ENDOD1在前列腺癌组织及细胞中的表达及意义

目的:观察比较核酸内切酶结构域内含蛋白1(endonuclease domain containing1,ENDOD1)在良性前列腺增生和前列腺癌组织中的表达差异;筛选存在ENDOD1特异性低表达的前列腺癌细胞系,继而通过调控该细胞ENDOD1蛋白表达,研究其在前列腺癌细胞中的生物学功能,初步探索ENDOD1基因与前列腺癌发生、进展的联系。方法:利用免疫组化SP法检测20例良性前列腺增生和21例前列腺癌术后标本组织中ENDOD1表达情况;利用RT-qPCR和Western blot方法观察ENDOD1的mRNA和蛋白在前列腺正常上皮细胞和不同类型前列腺癌细胞中的表达差异,筛选出特异性低表达细胞系;构建pCMV-N-Flag-ENDOD1重组质粒,转染前列腺癌细胞株,过表达ENDOD1蛋白,通过MTT法测定调控前后前列腺癌细胞活力的变化,流式细胞术检测细胞周期和凋亡,Transwell实验评价肿瘤细胞迁移和侵袭能力的改变。结果:免疫组化评分的方差分析结果显示ENDOD1表达与前列腺癌Gleason评分呈负性关联;RT-qPCR和Western blot实验结果表明ENDOD1在雄激素非依赖性前列腺癌细胞系PC3和DU145中存在着特异性低表达(P0.05)。同时,MTT实验显示,在DU145细胞中,过表达ENDOD1肿瘤细胞活力显著下降(P0.05);而流式细胞术检测结果表明过表达ENDOD1能够使DU145细胞周期停滞在G_0/G_1期,但细胞凋亡率无明显差异。此外,在Transwell实验中,过表达ENDOD1的DU145细胞迁移和侵袭能力明显下降(P0.05)。结论:ENDOD1在Gleason评分越高的前列腺癌中表达越低,同时在雄激素非依赖性前列腺癌细胞系存在着特异性低表达;而过表达ENDOD1能明显抑制雄激素非依赖性前列腺癌细胞的生长、迁移和侵袭能力。

Value of endonuclease domain containing 1 in progression of prostate cancer

AIM: To analyze the difference of endonuclease domain containing 1 (ENDOD1) expression between benign prostatic hyperplasia (BPH) tissues and prostate cancer (PCa) tissues and to investigate the effect of ENDOD1 on the biological function of human prostate cancer cells. METHODS: The BPH samples (n=20) and PCa samples (n=21) were processed and analyzed according to the instruction of immunohistochemical (IHC) staining. The mRNA and protein levels of ENDOD1 in the normal prostate epithelial cells and prostate cancer cells were evaluated by RT-qPCR and Western blot, respectively. The recombinant plasmids pCMV-N-Flag-ENDOD1 was constructed and was transfected into the human prostate cancer cells. The proliferation, apoptosis, migration and invasion abilities of the prostate cancer cells were evaluated by MTT assay, flow cytometry, Transwell migration and Matrigel invasion assays, respectively. RESULTS: The analysis of variance of the immunoreactivity score showed that PCa tissues with high Gleason score displayed significantly lower ENDOD1expression than that with low Gleason score and BPH (P<0.05). The expression of ENDOD1 at mRNA and protein levels in PC3 cells and DU145 cells was significantly lower than that in the LNCap cells (P<0.05). The proliferation of DU145 transfected with ENDOD1 was inhibited. The flow cytometry indicated that ENDOD1 over-expression in the DU145 cells resulted in a notable increase in G₀/G₁ phase arrest (P<0.05), but the apoptotic rates showed no statistical difference. The results of Transwell assay showed that migration and invasion abilities of the cells were also inhibited after transfection with over-expressing ENDOD1 plasmid (P<0.05). CONCLUSION: The expression of ENDOD1 significantly decreased in prostate cancer with high Gleaon score. Meanwhile, the ENDOD1 is specifically down-regulated in androgen independent prostate cancer (AIPC) cell lines. Over-expression of ENDOD1 remarkably inhibits the proliferation, migration and invasion abilities of AIPC.