Therapeutic glycoprotein production in mammalian cells

In the paper

“These cells can achieve substantial production rate, are suitable for large-scale industrial suspension culture and can be adapted to grow in various serum-free and chemically defined culture media (Kim et al., 2012;Lai et al., 2013).”

What the sources say

• ?Not checked — no full text of the sourcecites Kim et al., 2012 source
• Supported

  The Introduction states that CHO cells can adapt to suspension culture suitable for large-scale industrial use and can grow in serum-free and chemically defined media. It also reports recombinant protein titers in the gram-per-liter range, supporting the production-rate claim. (LLM, conf=0.94)

  cites Lai et al., 2013 source

In the paper

“Studies have demonstrated that proper glycosylation profiles can improve recombinant protein properties such as increase their stability and half-life in blood circulation and decrease their immunogenicity (Ashwell and Harford, 1982;Runkel et al., 1998;Ghaderi et al., 2010;Ghaderi et al., 2012;Jefferis, 2016a;Jefferis, 2016b;Kuriakose et al., 2016).”

What the sources say

• ?Not checked — no full text of the sourcecites Ashwell and Harford, 1982 source
• ?Not checked — no full text of the sourcecites Runkel et al., 1998 source
• Supported

  The paper’s introductory passage (indexed under Abstract; page unavailable) says N-glycan structure can affect stability against proteolysis, immunogenicity, and clearance rate. It also says increased sialylation could lengthen a therapeutic agent’s half-life. These passages support the citing sentence’s broad claim about what appropriate glycosylation can do. (LLM, conf=0.86)

  cites Ghaderi et al., 2010 source

In the paper

“Indeed, plants produce core α1,3-fructose and β1,2-xylose, which are completely absent in human cells and could be immunogenic (Karg et al., 2009;Ghaderi et al., 2012).”

What the sources say

• ?Not checked — no full text of the sourcecites Karg et al., 2009 source
• Partly supported

  The plant-based expression systems section says plant N-glycans may carry β1,2-xylose and α1,3-fucose residues that are absent in humans and may be immunogenic. The claim says “fructose” rather than the paper’s “fucose,” so that component is not supported as written. (LLM, conf=0.88)

  cites Ghaderi et al., 2012 sourceExperimental — accuracy not yet measured

In the paper

“Two other cell lines, the CAP (CEVEC's Amniocyte Production) cells of human amniocytes origin and the HuH-7 cells of human hepatocellular carcinoma origin, are presently tested for recombinant glycoprotein production in preclinical phases and both display human-like glycosylation profiles (Schiedner et al., 2008;Wolfel et al., 2011;Enjolras et al., 2012;Swiech et al., 2012;Wissing et al., 2015).”

What the sources say

• Partly supported

  The Results section (page unavailable) reports that hAAT produced in human amniocyte cell lines was glycosylated and sialylated, with test results comparable to hAAT from human serum. This supports a human-like feature for the amniocyte-derived cells, but the paper does not establish a full glycosylation profile for CAP cells or address HuH-7 cells. (LLM, conf=0.86)

  cites Schiedner et al., 2008 sourceExperimental — accuracy not yet measured
• Partly supported

  The Summary (page not provided) says proteins produced by CAP-T cells showed a fully human posttranslational modification pattern, also observed in the original CAP cells. The Background describes CAP cells as producing proteins with authentic human posttranslational modifications. These passages support the claim for CAP cells, but the paper does not address HuH-7 cells or their glycosylation profiles. (LLM, conf=0.88)

  cites Wolfel et al., 2011 sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites Enjolras et al., 2012 source

In the paper

“Even though these three products show diverse glycan profiles, they showed similar macrophage uptake, in vitro enzymatic activity, stability and efficacy (Ben Turkia et al., 2013;Tekoah et al., 2013).”

