The effect of IL-6 and TNF-α on the regulation of the KLK4 gene in prostate cancer cell models

Prostate cancer is a highly prevalent type of cancer worldwide, and numerous studies have been conducted over the years to improve its diagnosis and treatment. Various cytokines play significant roles in the development and differentiation of cancer. In prostate cancer, similar to other types of cancer, pro-inflammatory cytokines such as IL-6 and TNF-α are involved in regulating different biological processes, including cell proliferation, differentiation, and apoptosis. It has been established that the KLK4 gene, a member of the serine protease family, is overexpressed in prostate cancer. However, no studies have been found that explore the relationship between the KLK4 gene and the specified cytokines. This thesis aims to investigate the effect of the inflammatory cytokines IL-6 and TNF-α on the regulation of the KLK4 gene in prostate cancer. As a result of this thesis study, the effect of different doses of IL-6 and TNF-α on cell viability in androgen-dependent and independent cell lines was determined using the MTT assay. Subsequently, the effect of IL-6 and TNF-α cytokines on the regulation of the KLK4 gene was assessed at the mRNA and protein levels through Real-Time PCR and Western Blot analyses. The obtained data indicated that IL-6 promotes the expression of the KLK4 gene, while TNF-α suppresses its expression. To determine the transcriptional activity of the KLK4 gene, the effects of different promoter fragments on transcriptional activity in the presence of IL-6 and TNF-α were investigated. EMSA experiments demonstrated that IL-6 and TNF-α regulate transcriptional activity through the SMAD-3 and NFκB pathways in LNCaP cells.