Effect of BCL-2 Expression on Hybridoma Cell Growth During Stressful Conditions

Dose-dependent reduction of apoptosis in nutrient-limited cultures of NS/0 myeloma cells transfected with the E1B-19K adenoviral gene

“…Therefore, the improved viability obtained by engineering of NS/0 cells with E1B-19K did not allow for a significant improvement in terms of antibody productivity in batch cultures. This is in agreement with what was recently published by Fassnacht et al (1998) for TB/C3 hybridomas engineered with Bcl-2. One explanation for that result is that the exhaustion of glutamine or other limiting nutrients usually associated with the onset of the plateau phase may impair the protein synthesis machinery by limiting the availability of some essential amino acids (Mercille and Massie, 1994a).…”

“…Beneficial effects of Bcl-2 expression have been observed in a NS/0 mouse myeloma cell line (Ray and Diamond, 1994) and in an IL-6-dependent mouse myeloma cell line (Schwarze and Hawley, 1995). While a number of studies have reported that constitutive overexpression of Bcl-2 could be effective in delaying the onset of apoptosis in batch cultures of commercially important cell lines such as hybridomas (Fassnacht et al, 1998;Itoh et al, 1995;Simpson et al, 1997;Singh et al 1996), others have found that Bcl-2 had no effect on the viability of myeloma cells (Murray et al, 1996). As observed recently with other anti-apoptotic genes such as hsp70 (Mosser et al, 1997a), threshold levels of expression may be required in order to generate a measurable phenotype.…”

“…Moreover, it still remains unclear whether over-expression of Bcl-2 will result in improved productivity in batch cultures of production cell lines. Indeed, whereas Simpson et al (1997) reported a 40% improvement in MAb productivity in batch culture of TB/C3 hybridomas expressing Bcl-2, other researchers using the same clone in similar culture conditions have found no significant differences between resistant and control cell lines (Fassnacht et al, 1998).…”

Influence of Bcl-2 on cell death during the cultivation of a Chinese hamster ovary cell line expressing a chimeric antibody

“…One of the main targets for this type of research has been the bcl-2 gene, which is the best characterized of a rapidly growing list of apoptosis regulatory genes. Cell lines studied thus far in this respect include Burkitt's Lymphoma cells (Singh et al, 1996), insect cells (Alnemri et al, 1992;Mitchell-Logean and Murhammer, 1997) and hybridoma cell lines (Itoh et al, 1995;Simpson et al, 1997Simpson et al, , 1998Fassnacht et al, 1998Fassnacht et al, , 1999Terada, 1997). In all cases, cellular robustness was substantially enhanced and protein productivity increased between 40% and several-fold above that seen in control cell lines.…”

Apoptosis-resistant NS/0 E1B-19K myelomas exhibit increased viability and chimeric antibody productivity under cell cycle modulating conditions

“…Genes such as Bcl-2 (Fassnacht et al, 1998;Itoh et al, 1995;Murray et al, 1996;Singh et al, 1996), Bcl-2 in combination with Bag-1 (Terada et al, 1997) and adenoviral E1B-19K (Mercille et al, submitted) have been tested into production cell lines. While some researchers have observed that Bcl-2 overexpression could result in improved MAb productivity in batch culture (Simpson et al, 1997;Suzuki et al, 1997), others have found no effect (Fassnacht et al, 1998). In a previous study, we found that the dose-dependent enhancement of viability conferred by E1B-19K in batch cultures of NS/0 cells did not lead to significant antibody productivity throughout the prolonged stationary phase (Mercille et al, submitted).…”