RNA-seq of MMTV-Neu AXL KO tumors

AXL is activated by its ligand GAS6 and is expressed in triple-negative breast cancer cells. We report that AXL is also detected in HER2+ breast cancer specimens where its expression correlates with poor patients’ survival. Using murine models of HER2+ breast cancer, AXL, but not Gas6, was found essential for metastasis. We determined that AXL is required for intravasation, extravasation and growth at the metastatic site. AXL is expressed in HER2+ cancers displaying EMT signatures and contributes to sustain EMT in murine tumors. Interfering with AXL in patient-derived xenograft impaired TGF-β-induced cell invasion. Lastly, pharmacological inhibition of AXL decreased the metastatic burden of mice developing HER2+ breast cancer. Our data identify AXL as a potential co-therapeutic target during the treatment of HER2+ breast cancers to limit metastasis. Differential gene expression profile between MMTV-Neu tumors of AXL-/- and AXL+/+ by RNA sequencing (Illumina HiSEq 2000)