VHL表达缺失的肾透明细胞癌对蒽环类化疗药物敏感及其分子机制

Morethan 50% of the clear cell renal cell carcinoma(CCRCC) are VHL-deficient or lose-of-function mutant, which enables the accumulation of hypoxia inducing factor（HIF） and benefits the cancer growth and enables its resistance to chemotherapy, and thus it's a problem to cinical cancer chemotherapy. Recently,different chemotherapy agents were applied to VHL-deficient cells and its counterparts with VHL, and we found anthracycline is more sensitive to VHL-deficient CCRCC. Intriguingly, this sensitivity is HIF-independent. Then quantitative proteomics were used to genome-widely discover the VHL-downstream proteins, and these dysregulated proteoins downstream VHL were knockdown with RNAi to verify which protein is invovled in the anthracycline sensitivity. Aldehyde dehydrogenase 2（ALDH2）was found to be regulated by VHL and its kockdown makes the CCRCC highly sensitive to anthracyline. This project aims to systematically investigate the high sensitivity of anthracycline to CCRCC, the expression regulation of ALDH2 by VHL and the effect of ALDH2 on the anthracycline sensitivity, revealing the molecular mechanisms for the high sensitivity of VHL-deficient CCRCC to anthracycline. This works hopefully provides new target and experimental basis for the clinical chemotherapy of renal clear cell carcinoma.

50%以上的肾透明细胞癌（CCRCC）存在泛素连接酶VHL功能缺失，导致VHL的靶蛋白低氧诱导因子（HIF）累积，赋予肿瘤细胞生长优势和耐药特性，是肿瘤化学治疗的难点。最近，本课题组意外发现VHL表达缺失的CCRCC细胞对蒽环类药物敏感，转染VHL后对蒽环类药物敏感性反而下降；有趣的是，该效应与HIF的累积无关，提示有其它VHL下游蛋白调控肿瘤耐药性；我们利用定量蛋白质组学在全基因组范围内寻找VHL下游蛋白，并把下游蛋白用RNAi逐一沉默表达，发现VHL调控乙醛脱氢酶2（ALDH2）的表达，沉默ALDH2的表达可以显著增加CCRCC对蒽环类药物的敏感性。本项目基于这些原创性发现，深入研究VHL表达缺失的CCRCC对蒽环类药物的敏感性、VHL对ALDH2的调控以及ALDH2在药物敏感性中的作用，阐明VHL影响蒽环类药物敏感性的分子机制，为CCRCC的化学治疗提供新的治疗靶点和实验基础。

50%以上的肾透明细胞癌（CCRCC）存在泛素连接酶VHL功能缺失，导致VHL的靶蛋白低氧诱导因子（HIF）累积，赋予肾透明细胞癌肿瘤细胞生长优势和耐药特性，目前临床尚无肾透明细胞癌有效的化学治疗方法。本课题研究发现VHL表达缺失的CCRCC细胞对蒽环类药物敏感，转染VHL后对蒽环类药物敏感性反而下降；该效应与低氧诱导HIF1和HIF2的累积无关。我们利用定量蛋白质组学在全基因组范围内寻找VHL下游蛋白，并把下游调变的蛋白用RNAi逐一沉默表达，发现VHL调控乙醛脱氢酶2（ALDH2）的表达，沉默ALDH2的表达可以显著增加其底物4HNE的累积，增加CCRCC对蒽环类药物的敏感性。进一步研究发现，该调控不依赖于VHL的泛素连接酶活性，而是通过结合在ALDH2的转录因子HNF4的启动子区，调控其表达，进而调控ALDH2的表达。在本课题资助下，项目的主要成果“VHL deficiency augments anthracycline sensitivity of clear cell renal cell carcinomas by down-regulating ALDH2”，课题负责人作为通讯作者，发表在国际知名期刊Nature Communications，揭示了VHL表达缺失的CCRCC对蒽环类药物敏感，以及VHL对ALDH2的调控机制为CCRCC的化学治疗提供新的治疗靶点和实验基础，也为理解VHL的生物学功能提供了新的线索。