Epidemiological studies show that the incidence and mortality rates of prostate cancer (PCa) are significantly higher in African-American (AA) men when compared to Caucasian (CA) men in the US. Transforming growth factor β (TGFβ) signaling pathway is linked to health disparities in African-Americans. Recent studies suggest a role of TGFβ3 in cancer metastases and its effect on the migratory and invasive behavior; however, its role in prostate cancer in African American men has not been studied. We determined the circulating levels of TGFβ3 in AA and CA men diagnosed with PCa using ELISA. We analyzed serum samples from both AA and CA men diagnosed with and without PCa. We show that AA prostate cancer patients had higher levels of TGFβ3 protein compared to AA controls and CA patients. In fact, TGFβ3 protein levels in serum were higher in AA men without PCa compared to the CA population, which may correlate with more aggressive disease seen in AA men. Studies on AA derived PCa cell lines revealed that TGFβ3 protein levels were also higher in these cells compared to CA derived PCa cell lines. Our studies also reveal that TGFβ does not inhibit cell proliferation in AA derived PCa cell lines, but it does induce migration and invasion through activation of PI3K pathway. We suggest that increased TGFβ3 levels are responsible for development of aggressive prostate cancer in AA patients as a consequence of development of resistance to inhibitory effects of TGFβ on cell proliferation and induction of invasive metastatic behavior.
Carcinogenesis. 2018 Feb 21 [Epub ahead of print]
Bethtrice Elliott, DeAdra L Zackery, Vanessa A Eaton, Re'Josef T Jones, Fisseha Abebe, Camille C Ragin, Shafiq A Khan
Center for Cancer Research and Therapeutic Development, Clark Atlanta University, Atlanta, GA, USA., Fox Chase Cancer Center-Temple Health, Philadelphia, PA, USA.