Inhibition of HeLa Cell apoptosis by storage-protein 2.
Apoptosis is a barrier to maintaining high viable cell densities in animal cell culture. Silkworm hemolymph and its 30K protein have been reported to exhibit anti-apoptotic activity in various mammalian and insect cell systems. The 30K protein is thermally unstable at temperatures higher than 60 degrees C; however, the silkworm hemolymph heat-treated at 70-80 degrees C still exhibited anti-apoptotic activity. This indicates that silkworm hemolymph contains another anti-apoptotic compound other than 30K protein. In this article, the anti-apoptotic molecule other than 30K protein was found from the silkworm hemolymph and identified. This molecule was storage-protein 2 (SP2), which has no homology with any known anti-apoptotic protein. This molecule was heat-stable up to 80 degrees C, while 30K protein lost its activity at temperatures higher than 60 degrees C. When apoptosis was induced by staurosporine in HeLa cells, SP2 protein suppressed nuclear fragmentation and apoptotic body formation. Moreover, the generation of reactive oxygen species after apoptosis induction was inhibited, which means the inhibition occurred in an early step of the apoptotic process. Inhibition of apoptosis by the SP2 protein would lead to the minimization of cell death during commercial mammalian cell culture.
Rhee
Won Jong
WJ
School of Chemical and Biological Engineering, Seoul National University, Gwanak-Gu Sillim-Dong San 56-1, Seoul 151-744, Korea.
Lee
Eun Hee
EH
Park
Ju Hyun
JH
Lee
Ji Eun
JE
Park
Tai Hyun
TH
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D012831:Bombyx; D002852:Chromatography, Ion Exchange; D006367:HeLa Cells; D006458:Hemolymph / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D019476:Insect Proteins / Q000494:pharmacology*; D008969:Molecular Sequence Data; D014462:Ultrafiltration
D019476:Insect Proteins; C041137:storage proteins, Insecta