Glioblastoma (GBM) is the most aggressive form of brain cancer, with limited therapeutic options. While microglia contribute to GBM progression, the mechanisms by which they foster a protumorigenic immune environment remain poorly understood. We identify the zinc transporter Zrt- And Irt-Like Protein 4 (ZIP4) as a pivotal regulator of the GBM immune landscape. In orthotopic mouse models, ZIP4 drives tumor growth and behavioral changes. Mechanistically, ZIP4 modulates microglial plasticity through tumor-derived extracellular vesicles carrying triggering receptor expressed on myeloid cells-1 (TREM1), a process regulated by the zinc-dependent transcription factor Zinc Finger E-box Binding Homeobox 1 in GBM cells. TREM1 enhances microglial plasticity through the spleen associated tyrosine kinase-Pyruvate dehydrogenase kinase-signal transducer and activator of transcription 3 (SYK-PDK-STAT3) signaling axis, ultimately promoting an immune environment favorable to tumor progression. ZIP4 depletion or TREM1 inhibition attenuates tumor growth and behavioral effects in vivo by disrupting the tumor-microglia interaction. These findings establish ZIP4 as a key modulator of the GBM immune landscape and suggest a promising therapeutic target to counteract microglia-mediated tumor progression.
Keywords: TREM1; exosome; glioblastoma; microglia.