RNF185 control of COL3A1 expression limits prostate cancer migration and metastatic potential

RNF185 is a RING finger domain-containing ubiquitin ligase implicated in ER-associated degradation. Prostate tumor patient data analysis revealed a negative correlation between RNF185 expression and prostate cancer progression and metastasis. Likewise, several prostate cancer cell lines exhibited greater migration and invasion capabilities in culture upon RNF185 depletion. Subcutaneous inoculation of mouse prostate cancer MPC3 cells stably expressing shRNA against RNF185 into mice resulted in larger tumors and more frequent lung metastases. RNA-sequencing and Ingenuity Pathway Analysis identified wound healing and cellular movement among the most significant pathways upregulated in RNF185-depleted, compared to control prostate cancer cells. Gene Set Enrichment Analyses performed in samples from patients harboring low RNF185 expression and in RNF185-depleted lines confirmed the deregulation of genes implicated in EMT. Among those, COL3A1 was identified as the primary mediator of RNF185's ability to impact migration phenotypes. Correspondingly, enhanced migration and metastasis of RNF185 KD prostate cancer cells were attenuated upon co-inhibition of COL3A1. Our results identify RNF185 as a gatekeeper of prostate cancer metastasis, partly via its control of COL3A1 availability.

RNF185是一种含有环指结构域（RING finger domain）的泛素连接酶，参与内质网相关降解（ER-associated degradation）过程。对前列腺肿瘤患者的临床数据进行分析后发现，RNF185的表达水平与前列腺癌的进展及转移呈负相关关系。同样地，在体外培养的多株前列腺癌细胞系中，敲低RNF185可显著增强细胞的迁移与侵袭能力。将稳定表达靶向RNF185的短发夹RNA（short hairpin RNA，shRNA）的小鼠前列腺癌MPC3细胞皮下接种至小鼠体内，可形成体积更大的移植瘤，且肺转移的发生率显著升高。通过RNA测序（RNA-sequencing）与英格纽伊通路分析（Ingenuity Pathway Analysis）发现，相较于对照组前列腺癌细胞，RNF185敲低的细胞中，伤口愈合与细胞运动相关通路的上调幅度最为显著。针对RNF185低表达的患者样本以及RNF185敲低细胞系开展的基因集富集分析（Gene Set Enrichment Analyses）证实，上皮间质转化（Epithelial-Mesenchymal Transition, EMT）相关基因的表达存在失调现象。其中，COL3A1被确定为RNF185调控细胞迁移表型的核心介导因子。相应地，共抑制COL3A1可削弱RNF185敲低前列腺癌细胞的迁移与转移能力增强的表型。本研究结果表明，RNF185可作为前列腺癌转移的守门基因，其部分功能通过调控COL3A1的表达水平得以实现。