The pharmacological activities driven by these compounds are still not well understood but antagonism of dopamine receptors, activation of the cytochrome P450 system and blockage of ABCB1 activity may be plausible mechanisms induced by A5 and C1 treatments, which also lead to an additive toxic effect on patient-derived GBM cells co-treated with TMZ. The gene discussed is ABCB1; the disease is glioblastoma.