Dietary palmitate cooperates with Src kinase to promote prostate tumor progression

Abstract

Numerous genetic alterations have been identified during prostate cancer progression. The influence of environmental factors, particularly the diet, on the acceleration of tumor progression is largely unknown. Expression levels and/or activity of Src kinase are highly elevated in numerous cancers including advanced stages of prostate cancer. In this study, we demonstrate that high-fat diets (HFDs) promoted pathological transformation mediated by the synergy of Src and androgen receptor in vivo. Additionally, a diet high in saturated fat significantly enhanced proliferation of Src-mediated xenograft tumors in comparison with a diet high in unsaturated fat. The saturated fatty acid palmitate, a major constituent in a HFD, significantly upregulated the biosynthesis of palmitoyl-CoA in cancer cells in vitro and in xenograft tumors in vivo. The exogenous palmitate enhanced Src-dependent mitochondrial β-oxidation. Additionally, it elevated the amount of C16-ceramide and total saturated ceramides, increased the level of Src kinase localized in the cell membrane, and Src-mediated downstream signaling, such as the activation of mitogen-activated protein kinase and focal adhesion kinase. Our results uncover how the metabolism of dietary palmitate cooperates with elevated Src kinase in the acceleration of prostate tumor progression.