Polarization of M2 Macrophages by Interaction between Prostate Cancer Cells Treated with Trichomonas vaginalis and Adipocytes

Trichomonas vaginalis causes inflammation of the prostate and has been detected in tissues of prostate can- cers (PCa), prostatitis and benign prostatic hyperplasia. Obesity is a risk factor for PCa and causes a chronic subclinical inflammation. This chronic inflammation further exacerbates adipose tissue inflammation as results of migration and acti- vation of macrophages. Macrophages are the most abundant immune cells in the PCa microenvironment. M2 macro- phages, known as Tumor-Associated Macrophages, are involved in increasing cancer malignancy. In this study, condi- tioned medium (TCM) of PCa cells infected with live trichomonads contained chemokines that stimulated migration of the mouse preadipocytes (3T3-L1 cells). Conditioned medium of adipocytes incubated with TCM (ATCM) contained Th2 cy- tokines (IL-4, IL-13). Macrophage migration was stimulated by ATCM. In macrophages treated with ATCM, expression of M2 markers increased, while M1 markers decreased. Therefore, it is suggested that ATCM induces polarization of M0 to M2 macrophages. In addition, conditioned medium from the macrophages incubated with ATCM stimulates the prolifera- tion and invasiveness of PCa. Our findings suggest that interaction between inflamed PCa treated with T. vaginalis and adipocytes causes M2 macrophage polarization, so contributing to the progression of PCa.