College of Pharmacy, Touro University - California, Vallejo, California, United States of America.
PLoS One. 2011;6(12):e28530. doi: 10.1371/journal.pone.0028530. Epub 2011 Dec 9.
Two of the greatest challenges in regenerative medicine today remain (1) the ability to culture human embryonic stem cells (hESCs) at a scale sufficient to satisfy clinical demand and (2) the ability to eliminate teratoma-forming cells from preparations of cells with clinically desirable phenotypes. Understanding the pathways governing apoptosis in hESCs may provide a means to address these issues. Limiting apoptosis could aid scaling efforts, whereas triggering selective apoptosis in hESCs could eliminate unwanted teratoma-forming cells. We focus here on the BCL-2 family of proteins, which regulate mitochondrial-dependent apoptosis. We used quantitative PCR to compare the steady-state expression profile of all human BCL-2 family members in hESCs with that of human primary cells from various origins and two cancer lines. Our findings indicate that hESCs express elevated levels of the pro-apoptotic BH3-only BCL-2 family members NOXA, BIK, BIM, BMF and PUMA when compared with differentiated cells and cancer cells. However, compensatory expression of pro-survival BCL-2 family members in hESCs was not observed, suggesting a possible explanation for the elevated rates of apoptosis observed in proliferating hESC cultures, as well as a mechanism that could be exploited to limit hESC-derived neoplasms.
（1）培养足够数量的人胚胎干细胞（hESCs）以满足临床需求的能力，（2）从具有临床所需表型的细胞制备物中去除畸胎瘤形成细胞的能力。了解调控 hESC 细胞凋亡的途径可能为解决这些问题提供一种手段。限制细胞凋亡可能有助于扩大规模，而在 hESC 中触发选择性凋亡则可能消除不必要的畸胎瘤形成细胞。我们在此重点关注调节线粒体依赖性凋亡的 BCL-2 家族蛋白。我们使用定量 PCR 比较了 hESC 中所有人类 BCL-2 家族成员的稳定表达谱与来自不同来源的人类原代细胞和两种癌细胞系的表达谱。我们的研究结果表明，与分化细胞和癌细胞相比，hESC 中表达高水平的促凋亡 BH3-only BCL-2 家族成员 NOXA、BIK、BIM、BMF 和 PUMA。然而，在 hESC 中没有观察到促生存 BCL-2 家族成员的代偿性表达，这可能解释了在增殖的 hESC 培养物中观察到的高凋亡率，也为限制 hESC 源性肿瘤提供了一种可能的机制。
