尽管越来越多的证据表明钙激活的氯离子通道anocamin1(ANO1)在癌症转移中,其对前列腺癌转移潜能的直接影响以及表观遗传改变在这一过程中的可能意义尚不完全清楚.这里,我们显示ANO1在LNCap和DU145前列腺癌细胞系中最低表达,具有低转移潜能,但在高转移PC3前列腺癌细胞系中过表达。用DNMT抑制剂5-氮杂-2'-脱氧胞苷(5-Aza-CdR)处理LNCap和DU145细胞可增强ANO1表达,提示DNA甲基化是控制ANO1表达的机制之一。与这个概念一致,在LNCap和DU145细胞中,在ANO1启动子区的CpG岛检测到高甲基化,和5-Aza-CdR处理导致启动子CpG甲基化位点的剧烈去甲基化。在5-Aza-CdR处理后,转移指数,如细胞运动性,入侵,和转移相关基因表达,在LNCap和DU145细胞中显著改变。这些5-Aza-CdR诱导的转移标志是,然而,几乎完全被稳定的ANO1击倒。我们的体内观察进一步支持了这些体外发现,即异种移植小鼠模型中的ANO1表达增强了前列腺癌细胞向胫骨骨中的转移性播散和溶骨性病变的发展。总的来说,我们的结果有助于阐明ANO1表达在前列腺癌骨转移中的关键作用,其通过启动子CpG甲基化进行表观遗传调节。
Despite growing evidence implicating the calcium-activated chloride channel anoctamin1 (
ANO1) in cancer metastasis, its direct impact on the metastatic potential of prostate cancer and the possible significance of epigenetic alteration in this process are not fully understood. Here, we show that
ANO1 is minimally expressed in LNCap and DU145 prostate cancer cell lines with low metastatic potential but overexpressed in high metastatic PC3 prostate cancer cell line. The treatment of LNCap and DU145 cells with DNMT inhibitor 5-aza-2\'-deoxycytidine (5-Aza-CdR) potentiates ANO1 expression, suggesting that DNA methylation is one of the mechanisms controlling
ANO1 expression. Consistent with this notion, hypermethylation was detected at the CpG island of
ANO1 promoter region in LNCap and DU145 cells, and 5-Aza-CdR treatment resulted in a drastic demethylation at promoter CpG methylation sites. Upon 5-Aza-CdR treatment, metastatic indexes, such as cell motility, invasion, and metastasis-related gene expression, were significantly altered in LNCap and DU145 cells. These 5-Aza-CdR-induced metastatic hallmarks were, however, almost completely ablated by stable knockdown of ANO1. These in vitro discoveries were further supported by our in vivo observation that
ANO1 expression in xenograft mouse models enhances the metastatic dissemination of prostate cancer cells into tibial bone and the development of osteolytic lesions. Collectively, our results help elucidate the critical role of ANO1 expression in prostate cancer bone metastases, which is epigenetically modulated by promoter CpG methylation.