In-vitro effect of Ulipristal on proliferative and apoptotic indices and steroid hormone receptor expression in endometriotic stromal stem cells

Abstract

Study question: Does ulipristal acetate (UPA) affect cell proliferation, apoptosis and expression of estrogen and progesterone receptors in human endometriotic stromal cells in-vitro? Summary answer: In-vitro treatment of endometriotic stromal cells with UPA did not affect cell proliferation and apoptosis nor expression of steroid receptors. What is known already: UPA is a selective progesterone-receptor modulator (SPRM), which binds to the progesterone receptor with high affinity and suppresses proliferation of endometriosis. In a rat model with surgically induced endometriosis, UPA treatment leads to regression and atrophy of endometriosis in terms of volume of endometriosis and expression of apoptotic and proliferative markers. Currently there are no data on the effect of UPA on human endometriotic tissue. Study design, size, duration: Endometriotic cyst wall tissue was collected and dissociated with collagenase. Stromal cells were separated from epithelial cells using CD326 microbeads and cultured for 10 days until the cells reached 60-80% confluence. Equal portions of stromal cells were seeded into 6-well plates and treated with graded concentrations (0, 0.1, 1, 10 and 100 ng/ml) of UPA for 48 hours. Participants/materials, setting, methods: Ovarian endometriotic cyst samples were obtained from four women undergoing ovarian cystectomy or salpingo-oophorectomy. Endometriotic stromal cells were cultured on 25-mm Thermanox coverslips and treated with UPA for 48 hours. Immunohistochemical staining for proliferative marker Ki-67, apoptotic marker Bcl-2 and receptors for oestrogen (ER-α) and progesterone (PR) was performed. H-score was used to evaluate the protein expression. Control cells were not treated with UPA. Main results and the role of chance: Endometriotic stromal cells after treatment with UPA remained characteristically flat and spindle shaped demonstrating no morphological changes when compared with the control. UPA administration exhibited no significant change in the expression of proliferative (Ki-67) (1.55 +/- 0.77, 1.29 +/- 0.31, 1.36 +/- 0.56, 1.24 +/- 0.43, 1.35 +/-0.22 for UPA concentration 0, 0.1, 1, 10 and 100 ng/ml respectively, p = 0.721) and apoptotic (Bcl-2) markers (2.59 +/- 0.66, 1.76 +/- 0.95, 2.58 +/- 1.42, 2.02 +/- 0.78, 1.86 +/- 0.55 for UPA concentration 0, 0.1, 1, 10 and 100 ng/ml respectively, p = 0.165). There were also no significant change in the expression of hormone receptors of ER-α (0.54 +/- 0.25, 0.63 +/- 0.18, 0.64 +/- 0.24, 0.69 +/- 0.26, 0.67 +/- 0.33 for UPA concentration 0, 0.1, 1, 10 and 100 ng/ml respectively, p = 0.76) and PR (2.21 +/- 1.16, 2.33 +/- 1.80, 2.54 +/- 1.17, 2.25 +/- 1.32, 2.56 +/- 1.34 for UPA concentration 0, 0.1, 1, 10 and 100 ng/ml respectively, p = 0.970). Limitations, reasons for caution: The limited sample size contributed to high patient variation. Only one apoptotic and proliferative markers were assessed. There was no co-culture of oestrogen and progesterone with the endometriotic stromal cells which may underestimate the effect of UPA. Wider implications of the findings: Whether there was any role of UPA on endometriosis remained uncertain. Evaluation of other apoptotic and proliferative markers should be performed for understanding the effect of UPA on endometriosis. Trial registration number:Non-applicable