Parameters that determine cell fate during mitotic arrest

有丝分裂纺锤体中断导致纺锤体组装检查点(SAC)激活时间延长 可导致P53激活、中心粒脱离和细胞死亡。事实上，有一个 化疗策略经常应用于侵袭性和激素非依赖性癌症 是以有丝分裂纺锤体为靶点，这是一种基于微管的结构，是正常发育所必需的 染色体分离和细胞分裂。长春花碱或紫杉醇等药物可抑制 正常的微管组装动力学，导致有丝分裂停止和最终细胞死亡，通过 细胞凋亡。然而，尽管它们在临床上实施了几十年，但通过 哪种延长的有丝分裂延迟导致细胞死亡尚不清楚。此外，尽管 有丝分裂纺锤体对细胞分裂的普遍要求，目前仍有大量 细胞对纺锤体破坏的反应方式的异质性，这可能会降低抗 有丝分裂化疗策略。使用生化和活细胞成像的组合 方法，我们的初步数据显示，靶向两个运动蛋白纺锤体蛋白(KSP)，一个 纺锤体双极性所需的分子马达和磷脂酰肌醇3-激酶 (PI3K)/Akt/mTor信号通路显著加速有丝分裂细胞死亡的动力学 相对于有丝分裂停滞而言。此外，它还引起了来自 处理过的细胞。PI3K信号参与多种调节细胞的调节通路 生存、代谢和增殖，但PI3K活性促进细胞的机制 有丝分裂停滞期间的存活率尚不清楚。为了更好地了解PI3K信号是如何参与 细胞死亡的时间和细胞有丝分裂反应的变异性，我们将继续 应用高通量时间流逝成像、高分辨率4D成像和生化 细胞系电池的方法不同于它们对有丝分裂延迟的敏感性以及 依赖于PI3K信号。该项目的具体目标将1)定义保护 PI3K在正常细胞和癌细胞中的作用；以及2)决定PI3K的机制 在有丝分裂延迟期间促进细胞存活。如果成功，这些研究将为 未来的翻译研究将进一步开发针对有丝分裂活性的辅助疗法 无其他微管干扰物副作用的肿瘤细胞。

Prolonged activation of the spindle assembly checkpoint (SAC) due to mitotic spindle disruption can result in p53 activation, centriole disengagement and cell death. Indeed, one chemotherapeutic strategy frequently applied to aggressive and hormone-independent cancers is to target the mitotic spindle, a microtubule-based structure that is required for proper chromosome segregation and cell division. Drugs such as vinblastine or Paciltaxel suppress the normal microtubule assembly dynamics, leading to mitotic arrest and eventual cell death by apoptosis. However, despite their decades-long implementation in the clinic, the mechanisms by which prolonged mitotic delay results in cell death remains unclear. Further, despite the universality of the requirement of the mitotic spindle for cell division, there is still a great deal of heterogeneity in how cells respond to spindle disruption, which may reduce the efficacy of anti- mitotic chemotherapeutic strategies. Using a combination of biochemical and live cell imaging approaches, our preliminary data reveals that targeting both Kinesin Spindle Protein (KSP), a molecular motor required for spindle bipolarity, and the Phosphatidylinositide 3-kinase (PI3K)/Akt/mTOR signaling pathway dramatically accelerates the kinetics of mitotic cell death relative to mitotic arrest alone. Moreover, it elicits a more homogeneous response from the treated cells. PI3K signaling is involved in a variety of regulatory pathways that regulate cell survival, metabolism and proliferation, but the mechanism by which PI3K activity promotes cell viability during mitotic arrest is unknown. To better understand how PI3K signaling is involved in the timing of cell death and variability of cellular responses of mitotic delay, we will continue to apply high-throughput timelapse imaging, high-resolution 4D imaging and biochemical approaches to a battery of cell lines differ in their sensitivity to mitotic delay as well as dependence on PI3K signaling. The Specific Aims of this project will 1) Define the protective role of PI3K in normal and cancer cells; and 2) Determine the mechanism by which PI3K promotes cell survival during mitotic delay. If successful, these studies will lay the foundation for future translational studies to further develop adjuvant therapies that will target mitotically active tumor cells without the side effects associated with other microtubule disruptors.