African-American Men Experience More Aggressive Prostate Cancer

By Will Boggs MD

May 04, 2016

NEW YORK (Reuters Health) - Prostate cancer cells from African-American men exhibit mitochondrial dysfunction not seen in prostate cancer cells from Caucasian men, dysfunction that contributes to greater aggressiveness and metastatic potential, according to a new study.

"We find severe mitochondrial dysfunctions in terms of highly reduced levels of reactive oxygen species, which may function as a survival mechanism to promote cancer cell proliferation and cancer cell survival in African-American men with prostate cancer," Dr. Dhyan Chandra from Roswell Park Cancer Institute, Buffalo, New York, told Reuters Health by email.

The incidence of prostate cancer is 50% higher and mortality rates are two to three times higher in African-American men than in Caucasian men. One reason for these disparities might relate to differences in mitochondrial function.

Dr. Chandra's team investigated the underlying mechanism of cellular proliferation, cell death, cellular invasion, and metastasis in African-American and Caucasian prostate cancer cells and studied the impact of dichloroacetate (DCA), which restores mitochondrial function and causes decreased tumor growth in many cancers.

DCA caused significantly more growth suppression and cell death in Caucasian cells than in African-American cells and failed to reduce cancer stem cell populations in African-American cells compared with Caucasian cells, according to the April 26 British Journal of Cancer online report.

DCA also induced mitochondrial reactive oxygen species (ROS) to a greater extent in Caucasian cells than in African-American cells.

Compared with Caucasian cells, African-American cells possessed defective heat shock protein responses, were more aggressive and metastatic, and possessed a significant survival advantage.

Moreover, DCA enhanced taxol- and doxorubicin-induced cell death in Caucasian cells but not in African-American cells.

"Since taxane-based therapy is commonly prescribed to prostate cancer patients, this regimen may not be the best treatment strategy for prostate cancer patients with severe mitochondrial dysfunction," Dr. Chandra said.

"Together," the researchers write, "we conclude that the presence of severe mitochondrial dysfunction in African-American compared with Caucasian prostate cancer cells could be one of the potential reasons for the increased resistance, metastatic potential, and tumor recurrence in case of African-American patients compared with Caucasian counterpart in the clinic."

"Current evidence suggests that prostate cancer is different in every individual, and each patient requires personalized care," Dr. Chandra concluded. "A great deal of research is needed to make any clinical recommendation."

The National Cancer Institute and the Department of Defense supported this research. The authors made no disclosures.

SOURCE: http://bit.ly/26PWL0x

Br J Cancer 2016.

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