Downregulation of cell surface CA125 MUC16 induces epithelial-to-mesenchymal transition and restores EGFR signalling in NIH:OVCAR3 ovarian carcinoma cells

• Published in: British journal of cancer 2011-03, Vol.104 (6), p.989-999
• Main Authors: Comamala, M, Pinard, M, Thériault, C, Matte, I, Albert, A, Boivin, M, Beaudin, J, Piché, A, Rancourt, C
• Format: Article
• Language: English
• Subjects: 631/80/84/2176; 631/80/86; 692/699/67/1517/1709; 692/699/67/1857; Antigens, Surface - metabolism; Antigens, Surface - physiology; beta Catenin - metabolism; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; CA-125 Antigen - metabolism; CA-125 Antigen - physiology; Cadherins - metabolism; Cancer Research; Carcinoma - metabolism; Carcinoma - pathology; Cell Line, Tumor; Cell Movement - drug effects; Down-Regulation - physiology; Drug Resistance; Epidemiology; Epithelial-Mesenchymal Transition - physiology; Female; Female genital diseases; Gene Knockdown Techniques; Gynecology. Andrology. Obstetrics; Humans; Medical sciences; Membrane Proteins - antagonists & inhibitors; Membrane Proteins - metabolism; Membrane Proteins - physiology; Molecular Diagnostics; Molecular Medicine; Oncology; Ovarian Neoplasms - metabolism; Ovarian Neoplasms - pathology; Protein Binding - drug effects; Receptor, Epidermal Growth Factor - metabolism; Receptor, Epidermal Growth Factor - physiology; RNA, Small Interfering - pharmacology; Tumors
• ISSN: 0007-0920; 1532-1827
• DOI: 10.1038/bjc.2011.34

Background: Epithelial ovarian cancer (EOC) cells are prone to metastasise throughout the peritoneal cavity. The epithelial-to-mesenchymal transition (EMT) is a necessary step towards metastatic tumour progression. CA125/MUC16 mucin is a high-molecular-weight glycoprotein overexpressed in the majority of serous carcinomas, suggesting a possible role in the pathogenesis of these cancers. Methods: The role of CA125/MUC16 in EMT was investigated using single-chain antibody-mediated knockdown of cell surface CA125/MUC16 in overexpressing EOC NIH:OVCAR3 cells. Results: CA125/MUC16 knockdown was associated with morphological alterations along with decreased surface expression of epithelial markers (E-cadherin, cytokeratin-18) and increased expression of mesenchymal markers (N-cadherin, vimentin). Co-immunoprecipitation experiments revealed that CA125/MUC16 binds to E-cadherin and β -catenin complexes. The in vitro studies showed disruption of cell–cell junctions, enhanced motility, migration and invasiveness in CA125/MUC16 knockdown cells. Enhanced epidermal growth factor receptor (EGFR) activation was observed in CA125/MUC16 knockdown cells along with increased Akt and ERK1/2 phosphorylation, which are downstream effectors of EGFR, and increased MMP-2 and MMP-9 expression and activities. Epidermal growth factor receptor inhibition strongly inhibited the motility of CA125/MUC16 knockdown cells. Conclusions: Our findings suggest that CA125/MUC16 plays a role in EMT, presumably through its interaction with E-cadherin and β -catenin complexes and by modulating EGFR and its downstream signalling pathway in NIH:OVCAR3 cells.