BNIP3-mTOR Signaling Mediates Resistance to MET Inhibition in Glioblastoma

Abstract

Glioblastoma (GBM) is an aggressive primary brain malignancy with poor prognosis due to rapid progression, extensive invasiveness, and intrinsic resistance to standard therapies. Aberrant activation of receptor tyrosine kinases (RTKs), particularly MET, drives tumor proliferation, invasion, and therapy resistance. Here, we show that MET inhibition with crizotinib induces senescence and mitochondrial dysfunction in glioma-initiating cells (GICs), in part via downregulation of the mitochondrial protein BNIP3. However, BNIP3 downregulation activates mTOR signaling, enabling adaptive resistance. Targeting mTOR with everolimus in combination with crizotinib synergistically enhances anti-tumor effects, inducing apoptosis, senescence, and necroptosis, and significantly reducing cell viability and sphere-forming capacity. In orthotopic GBM xenograft models, this combination, particularly in a sequential regimen, markedly prolongs survival without overt toxicity. Our findings identify a BNIP3-mTOR signaling axis as a critical mediator of resistance to MET inhibition and provide a mechanistic rationale for combined MET and mTOR targeting as a promising therapeutic strategy in GBM. Statement of Translational RelevanceGlioblastoma (GBM) remains a highly aggressive and treatment-resistant brain tumor with limited therapeutic options. Our study identifies a BNIP3-mTOR signaling axis as a key mediator of resistance to MET inhibition. We show for the first time that combined MET and mTOR inhibition exhibits synergistic effects against GBM in vitro and in vivo. This combination prolongs survival without overt toxicity, providing a strong preclinical rationale for clinical evaluation in GBM patients with high MET expression and offering a promising strategy to overcome adaptive resistance.