Astley Kelly, Naciri Mariam, Racher Andrew, Al-Rubeai Mohamed
Department of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
J Biotechnol. 2007 Jun 30;130(3):282-90. doi: 10.1016/j.jbiotec.2007.04.012. Epub 2007 May 1.
The up-regulation of cyclin-dependent kinase inhibitor p21 has been shown to enhance productivity of monoclonal antibodies and has been linked to various regulatory processes. To identify the potential role of p21 in adaptation to suspension and protein-free cultures, we studied the survival and growth of anchorage- and serum-dependent CHO cell lines that differed only in the period of p21-induced arrest. p21 overexpression led to rapid adaptation of cells to suspension and protein-free cultures. The period taken to achieve adaptation was correlated with the time the cells were arrested after transfer from the monolayer and serum-fed culture. Interestingly, cell aggregation associated with protein-free suspension culture was reduced in p21 culture in response to the loss of cellular adherence. The processes of adaptation to suspension and arrest did not decrease monoclonal antibody productivity. In contrast, following adaptation to protein-free growth media, an overall increase in specific productivity was observed. The ability of cells to survive in protein-free suspension cultures was due to the requirement of G1 cells to growth factors and to their relatively high resistance to the hydrodynamic forces. This improved process has the advantage of reducing the duration of critical path activity for developing CHO commercial cell lines from 72 to 36 days.
细胞周期蛋白依赖性激酶抑制剂p21的上调已被证明可提高单克隆抗体的产量，并与各种调节过程有关。为了确定p21在适应悬浮培养和无蛋白培养中的潜在作用，我们研究了仅在p21诱导的停滞期不同的贴壁依赖性和血清依赖性CHO细胞系的存活和生长情况。p21的过表达导致细胞快速适应悬浮培养和无蛋白培养。实现适应所需的时间与从单层和血清喂养培养物转移后细胞停滞的时间相关。有趣的是，由于细胞黏附丧失，在p21培养中与无蛋白悬浮培养相关的细胞聚集减少。适应悬浮培养和停滞的过程并未降低单克隆抗体的产量。相反，在适应无蛋白生长培养基后，观察到比生产率总体增加。细胞在无蛋白悬浮培养中存活的能力归因于G1期细胞对生长因子的需求以及它们对流体动力的相对高抗性。这一改进的过程具有将开发CHO商业细胞系关键路径活动的持续时间从72天缩短至36天的优势。
