Effects of Cellular Apoptosis on Productivity of a Mammalian Cell Culture Process

Cote, Shelly A.

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Effects of Cellular Apoptosis on Productivity of a Mammalian Cell Culture Process

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Apoptosis, programmed cell death, is a hot topic in recent research due to the potential applications to various areas by regulating its pathway. In industrial large scale animal cell culture processes, research on how to regulate or predict the apoptotic pathway and understanding what signals the apoptotic cascade has lead to a new opportunity to enhance process robustness, improve final performance including productivity, and eventually, reduce production costs. Current industrial cell culture processes normally involve a high cell density process in a large-scale bioreactor as a suspension culture that proliferates the cells beyond their optimal growth conditions. Under these conditions, apoptosis will be triggered, and consequently, cell viability will be decreased, and the chance for product degradation by the release of intracellular proteases and glycosidases will increase. Therefore, characterizing which culture conditions will induce apoptosis during a particular cell culture process can be a valuable tool to optimize cell viability and possibly productivity. Since the conventional method for cell count and viability measurement does not differentiate the cells in early to mid-stage apoptosis from the normal cells, it would be difficult to understand the effect of early stage apoptosis. This study elucidates the correlation between the culture conditions and apoptosis during a mammalian cell culture process and its effects on the productivity using real-time apoptotic assays for accurate cellular growth and death profiles. Apoptosis induced by low pH, glucose and glutamine limitation, lactate toxicity and Camptothecin has been shown to significantly increase the yield and specific productivity most likely due to release of product during secondary necrosis at the culmination of the apoptosis pathway.

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