Repositioning of approved drugs is an alternative time- and cost-saving strategy to classical drug development. Statins are 3-hydroxy-3-methylglutaryl-CoA (HMG CoA) reductase inhibitors that are usually used as cholesterol-lowering medication, and they also exhibit anti-inflammatory effects. In the present study, we observed that the addition of Pitavastatin at nanomolar concentrations inhibits the proliferation of CD3/CD28 antibody-stimulated human T cells of healthy donors in a dose-dependent fashion. The 50% inhibition of proliferation (IC50) were 3.6 and 48.5 nM for freshly stimulated and pre-activated T cells, respectively. In addition, Pitavastatin suppressed the IL-10 and IL-17 production of stimulated T cells. Mechanistically, we found that treatment of T cells with doses <1 µM of Pitavastatin induced hyperphosphorylation of ERK1/2, and activation of caspase-9, -3 and -7, thus leading to apoptosis. Mevalonic acid, cholesterol and the MEK1/2 inhibitor U0126 reversed this Pitavastatin-mediated ERK1/2 activation and apoptosis of T cells. In summary, our results suggest that Pitavastatin is a highly potent inhibitor of T-cell proliferation, which induces apoptosis via pro-apoptotic ERK1/2 activation, thus representing a potential repositioning candidate for the treatment of T-cell-mediated autoimmune diseases.
Keywords: ERK1/2 activation; Pitavastatin; apoptosis; drug repositioning; inhibitor of T-cell proliferation.