VEGFR2 inhibition hampers breast cancer cell proliferation <i>via</i> enhanced mitochondrial biogenesis

Objective: Vascular endothelial growth factor (VEGF), apart from its predominant roles in angiogenesis, can enhance cancer cellproliferation, but its mechanisms remain elusive. The purpose of the present study was therefore to identify how VEGF regulatescancer cell proliferation. Methods: VEGF effects on cancer cell proliferation were investigated with the VEGF receptor 2 inhibitor, Ki8751, and the breastcancer cell lines, MCF-7 and MDA-MB-231, using flow cytometry, mass spectrometry, immunoblotting, and confocal microscopy.Data were analyzed using one-way analysis of variance followed by Tukey’s multiple comparison test. Results: VEGF blockade by Ki8751 significantly reduced cancer cell proliferation, and enhanced breast cancer cell apoptosis.Mass spectrometric analyses revealed that Ki8751 treatment significantly upregulated the expression of mitochondrial proteins,suggesting the involvement of mitochondrial biogenesis. Confocal microscopy and flow cytometric analyses showed that Ki8751treatment robustly increased the mitochondrial masses of both cancer cells, induced endomitosis, and arrested cancer cells in the highaneuploid phase. VEGFR2 knockdown by shRNAs showed similar effects to those of Ki8751, confirming the specificity of Ki8751treatment. Enhanced mitochondrial biogenesis increased mitochondrial oxidative phosphorylation and stimulated reactive oxygenspecies (ROS) production, which induced cancer cell apoptosis. Furthermore, Ki8751 treatment downregulated the phosphorylationof Akt and PGC1α, and translocated PGC1α into the nucleus. The PGC1α alterations increased mitochondrial transcription factorA (TFAM) expression and subsequently increased mitochondrial biogenesis. Conclusions: VEGF enhances cancer cell proliferation by decreasing Akt-PGC1α-TFAM signaling-mediated mitochondrialbiogenesis, ROS production, and cell apoptosis. These findings suggested the anticancer potential of Ki8751 via increasedmitochondrial biogenesis and ROS production.