Identification of critical therapeutic nodes to overcome Asparagine deprivation resistance in melanoma

Asparagine deprivation by L-Asparaginase is a successful therapeutic strategy in Acute Lymphoblastic Leukemia, with resistance occurring due to upregulation of ASNS. L-Asparaginase efficacy in solid tumors is hampered by dose-related toxicities. Large scale loss of function genetic screens identified ASNS, the only human enzyme synthetizing asparagine, as a cancer dependency in several solid malignancies, including melanoma. We here evaluate the therapeutic potential of targeting ASNS in melanoma cells in-vitro and in-vivo. Using ex-vivo quantitative proteome and transcriptome profiling, we observed that concomitant ASNS deletion and asparagine deprivation elicit a compensatory mechanism allowing tumor growth. Genome wide CRISPR screens upon manipulation of aminoacid levels identifies MAPK and GCN2 as critical nodes mediating the observed resistance mechanism. Importantly MEK and GCN2 inhibitor synergize with L-Asparaginase suggesting novel potential therapeutic strategy in melanoma.