Role of SUCLA2 in anoikis resistance and tumor metastasis

项目摘要 转移性癌症很难治疗，而且往往无法治愈。表征促转移细胞途径是 因此对于鉴定新的治疗靶点和转移的生物标志物以改善临床 癌症患者的预后。细胞代谢失调是癌症的公认标志，但 越来越多的研究强调了原发性和转移性癌细胞之间的代谢差异。而 高度增殖的原发性肿瘤细胞通常表现出瓦尔堡效应，其特征在于对有氧代谢的偏好。 糖酵解产生ATP，线粒体生物合成和氧化磷酸化的基因被报道， 在转移性癌细胞中被上调。因此，了解线粒体的不同作用， 代谢途径和酶在播散的癌细胞是至关重要的决定因素，使癌症 细胞转移的优势。为了在远处器官定居，癌细胞必须首先抵抗失巢凋亡： 凋亡性细胞死亡机制由与细胞外基质的适当接触的丧失触发。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。 在肺癌细胞中针对120种线粒体酶的无偏RNAi筛选，并鉴定了ATP特异性的 琥珀酰辅酶A合成酶β亚基（SUCLA 2）作为一个因素，可能是重要的癌细胞存活后 ECM分离。SUCLA 2的稳定敲低使多种癌细胞系在培养时对失巢凋亡敏感 在体外非粘附条件下。对公开数据的生物信息学分析表明， 肿瘤SUCLA 2 mRNA表达与患者生存率低相关，我们的免疫组化 染色表明，与匹配的原发性肺癌相比，转移性肺癌中SUCLA 2蛋白水平更高， 肿瘤的此外，我们的初步数据表明，SUCLA 2敲低显著增加了氧气， 在ECM分离的癌细胞中，细胞的光消耗率（OCR）和活性氧（ROS）水平。在这 我们将采用多种方法来验证我们的假设，即SUCLA 2促进抗失巢凋亡 和肿瘤转移。的具体目标 建议的研究是1）确定SUCLA 2是否促进失巢凋亡抵抗和癌症转移 2）以酶依赖的方式对细胞进行刺激; 2）破译SUCLA 2 有助于细胞代谢，促进癌细胞抗失巢凋亡。从长远来看，我们希望 全面表征SUCLA 2在癌细胞失巢凋亡中作用的代谢途径 耐药性，这将是至关重要的，以提供更好的理解代谢信号机制 潜在的转移性进展。

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.