Molecular Targets Laboratory, SAIC-Frederick, Inc., National Cancer Institute, Frederick, Maryland 21702, USA.
Cancer Res. 2011 Jan 1;71(1):134-42. doi: 10.1158/0008-5472.CAN-10-0757.
Clear cell renal cell carcinoma (CCRCC) evolves due to mutations in the Von Hippel-Lindau (VHL) tumor suppressor gene. Although the loss of VHL enables survival and proliferation of CCRCC cells, it is also expected to introduce vulnerabilities that may be exploited for therapeutics discovery. To this end, we developed a high-throughput screen to identify small molecules derived from plants, microorganisms, and marine organisms to which CCRCC cells are sensitive. Screening over 8,000 compounds using this approach, we report here the identification of the microbially derived compound carminomycin I (CA) as an effective inhibitor of VHL-defective (VHL(-/-)) CCRCC cell proliferation. CA also induced apoptosis in CCRCC cells by a mechanism independent of p53 or hypoxia-inducible factor 2. We found that P-glycoprotein (P-gp) sequestered CA within the Golgi complex. Interestingly, Golgi sequestration was critical for the antiproliferative effects of CA and P-gp inhibitors abrogated this activity. Furthermore, CA induced cleavage of the Golgi protein p115 and the translocation of its C-terminal fragment to the nucleus. Finally, examination of the activity of the VHL-interacting Golgi protein, endoplasmic reticulum-Golgi intermediate compartment, ERGIC-53 showed that VHL could mediate protection from CA in CCRCC cells. Our natural product-based screening approach has revealed the P-gp-mediated localization of anticancer compounds within the Golgi in CCRCC cells as a potential strategy of targeting VHL-deficient CCRCC cells.
透明细胞肾细胞癌（CCRCC）的发生是由于 Von Hippel-Lindau（VHL）肿瘤抑制基因的突变。虽然 VHL 的缺失使 CCRCC 细胞能够存活和增殖，但它也可能会引入一些弱点，这些弱点可能会被用于治疗发现。为此，我们开发了一种高通量筛选方法，以鉴定对 CCRCC 细胞敏感的源自植物、微生物和海洋生物的小分子。通过这种方法筛选了超过 8000 种化合物，我们在这里报告了微生物来源的化合物 carminomycin I（CA）的鉴定，它是 VHL 缺陷型（VHL(-/-)）CCRCC 细胞增殖的有效抑制剂。CA 还通过一种不依赖于 p53 或缺氧诱导因子 2 的机制诱导 CCRCC 细胞凋亡。我们发现 P-糖蛋白（P-gp）将 CA 隔离在高尔基体复合物中。有趣的是，高尔基体隔离对于 CA 的抗增殖作用至关重要，而 P-gp 抑制剂则消除了这种活性。此外，CA 诱导了高尔基蛋白 p115 的切割，以及其 C 末端片段向核内的易位。最后，对 VHL 相互作用的高尔基蛋白、内质网-高尔基体中间区、ERGIC-53 的活性进行了检查，结果表明 VHL 可以介导 CCRCC 细胞对 CA 的保护。我们基于天然产物的筛选方法揭示了 P-gp 介导的抗癌化合物在 CCRCC 细胞中的高尔基体内定位作为靶向 VHL 缺陷型 CCRCC 细胞的潜在策略。