What the sources say

• Partly supported

  The Introduction (page not specified) describes different glycan compositions, while the trial results report non-inferior clinical efficacy for velaglucerase alfa versus imiglucerase. But the Introduction says velaglucerase alfa enters cultured human macrophages more rapidly, not at a similar rate. This paper does not establish comparable in vitro activity or stability, or compare a carrot-cell product. (LLM, conf=0.90)

  cites Ben Turkia et al., 2013 sourceExperimental — accuracy not yet measured
• Partly supported

  The Introduction table identifies the three enzymes as produced in human fibrosarcoma, CHO, and carrot cells. The Discussion reports different glycan profiles but comparable enzymatic activity, stability, and macrophage uptake. It says clinical trial data *suggest* no significant differences in clinical improvement, rather than establishing similar efficacy as a finding of this study. (LLM, conf=0.83)

  cites Tekoah et al., 2013 sourceExperimental — accuracy not yet measured

In the paper

“Notably, neutralizing anti-Imiglucerase antibodies were observed in 24% of patients, with an impact on the protein activity (Ben Turkia et al., 2013).”

What the sources say

• Partly supported

  The Discussion reports anti-imiglucerase antibodies in 23.5% of treated patients, approximately 24%. The Adverse events section identifies neutralizing antibodies that inhibited enzyme activity in vitro in one patient, but does not say that all four antibody-positive patients had neutralizing antibodies. The claim incorrectly applies the 24% figure to neutralizing antibodies. (LLM, conf=0.91)

  cites Ben Turkia et al., 2013 sourceExperimental — accuracy not yet measured

In the paper

“To date, only viral vectors used in gene therapy have been produced by transient transfections for clinical applications (Wright, 2009).”

What the sources say

• Partly supported

  The paper’s opening section describes transient transfection-based methods for generating clinical-grade AAV vectors, which are viral vectors used in gene therapy. It does not establish the claim’s exclusivity—that only gene-therapy viral vectors had been produced this way for clinical applications. (LLM, conf=0.85)

  cites Wright, 2009 sourceExperimental — accuracy not yet measured

In the paper

“It is produced in HEK293-F cell line and has shown similar glycosylation profile to the plasma-derived factor VIII, deprived of α-gal and Neu5Gc (Casademunt et al., 2012;Kannicht et al., 2013).”

What the sources say

• Partly supported

  The Methods and results passage identifies HEK 293 F cells as the source of the rhFVIII, and the Discussion says the product lacks Neu5Gc-type sialic acids and Galα1,3Gal (α-gal). Our copy does not establish that its glycosylation profile is similar to plasma-derived factor VIII; its discussion of an authentic human pattern of post-translational modifications does not make that comparison. No page numbers are available in the indexed passages. (LLM, conf=0.88)

  cites Casademunt et al., 2012 sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites Kannicht et al., 2013 source

In the paper

“Because the genome contains numerous sequence repetitions or has highly homologous DNA sequences, efforts have been made in the last years to improve the offtarget effects and the specificity of these enzymes (Miller et al., 2007;Szczepek et al., 2007;Guo et al., 2010;Doyon et al., 2011).”

What the sources say

• ?Not checked — no full text of the sourcecites Miller et al., 2007 source
• Partly supported

  The Results (page not provided) say the authors altered ZFN dimerization to improve cleavage specificity, and the Discussion links ZFN toxicity to off-target cleavage at related DNA sites. The paper does not address TALENs or establish that numerous genomic repetitions or highly homologous sequences motivated this work. (LLM, conf=0.86)

  cites Szczepek et al., 2007 sourceExperimental — accuracy not yet measured
• Partly supported

  The Discussion says that improving the FokI cleavage domain’s discrimination between highly homologous target sites may increase ZFN specificity and reduce off-target cleavage. It does not address TALENs or establish that numerous genomic repetitions motivated these efforts; the specificity and off-target benefits are framed as possibilities, not demonstrated outcomes. (LLM, conf=0.85)

  cites Guo et al., 2010 sourceExperimental — accuracy not yet measured

In the paper

“As second generation tools, different endonucleases have been employed.This category includes zinc finger nucleases (ZFN), meganucleases, transcription activators like effectors nucleases (TALEN) and CRISPR/Cas9 (Durai et al., 2005;Porteus and Carroll 2005;Cabaniols et al., 2010;Silva et al., 2011;Kim et al., 2012;Sanjana et al., 2012;Cho et al., 2013;Sun and Zhao, 2013).”

