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.