AXL inhibition improves BRAF-targeted treatment in melanoma

More than half of metastatic melanoma patients receiving standard therapy fail to achieve a long-term survival due to primary and/or acquired resistance. Tumor cell ability to switch from epithelial to a more aggressive mesenchymal phenotype, attributed with AXL(high) molecular profile in melanoma, has been recently linked to such event, limiting treatment efficacy. In the current study, we investigated the therapeutic potential of the AXL inhibitor (AXLi) BGB324 alone or in combination with the clinically relevant BRAF inhibitor (BRAFi) vemurafenib. Firstly, AXL was shown to be expressed in majority of melanoma lymph node metastases. When treated ex vivo, the largest reduction in cell viability was observed when the two drugs were combined. In addition, a therapeutic benefit of adding AXLi to the BRAF-targeted therapy was observed in pre-clinical AXL(high) melanoma models in vitro and in vivo. When searching for mechanistic insights, AXLi was found to potentiate BRAFi-induced apoptosis, stimulate ferroptosis and inhibit autophagy. Altogether, our findings propose AXLi as a promising treatment in combination with standard therapy to improve therapeutic outcome in metastatic melanoma.