Abstract 4921: TGF-beta signaling proteins and CYP24A1 may serve as surrogate markers for progesterone calcitriol treatment in ovarian and endometrial cancers of different histological types

Abstract

Strategies are needed to coordinately block drivers and induce suppressors of cancer to reduce incidence and improve outcomes for individuals with inherited or acquired risk. We previously reported the chemopreventive and therapeutic efficacy of the combination of progestin and calcitriol in transformed and malignant endometrioid endometrial cancer and in ovarian cancer models involving attenuated expression of TGF-β signaling proteins and progestin-mediated inhibition of calcitriol-induced CYP24A1 expression. This study aims to expand the applications for this combination to other subtypes of endometrial and ovarian cancers including those with mutations in ARID1A or PIK3CA, DNA mismatch repair deficiency or BRCA1-null status. The end points for this in vitro investigation included assessments of cell growth and the expression of TGF-β ligands, receptors, SMAD proteins and CYP24A1. Treatment of ovarian clear cell carcinoma, endometrioid carcinoma, papillary serous adenocarcinoma, BRCA1 null, and DNA mismatch repair deficient endometrial cancer cell lines with progesterone alone or in combination with calcitriol inhibited cell growth and expression of TGF-β1, TGF-β2, TGF-Rβ1, TGF-βR2, pSMAD2/3 and CYP24A1. Expression of TGF-βR3, SMAD-4, PR and VDR was not altered in any cell line tested except, ES-2, where VDR expression was upregulated in response to treatment. These results suggest that progesterone alone and progesterone-calcitriol combination have broad application in both chemopreventive and therapeutic settings that merit further development in a wide variety of ovarian and endometrial cancers, including those derived from germline or somatic mechanisms. Moreover, our data suggest that TGF-β signaling proteins and CYP24A1 may be effective surrogate markers indicative of treatment response. Citation Format: Ana Paucarmayta, Hannah Taitz, Yovanni Casablanca, Gustavo C. Rodriguez, G L. Maxwell, Kathleen M. Darcy, Viqar Syed. TGF-beta signaling proteins and CYP24A1 may serve as surrogate markers for progesterone calcitriol treatment in ovarian and endometrial cancers of different histological types [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4921.