New discovery about the role of vitamin D in prostate cancer

New research from Cedars-Sinai Cancer suggests that Vitamin D deficiency may be the cause of African American men experiencing more aggressive prostate cancer at a younger age compared to European American men. The study, published today in Cancer Research Communications and conducted by multiple institutions, could potentially lead to revised nutritional guidelines.

While previous research has explored the role of Vitamin D in health disparities, this study is the first to investigate its functions in a genome-wide manner in African American versus European American men.

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According to Moray Campbell, Ph.D., a research scientist at Cedars-Sinai Cancer and senior author of the study, "African American men are more likely than European American men to develop prostate cancer, and are twice as likely to die from the disease. Large-scale studies have shown that differences in access to healthcare do not fully explain this health disparity, and our study identifies biological factors that could provide an explanation."

According to Campbell, Vitamin D not only aids in the absorption of calcium for bone health, but it also promotes cell maturation. Unlike normal cells, cancer cells do not mature and eventually die. Instead, they continue to divide and create abnormal cells.

"When there are insufficient levels of Vitamin D to promote cell maturation, tumor cells continue to multiply uncontrollably," Campbell explained.

In their research, Campbell and his colleagues discovered that the Vitamin D receptor, a protein that facilitates the use of Vitamin D in the body, appears to have adapted differently in individuals of African ancestry.

"The ancestors of African American and European American men adapted to the climates of their origin," Campbell elaborated. "African men have higher melanin levels in their skin, which protects them against the sun's strong rays and also assists the body in producing Vitamin D. As a result, their descendants in the United States, where there are fewer hours of bright sunshine per year compared to African countries, often suffer from Vitamin D deficiency."

Researchers examined prostate cancer cells from patients of African and European descent that were developed in the lab of Clayton Yates, Ph.D., at Johns Hopkins School of Medicine. They observed differences in how these groups of cells responded to exposure to vitamin D.

"Their reaction to vitamin D differed significantly, including which genes the vitamin D receptor controlled and to what extent," Campbell explained. "This different response in African American men made them more susceptible to prostate cancer."

Campbell stated that further research in this area could result in revised nutritional guidelines for vitamin D intake based on genetic ancestry, for both bone and prostate health. He also emphasized the need for additional work to determine the optimal level of vitamin D for each group and to examine how the vitamin D receptor interacts with other proteins associated with prostate cancer.

Dan Theodorescu, MD, Ph.D., director of Cedars-Sinai Cancer and the PHASE ONE Distinguished Chair, stated that "Cedars-Sinai Cancer provides care to one of the most diverse populations in the U.S., and this study is one of the many initiatives aimed at uncovering the underlying causes of health disparities." He added that the study highlights the importance of multi-institutional collaboration and the Community Outreach and Engagement (COE) team's role in involving diverse populations in cancer research.

Campbell and his colleagues plan to conduct further research on a group of microRNAs that help regulate gene expression in regions of the genome controlled by the vitamin D receptor. They discovered a link between these microRNAs and prostate cancer that could eventually lead to the development of blood tests that provide a more comprehensive view of prostate health. The team also intends to investigate the relationship between vitamin D and health disparities in other hormone-dependent cancers, such as breast cancer.