From the ‡The Sir Peter MacCallum Department of Oncology, The University of Melbourne, Victoria, Australia.
§Tumor Suppression Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia.
Mol Cell Proteomics. 2018 Jun;17(6):1170-1183. doi: 10.1074/mcp.RA117.000504. Epub 2018 Feb 20.
Prostate cancer is a common cause of cancer-related death in men. E6AP (E6-Associated Protein), an E3 ubiquitin ligase and a transcription cofactor, is elevated in a subset of prostate cancer patients. Genetic manipulations of E6AP in prostate cancer cells expose a role of E6AP in promoting growth and survival of prostate cancer cells and However, the effect of E6AP on prostate cancer cells is broad and it cannot be explained fully by previously identified tumor suppressor targets of E6AP, promyelocytic leukemia protein and p27. To explore additional players that are regulated downstream of E6AP, we combined a transcriptomic and proteomic approach. We identified and quantified 16,130 transcripts and 7,209 proteins in castration resistant prostate cancer cell line, DU145. A total of 2,763 transcripts and 308 proteins were significantly altered on knockdown of E6AP. Pathway analyses supported the known phenotypic effects of E6AP knockdown in prostate cancer cells and in parallel exposed novel potential links of E6AP with cancer metabolism, DNA damage repair and immune response. Changes in expression of the top candidates were confirmed using real-time polymerase chain reaction. Of these, clusterin, a stress-induced chaperone protein, commonly deregulated in prostate cancer, was pursued further. Knockdown of E6AP resulted in increased clusterin transcript and protein levels and Concomitant knockdown of E6AP and clusterin supported the contribution of clusterin to the phenotype induced by E6AP. Overall, results from this study provide insight into the potential biological pathways controlled by E6AP in prostate cancer cells and identifies clusterin as a novel target of E6AP.
前列腺癌是男性癌症相关死亡的常见原因。E6AP（E6 相关蛋白）是一种 E3 泛素连接酶和转录共因子，在一部分前列腺癌患者中升高。在前列腺癌细胞中对 E6AP 的遗传操作揭示了 E6AP 在促进前列腺癌细胞生长和存活中的作用，然而，E6AP 对前列腺癌细胞的影响是广泛的，不能完全用 E6AP 先前确定的肿瘤抑制靶标，早幼粒细胞白血病蛋白和 p27 来解释。为了探索 E6AP 下游受调控的其他因子，我们结合了转录组学和蛋白质组学方法。我们鉴定和定量了去势抵抗性前列腺癌细胞系 DU145 中的 16130 个转录本和 7209 个蛋白质。E6AP 敲低总共改变了 2763 个转录本和 308 个蛋白质。通路分析支持 E6AP 敲低在前列腺癌细胞中的已知表型效应，并同时暴露了 E6AP 与癌症代谢、DNA 损伤修复和免疫反应的新潜在联系。使用实时聚合酶链反应证实了顶级候选物表达变化。在这些变化中，通常在前列腺癌中失调的应激诱导伴侣蛋白，即聚集蛋白，被进一步研究。E6AP 敲低导致聚集蛋白转录本和蛋白水平增加，同时敲低 E6AP 和聚集蛋白支持聚集蛋白对 E6AP 诱导表型的贡献。总体而言，这项研究的结果提供了对 E6AP 在前列腺癌细胞中控制的潜在生物学途径的深入了解，并确定了聚集蛋白是 E6AP 的一个新靶标。
