Exploiting mTORC1-driven cancer cell vulnerabilities

项目摘要 实体瘤的恶性微环境以血管生成不规则和不良为特征。 氧气(O2)和养分供应。当正常细胞调整它们的生长和增殖速度时 通过调节合成代谢和分解代谢途径对营养供应变化的反应，癌症 即使在营养缺乏的情况下，细胞也表现出不受调控的生长。MTORC1复合体是一种特别的 它是重要的生长调节剂，已知在许多类型的人类癌症中高度活跃。我们发现 携带mTORC1基因的小鼠胚胎成纤维细胞(MEF)发生凋亡 当同时缺乏氧气和血清时，细胞死亡。我们最近公布的数据 证明在这些条件下，细胞凋亡是由于不饱和脂类和 内质网应激升高。这种表型并不局限于MEF；我们发现许多癌细胞株 在相同的条件下，也表现出高水平的不饱和脂质依赖的细胞死亡，强烈 这表明，这种细胞死亡机制是不受控制的生长的普遍后果。我们的 数据表明，未折叠蛋白反应(UPR)参与介导细胞死亡，并提示 在这些条件下，活性氧物种(ROS)在促进细胞凋亡中发挥着重要作用。我们的 初步数据表明，UPR传感器IRE1？及其下游效应物硫氧还蛋白抑制 蛋白(TXNIP)在调节不饱和脂肪剥夺引起的细胞死亡中起关键作用。中环 这一设想的假设是，在肿瘤样应激下mTORC1的异常调节诱导 通过依赖于UPR和ROS的机制进行细胞凋亡。基于这一假设，我将继续 以下具体目标：具体目标1：确定UPR如何促进肿瘤下的细胞死亡- 就像压力一样。特定目标2：测试TXNIP介导的氧化还原状态和 肿瘤样应激条件下细胞死亡过程中的代谢。 使用自体TSC2-/-肾肿瘤的初步数据表明该细胞在体内的作用 这里描述的死亡表型。我们将用一个同种异体肿瘤模型来补充这个模型，并使用 以检测内质网应激介导的细胞凋亡是否可以被用来靶向缺氧的肿瘤细胞。对这件事 最后，我将追求具体目标3：建立mTORC1驱动的细胞死亡在体内的相关性 营养物质和氧气的缺乏。提出的研究将有助于确定针对癌症的新策略。 特别是细胞。

Project Summary The hostile microenvironment of solid tumors is characterized by irregular vascularization and poor oxygen (O2) and nutrient supply. While normal cells adjust their rates of growth and proliferation in response to changes in nutrient availability by modulating anabolic and catabolic pathways, cancer cells exhibit unregulated growth even under nutrient scarcity. The mTORC1 complex is a particularly important regulator of growth and is known to be highly active in many types of human cancer. We find that mouse embryonic fibroblasts (MEFs) harboring constitutively active mTORC1 undergo apoptotic cell death when exposed to simultaneous deprivation of O2 and serum. Our recently published data demonstrate that apoptosis under these conditions occurs due to a limitation in unsaturated lipids and elevated ER-stress. This phenotype is not limited to MEFs; we find that a number of cancer cell lines also exhibit high levels of unsaturated lipid -dependent cell death under the same conditions, strongly suggesting that this mechanism of cell death is a widespread consequence of unregulated growth. Our data implicate the unfolded protein response (UPR) in mediating cell death and also suggest an important role for reactive oxygen species (ROS) in promoting apoptosis under these conditions. Our preliminary data suggest that the UPR sensor IRE1¿ and its downstream effector thioredoxin inhibiting protein (TXNIP) are critical in mediating cell death from unsaturated lipid deprivation. The central hypothesis of this proposal is that mTORC1 dysregulation under tumor-like stress induces apoptosis via a UPR- and ROS-dependent mechanism. Based on this hypothesis, I will pursue the following specific aims: Specific Aim 1: To determine how the UPR promotes cell death under tumor- like stress. Specific Aim 2: To test the involvement of TXNIP-mediated changes in redox status and metabolism in mediating cell death under tumor-like stress. Preliminary data using autochthonous Tsc2-/- renal tumors suggests an in vivo role for the cell death phenotype described here. We will compliment this model with an allograft tumor model and use it to test whether ER stress-mediated apoptosis can be exploited to target hypoxic tumor cells. To this end, I will pursue Specific Aim 3: To establish the in vivo relevance of mTORC1-driven cell death under nutrient and O2 deprivation. The studies proposed will help identify novel strategies for targeting cancer cells specifically.