Role of SUCLA2 in anoikis resistance and tumor metastasis

项目概要 转移性癌症很难治疗并且通常无法治愈。促转移细胞途径的特征是 因此，对于确定新的治疗靶点和转移生物标志物以改善临床至关重要 癌症患者的预后。细胞代谢失调是癌症的一个公认标志，但 越来越多的研究强调了原发性癌细胞和转移性癌细胞之间的代谢差异。同时 高度增殖的原发性肿瘤细胞通常表现出瓦伯格效应，其特点是偏好有氧运动 据报道，糖酵解产生 ATP、线粒体生物发生和氧化磷酸化的基因 在转移性癌细胞中上调。因此，了解线粒体的不同作用 播散性癌细胞中的代谢途径和酶对于确定导致癌症的因素至关重要 细胞具有转移优势。为了定植远处的器官，癌细胞必须首先抵抗失巢凋亡： 与细胞外基质失去适当接触而引发的细胞凋亡机制。我们实验室有 先前证明线粒体酶谷氨酸脱氢酶 1 (GDH1) 有助于 通过重新激活 AMPK 来调节生物能反应，从而实现失巢凋亡抵抗和转移 LKB1 缺陷型肺癌。然而，其他线粒体酶在失巢凋亡抵抗中的作用仍然存在 不太了解。为了确定对癌细胞失巢凋亡抵抗力重要的其他因素，我们进行了一项 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（SUCLA2）作为一个因素，可能对术后癌细胞的存活很重要 ECM分队。 SUCLA2 的稳定敲低使多种癌细胞系在培养时对失巢凋亡敏感 在体外非贴壁条件下。对公开数据的生物信息分析表明，较高 肿瘤 SUCLA2 mRNA 表达与患者生存率低相关，我们的免疫组织化学 染色表明，与匹配的原发性肺癌相比，转移性肺癌中的 SUCLA2 蛋白水平更高 肿瘤。此外，我们的初步数据表明 SUCLA2 敲低显着增加了氧气 ECM 分离癌细胞中的消耗率 (OCR) 和活性氧 (ROS) 水平。在这个 提议，我们将采用多种方法来检验我们的假设，即 SUCLA2 促进失巢凋亡抵抗 通过调节 ECM 脱离后的细胞氧化还原状态来抑制肿瘤转移。该计划的具体目标 拟议的研究是 1) 确定 SUCLA2 是否促进失巢凋亡抵抗和癌症转移 2) 破译 SUCLA2 的分子机制 有助于细胞代谢，促进癌细胞失巢凋亡抵抗。从长远来看，我们力求 全面表征 SUCLA2 在癌细胞失巢凋亡中作用的代谢途径 耐药性，这对于更好地理解代谢信号机制至关重要 潜在的转移进展。

PROJECT SUMMARY Metastatic cancer is difficult to treat and often incurable. Characterizing pro-metastatic cellular pathways is therefore crucial for identifying new therapeutic targets and biomarkers for metastasis to improve clinical prognosis of cancer patients. Dysregulated cellular metabolism is a well-established hallmark of cancer, but a growing body of research highlights metabolic differences between primary and metastatic cancer cells. 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, understanding the differential roles of mitochondrial metabolic pathways and enzymes in disseminated cancer cells is crucial for determining factors that give cancer cells a metastatic advantage. In order to colonize distant organs, 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 multiple 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 preliminary data suggests that SUCLA2 knockdown significantly increases oxygen consumption rates (OCR) and reactive oxygen species (ROS) levels in ECM detached cancer cells. In this proposal, we will employ multiple approaches to test our hypothesis that SUCLA2 promotes anoikis resistance and tumor metastasis by modulating cellular redox status following ECM detachment. The specific aims of the proposed research are 1) To determine whether SUCLA2 promotes anoikis resistance and metastasis of cancer cells in an enzyme-dependent manner and 2) To decipher the molecular mechanism by which SUCLA2 contributes to cellular metabolism to promote cancer cell anoikis resistance. In the long term, we seek to comprehensively characterize the metabolic pathways underlying SUCLA2's role in cancer cell anoikis resistance, which will be critical to providing a greater understanding of the metabolic signaling mechanisms underlying metastatic progression.