Investigation of miRNA expression changes affecting DNA repair enzyme gene expressions in prostate cancer

Prostate cancer is a significant global health concern and ranks as the second most common cancer type among men. The pathogenesis of prostate cancer is associated with genetic and epigenetic changes, which may also be linked to DNA repair mechanisms, as well as hormonal imbalances and environmental factors. Deficiencies in double-strand break repair mechanisms are particularly known to play a critical role in the development and progression of prostate cancer. MicroRNAs (miRNAs) are small, single-stranded, non-coding RNA molecules transcribed from intronic or exonic DNA sequences, playing a crucial role in the post transcriptional regulation of gene expression. In this study, the expression levels of miR-155, miR-1246, miR-210, miR-34c, and miR-421, which are associated with double-strand break repair mechanisms, were analyzed in tumor and normal tissues from 50 pathologically confirmed prostate cancer patients using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Clinical findings of the patients were also evaluated. No statistically significant differences were observed in the expression levels of miR-155, miR-1246, miR-210, xvii and miR-421 between tumor and normal tissues (p>0.05). However, the expression level of miR-34c was significantly lower in tumor tissues compared to normal tissues (p=0.001). The fold change in gene expression (2–ΔΔCT) was determined to be 0.31. Correlation analyses revealed associations among different miRNAs in both normal and tumor tissues. A negative correlation was observed between age and miR-34c expression in tumor tissues (r: -0.362, p=0.008), with miR-34c expression decreasing as age increased. Additionally, a statistically significant positive correlation was found between PSA levels and miR-210 (r: 0.353, p=0.011) and miR-1246 (r: 0.594, p<0.0001) in tumor tissues, indicating that miR-210 and miR-1246 expression levels increase as PSA levels rise. The findings suggest that miR-34c may play an important role in the development and progression of prostate cancer. This study is expected to contribute to the understanding of the relationships between prostate cancer, DNA repair mechanisms, and DNA damage repair.