Investigation of genes affected by miRNAs associated with prostate cancer by in silico and experimental analyses

Prostate cancer (PCa) is the second most commonly diagnosed cancer among men worldwide and the fifth leading cause of cancer death. Despite its high prevalence, diagnostic methods can lead to misdiagnosis, resulting in unbearable side effects. The difficult part of PCa is that the tumor becomes heterogeneous, with multiple signaling pathways involved. In this case, tumor progression and metastasis are inevitable. More studies on PCa are needed to prevent this situation. Based on these results, the aim of this study is to investigate the effects of miR-375 and miR-125b-5p and their targets and the effects of these miRNAs or genes thought to be effective on the PI3K signaling pathway in prostate cancer cells. In order to determine the potential targets of miR-375 and miR-125b-5p in the project, estimated target genes were determined by miRNA target prediction tools. Afterwards, whether the genes were validated and their functions in signaling pathways were examined. After the study design, transfection was performed using miR-375 and miR-125b-5p mimics/inhibitors. The effects of changes in the expression level of miRNAs on cell viability and cell migration in PCa cells were examined. qRT-PCR and western blotting were performed to evaluate the changes in the expression and protein levels of the relevant genes. The results showed that upregulation of miR-375 and miR-125b-5p decreased cell viability. In the wound healing test, miR-375 upregulation did not prevent cell migration, while miR-125-5p upregulation reduced cell migration. In contrast, downregulation of both miRNAs decreased cell migration. Expression analyses suggested that miR-375 does not target TSC1, while miR-125b-5p may target CYTH1, although no significant change was observed. It has also been shown that miR-375 and miR-125b-5p affect molecules in the signaling pathway and may be an important regulator of signaling pathways, especially miR-375 regulates an important molecule such as mTOR. However, its effects in cells differ. In conclusion, the data obtained in this study are important in terms of understanding the effects of PI3K signaling pathway, which has an important place in cancer development, on prostate cancer and will contribute to the literature. It is an important study in terms of the use of miRNAs as biomarkers or the development of new treatment options.