Effect of Estrogen and Progesterone on Gene Expression of Growth Regulatory Molecules and Proto-Oncogene in Vascular Smooth Muscle Cells

Abstract

We examined influences of estrogen and progestogen on gene expression of the growth regulatory molecules: platelet-derived growth factor (PDGF), interleukin-1 (IL-1), interleukin-6 (IL-6) and proto-oncogene c- myc in vascular smooth muscle cells (VSMC) by reverse transcription-polymerase chain reaction (RT-PCR) and Southern-blotting. VSMC were exposed to estrone-sulfate (E₁-S) and medroxyprogesterone acetate (MPA) to induce differentiation. E₁-S inhibited the expression of PDGF-A chain, IL-1, IL-6 and c-myc mRNA, whereas MPA had no effect. Inhibition by E₁-S was not affected by treatment combined with MPA. These findings suggest that estrogen modulates these growth regulatory molecules and c-myc gene expression in VSMC but not progestogen. We concluded that estrogen may have a direct atheroprotective effect through inhibition of growth regulatory factors.