RBFOX2 acts as a tumor suppressor in metastatic pancreatic cancer

RBFOX2 plays a key role in tissue-specific alternative splicing regulation. Aberrant expression of RBFOX2 in many cancers causes altered splicing of specific targets. Recent studies suggest that RBFOX2 is important in establishing an invasive phenotype through its regulation of mesenchymal-specific splicing events during EMT. In an attempt to investigate the role of RBFOX2 and its splicing targets in the development of metastatic pancreatic cancer we have established a model system using human primary pancreatic tumor samples (primary tumors) and human metastatic ascites cells (ascites) obtained from pancreatic cancer patients.ֲ The ascites was used to generate either solid tumors in mice (PDX tumors) or metastatic cell lines (PDX-derived cell lines) by xenografting. Using our model system, we found that RBFOX2 is down-regulated in the metastatic tumors compared to primary tumors. Overexpression of RBFOX2 in patient-derived metastatic cell lines induced cell death and inhibited cell migration in vitro and in vivo, while knockout of RBFOX2 promoted the tumorigenic abilities and migration of primary pancreatic cancer cells. Taken together, these findings suggest that RBFOX2 acts as a tumor suppressor in metastatic pancreatic cancer. Deep RNA sequencing of these cell lines revealed both known and novel RBFOX2 regulated alternative splicing targets.ֲ Bioinformatics analysis of these splicing targets showed enrichment of targets in the Rho and Hippo signaling pathway, pathways known to have a role in migration. We will use CRISPR sgRNAs to target individual alternative splicing events based on specific biological pathways. These sgRNAs, targeting either 3` or 5` splice sites, will be introduced into cells and the cells will be tested in a lung metastases assay in vivo. Understanding the biological importance of RBFOX2 and its involvement in pancreatic metastatic tumors has the potential to aid early diagnosis and shed light on novel approaches for treatment.