Targeting EphA2 and DDR signaling can overcome the BRAF and MEK inhibitors acquired resistance in melanoma cell lines

Abstract

The BRAF and MEK inhibitors combined strategies have dramatically changed the outcome of BRAF-mutated metastatic melanoma patients. However, despite the initial promising results, the onset of primary or acquired resistance occurs in nearly half of the patients at about one year from the diagnosis. Understanding the mechanisms of resistance to these inhibitors is therefore critical for planning more effective therapeutic strategies able to improve patient outcomes. To this aim we generated BRAF and MEK inhibitors resistant melanoma cells starting from the SAN and A375 lines, both harboring the most common BRAF-V600 mutation and sensitive to these drugs. The obtained double-resistant cell lines were characterized by MTT cell proliferation, migration, invasion assays, phosphoarray and western blot analysis. Here we report that the overexpression of several Tyrosine Kinase Receptors (TKRs), such as EphA2 and DDRs, drives the resistance to these drugs and that this resistance can be overcome by treatment with ALW‑II‑41‑27 multikinase inhibitor. ALW‑II‑41‑27 blocks not only TKRs expression, but also the related downstream AKT and MAPK signaling pathways and its efficacy is documented by decreased cell viability and reduced cell invasion/migration of the resistant cells. Our results can delineate a novel promising therapeutic approach to overcoming the drug resistance occurring in BRAF-mutated metastatic melanoma.

Role and Function of Receptor Tyrosine Kinases in BRAF Mutant Cancers

“…FLI1 silencing also reduced phospho-EphA2 and re-sensitized resistant cells to vemurafenib [338]. EphA2 was overexpressed together with DDR1 and DDR2 in double vemurafenib-and cobimetinib (MEK inhibitor)-resistant BRAF V600E melanoma, and treatment of the drug-resistant cells with ALW-II-41-27 downregulated phospho-EphA2 together with phospho-AKT and phospho-MEK levels [329].…”

“…DDR1 and DDR2 were overexpressed together with ephedrine receptors in double vemurafenib-and MEK inhibitor-cobimetinib-resistant BRAF V600E melanoma. The multikinase inhibitor ALW-II-41-27 showed antiproliferative and anti-migratory activities and suppressed DDR1/2 phosphorylation as well as phospho-AKT and phospho-MEK levels in the drug-resistant cells [329].…”