title: Bcl-x(L) overexpression delays the onset of autophagy and apoptosis in hyperosmotic recombinant Chinese hamster ovary cell cultures.
abstract: Hyperosmolality in recombinant Chinese hamster ovary (rCHO) cell cultures induces autophagy and apoptosis. To investigate the effect of Bcl-x(L) overexpression on autophagy and apoptosis in hyperosmotic rCHO cell cultures, an erythropoietin (EPO)-producing rCHO cell line with regulated Bcl-x(L) overexpression was subjected to hyperosmolality resulting from NaCl addition in a batch culture and nutrient supplementation in a fed-batch culture. In the batch culture, Bcl-x(L) overexpression suppressed apoptosis, as evidenced by a decreased amount of cleaved caspase-7 and PARP. Concurrently, Bcl-x(L) overexpression also delayed autophagy, as indicated by reduced LC3 conversion, from LC3-I to LC3-II. As a result, the cell viability and EPO production were improved by Bcl-x(L) overexpression. In the fed-batch culture, the simultaneous application of Bcl-x(L) overexpression and nutrient feeding increased the culture longevity and maximum EPO concentration. Taken together, Bcl-x(L) overexpression delayed autophagy and apoptosis in hyperosmotic rCHO cell cultures, resulting in increased EPO production.
authors.affiliation: Department of Biological Sciences, Graduate School of Nanoscience & Technology, KAIST, 373-1 Kusong-Dong, Yusong-gu, Daejon 305-701, Republic of Korea.
authors.forename: Young Kue
authors.initials: YK
authors.lastname: Han
authors.forename: Tae Kwang
authors.initials: TK
authors.lastname: Ha
authors.forename: Yeon-Gu
authors.initials: YG
authors.lastname: Kim
authors.forename: Gyun Min
authors.initials: GM
authors.lastname: Lee
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001343:Autophagy / Q000502:physiology*; D061249:Batch Cell Culture Techniques / Q000379:methods*; D001709:Biotechnology; D015153:Blotting, Western; D016466:CHO Cells; D048708:Cell Growth Processes / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D006224:Cricetinae; D003412:Cricetulus; D004318:Doxycycline / Q000494:pharmacology; D004921:Erythropoietin / Q000032:analysis / Q000378:metabolism; D009994:Osmolar Concentration; D011994:Recombinant Proteins / Q000032:analysis / Q000378:metabolism; D051020:bcl-X Protein / Q000096:biosynthesis*
chemical_list: D011994:Recombinant Proteins; D051020:bcl-X Protein; D004921:Erythropoietin; D004318:Doxycycline