Diffuse intrinsic pontine glioma (DIPG) remains an incurable childhood brain tumor for which novel therapeutic approaches are desperately needed. Previous studies have shown that the menin inhibitor MI-2 exhibits promising activity in preclinical DIPG and adult glioma models, although the mechanism underlying this activity is unknown. Here, using an integrated approach, we show that MI-2 exerts its antitumor activity in glioma largely independent of its ability to target menin. Instead, we demonstrate that MI-2 activity in glioma is mediated by disruption of cholesterol homeostasis, with suppression of cholesterol synthesis and generation of the endogenous liver X receptor ligand, 24,25-epoxycholesterol, resulting in cholesterol depletion and cell death. Notably, this mechanism is responsible for MI-2 activity in both DIPG and adult glioma cells. Metabolomic and biochemical analyses identify lanosterol synthase as the direct molecular target of MI-2, revealing this metabolic enzyme as a vulnerability in glioma and further implicating cholesterol homeostasis as an attractive pathway to target in this malignancy.
Keywords: MI-2; glioma; lanosterol synthase; menin inhibitor; target identification.