What the sources say

• Supported

  The Abstract identifies zinc finger nucleases as custom-designed proteins that cut specific DNA sequences, and the “Engineering of ZFNs” section describes their endonuclease component. In this multiply cited list, Durai et al. supports the identification of ZFNs as one of the nuclease tools; it is not needed to substantiate the other listed tools. (LLM, conf=0.92)

  cites Durai et al., 2005 source
• ?Not checked — no full text of the sourcecites Porteus and Carroll 2005 source
• ?Not checked — no full text of the sourcecites Cabaniols et al., 2010 source

In the paper

“Also, the PiggyBac™ (System Bioscience inc.) transposon system uses an efficient transposase purified from the cabbage looper (Trichoplusia ni) to easily integrate the gene of interest into the host genome (Ding et al., 2005).”

What the sources say

• ?Could not verify

  The supplied passage and the additional indexed passages have no section or page labels and contain unrelated, repetitive Arabic text. Searches for the cabbage looper, purified transposase, and genomic integration found no passage in our copy that addresses the claim. (LLM, conf=0.78)

  cites Ding et al., 2005 sourceExperimental — accuracy not yet measured

In the paper

“Expressing these glycoproteins in HEK293 resulted in greater tyrosine sulfation and glutamic acid γ-carboxylation compared to CHO cells and excluded any α-gal and Neu5Gc from the manufactured products (Berkner, 1993;Kannicht et al., 2013;Peters et al., 2013;McCue et al., 2014McCue et al., , 2015)).”

What the sources say

• ?Not checked — no full text of the sourcecites Berkner, 1993 source
• ?Not checked — no full text of the sourcecites Kannicht et al., 2013 source
• Partly supported

  The Materials and methods section reports that rFVIIIFc was produced in HEK293 cells, and the Results section reports nearly complete tyrosine sulfation. Neither section establishes greater sulfation than in CHO cells. The paper does not substantiate the sentence’s claims about rFIXFc, γ-carboxylation, or exclusion of α-gal and Neu5Gc. (LLM, conf=0.88)

  cites Peters et al., 2013 sourceExperimental — accuracy not yet measured

In the paper

“It has been shown that an UCOE can also prevent DNA methylation of the CMV promoter region, thus preventing gene expression silencing (Lindahl Allen and Antoniou, 2007;Zhang et al., 2010a).”

What the sources say

• Partly supported

  The Introduction reports that the HNRPA2B1-CBX3 UCOE negates DNA-methylation-mediated silencing of hCMV-promoter-driven transgenes in stably transfected tissue-culture cells. It does not specifically say that the UCOE prevents methylation of the CMV promoter region; the paper’s own methylation analysis concerns the HNRPA2B1-CBX3 locus, not that promoter. (LLM, conf=0.85)

  cites Lindahl Allen and Antoniou, 2007 sourceExperimental — accuracy not yet measured
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Zhang et al., 2010a

In the paper

“Cell cycle progression was also faster when using c-myc oncogene in CHO cells (Kuystermans and Al-Rubeai, 2009).”

What the sources say

• Supported

  The Results and Discussion (Cell Cycle) report a significantly shorter potential cell-cycle time in cMycCHO cells than in control CHO-K1 cells. They attribute the faster progression to a 36.4% shorter G1 phase and an earlier G1-to-S transition. (LLM, conf=0.94)

  cites Kuystermans and Al-Rubeai, 2009 source

In the paper

“They were discovered by a genomic screen of elements that would increase transgene expression.(Kwaks et al., 2003;Sautter and Enenkel, 2005;Hoeksema et al., 2011;Van Blokland et al., 2011;Harraghy et al., 2015).”

