Characterization of the effects of butyric acid on cell proliferation, cell cycle distribution and apoptosis

We examined concentration-dependent changes in cell cycle distribution and cell cycle-related proteins induced by butyric acid. Butyric acid enhanced or suppressed the proliferation of Jurkat human T lymphocytes depending on concentration. A low concentration of butyric acid induced a massive increase in the number of cells in S and G₂/M phases, whereas a high concentration significantly increased the accumulation of cells in G ₂/M phase, suppressed the accumulation of cells in G ₀/G₁ and S phases, and induced apoptosis that cell cycle-related protein expression in Jurkat cells treated with high levels of butyric acid caused a marked decrease in cyclin A, cyclin E, cyclin-dependent kinase 2 (CDK2), CDK4 and CDK6 protein levels in G₀/G₁ and S phases, with apoptosis induction, and a decrease in cyclin B, Cdc25c and p27^KIP1 protein levels, as well as an increase in p21 ^CIP1/WAF1 protein level, in the G₂/M phase. Taken together, our results indicate that butyric acid has bimodal effects on cell proliferation and survival. The inhibition of cell growth followed by the increase in apoptosis induced by high levels of butyric acid were related to an increase in cell death in G₀/G₁ and S phases, as well as G₂/M arrest of cells. Finally, these results were further substantiated by the expression profile of butyric acid-treated Jurkat cells obtained by means of cDNA array.