miR-377-3p suppresses cell proliferation and promotes apoptosis of prostate cancer cells

Objective: The aim of the current study was to explore the effects of miR-377-3p overexpression and miR-21 downregulation on proliferation and apoptosis rates of prostate cancer cells. Methods: Quantitative reverse transcription polymerase chain reaction was employed to detect expression of miR-21 and miR-377-3p in prostate cancer and para-cancerous normal tissues. Moreover, miR-21 inhibitors and miR-377-3p overexpression vectors were transfected into cell line PC-3. Cells were divided into four groups, including experimental group A (transfected with miR-377-3p), experimental group B (transfected with miR-21 inhibitor), negative control group, and blank group. CCK-8 testing and flow cytometry were used to detect the proliferation capacity and apoptosis of prostate cancer cells, respectively. Possible target genes of miR-21 and miR-377-3p, such as PAK2 and PDCD4, were detected by RT-PCR and Western blotting, respectively. Results: Relative expression of miR-21 in prostate cancer tissues was significantly higher than that in para-cancerous tissues (P<0.05). Relative expression of miR-377-3p in prostate cancer tissues was significantly lower than that in para-cancerous tissues (P<0.05). After transfection with miR-21 inhibitors, expression of miR-21 in PC-3 cells was significantly decreased, while that of miR-377-3p in PC-3 cells was significantly increased. Cell viability in experimental group A and experimental group B was not significantly different between the two groups (P>0.05), but significantly lower than that in the negative control group and blank groups (P<0.05). Apoptosis rates in experimental group A and experimental group B were not significantly different (P>0.05). However, these rates were significantly higher than those in negative control and blank groups (P<0.05). Expression of PAK2 protein in the experimental group A was significantly lower than that in the blank group and negative control group. Levels of PDCD4 mRNA and PDCD4 protein in the experimental group B were significantly higher than those in the blank group and control group (P<0.05) Conclusion: miR-21 is highly expressed in PC-3 cells, while miR-377-3p is downregulated. Inhibition of miR-21 expression and overexpression of miR-377-3p may inhibit proliferation of PC-3 cells and promote apoptosis. Moreover, miR-21 and miR-377-3p may be considered molecules of significance for targeted therapy of prostate cancer.