RNA-seq of NIC+,CdGAPwt/wt and NIC+,CdGAPfx/fx tumors

CdGAP/ARHGAP31 is a molecular target of TGFb-mediated EMT and required for Her2-positive breast cancer growth and metastasis Metastasis is the leading cause of death in breast cancer patients. The epithelial-to-mesenchymal transition (EMT) has a crucial role in metastasis and is highly critical for tumor cell dissemination. CdGAP/ARHGAP31 is highly expressed in breast cancer tissues and is associated with poor clinical outcome in breast cancer patients. CdGAP cooperates in a GAP-independent manner with the transcriptional repressor Zeb2 to function as a critical modulator of breast cancer through repression of E-cadherin transcription. In this study, we used a murine model of Her2+ breast cancer to investigate further the role of CdGAP in breast tumorigenesis. We found that CdGAP was essential for tumor formation and metastasis to the lungs in the Her2+ mouse breast cancer model. We determined that CdGAP is required for intravasation and growth at the metastatic sites. By using global gene expression approaches, we found that CdGAP depletion in Her2+ primary tumors was associated with an EMT signature, including a decreased expression of the metastatic factor claudin-2 and an increase in E-cadherin expression. In Her2+ breast cancer cells, CdGAP expression is positively regulated by the TGFb canonical pathway in a smad-dependent manner and regulates cell proliferation, migration, invasion, and adhesion. CdGAP was found to interact with the focal adhesion protein Talin and regulates focal adhesion dynamics in breast cancer cells. Collectively, CdGAP appears as a potential anti-metastatic target for the treatment of Her2+ breast cancer. Differential gene expression profile between tumors from NIC+,CdGAPwt/wt mice and NIC+,CdGAPfx/fx mice (Illumina HiSEq 2000)