Nodal induces apoptosis and inhibits proliferation in ovarian endometriosis-clear cell carcinoma lesions.

BACKGROUND: Expression of Nodal, a member of the TGF-ß superfamily, is commonly absent in differentiated tissues, while its re-expression occurs in a variety of human malignancy. However, little is known about its involvement in ovarian tumorigenesis. Herein, we focused on the functional roles of Nodal in ovarian endometriosis-carcinoma lesions. METHODS: Regulation and function of Nodal and its associated molecules, including Smad2, GSK-3ß, and several cell kinetics-related molecules, were assessed using clinical samples consisting of 108 ovarian carcinomas and 33 endometriotic lesions, as well as ES-2 (ovarian clear cell carcinoma; OCCCa) and Ishikawa (endometrial carcinoma) cell lines. RESULTS: Nodal expression was significantly higher in endometriosis and OCCCa lesions as compared to that of non-OCCCas, with positive correlations to phosphorylated forms of both Smad2 (pSmad2) and GSK-3ß. When compared to endometriotic lesions, the expression of Nodal and pSmad2 was significantly decreased in OCCCa. Treatment of Ishikawa cells with TGF-ß1 resulted in transcriptional upregulation of Nodal, along with increased pSmad2 expression, while inhibition of GSK-3ß also induced an increase in Nodal expression at the posttranslational level. Both ES-2 and Ishikawa cells stably overexpressing Nodal had increased susceptibility to apoptosis in response to treatment with cisplatin and doxorubicin, respectively, together with higher cleaved caspase-3 expression and decreased Bcl2/Bax ratio. Moreover, the stable Nodal-overexpressing cells showed reduced cell proliferation, along with increased expression of p27kip1 and p21waf1. In clinical samples, a significantly higher number of apoptotic cells and lower Ki-67 labeling indices were observed in Nodal-positive as compared to Nodal-negative OCCCa. CONCLUSIONS: These findings suggest that Nodal is a multifunctional cytokine involved in the modulation of cell kinetics in ovarian endometriosis-OCCCa lesions.

Alterations in ß-catenin, microsatellite instability, and HNF-1ß levels are independently associated with ovarian endometriosis-associated tumorigenesis.

We focused on specific molecular events during the development of endometriosis-associated ovarian endometrioid carcinoma (OEmCa) and ovarian clear cell carcinoma (OCCCa). Alterations in ß-catenin (encoded by CTNNB1) and microsatellite instability (MSI), as well as changes in the expression levels of HNF-1ß and DNA mismatch repair (MMR) proteins were investigated in 50 OEmCas and 21 OCCCas with endometriotic lesions. Mutations of CTNNB1 were identified in 28 (56%) of the 50 OEmCa cases and 26 (41.9%) of the 62 coexisting endometriosis lesions. MSI-high (H) was observed in 7 (14.6%) of the 48 OEmCa and 14 (23.3%) of the 60 coexisting endometriosis, and was significantly associated with loss of MMR protein expression, but not CTNNB1 mutations. Nonidentical CTNNB1 status between 2 different epithelial lesions within endometriosis was observed in 8 of 10 informative endometriosis cases that had adjacent OEmCa. Similar findings for MSI features were also found in 2 of 3 informative cases, suggesting that endometriotic lesions may predominantly consist of polyclonal cells. In contrast, high HNF-1ß expression was significantly associated with SLC3A1 expression, which plays a major role in HNF-1ß-triggered induction of reactive oxygen species in OCCCas, independent of abnormalities in both ß-catenin and MSI/MMR status. Finally, 4 inflammatory parameters associated with repeated hemorrhaging in endometriosis were significantly higher in endometriosis with MSI-high when compared with that with MSS, independent of both ß-catenin and HNF-1ß status. In conclusion, different molecular pathways including alterations in ß-catenin, MSI, and HNF-1ß levels may contribute to tumorigenesis in endometriosis-associated carcinoma.