Metabolic reprogramming and tumor progression in LKB1 deficient NSCLC

项目摘要 细胞代谢失调是癌症的一个共同特征，但越来越多的研究表明， 突出了原发性肿瘤内和肿瘤细胞内代谢表型的显著差异， 转移到远处器官。虽然高度增殖的原发性肿瘤细胞通常表现出瓦尔堡效应， 以有氧糖酵解产生ATP的偏好为标志，线粒体生物合成的基因， 氧化磷酸化据报道在转移性癌细胞中上调。因此，详细 肺癌中重编程代谢途径的特征可能揭示有用的靶点， 肿瘤进展和改善患者存活率。为了转移，癌细胞必须首先抵抗失巢凋亡： 一种凋亡性细胞死亡机制，由与细胞外基质的适当接触丧失引发。我们的实验室 先前证明，线粒体酶谷氨酸脱氢酶1（GDH 1）有助于 通过AMPK的重新激活调节生物能量反应， LKB 1缺陷型肺癌然而，其他线粒体酶在抗失巢凋亡中的作用仍然存在， 不太了解。为了确定癌细胞抗失巢凋亡的其他重要因素，我们进行了一项研究。 针对肺癌细胞中120种线粒体酶的无偏RNAi筛选，并鉴定了ATP- 特异性琥珀酰辅酶A合成酶β亚基（SUCLA 2）作为癌细胞重要因子 ECM脱离后的存活率。SUCLA 2致敏肺癌细胞系对失巢凋亡的稳定敲低， 在体外非贴壁条件下培养。对公开数据的生物信息学分析表明， 较高的肿瘤SUCLA 2 mRNA表达与较差的患者生存率相关，我们的研究表明， 免疫组化染色提示转移性肺癌中SUCLA 2蛋白水平较高， 与匹配的原发性肿瘤相比。此外，我们的数据表明，SUCLA 2敲低显著 增加ECM分离的癌细胞中活性氧（ROS）的产生和失巢凋亡敏感性， 这可以通过补充抗氧化剂NAC来逆转。在本研究计划的前半部分，我们将 采用多种方法来破译SUCLA 2如何调节细胞氧化还原状态以促进失巢凋亡 耐药性和肿瘤转移。提案的后半部分列出了一个富有成效的博士后计划 奖学金（K 00），将建立在申请人的博士前F99培训，并准备好他开始职业生涯， 一位独立的癌症研究者

PROJECT SUMMARY Dysregulated cellular metabolism is a common characteristic of cancer, but a growing body of research highlights significant differences in metabolic phenotypes both within primary tumors, and in tumor cells that metastasize to distant organs. While highly proliferative primary tumor cells often exhibit the Warburg effect, marked by a preference for aerobic glycolysis to generate ATP, genes for mitochondrial biogenesis and oxidative phosphorylation are reported to be upregulated in metastatic cancer cells. Therefore, detailed characterization of reprogrammed metabolic pathways in lung cancer may reveal useful targets to combat tumor progression and improve patient survival. In order to metastasize, cancer cells must first resist anoikis: an apoptotic cell death mechanism triggered by loss of proper contact with the extracellular matrix. Our lab has previously demonstrated that the mitochondrial enzyme glutamate dehydrogenase 1 (GDH1) contributes to anoikis resistance and metastasis by regulating the bioenergetic response through reactivation of AMPK in LKB1-deficient lung cancer. However, the role of other mitochondrial enzymes in anoikis resistance remains poorly understood. To identify other factors important for cancer cell anoikis resistance, we performed an unbiased RNAi screen targeting 120 mitochondrial enzymes in lung cancer cells and identified the ATP- specific Succinyl-CoA Synthetase beta subunit (SUCLA2) as a factor that may be important for cancer cell survival after ECM detachment. Stable knockdown of SUCLA2 sensitized lung cancer cell lines to anoikis when cultured under non-adherent conditions in vitro. Bioinformatic analysis of publicly available data indicates that higher tumor SUCLA2 mRNA expression is associated with poor patient survival, and our immunohistochemistry staining suggests that SUCLA2 protein levels are higher in metastatic lung cancer compared to matched primary tumors. Additionally, our data suggests that SUCLA2 knockdown significantly increases reactive oxygen species (ROS) production and anoikis sensitivity in ECM detached cancer cells, which can be reversed with antioxidant NAC supplementation. In the first half of this research proposal, we will employ multiple approaches to decipher how SUCLA2 modulates cellular redox status to promote anoikis resistance and tumor metastasis. The second half of the proposal lays out a plan for a productive postdoctoral fellowship (K00) that will build on applicant's predoctoral F99 training and prepare him well to start a career as an independent cancer researcher.