Lyu Junfang, Yang Eun Ju, Head Sarah A, Ai Nana, Zhang Baoyuan, Wu Changjie, Li Ruo-Jing, Liu Yifan, Yang Chen, Dang Yongjun, Kwon Ho Jeong, Ge Wei, Liu Jun O, Shim Joong Sup
Faculty of Health Sciences, University of Macau, Taipa, Macau SAR, China.
Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; The SJ Yan and HJ Mao Laboratory of Chemical Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
Cancer Lett. 2017 Nov 28;409:91-103. doi: 10.1016/j.canlet.2017.09.009. Epub 2017 Sep 18.
Cholesterol is an important modulator of membrane protein function and signaling in endothelial cells, thus making it an emerging target for anti-angiogenic agents. In this study, we employed a phenotypic screen that detects intracellular cholesterol distribution in endothelial cells (HUVEC) and identified 13 existing drugs as cholesterol trafficking inhibitors. Cepharanthine, an approved drug for anti-inflammatory and cancer management use, was amongst the candidates, which was selected for in-depth mechanistic studies to link cholesterol trafficking and angiogenesis. Cepharanthine inhibited the endolysosomal trafficking of free-cholesterol and low-density lipoprotein in HUVEC by binding to Niemann-Pick disease, type C1 (NPC1) protein and increasing the lysosomal pH. The blockade of cholesterol trafficking led to a cholesterol-dependent dissociation of mTOR from the lysosomes and inhibition of its downstream signaling. Cepharanthine inhibited angiogenesis in HUVEC and in zebrafish in a cholesterol-dependent manner. Furthermore, cepharanthine suppressed tumor growth in vivo by inhibiting angiogenesis and it enhanced the antitumor activity of the standard chemotherapy cisplatin in lung and breast cancer xenografts in mice. Altogether, these results strongly support the idea that cholesterol trafficking is a viable drug target for anti-angiogenesis and that the inhibitors identified among existing drugs, such as cepharanthine, could be potential anti-angiogenic and antitumor agents.
胆固醇是内皮细胞中膜蛋白功能和信号传导的重要调节因子，因此使其成为抗血管生成药物的一个新兴靶点。在本研究中，我们采用了一种表型筛选方法来检测内皮细胞（人脐静脉内皮细胞）内的胆固醇分布，并鉴定出13种现有药物为胆固醇转运抑制剂。千金藤素是一种已被批准用于抗炎和癌症治疗的药物，它是候选药物之一，被选用于深入的机制研究，以阐明胆固醇转运与血管生成之间的联系。千金藤素通过与尼曼-匹克病C1型（NPC1）蛋白结合并提高溶酶体pH值，抑制了人脐静脉内皮细胞中游离胆固醇和低密度脂蛋白的内溶酶体转运。胆固醇转运的阻断导致mTOR从溶酶体上胆固醇依赖性解离，并抑制其下游信号传导。千金藤素以胆固醇依赖性方式抑制人脐静脉内皮细胞和斑马鱼中的血管生成。此外，千金藤素通过抑制血管生成在体内抑制肿瘤生长，并增强了标准化疗药物顺铂对小鼠肺癌和乳腺癌异种移植瘤的抗肿瘤活性。总之，这些结果有力地支持了这样一种观点，即胆固醇转运是抗血管生成的一个可行药物靶点，并且在现有药物中鉴定出的抑制剂，如千金藤素，可能是潜在的抗血管生成和抗肿瘤药物。
