Heat shock protein 27 overexpression in CHO cells modulates apoptosis pathways and delays activation of caspases to improve recombinant monoclonal antibody titre in fed-batch bioreactors.
CHO cells are major production hosts for recombinant biologics including the rapidly expanding recombinant monoclonal antibodies (mAbs). Heat shock protein 27 (HSP27) expression was observed to be down-regulated towards the late-exponential and stationary phase of CHO fed-batch bioreactor cultures, whereas HSP27 was found to be highly expressed in human pathological cells and reported to have anti-apoptotic functions. These phenotypes suggest that overexpression of HSP27 is a potential cell line engineering strategy for improving robustness of CHO cells. In this work, HSP27 was stably overexpressed in CHO cells producing recombinant mAb and the effects of HSP27 on cell growth, volumetric production titer and product quality were assessed. Concomitantly, HSP27 anti-apoptosis functions in CHO cells were investigated. Stably transfected clones cultured in fed-batch bioreactors displayed 2.2-fold higher peak viable cell density, delayed loss of culture viability by two days and 2.3-fold increase in mAb titer without affecting the N-glycosylation profile, as compared to clones stably transfected with the vector backbone. Co-immunoprecipitation studies revealed HSP27 interactions with Akt, pro-caspase 3 and Daxx and caspase activity profiling showed delayed increase in caspase 2, 3, 8 and 9 activities. These results suggest that HSP27 modulates apoptosis signaling pathways and delays caspase activities to improve performance of CHO fed-batch bioreactor cultures.
Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Janice G L
JG
Tan
Yih Yean
YY
Lee
Tianhua
T
Wang
Miranda G S
MG
Yap
Tin Wee
TW
Tan
Say Kong
SK
Ng
D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis*; D017209:Apoptosis; D061249:Batch Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D016466:CHO Cells; D020169:Caspases / Q000378:metabolism*; D049109:Cell Proliferation; D002470:Cell Survival; D003412:Cricetulus; D055551:HSP27 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D011994:Recombinant Proteins / Q000096:biosynthesis
D000911:Antibodies, Monoclonal; D055551:HSP27 Heat-Shock Proteins; D011994:Recombinant Proteins; D020169:Caspases
Apoptosis; Chinese hamster ovary (CHO); Fed-batch bioreactor; Heat shock protein 27 (HSP27); Monoclonal antibody production