A NOVEL LOW-DOSE COMBINATION DRUG THERAPY FOR ENDOMETRIOSIS THAT INCREASES PROGESTERONE RECEPTOR TO ENHANCE PROGESTIN EFFICACY

Abstract

Endometriosis is an estrogen-dependent disease that is a leading cause of pelvic pain and infertility worldwide. While ectopic endometrial tissue should theoretically regress with progesterone treatment, resistance to progesterone is common, limiting the effectiveness of hormonal therapies to treat established disease and to prevent post-surgical disease recurrence. We sought to apply a quality-by-design (QbD) approach to develop a novel sensitizing therapy for endometriosis by targeting progesterone receptor (PR) expression. Our group has previously successfully utilized a QbD approach to develop a novel combination of clinical compounds to induce estrogen receptor alpha (ESR1) in hormone-positive breast cancer cells to sensitize them to tamoxifen therapy; similar to endometriosis, many types of breast cancer are resistant to hormonal therapies. This QbD approach leverages advanced automation technology and predictive mathematical modeling to investigate the additive and synergistic effects of combinatorial drug treatment on gene expression in immortalized cell lines. We selected 12 different compounds that are either known to be involved in sex hormone signaling, used in the treatment of endometrioid ovarian cancer (arising from endometriosis), and/or currently used or under investigation for the treatment of endometriosis. Using our custom-design QbD platform, we measured the relative effects of these compounds, each at concentrations well below their efficacious dose, on a variety of genes in 12Z cells (an immortalized endometriotic cell line). We identified five drugs (belinostat, celecoxib, everolimus, bentamapimod, and paclitaxel) that in combination have a synergistic effect on PR expression. In vitro studies confirmed elevated PR expression in both RNA and protein. After three days of drug treatment on 12Z cells compared to controls, combinatorial drug treatment resulted in a 8.8 fold increase in PR expression levels with no change in ESR1 levels. This work offers a novel combinatorial drug therapy and proof-of-concept for endometriosis treatment. It also provides new insight into the mechanisms by which known endometriosis drugs reduce disease burden. Efforts are underway to utilize a mouse model of endometriosis to determine whether this drug cocktail can enhance PR expression and thereby efficacy of progestin therapy. Future work will involve determining the precise molecular pathways by which these drugs act to enhance PR expression.