Metabolism-dependent secondary effect of anti-MAPK cancer therapy on DNA repair

Amino acid bioavailability impacts mRNA translation in a codon depending manner. Here, we report that the anti-cancer MAPK inhibitors (MAPKi) decrease the intracellular concentration of aspartate and glutamate in melanoma cells. This results in the accumulation of ribosomes on codons corresponding to these amino acids and triggers the translation-dependent degradation of mRNAs encoding aspartate- and glutamate-rich proteins mostly involved in DNA metabolism. Consequently, cells that survive to MAPKi degrade aspartate and glutamate to generate energy, which simultaneously decreases their needs in amino acids owing to the downregulation of aspartate- and glutamate-rich proteins involved in cell proliferation. Concomitantly, the downregulation of aspartate- and glutamate-rich proteins involved in DNA repair increases DNA damage loads. Thus, DNA repair defects, and therefore mutations, are, at least in part, a secondary effect of the metabolic adaptation of cells exposed to MAPKi.