Hispolon attenuates balloon-injured neointimal formation and modulates vascular smooth muscle cell migration via AKT and ERK phosphorylation

The pathological mechanism of restenosis is attributed primarily to excessive proliferation and migration of vascular smooth muscle cells (VSMC). The preventive effects of hispolon (1) on balloon injury-induced neointimal formation were investigated, and 1 showed potent activity in inhibiting fetal bovine serum-induced VSMC outgrowth. Hispolon (1) significantly inhibited VSMC migration, as shown by trans-well assays. Compound 1 decreased the expression and secretion of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9). The expression of the endogenous inhibitors of these proteins, namely, tissue inhibitors of MMP (TIMP-1 and TIMP-2), increased. The inhibition by noncytotoxic doses of 1 of VSMC migration was through its negative regulatory effects on FAK phosphorylation, ERK1/2 phosphorylation, and PI3K/AKT. These results demonstrate that 1 can inhibit the migration of VSMC by reduced expression of MMP-9 through the suppression of the FAK signaling pathway and of the activity of PI3K/AKT. The data obtained suggest that 1 might block balloon injury-induced neointimal hyperplasia via the inhibition of VSMC proliferation and migration, without inducing apoptosis.