Role of SUCLA2 in anoikis resistance and tumor metastasis

项目总结 转移性癌症很难治疗，而且往往是无法治愈的。前转移细胞通路的特征是 因此对于发现新的治疗靶点和转移的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的标志，但 越来越多的研究强调了原发和转移癌细胞之间的代谢差异。而当 高度增殖的原发肿瘤细胞通常表现出沃伯格效应，其特征是偏爱有氧 糖酵解产生ATP，线粒体生物发生和氧化磷酸化的基因被报道 在转移性癌细胞中上调。因此，理解线粒体的不同作用 播散性癌细胞中的代谢途径和酶是决定致癌因素的关键 细胞是转移的优势.为了在远处的器官中定居，癌细胞必须首先抵抗失巢凋亡： 由于失去与细胞外基质的适当接触而触发的细胞死亡机制。我们的实验室有 先前证明，线粒体酶谷氨酸脱氢酶1(GDH1)有助于 通过激活AMPK调节细胞的生物能量反应与肿瘤细胞的失巢抵抗和转移 LKB1基因缺陷的肺癌。然而，其他线粒体酶在失巢失巢抵抗中的作用仍然存在。 人们对此知之甚少。为了确定癌细胞失巢抵抗的其他重要因素，我们进行了一项 针对肺癌细胞中120个线粒体酶的无偏向RNAi筛选及鉴定 琥珀酰辅酶A合成酶β亚基(SUCLA2)可能是影响肿瘤细胞存活的重要因素 ECM支队。SUCLA2致敏的多种癌细胞在培养时对失巢凋亡的稳定敲除 在体外非贴壁条件下。公开数据的生物信息学分析表明，更高的 肿瘤SUCLA2 mRNA的表达与患者的生存不良有关，我们的免疫组织化学 染色显示转移性肺癌的SUCLA2蛋白水平高于匹配的原发肺癌 肿瘤。此外，我们的初步数据表明，SUCLA2基因敲除后显著增加了氧气 ECM分离癌细胞的消耗速率(OCR)和活性氧(ROS)水平。在这 提案中，我们将使用多种方法来验证我们的假设，即SUCLA2促进失巢抵抗 ECM脱离后，通过调节细胞氧化还原状态，促进肿瘤转移。《公约》的具体目标 建议的研究是：1)确定SUCLA2是否促进肿瘤的失巢凋亡抵抗和转移 2)破译SUCLA2的分子机制 有助于细胞代谢，促进癌细胞对失巢凋亡的抵抗。从长远来看，我们致力于 SUCLA2‘S在癌细胞失巢凋亡中作用的代谢途径研究 抗性，这将是提供更多的代谢信号机制的关键 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.