What the sources say

• ?Not checked — no full text of the sourcecites Kwaks et al., 2003 source
• ?Not checked — no full text of the sourcecites Sautter and Enenkel, 2005 source
• Supported

  The Discussion describes an earlier screen for STAR elements and says the search was based on the expectation that blocking gene repression would increase expression of a reporter gene. It distinguishes that earlier search from this paper’s screen, which identified Rb1 fragments rather than STAR elements. (LLM, conf=0.85)

  cites Hoeksema et al., 2011 source

In the paper

“It was also demonstrated that MAR and UCOE helped decrease the variability of expression between the different clones and contributed in maintaining an active transcriptional state for better transgene expression (Williams et al., 2005;Galbete et al., 2009;Harraghy et al., 2011).”

What the sources say

• Partly supported

  The Results and Discussion report that the CpG-island vectors increased the proportion of expressing clones, and the Conclusion says the findings are consistent with UCOEs maintaining a more open chromatin domain. But the paper does not demonstrate reduced expression variability between clones with the vectors studied; the Conclusion says they showed greater variability than the larger CpG-island construct used in earlier work. This paper studies UCOEs, not MARs. The indexed copy provides section labels but no page numbers. (LLM, conf=0.86)

  cites Williams et al., 2005 sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites Galbete et al., 2009 source
• ?Not checked — no full text of the sourcecites Harraghy et al., 2011 source

In the paper

“Cst-II, a bacterial sialyltransferase that can catalyze α2,8 sialylation, allows efficient polysialylation by the bacterial polysialyltransferase on recombinant alpha-1-antitrypsin in vitro and this results in a significantly longer half-life in mice, without affecting its specific activity (Lindhout et al., 2011).”

What the sources say

• Partly supported

  The Abstract describes Cst-II priming A1AT for in vitro polysialylation, and the Results report a longer terminal half-life in mice without adversely affecting its in vitro inhibitory activity. However, the Discussion says the A1AT used was derived from human plasma, not recombinant A1AT. (LLM, conf=0.90)

  cites Lindhout et al., 2011 sourceExperimental — accuracy not yet measured

In the paper

“Co-expression of the same enzymes in HEK293 also helped optimizing sialylation of human Fc-IVIg (intravenous immunoglobulin), therefore enhancing its therapeutic activity (Washburn et al., 2015).”

What the sources say

• Partly supported

  Materials and Methods says B4GalT1 and ST6Gal1 were produced by transient expression in HEK293 cells, but does not say they were co-expressed. The Results describe using the enzymes in an optimized sialylation reaction, and the Discussion reports enhanced anti-inflammatory activity of the resulting IVIg. The paper therefore supports the enzyme-based sialylation and activity, but not the claimed co-expression mechanism. (LLM, conf=0.88)

  cites Washburn et al., 2015 sourceExperimental — accuracy not yet measured

In the paper

“Others have tried to reduce the fucosyltransferase level using siRNA (Imai-Nishiya et al., 2007).”

What the sources say

• Supported

  The Results section, “Single gene knockdown of FUT8, GMD, and GFT in antibody-producing cells,” reports introducing an siRNA expression vector against FUT8, the α1,6-fucosyltransferase gene, into antibody-producing cells. It reports that target-gene mRNA fell by more than 90%, supporting the claim that researchers tried to reduce fucosyltransferase levels using siRNA. (LLM, conf=0.94)

  cites Imai-Nishiya et al., 2007 source

In the paper

“A bottleneck at the malate dehydrogenase II (MDHII) level was characterized for the tricarboxylic acid (TCA) cycle in CHO cells and pyruvate metabolism was shown to vary between high producing and low producing anti-CD20 CHO clones (Chong et al., 2010;Ghorbaniaghdam et al., 2014).”

