Resveratrol and pterostilbene regulate MED28 (magicin/EG1) expression and cell growth in MCF7 human breast cancer cells

• Resveratrol and pterostilbene reduced the expression of MED28 and cyclin D1.
• Resveratrol and pterostilbene reduced MED28-induced NFκB binding activity.
• Resveratrol showed a dose–response inhibition on EGF-induced NFκB binding activity.
• MED28 regulated cyclin D1 expression and cell cycle progression.
• MED28 regulated the expression of FOXO3a and NFκB.

Resveratrol and pterostilbene exhibit numerous biological effects, including antiproliferative and proapoptotic activities, in various experimental settings. Mammalian Mediator subunit MED28 is highly expressed in several types of tumor including breast cancer. Recently, we have reported that MED28 regulates cellular migration and invasion in human breast cancer cells, whereas resveratrol can inhibit the effect. In the current study we investigated the effect of resveratrol and pterostilbene on MED28 expression and cell growth in human breast cancer cells. MED28 suppression delayed cell cycle progression, and reduced the expression of cyclin D1 and p-RelA/p65 as well as the transcriptional activity of NFκB, but increased the levels of p27 and FOXO3a. Overexpression of MED28 enhanced S phase entry and increased p-p65 expression. Resveratrol and pterostilbene reduced the expression of MED28 and cyclin D1, and mediated the transcriptional activity of NFκB, thereby suppressing the growth-promoting role of MED28.