The X-link inhibitor of apoptosis protein (XIAP) enhances the survivability of C2E7 hybridoma cells under a serum deprived condition

Abstract

Hybridoma C2E7 Cell cultured in a serum deprived condition was only survived not longer than 5 days in a batch culture, whereas for the culture supplemented with 10% of serum showed a far superior proliferation and survivability. The serum supplemented culture was able to survive for more than 9 days in a batch culture and recorded a 6.6 fold increase in maximum cell density. After 5 days of batch culture, the viability of the control culture still more than 50% viable, while for the serum deprived culture the viability of the cells dropped to 17%. The mechanism of the cell death is predominantly via apoptosis which is shown in a classical ladder type pattern on a DNA gel and florescence microscopic analysis. The caspases are the most important apoptotic executors which are responsible for the activation and deactivation of other cellular proteins involved in the apoptotic process or directly involved in cell dismantling. In the cytosol, the activation of caspases can be regulated by another protein called inhibitor of apoptosis protein (IAP). In order to investigate the influence of the XIAP on the apoptosis induced by serum deprivation, we have transfected the hybridoma C2E7 cells with XIAP gene. In a culture without any serum supplementation, the XIAP cell was able to maintain greater than 75% viability for over 4 days, while the viability of control cells decreased to below 6%. No further,increment was observed in the total cell number for the control cell under serum free conditions, while the XIAP cell recorded a 13% increase in total cell number. This result shows that the XIAP cell is still able to proliferate without the presence of any serum components.