What the sources say

• ?Not checked — no full text of the sourcecites Chong et al., 2010 source
• Partly supported

  The Materials and Methods section identifies the high- and low-producing clones as producers of anti-CD20 antibody. The Discussion reports different pyruvate dehydrogenase and pyruvate carboxylase fluxes between those clones, supporting the pyruvate-metabolism part of the sentence. The passages from this paper do not characterize a TCA-cycle bottleneck at MDHII. (LLM, conf=0.88)

  cites Ghorbaniaghdam et al., 2014 sourceExperimental — accuracy not yet measured

In the paper

“A first large-scale proteomic analysis identified 6164 proteins from both the proteome and glycoproteome of CHO-K1 cells (Baycin-Hizal et al., 2012).”

What the sources say

• Supported

  The Experimental Procedures identify CHO-K1 as the cell line used for proteomic analysis. The Conclusion reports 6,164 proteins identified when the proteomic and glycoproteomic analyses were combined, and the Discussion describes the study as a first large-scale high-throughput proteomics study using the CHO genome. Page numbers are unavailable in our copy. (LLM, conf=0.93)

  cites Baycin-Hizal et al., 2012 source

In the paper

“Also, as discussed earlier, inhibition of the mmu-miR-466 h microRNA was shown to increase apoptosis resistance of these cells (Druz et al., 2011;Druz et al., 2013).”

What the sources say

• Supported

  The Discussion reports that inhibiting mmu-miR-466h in CHO cells exposed to nutrient-depleted media decreased caspase-3/7 activity and increased cell viability relative to controls. This supports increased resistance to apoptosis, although the inhibition did not prevent apoptosis entirely. (LLM, conf=0.92)

  cites Druz et al., 2011 source
• Supported

  The Results section reports that inhibiting mmu-miR-466h-5p in CHO cells delayed Caspase-3/7 activation and the onset of the apoptotic cascade. The Discussion also links the inhibition to extended cell viability under apoptotic conditions. Page numbers are not provided in our copy. (LLM, conf=0.93)

  cites Druz et al., 2013 source

In the paper

“Besides, in vitro galactosylation and sialylation of IgG1 Fc glycans did not show any impact on ADCC activity but showed a slight improvement of binding to FcγRIIa (Thomann et al., 2015).”

What the sources say

• Partly supported

  The Summary of results (Table 2) reports that increased sialylation had no impact on ADCC and that both galactosylation and sialylation increased FcγRIIa binding (slightly in the column assay). But it reports that increased galactosylation increased ADCC activity, contrary to the claim that neither modification affected ADCC. (LLM, conf=0.92)

  cites Thomann et al., 2015 sourceExperimental — accuracy not yet measured

In the paper

“Using this expression system for transient anti-CD-20 production, recombinant proteins had very short sialylated N-glycans with high homogeneity on the Fc domain and reduced affinity to FcγRs compared to proteins expressed in wild-type 293S.”

What the sources say

• Partly supported

  Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  cites Meuris et al., 2014 sourceExperimental — accuracy not yet measured

In the paper

“It is involved in the production of over 70% of recombinant biopharmaceutical proteins, most of them being monoclonal antibodies (mAbs) (Durocher and Butler, 2009;Kim et al., 2012;Butler and Spearman, 2014).”

What the sources say

• ?Not checked — no full text of the sourcecites Durocher and Butler, 2009 source
• ?Not checked — no full text of the sourcecites Kim et al., 2012 source
• ?Not checked — no full text of the sourcecites Butler and Spearman, 2014 source

In the paper

“A significant portion of these products are recombinant proteins, with an ongoing increase in the number of them produced in mammalian expression platforms (Walsh, 2014).”

What the sources say

• ?Not checked — no full text of the sourcecites Walsh, 2014 source

In the paper

“Furthermore, these cells are refractory to infection by human viruses, which minimizes biosafety risks for commercial production purpose (Boeger et al., 2005).”

What the sources say

• ?Not checked — no full text of the sourcecites Boeger et al., 2005 source

In the paper

“One way to favor human-like glycosylation would be to use human cell lines for recombinant protein production.This strategy would warrant that proteins harbor, if not the ideal glycosylation pattern, at least a non-immunogenic glycans (Swiech et al., 2012).”

