Subtype-Specific Alterations in Copper Trafficking Associated with KRAS Mutations in Isogenic Colorectal Cancer Cell Lines.

Copper bioavailability has been identified as a potential target for KRAS-mutant colorectal cancer, a disease for which treatment options remain limited. Therefore, we investigated copper homeostasis in isogeneic colorectal cancer cell models carrying distinct KRAS codon 12 mutations (G12C, G12D and G12V). Our results show that copper homeostasis differs among KRAS-mutant cells in a mutation-specific manner, with the greatest change observed in G12V, followed by G12C and then G12D. Specifically, G12V-mutant cells show reduced copper levels, increased copper uptake, reduced intracellular copper levels after prolonged exposure to exogenous copper, reduced sensitivity to copper-induced toxicity, protection against intracellular copper chelators (neocuproine, DpC, Dp44mT), and increased expression of the copper transporter ATP7A. In contrast, G12D mutant cells exhibit minimal differences in copper metabolism compared to controls, while G12C display an intermediate phenotype between the other two mutations. Notably, the copper chelator ammonium tetrathiomolybdate inhibited cell growth in all KRAS-mutant cells. Our results suggest that KRAS-mutant colorectal cancer cells are sensitive to perturbations in copper homeostasis in a mutation subtype-specific manner.