PMID- 22367610
OWN - NLM
STAT- MEDLINE
DCOM- 20120905
LR  - 20120516
IS  - 1432-0614 (Electronic)
IS  - 0175-7598 (Linking)
VI  - 94
IP  - 5
DP  - 2012 Jun
TI  - Understanding the mechanistic roles of 30Kc6 gene in apoptosis and specific 
      productivity in antibody-producing Chinese hamster ovary cells.
PG  - 1243-53
LID - 10.1007/s00253-012-3899-1 [doi]
AB  - Previously, we reported that the expression of Bombyx mori 30Kc6 gene in Chinese 
      hamster ovary (CHO) cells increases recombinant protein production by both 
      inhibiting apoptosis and enhancing specific productivity. In this study, in order 
      to gain a thorough understanding of the roles of 30Kc6 gene in antibody 
      production, the mechanisms modulating cell apoptosis and specific productivity 
      were investigated. 30Kc6 gene was introduced into a CHO cell line producing a 
      chimeric anti-human CD20 monoclonal antibody. The stable expression of 30Kc6 
      increased cell viability and productivity by 46.7% and 3.4-folds, respectively. 
      It was observed that the Bax translocation from cytosol to mitochondria and the 
      cytochrome c (cyt c) release from mitochondrial intermembrane space to cytosol 
      were repressed, which resulted in a decrease in the activation of apoptosis 
      executioner, caspase-3. On the other hand, 30Kc6 expression increased the 
      specific productivity by 2.3-folds. However, at the transcription level, the 
      relative levels of heavy and light chain mRNAs increased only by 8.3% and 8.7%, 
      respectively, which was not accountable for the observed increment in the 
      specific productivity. Instead, the mitochondrial membrane potential was 
      maintained and the ATP generation was stimulated. A higher ATP level could 
      activate the mammalian target of rapamycin (mTOR), which drives the translation 
      initiation and elongation by phosphorylating eukaryotic initiation factor 4E 
      binding protein 1 (4EBP1) and S6 kinase 1 (S6K1). In the 30Kc6-expressing cells, 
      both the 4EBP1 and S6K1 were phosphorylated at higher levels, which indicated 
      that the increased specific productivity primarily resulted from the boost of 
      translation process. Furthermore, it was also found that the specific uptake 
      rates of glucose and glutamine were not affected by 30Kc6 expression, 
      demonstrating that the enhanced ATP generation and consequently maintained mTOR 
      activity were due to 30Kc6 expression but not the different metabolic uptake 
      rates. In conclusion, 30Kc6 expression inhibited apoptosis by repressing the Bax 
      translocation, which down-regulated the downstream cascade responses including 
      cyt c release and caspase-3 activation. Also, 30Kc6 expression increased the 
      specific productivity by enhancing the translation process.
FAU - Wang, Zesong
AU  - Wang Z
AD  - State Key Laboratory of Bioreactor Engineering, East China University of Science 
      and Technology, Shanghai, China.
FAU - Ma, Xuhui
AU  - Ma X
FAU - Fan, Li
AU  - Fan L
FAU - Rhee, Won Jong
AU  - Rhee WJ
FAU - Park, Tai Hyun
AU  - Park TH
FAU - Zhao, Liang
AU  - Zhao L
FAU - Tan, Wen-Song
AU  - Tan WS
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20120226
PL  - Germany
TA  - Appl Microbiol Biotechnol
JT  - Applied microbiology and biotechnology
JID - 8406612
RN  - 0 (30Kc6 protein, Bombyx mori)
RN  - 0 (Antibodies, Monoclonal)
RN  - 0 (Inhibitor of Apoptosis Proteins)
RN  - 0 (Insect Proteins)
RN  - 0 (Recombinant Proteins)
RN  - 0 (bcl-2-Associated X Protein)
RN  - 9007-43-6 (Cytochromes c)
SB  - IM
MH  - Animals
MH  - Antibodies, Monoclonal/*biosynthesis
MH  - *Apoptosis
MH  - Bombyx
MH  - CHO Cells
MH  - Cell Survival
MH  - Cricetinae
MH  - Cricetulus
MH  - Cytochromes c/antagonists & inhibitors
MH  - Humans
MH  - Inhibitor of Apoptosis Proteins/genetics/*metabolism
MH  - Insect Proteins/genetics/*metabolism
MH  - Protein Biosynthesis
MH  - Recombinant Proteins/biosynthesis
MH  - bcl-2-Associated X Protein/antagonists & inhibitors
EDAT- 2012/03/01 06:00
MHDA- 2012/09/06 06:00
CRDT- 2012/02/28 06:00
PHST- 2011/10/02 00:00 [received]
PHST- 2012/01/10 00:00 [accepted]
PHST- 2012/01/06 00:00 [revised]
PHST- 2012/02/28 06:00 [entrez]
PHST- 2012/03/01 06:00 [pubmed]
PHST- 2012/09/06 06:00 [medline]
AID - 10.1007/s00253-012-3899-1 [doi]
PST - ppublish
SO  - Appl Microbiol Biotechnol. 2012 Jun;94(5):1243-53. doi: 
      10.1007/s00253-012-3899-1. Epub 2012 Feb 26.