What the sources say

• ?Not checked — no full text of the sourcecites Swiech et al., 2012 source

In the paper

“This technology had good success in increasing the success rate and reducing timelines for the generation of stable industrial-grade CHO cell lines stably expressing monoclonal antibodies (Kito et al., 2002;Huang et al., 2007;Zhang et al., 2015).”

What the sources say

• ?Not checked — no full text of the sourcecites Kito et al., 2002 source
• ?Not checked — no full text of the sourcecites Huang et al., 2007 source
• ?Not checked — no full text of the sourcecites Zhang et al., 2015 source

In the paper

“These large glycoproteins are abundantly glycosylated and sulfated and are thus challenging to manufacture (Soukharev et al., 2002;Ishaque et al., 2007;Nivitchanyong et al., 2007).”

What the sources say

• ?Not checked — no full text of the sourcecites Soukharev et al., 2002 source
• ?Not checked — no full text of the sourcecites Ishaque et al., 2007 source
• ?Not checked — no full text of the sourcecites Nivitchanyong et al., 2007 source

In the paper

“This technique has already been validated in CHO cells and reduces the production variability between clones (Lee et al., 2015b).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Lee et al., 2015b

In the paper

“However, conflicting results in the literature have led to the conclusion that MAR activity could be sequence-specific and is influenced by specific vector configuration (Harraghy et al., 2015).”

What the sources say

• ?Not checked — no full text of the sourcecites Harraghy et al., 2015 source

In the paper

“Yet, it is ideal for high throughput screening for hits identification and very helpful for early stage product characterization (Ozturk and Hu, 2005;Rosser et al., 2005;Rita Costa et al., 2010).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Ozturk and Hu, 2005
• ?Not checked — no full text of the sourcecites Rosser et al., 2005 source
• ?Not checked — no full text of the sourcecites Rita Costa et al., 2010 source

In the paper

“Other selection systems have been developed more recently, such as the OSCAR™ system from the University of Edinburgh, that uses minigene vectors encoding the hypoxanthine phosphoribosyltransferase (HPRT), essential for purine synthesis (Melton et al., 2001;Costa et al., 2012).”

What the sources say

• ?Not checked — no full text of the sourcecites Melton et al., 2001 source
• ?Not checked — no full text of the sourcecites Costa et al., 2012 source

In the paper

“Baby Hamster Kidney (BHK) cells are mostly been used for the production of vaccines (Durocher and Butler, 2009).”

What the sources say

• ?Not checked — no full text of the sourcecites Durocher and Butler, 2009 source

In the paper

“However, these cells produce glycoproteins with high-mannose glycans structures, which may be immunogenic and less potent in humans (Dean, 1999;Gemmill and Trimble, 1999;Gerngross, 2004;Dumont et al., 2015).”

What the sources say

• ?Not checked — no full text of the sourcecites Dean, 1999 source
• ?Not checked — no full text of the sourcecites Gemmill and Trimble, 1999 source
• ?Not checked — no full text of the sourcecites Gerngross, 2004 source

In the paper

“Indeed, during transient transfection, the plasmid DNA is mostly kept extrachromosomally, the cells rapidly losing it during division, therefore limiting the amount of expressed proteins.”

In the paper

“Epoeitin delta produced in HT-1080 was found to have better homogeneity of its tetra-antennary glycans, higher sialic acid content and no Neu5Gc, compared to CHO-produced erythropoietin (Llop et al., 2008).”

What the sources say

• ?Not checked — no full text of the sourcecites Llop et al., 2008 source

In the paper

“This approach could eventually help biopharmaceutical companies minimize the randomness of gene insertion and increase the predictability for high transgene expression (Estes and Melville, 2014).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Estes and Melville, 2014

In the paper

“One should also keep in mind that such specific integration may not be a one-size-fits-all approach as some therapeutic proteins may require a particular level of expression to fold properly, or to acquire adequate quality attributes (e.g.glycosylation, proteolytic processing, etc.)”

In the paper

“It has recently showed high-level protein production and α2,3 and α2,6-sialic acid linkages (Picanco-Castro et al., 2013).”

