Cancer stem cells (CSCs), or alternatively called tumor initiating cells (TICs), are a subpopulation of tumor cells, which possesses the ability to self-renew and differentiate into bulk tumor mass. An accumulating body of evidence suggests that CSCs contribute to the growth and recurrence of tumors and the resistance to chemo- and radiotherapy. CSCs achieve self-renewal through asymmetric division, in which one daughter cell retains the self-renewal ability, and the other is destined to differentiation. Recent studies revealed the mechanisms of asymmetric division in normal stem cells (NSCs) and, to a limited degree, CSCs as well. Asymmetric division initiates when a set of polarity-determining proteins mark the apical side of mother stem cells, which arranges the unequal alignment of mitotic spindle and centrosomes along the apical-basal polarity axis. This subsequently guides the recruitment of fate-determining proteins to the basal side of mother cells. Following cytokinesis, two daughter cells unequally inherit centrosomes, differentiation-promoting fate determinants, and other proteins involved in the maintenance of stemness. Modulation of asymmetric and symmetric division of CSCs may provide new strategies for dual targeting of CSCs and the bulk tumor mass. In this review, we discuss the current understanding of the mechanisms by which NSCs and CSCs achieve asymmetric division, including the functions of polarity- and fate-determining factors.

中文翻译：

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控制癌症干细胞不对称和对称自我更新的分子机制

癌症干细胞 (CSC) 或称为肿瘤起始细胞 (TIC) 是肿瘤细胞的一个亚群，具有自我更新和分化成大块肿瘤块的能力。越来越多的证据表明，CSC 有助于肿瘤的生长和复发以及对化疗和放疗的抵抗力。CSCs通过不对称分裂实现自我更新，其中一个子细胞保留自我更新能力，另一个注定要分化。最近的研究揭示了正常干细胞 (NSC) 以及在有限程度上也包括 CSC 中不对称分裂的机制。当一组决定极性的蛋白质标记母干细胞的顶端时，不对称分裂就开始了，沿着顶端 - 基底极性轴排列有丝分裂纺锤体和中心体的不等对齐。这随后引导命运决定蛋白向母细胞的基底侧募集。胞质分裂后，两个子细胞不平等地继承中心体、促进分化的命运决定因素和其他参与维持干性的蛋白质。调节 CSCs 的不对称和对称分裂可能为 CSCs 和大块肿瘤块的双重靶向提供新的策略。在这篇综述中，我们讨论了目前对 NSCs 和 CSCs 实现不对称分裂机制的理解，包括极性和命运决定因素的功能。两个子细胞不平等地继承中心体、促进分化的命运决定因素和其他参与维持干性的蛋白质。调节 CSCs 的不对称和对称分裂可能为 CSCs 和大块肿瘤块的双重靶向提供新的策略。在这篇综述中，我们讨论了目前对 NSCs 和 CSCs 实现不对称分裂机制的理解，包括极性和命运决定因素的功能。两个子细胞不平等地继承中心体、促进分化的命运决定因素和其他参与维持干性的蛋白质。调节 CSCs 的不对称和对称分裂可能为 CSCs 和大块肿瘤块的双重靶向提供新的策略。在这篇综述中，我们讨论了目前对 NSCs 和 CSCs 实现不对称分裂机制的理解，包括极性和命运决定因素的功能。