Identification of Resistance Genes to BRAF Inhibitor in Melanoma by piggyBac Transposon Activation Mutagenesis Screen

Genotype directed anti-cancer therapies such BRAF inhibitor in BRAF mutant melanoma can show remarkable clinical efficacy but resistance limits their benefit. We show that a transposon activation screen efficiently identifies resistance genes to BRAF and captures a number of previously uncharacterized resistance mechanisms, including an E3 ubiquitin ligase NEDD4L and the Hippo pathway effector WWTR1 (TAZ). Resistance can be reversed by combining BRAF inhibition with tyrosine kinase inhibitors as observed previously for other resistance genes. Moreover, an integrative analysis of several gain- and loss-of-function genetic screens performed in the same context reveals smaller functional diversity of resistance mechanisms to MAPK inhibition than suggested by the broad range of resistance genes identified, implying common therapeutic strategies. A375 cells with lentiviral vector controls or WWTR1 cDNA plasmid.