What the sources say

• ?Not checked — no full text of the sourcecites Picanco-Castro et al., 2013 source

In the paper

“ZFN, TALEN and CRISPR/Cas9 technologies are however mostly used for gene-specific knockout.”

In the paper

“Although tremendous efforts are required to isolate a highly productive and stable recombination host cell line compared to random integration strategies, it remains a very attractive avenue that should help control and predict the expression level of the daughter clones (Estes and Melville, 2014).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Estes and Melville, 2014

In the paper

“When it comes to production of glycoproteins in large quantities, stable gene expression systems remain the preferred avenue.”

In the paper

“As first generation tools, several recombinases have been used for targeted site approaches, among which the Cre/Lox and the Flp/FRT were mostly utilized (Kito et al., 2002;Huang et al., 2007;Kim et al., 2012).”

What the sources say

• ?Not checked — no full text of the sourcecites Kito et al., 2002 source
• ?Not checked — no full text of the sourcecites Huang et al., 2007 source
• ?Not checked — no full text of the sourcecites Kim et al., 2012 source

In the paper

“Since then, some FUT8 knock-out CHO cell lines have been established and one is currently available on the market for glycoprotein productions.”

In the paper

“To explain such discrepancies between studies, it was recently determined that CHOK1 hosts have larger endoplasmic reticulum and higher mitochondrial mass compared to DUXB11-derived CHO cells (Hu et al., 2013).”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Hu et al., 2013

In the paper

“The first FUT8 -/-cell line was created by sequential homologous recombination (Yamane-Ohnuki et al., 2004).”

What the sources say

• ?Not checked — no full text of the sourcecites Yamane-Ohnuki et al., 2004 source

In the paper

“For example, yeasts and insect cells can produce high-mannose or paucimannose oligosaccharides, while plant cells introduce undesirable α1,3-fucose and β1,2-xylose.”

In the paper

“However, both Neu5Gc and α-gal levels are significantly higher in murine cells such as NS0 and Sp2/0, compared to hamster cells.”

In the paper

“Although the effects on cell longevity are clear in these studies, many conflicting results regarding enhanced productivity with anti-apoptosis engineering have been reported (Kim et al., 2012).”

What the sources say

• ?Not checked — no full text of the sourcecites Kim et al., 2012 source

In the paper

“For example, the E2F-1 cell cycle transcription factor overexpression contributes to increase viable cell density in CHO batch cultures (Majors et al., 2008).”

What the sources say

• ?Not checked — no full text of the sourcecites Majors et al., 2008 source

In the paper

“This shift toward protein production favors sustained nutrient availability and reduced secondary metabolite accumulation.”

In the paper

“It has been suggested that translational and/or post-translational processes might also be rate-limiting for protein production, because of the lack of correlation between gene copy number and the amount of secreted proteins (Wilson et al., 1990;Mohan et al., 2008).”

What the sources say

• ?Not checked — no full text of the sourcecites Wilson et al., 1990 source
• ?Not checked — no full text of the sourcecites Mohan et al., 2008 source

In the paper

“All strategies resulted in increased protein production.”

In the paper

“Moreover, combining these inhibitors with mild hypothermia (30-32 °C) during production phase or with antiapoptosis cell engineering could also increase productivity (Kim and Lee, 2000;Kim and Lee, 2002;Sung et al., 2007;Kim et al., 2009a;Chen et al., 2011).”

What the sources say

• ?Not checked — no full text of the sourcecites Kim and Lee, 2000 source
• ?Not checked — no full text of the sourcecites Kim and Lee, 2002 source
• ?Not checked — no full text of the sourcecites Sung et al., 2007 source

In the paper

“ATF4, another critical transcription factor in the UPR system, has been overexpressed to restore translation and enhance levels of anti-thrombin III produced in CHO cells (Ohya et al., 2008).”

