VEGFR2 inhibition hampers breast cancer cell proliferation via enhanced mitochondrial biogenesis

Objective: Vascular endothelial growth factor (VEGF), apart from its predominant roles in angiogenesis, can enhance cancer cell proliferation, but its mechanisms remain elusive. The purpose of the present study was therefore to identify how VEGF regulates cancer cell proliferation. Methods: VEGF effects on cancer cell proliferation were investigated with the VEGF receptor 2 inhibitor, Ki8751, and the breast cancer 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 Ki8751 treatment robustly increased the mitochondrial masses of both cancer cells, induced endomitosis, and arrested cancer cells in the high aneuploid phase. VEGFR2 knockdown by shRNAs showed similar effects to those of Ki8751, confirming the specificity of Ki8751 treatment. Enhanced mitochondrial biogenesis increased mitochondrial oxidative phosphorylation and stimulated reactive oxygen species (ROS) production, which induced cancer cell apoptosis. Furthermore, Ki8751 treatment downregulated the phosphorylation of Akt and PGC1 alpha, and translocated PGC1 alpha into the nucleus. The PGC1 alpha alterations increased mitochondrial transcription factor A (TFAM) expression and subsequently increased mitochondrial biogenesis. Conclusions: VEGF enhances cancer cell proliferation by decreasing Akt-PGC1 alpha-TFAM signaling-mediated mitochondrial biogenesis, ROS production, and cell apoptosis. These findings suggested the anticancer potential of Ki8751 via increased mitochondrial biogenesis and ROS production.

Automated summary

In this study, it was found that inhibition of VEGF by Ki8751 suppressed cancer cell proliferation by increasing mitochondrial biogenesis and ROS production. Ki8751 also modulated mitochondrial biogenesis and cancer cell apoptosis by inhibiting the Akt-PGC1 alpha-TFAM signaling pathway.