The novel role of IL-37 in prostate cancer: evidence as a promising radiosensitizer.

Prostate cancer (PCa) is the most common non-cutaneous cancer in men in the USA. Radiation therapy (RT) is widely considered the standard treatment for PCa. IL-37 is an IL-1 family member, and it has been extensively studied in immunity. However, no studies have been done regarding its potential as a radiosensitizer. This study is designed to investigate the direct effect of IL-37 on growth of DU145 and PC-3, two widely studied PCa cell lines, and to investigate whether IL-37 could be used as a radiosensitizer for PCa. Clonogenic survival and quick cell proliferation assays along with immunohistochemistry, TUNEL staining, and caspace-3 activity assay kits as well as RT-PCR were used in this study. Our results showed that IL-37 has little direct effect on growth of PCa. However, IL-37/RT enhanced RT-induced inhibition of cell proliferation and apoptosis in both cell lines. We further found that IL-37/RT upregulated the mRNA expression of p27, Fas, and Bax, while downregulating the mRNA expression of cdk2 in DU145 cells. These findings suggest that IL-37 has the potential to be used as a radiosensitizer for PCa and warrants further investigation.