Retinoic acid regulates endometriotic stromal cell growth through upregulation of Beclin1

Purpose To elucidate the role of retinoic acid (RA) in autophagy-mediated endometriosis. Methods The mRNA and protein expressions of autophagy markers were examined in Ishikawa cells and endometriotic stromal cells (ESCs) after RA treatment. Beclin1 expression was specifically analyzed in clinical samples of endometriosis. The effect of Beclin1 knockdown on ESC growth was assessed, and the effect of autophagy inhibition on the sensitivity of endometriotic cells to RA was analyzed. Results RA treatment enhanced the autophagy in ESCs, and Beclin1 expression showed a negative correlation with the clinical stage of endometriosis. Beclin1 knockdown enhanced ESC growth, whereas RA treatment reversed this effect. Furthermore, inhibition of autophagy by chloroquine (CQ) and Beclin1 knockdown did not show any positive effect on the sensitivity of endometriotic cells to RA. Conclusions RA treatment induces autophagy and Beclin1 may play an important role in endometriosis progression.