MUC16 contributes to the metastasis of pancreatic ductal adenocarcinoma through focal adhesion mediated signaling mechanism
Sakthivel Muniyan1,*, Dhanya Haridas1,*, Seema Chugh1, Satyanarayana Rachagani1, Imayavaramban Lakshmanan1, Suprit Gupta1, Parthasarathy Seshacharyulu1, Lynette M. Smith2, Moorthy P. Ponnusamy1,3 and Surinder K. Batra1,3,4
1 Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
2 Department of Biostatistics, University of Nebraska Medical Center, Omaha, NE, USA
3 Fred and Pamela Buffett Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
4 Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
* Equal contribution
Correspondence:
Surinder K. Batra, email:
Keywords: MUC16, pancreatic cancer, metastasis, FAK and CRISPR/Cas9
Received: December 26, 2015 Accepted: April 20, 2016 Published: April 26, 2016
Abstract
MUC16, a heavily glycosylated type-I transmembrane mucin is overexpressed in several cancers including pancreatic ductal adenocarcinoma (PDAC). Previously, we have shown that MUC16 is significantly overexpressed in human PDAC tissues. However, the functional consequences and its role in PDAC is poorly understood. Here, we show that MUC16 knockdown decreases PDAC cell proliferation, colony formation and migration in vitro. Also, MUC16 knockdown decreases the tumor formation and metastasis in orthotopic xenograft mouse model. Mechanistically, immunoprecipitation and immunofluorescence analyses confirms MUC16 interaction with galectin-3 and mesothelin in PDAC cells. Adhesion assay displayed decreased cell attachment of MUC16 knockdown cells with recombinant galectin-1 and galectin-3 protein. Further, CRISPR/Cas9-mediated MUC16 knockout cells show decreased tumor-associated carbohydrate antigens (T and Tn) in PDAC cells. Importantly, carbohydrate antigens were decreased in the region that corresponds to MUC16 and suggests for the decreased MUC16-galectin interactions. Co-immunoprecipitation also revealed a novel interaction between MUC16 and FAK in PDAC cells. Interestingly, we observed decreased expression of mesenchymal and increased expression of epithelial markers in MUC16-silenced cells. Additionally, MUC16 loss showed a decreased FAK-mediated Akt and ERK/MAPK activation. Altogether, these findings suggest that MUC16-focal adhesion signaling may play a critical role in facilitating PDAC growth and metastasis.
