1,25-Dihydroxyvitamin D3 Suppresses Prognostic Survival Biomarkers Associated with Cell Cycle and Actin Organization in a Non-Malignant African American Prostate Cell Line

Vitamin D3 is a steroid hormone that has been shown to prevent tumor growth in prostate cells. Not having enough vitamin D3 in the blood has been linked to advanced prostate cancer and mortality, especially in African American men. We wanted to understand how vitamin D affected pathways that keep prostate cells from becoming cancerous, which could lead to new therapeutic targets and treatments, especially for African American men who tend to be more prone to being vitamin D deficient compared to European men. Here, we studied a non-cancerous African American prostate cell line treated with the active form of vitamin D with a concentration similar to what is found in the body for 24 h. Using RNA whole-transcriptome sequencing, we compared these treated cells with untreated cells to assess genes and pathways significantly changed due to treatment. We found that vitamin D affected the activity of 1600 genes, mainly suppressing pathways linked to prostate cell movement, growth, and viability. Only two genes, ANLN and ECT2, were strongly correlated with prostate cancer prognosis. Downregulation of ANLN and ECT2 was also shown to repress signaling pathways involved in prostate cell movement, growth, malignant transformation, and viability. In further validation utilizing prostate cancer cohorts comprised of African American and European American men, patients tended to have better sur-vival rates when these genes were less active. Our results suggest that vitamin D decreases the activity of these genes and could be important for preventing prostate cancer, especially for African American men. This could lead to the development of new treatments targeting specific genes and pathways involved in prostate cancer growth.