Ifandi Vasiliki, Al-Rubeai Mohamed
Department of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
Biotechnol Prog. 2005 May-Jun;21(3):671-7. doi: 10.1021/bp049594q.
Proliferation and cell death are regarded as key targets for the optimization of animal cell culture processes and for the maximization of product yield. Although chemical and physical factors are vitally important, of primary interest is the utilization of genetic engineering to regulate cellular processes. CHO cells were first genetically modified to enhance proliferation rate in both suspension and monolayer cultures. Under the constitutive control of c-myc overexpression the CHO cultures showed an increase in growth rate and maximum cell number accompanied by a similar decrease in specific glucose consumption rate. Although the c-myc transfected cell line exhibited apoptosis at much lower rates than is widely reported and associated with the overexpression of c-Myc, it was nevertheless apparent that c-Myc was responsible for the induction of higher apoptotic rates when compared with the control cell line. Hence, the anti-apoptotic gene bcl-2 was also used to transfect the c-Myc CHO cell line, to reduce cell death. Overexpression of both oncoproteins resulted in a cell line that exhibited higher proliferation rates and maximum cell numbers, with a decrease in apoptosis when compared to the parental cell line. In conclusion, it was shown that Bcl-2 protein overexpression specifically abrogates c-Myc-induced apoptosis without affecting the c-Myc mitogenic function.
增殖和细胞死亡被视为优化动物细胞培养过程以及最大化产物产量的关键靶点。尽管化学和物理因素至关重要，但首要关注的是利用基因工程来调控细胞过程。CHO细胞首次经过基因改造，以提高其在悬浮培养和单层培养中的增殖速率。在c-myc过表达的组成型控制下，CHO培养物的生长速率和最大细胞数增加，同时比葡萄糖消耗速率出现类似程度的降低。尽管c-myc转染的细胞系凋亡率比广泛报道的与c-Myc过表达相关的凋亡率低得多，但与对照细胞系相比，c-Myc显然仍会导致更高的凋亡率。因此，抗凋亡基因bcl-2也被用于转染c-Myc CHO细胞系，以减少细胞死亡。两种癌蛋白的过表达产生了一个细胞系，该细胞系与亲代细胞系相比，表现出更高的增殖速率和最大细胞数，且凋亡减少。总之，研究表明Bcl-2蛋白过表达可特异性消除c-Myc诱导的凋亡，而不影响c-Myc的促有丝分裂功能。
