沉默 miR-193a-5p 可增加前列腺癌细胞对多西他赛的化疗敏感性。
Silencing of miR-193a-5p increases the chemosensitivity of prostate cancer cells to docetaxel.
机构信息
Department of Urology, The Second Hospital of Hebei Medical University, 215 Heping West Road, Shijiazhuang, 050000, China.
Department of Biochemistry and Molecular Biology, Ministry of Education of China, Hebei Medical University, No. 361 Zhongshan E Rd, Shijiazhuang, 050017, China.
出版信息
J Exp Clin Cancer Res. 2017 Dec 8;36(1):178. doi: 10.1186/s13046-017-0649-3.
BACKGROUND
Docetaxel-based chemotherapy failure in advanced prostate carcinoma has partly been attributed to the resistance of prostate cancer (PC) cells to docetaxel-induced apoptosis. Hence, there is an urgent need to identify mechanisms of docetaxel chemoresistance and to develop new combination therapies.
METHODS
miR-193a-5p level was evaluated by qPCR in prostate tissues and cell lines, and its expression in the tissues was also examined by in situ hybridization. PC cell line (PC3 cell) was transfected with miR-193a-5p mimic or its inhibitor, and then cell apoptosis and the expression of its downstream genes Bach2 and HO-1 were detected by TUNEL staining and Western blotting. Luciferase reporter assay was used to detect the effect of miR-193a-5p and Bach2 on HO-1 expression. Xenograft animal model was used to test the effect of miR-193a-5p and docetaxel on PC3 xenograft growth.
RESULTS
miR-193a-5p was upregulated in PC tissues and PC cell lines, with significant suppression of PC3 cell apoptosis induced by oxidative stress. Mechanistically, miR-193a-5p suppressed the expression of Bach2, a repressor of the HO-1 gene, by directly targeting the Bach2 mRNA 3'-UTR. Docetaxel treatment modestly decreased Bach2 expression and increased HO-1 level in PC3 cells, whereas a modest increase of HO-1 facilitated docetaxel-induced apoptosis. Notably, docetaxel-induced miR-193a-5p upregulation, which in turn inhibits Bach2 expression and thus relieves Bach2 repression of HO-1 expression, partly counteracted docetaxel-induced apoptosis, as evidenced by the increased Bcl-2 and decreased Bax expression. Accordingly, silencing of miR-193a-5p enhanced sensitization of PC3 cells to docetaxel-induced apoptosis. Finally, depletion of miR-193a-5p significantly reduced PC xenograft growth in vivo.
CONCLUSIONS
Silencing of miR-193a-5p or blockade of the miR-193a-5p-Bach2-HO-1 pathway may be a novel therapeutic approach for castration-resistant PC.
背景
基于多西紫杉醇的化疗在晚期前列腺癌中的失败部分归因于前列腺癌细胞对多西紫杉醇诱导的细胞凋亡的耐药性。因此，迫切需要确定多西紫杉醇耐药的机制，并开发新的联合治疗方法。
方法
通过 qPCR 评估前列腺组织和细胞系中的 miR-193a-5p 水平，并通过原位杂交检测组织中的表达。用 miR-193a-5p 模拟物或其抑制剂转染前列腺癌细胞系（PC3 细胞），然后通过 TUNEL 染色和 Western blot 检测细胞凋亡和其下游基因 Bach2 和 HO-1 的表达。荧光素酶报告基因检测用于检测 miR-193a-5p 和 Bach2 对 HO-1 表达的影响。异种移植动物模型用于测试 miR-193a-5p 和多西紫杉醇对 PC3 异种移植生长的影响。
结果
miR-193a-5p 在前列腺组织和前列腺细胞系中上调，显著抑制氧化应激诱导的 PC3 细胞凋亡。机制上，miR-193a-5p 通过直接靶向 Bach2 mRNA 3'-UTR 抑制 Bach2 的表达，Bach2 是 HO-1 基因的抑制剂。多西紫杉醇治疗可适度降低 PC3 细胞中 Bach2 的表达并增加 HO-1 水平，而适度增加 HO-1 可促进多西紫杉醇诱导的细胞凋亡。值得注意的是，多西紫杉醇诱导的 miR-193a-5p 上调，进而抑制 Bach2 表达，从而减轻 Bach2 对 HO-1 表达的抑制，部分抵消了多西紫杉醇诱导的细胞凋亡，表现为 Bcl-2 表达增加和 Bax 表达减少。因此，沉默 miR-193a-5p 增强了 PC3 细胞对多西紫杉醇诱导的细胞凋亡的敏感性。最后，体内沉默 miR-193a-5p 显著减少了 PC 异种移植的生长。
结论
沉默 miR-193a-5p 或阻断 miR-193a-5p-Bach2-HO-1 通路可能是治疗去势抵抗性前列腺癌的一种新的治疗方法。
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