title: Effect of Bcl-xL overexpression on apoptosis and autophagy in recombinant Chinese hamster ovary cells under nutrient-deprived condition.
abstract: Upon nutrient deprivation during culture, recombinant Chinese hamster ovary (rCHO) cells are subjected to two types of programmed cell death (PCD), apoptosis and autophagy. To investigate the effect of Bcl-x(L) overexpression on apoptosis and autophagy in rCHO cells, an erythropoietin (EPO)-producing rCHO cell line with regulated Bcl-x(L) overexpression (EPO-off-Bcl-x(L)) was established using the Tet-off system. The expression level of Bcl-x(L) in EPO-off-Bcl-x(L) cells was tightly regulated by doxycycline in a dose-dependent manner. Bcl-x(L) overexpression enhanced cell viability and extended culture longevity in batch culture. Upon nutrient depletion in the later stage of batch culture, Bcl-x(L) overexpression suppressed apoptosis by inhibiting the activation of caspase-3 and -7. Simultaneously, Bcl-x(L) overexpression also delayed autophagy, characterized by LC3-II accumulation. Immunoprecipitation analysis with a Flag-tagged Bcl-x(L) revealed that Bcl-x(L) interacts with Bax and Bak, essential mediators of caspase-dependent apoptosis, as well as with Beclin-1, an essential mediator of autophagy, and may inhibit their pro-cell death function. Taken together, it was found that Bcl-x(L) overexpression inhibits both apoptosis and autophagy in rCHO cell culture.
authors.affiliation: Department of Biological Sciences, KAIST, 373-1 Kusong-Dong, Yusong-Gu, Daejon, Korea.
authors.forename: Yeon-Gu
authors.initials: YG
authors.lastname: Kim
authors.forename: Jee Yon
authors.initials: JY
authors.lastname: Kim
authors.forename: Chaya
authors.initials: C
authors.lastname: Mohan
authors.forename: Gyun Min
authors.initials: GM
authors.lastname: Lee
mesh_terms: D000818:Animals; D017209:Apoptosis; D001343:Autophagy; D016466:CHO Cells; D018929:Cell Culture Techniques; D006224:Cricetinae; D003412:Cricetulus; D003470:Culture Media / Q000737:chemistry*; D005786:Gene Expression Regulation; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D003470:Culture Media; D051028:bcl-2-Associated X Protein