Expression of E-cadherin transcriptional regulators in ovarian carcinoma

Unlike most epithelial cancers, E-cadherin expression is upregulated in ovarian carcinoma effusions compared with corresponding primary tumors. In the present study, we analyzed the anatomic site-specific expression of transcription factors that negatively regulate E-cadherin in ovarian carcinoma. Using reverse-transcription polymerase chain reaction, mRNA in situ hybridization, and Western blotting, we analyzed the expression and localization of the Snail, Slug, and SIP1 transcription factors and E-cadherin in 78 effusions, 41 primary carcinomas, and 15 solid metastases. Slug mRNA and protein expression was highest in metastases (p=0.042 and p<0.001, respectively). Snail mRNA was comparable at all anatomic sites, but higher protein expression was found in primary tumors and solid metastases compared with effusions (p<0.001). SIP1 mRNA expression was higher in effusions (p<0.001) compared to other sites. Confocal microscopy analysis of fresh and cultured cells from effusion specimens revealed cytoplasmic localization of the Snail protein in primary tumor cells, with a nuclear shift following culturing of these cells. In conclusion, E-cadherin and its negative regulators show site-dependent expression in ovarian carcinoma. In solid tumors, E-cadherin is negatively regulated by Snail and Slug. In effusions, SIP1 may be the main regulator of E-cadherin, but with a lesser level of suppression compared with primary tumors and solid metastases.