Exploiting mTORC1-driven cancer cell vulnerabilities

利用 mTORC1 驱动的癌细胞漏洞

• 批准号: 8880851
• 负责人: Daniel Ackerman
• 金额: $ 5.8万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8880851
• 关键词: Allografting; Antioxidants; Apoptosis; Apoptotic; Autophagocytosis; Cancer cell line; Catabolic Process; Cell Death; Cell Survival; Cells; Complex; Data; Disease Progression; Embryo; Exhibits; Fibroblasts; Genetic Translation; Growth; Human; Hypoxia; In Vitro; Kidney Neoplasms; Lead; Lipids; Malignant Neoplasms; Mediating; Membrane; Metabolic; Metabolism; Modeling; Mus; Normal Cell; Nutrient; Oxidation-Reduction; Oxygen; Pathway interactions; Phenotype; Phosphotransferases; Process; Protein Biosynthesis; Proteins; Publishing; Reactive Oxygen Species; Refractory; Role; Serum; Signal Transduction; Solid Neoplasm; Stress; TSC2 gene; Testing; Therapeutic; Thioredoxin; Unsaturated Fats; Unsaturated Fatty Acids; Vascular blood supply; Vascularization; base; cancer cell; cancer therapy; cell transformation; deprivation; design; experience; in vivo; insight; killings; neoplastic cell; novel strategies; public health relevance; response; sensor; tumor

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.

项目摘要 实体瘤的不利微环境的特征是不规则的血管化和不良的微环境。 氧气（O2）和营养供应。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物质可用性变化的反应，癌症 细胞甚至在营养缺乏的情况下也表现出不受调节的生长。mTORC 1复合物是一种特别的 是重要的生长调节因子，已知在许多类型的人类癌症中具有高度活性。我们发现 小鼠胚胎成纤维细胞（MEFs）携带组成型活性mTORC 1经历凋亡 当暴露于同时剥夺O2和血清时细胞死亡。我们最近公布的数据 证明在这些条件下发生凋亡是由于不饱和脂质的限制， ER应激升高。这种表型不仅限于MEFs，我们发现许多癌细胞系 在相同条件下，也表现出高水平的不饱和脂质依赖性细胞死亡， 这表明这种细胞死亡机制是不受调节的生长的普遍结果。我们 数据暗示未折叠蛋白反应（UPR）介导细胞死亡，也表明 在这些条件下，活性氧（ROS）在促进细胞凋亡中的重要作用。我们 初步数据表明，UPR传感器IRE 1？及其下游效应器硫氧还蛋白抑制 蛋白（TXNIP）在介导不饱和脂质剥夺引起的细胞死亡中至关重要。中央 这一建议的假设是，在肿瘤样应激下mTORC 1失调诱导 通过UPR和ROS依赖性机制诱导细胞凋亡。基于这一假设，我将继续 具体目标1：确定UPR如何促进肿瘤下的细胞死亡- 比如压力具体目标2：检测TXNIP介导的氧化还原状态变化的参与， 在肿瘤样应激下介导细胞死亡的代谢。 使用自体Tsc 2-/-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。我们将用同种异体移植肿瘤模型补充该模型，并使用 以测试ER应激介导的凋亡是否可以用于靶向缺氧肿瘤细胞。本 最后，我将追求具体目标3：建立mTORC 1驱动的细胞死亡在体内的相关性， 营养和氧气缺乏。这些研究将有助于确定针对癌症的新策略 细胞具体