Mitochondrial DNA depletion promotes vasculogenic properties through mesenchymal alteration in glioblastoma

Glioblastoma, the most aggressive brain tumour with high and heterogenic vascularity, frequently courses with mtDNA depletion. However, the effects of mtDNA depletion on mesenchymal characteristics responsible for aggressiveness and vasculogenic mimicry in glioblastoma, have not been thoroughly revealed. We aimed to investigate the effects of mtDNA depletion on EMT and vasculogenic properties in glioblastoma. mtDNA depletion was induced by low-dose ethidium bromide and then its effects on EMT and related vascular changes were analyzed. Mesenchymal and endothelial markers were analyzed by qRT-PCR and flow cytometry. Vasculogenic properties were determined through the Matrigel angiogenesis assay, periodic acid-Schiff (PAS) staining and the endothelial differentiation assay. SLUG gene, a key EMT regulator, was downregulated using RNA interference to confirm the contribution of EMT in vasculogenesis. mtDNA depletion increased mesenchymal markers, subsequent vasculogenic properties and aggressive phenotype. These were reversed by downregulating SLUG. The novel linkage between mtDNA depletion and accelerated vasculogenesis after EMT was demonstrated.