Protein expression and cellular localization of Estrogen Receptors alpha and beta in endometriosis-associated epithelial ovarian cancer cell lines

BASTON, JUAN IGNACIO; FERELLA, LUCIANA; SINGLA, JOSÉ JAVIER; GONZALEZ, ALEJANDRO MARTÍN; MERESMAN, GABRIELA

Ginebra

Congreso; 33º Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE); 2017

European Society of Human Reproduction and Embryology (ESHRE)

Study question: to evaluate the protein expression and determine the cellular localization of ERα and ERβ in cell lines derived from human endometrioid and clear-cell EOC. Summary answer: Both endometriosis-associated cell lines expressed these steroid receptor proteins. ERα was mainly localized into the cellular nucleus, whereas ERβ was mostly localized into cytoplasm.What is known already: The pathophysiological mechanisms involved in the etiology of the endometriosis-associated EOC, such as endometrioid and clear-cell ovarian tumors, are not entirely known yet. However it is well-known that the local hormonal environment that promotes the development of these ovarian carcinomas is similar to the peritoneal hormonal environment found in patients with endometriosis, where the steroid hormones levels, mainly estradiol, are particularly high. Therefore, it is crucial the development of suitable experimental models in order to allow an accurate characterization of the potential role exerted by the endometriotic lesions-released estrogens on the occurrence and progression of endometriosis-associated EOC.Study design, size, and duration: Human epithelial ovarian cancer cell lines were cultured under standard conditions until confluence to further analysis of ERα and ERβ protein expression and cellular localization. Participants/materials, setting, methods: TOV-112D cell line (ATCC CRL-11731) derived from a human endometrioid-type ovarian carcinoma and TOV-21G cell line (ATCC CRL-11730) derived from a human clear-cell ovarian carcinoma were purchased from the American Type Culture Collection (ATCC). The protein expression and cellular localization of ERα and ERβ in each cell line was analyzed by Western blot and indirect immunofluorescence (IFI) respectively, in 4 independent experiments.Main results and the role of chance: We found that both EOC cell lines expressed ERα and ERβ proteins, being the ERα expression qualitatively stronger than ERβ in both cell lines. These results suggest that these endometriosis-associated EOC cell lines have the necessary molecular machinery to respond to steroid hormones stimuli. In addition, we found that in both cell lines ERα was mostly located into the nucleus, indicating that this receptor had been activated by its canonical ligand, dimerized and translocated to the cellular nucleus, where it regulates the transcription of its target genes. ERβ was mainly found in the cytoplasm, where it is mostly inactive.Limitations, reasons for caution: This is an initial descriptive study, so it is very important to make it clear that functional studies will be addressed to fully understand the role of the estradiol secreted by endometriotic lesion on the pathophysiological mechanisms underlying the etiology of endometriosis-associated EOC.Wider implications of the findings: These cell lines are endowed with the necessary molecular machinery (i.e. ERα and ERβ) to respond to estradiol released by endometriotic lesions, thus becoming a suitable in vitro model to study the potential role of steroid hormones on the onset and development of endometriosis-associated EOC.Study Funding: National Agency for Promotion of Science and Technology (ANPCYT), National Council for Scientific and Technological Research (CONICET), Rene Barón Foundation, Florencio Fiorini Foundation and Alberto J. Roemmers Foundation; Buenos Aires, Argentina.