Our studies show for the first time that GaM inhibits mitochondrial function by interfering with the Fe-S assembly mechanism necessary for the activity of complex I and that both GaM and metformin in combination synergistically inhibit the proliferation of glioblastoma cell lines and glioblastoma stem cells in vitro. Phase 1 clinical trials of oral GaM have been conducted healthy individuals and cancer patients [15, 16], while metformin is used clinically to treat patients with T2DM. Here, GLS is linked to glioblastoma.