claim: may not pass S3 (load-bearing).

Downregulation of PU.1 was identified as a mechanism for leukemias generated by PML-RARa, FLT3-ITD, and AML1-ETO.

“Moreover, downregulation of PU.1 was identified as a mechanism for the induction of leukemias generated by PML-RARa, FLT3-ITD, and AML1-ETO.[43][44][45]”

• cites [43] Rosenbauer, 2007, Transcription factors in myeloid development: balancing differentiation with transformation, Nat Rev Immunol sourceNot checked — no full text of the source
• cites [44] Mizuki, 2003, Suppression of myeloid transcription factors and induction of STAT response genes by AML-specific Flt3 mutations, Blood sourceNot checked — no full text of the source
• cites [45] Vangala, 2003, The myeloid master regulator transcription factor PU.1 is inactivated by AML1-ETO in t(8;21) myeloid leukemia, Blood sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

USP22 is necessary for stability and transcriptional activation of Myc in fibroblasts and breast cancer cell lines.

“Previous reports have shown that USP22 is necessary for the stability and transcriptional activation of Myc in fibroblasts and breast cancer cell lines.14”

• cites [14] Zhang, 2008, The putative cancer stem cell marker USP22 is a subunit of the human SAGA complex required for activated transcription and cell-cycle progression, Mol Cell sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

In murine AML models with decreased PU.1, c-Myc expression is elevated.

“Studies in murine models of AML with decreased levels of PU.1 showed an elevated expression of c-Myc.28”

• cites [28] Rosenbauer, 2004, Acute myeloid leukemia induced by graded reduction of a lineage-specific transcription factor, PU.1, Nat Genet sourceNot checked — no full text of the source

May combine two claims.

The authors used a mouse genetic model to examine USP22 under oncogenic conditions and found an unexpected function for USP22 in leukemogenesis.

“By using a genetic mouse model to study USP22 function under oncogenic conditions for the first time, we uncovered an unexpected role for USP22 in leukemogenesis.”

May combine two claims.

Although no direct correlation or survival difference with USP22 mRNA, molecular signature in KMUKO progenitors resembles pediatric AML with poor prognosis.

“These results indicate that, although we did not see a direct correlation or survival difference when analyzing USP22 mRNA, the molecular signature observed in KMUKO progenitors resembles that of pediatric AML with poor prognosis.”

May combine two claims.

Upon USP22 deletion, PU.1 levels decreased, leading to a myeloid differentiation block and transformation into myeloid leukemia.

“Upon USP22 deletion, PU.1 levels were decreased, leading to a myeloiddifferentiation block and transformation into myeloid leukemia.”

May combine two claims.

In absence of USP22, PU.1 protein and its target genes decrease, leading to differentiation block and leukemic transformation.

“In the absence of USP22, the levels of PU.1 protein and its target genes decrease, leading to a differentiation block and leukemic transformation.”