What the sources say

• ?Not checked — no full text of the sourcecites Ohya et al., 2008 source

In the paper

“Furthermore, overexpression of the mir-17 microRNA in CHO was shown to augment cell proliferation speed, leading to higher Epo-Fc yield (Jadhav et al., 2012).”

What the sources say

• ?Not checked — no full text of the sourcecites Jadhav et al., 2012 source

In the paper

“Moreover, as opposed to human cells, CHO and BHK cells do not express any α2,6-sialyltransferase activity and can generate glycans with terminal Neu5Gc and α-gal.”

In the paper

“As early strategies, CHO Lec13 cells and rat hybridoma YB2/0 cells were employed, the former for its impaired synthesis of GDP-fucose and the latter for its reduced expression level of the fucosyltransferase FUT8 (Durocher and Butler, 2009).”

What the sources say

• ?Not checked — no full text of the sourcecites Durocher and Butler, 2009 source

In the paper

“This reduced affinity might be required to increase safety, for example in the context of neutralizing antibodies used for inflammatory cytokine targeting (Lux et al., 2013).”

What the sources say

• ?Not checked — no full text of the sourcecites Lux et al., 2013 source

In the paper

“Besides, glycoengineering strategies have been developed to reduce fucosylation or increase sialylation of biologics.”

In the paper

“The tobacco plant Nicotiana benthamiana expression system was genetically modified to carry the human-type sialylation pathway and to generate mono-and disialylated structures with α2,3 and α2,6 linkage (Kallolimath et al., 2016).”

What the sources say

• ?Not checked — no full text of the sourcecites Kallolimath et al., 2016 source

In the paper

“In an effort to characterize the contributions of the various glycosylation enzymes in CHO-K1 cells, knockouts of 19 glycosyltransferase genes were recently achieved and EPO glycosylation was characterized to measure their impact (Yang et al., 2015).”

What the sources say

• ?Not checked — no full text of the sourcecites Yang et al., 2015 source

In the paper

“Since expression of the β1,4-mannosyl-glycoprotein 4-β-N-acetylglucosaminyltransferase III (GnTIII) blocks fucosylation, CHO cells were engineered with both GnTIII and Golgi mannosidase II (ManII) for IgG production (Davies et al., 2001;Ferrara et al., 2006).”

What the sources say

• ?Not checked — no full text of the sourcecites Davies et al., 2001 source
• ?Not checked — no full text of the sourcecites Ferrara et al., 2006 source

In the paper

“The biopharmaceutical industry has entered the “omics” era, where systems biology is a central concept (Kildegaard et al., 2013).”

What the sources say

• ?Not checked — no full text of the sourcecites Kildegaard et al., 2013 source

In the paper

“The mammalian genomes possess 4 sialidase genes or pseudogenes (depending on the specie) which are expressed in various cellular compartments (Warner et al., 1993;Ferrari et al., 1994;Zhang et al., 2010b).”

What the sources say

• ?Not checked — no full text of the sourcecites Warner et al., 1993 source
• ?Not checked — no full text of the sourcecites Ferrari et al., 1994 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Zhang et al., 2010b

In the paper

“Therefore, it has become attractive for the industry to produce proteins with optimal sialylation as it could generate substantial savings and confer a therapeutical advantage for the patients.”

In the paper

“Consequently, the anti-CS1 antibody produced with these cells is afucosylated and has enhanced in vitro ADCC activity and in vivo anti-tumor activity compared to the same antibody produced in HEK293 cells (Gomathinayagam et al., 2015).”

What the sources say

• ?Not checked — no full text of the sourcecites Gomathinayagam et al., 2015 source

In the paper

“Using iTRAQ, MCM2 and MCM5 helicases were identified as cell growth markers in CHO cells (Carlage et al., 2012).”

What the sources say

• ?Not checked — no full text of the sourcecites Carlage et al., 2012 source

In the paper

“Besides, chaperones BiP and PDI were differentially expressed in stationary compared to exponential phase in CHO cells overexpressing Bcl-xl (Carlage et al., 2012).”

What the sources say

• ?Not checked — no full text of the sourcecites Carlage et al., 2012 source