Ki8751 Enhances Breast Cancer Cell Apoptosis Via Regulated Mitochondrial Biogenesis

[objective]Vascular endothelial growth factor(VEGF),apart from its predominant roles in angiogenesis,can enhance cancer cell proliferation,under which the mechanisms remain elusive.The present study thus investigated how VEGF receptor 2 inhibitor,Ki8751,reduced cell proliferation via influenced mitochondrial biogenesis with the breast cancer cell lines MCF-7 and MDA-MB-231.[Method]Human breast cancer cell lines MCF-7 and MDA-MB-231 were used in our in vitro experiments,they were cultured in the presence of 0,2.5?M and 5?M Ki8751 for 24,48 and 72h.Cell proliferation was determined using a cell counting kit-8(CCK-8)assay,for the analysis of cell apoptosis,the cells were stained with Annexin V and propidium iodide(PI)at various time points.The mitochondrial mass and cell morphological alterations were observed by laser confocal microscopy.Western blot and flow cytometric analyses showed that Ki8751 treatment enhanced mitochondrial biogenesis with related protein expression and reactive oxygen species(ROS)changes.VEGFR2 knockdown was applied to detect VEGFR2 expression and mitochondrial mass in breast cancer cells treated by shRNAs.Data of three independent repeated experiments are presented as means±SEM.Comparisons between treatments were analysed by one-way ANOVA or repeated measurement analysis of variance using GraphPad 6.P<0.05 was deemed statistically significant.[Results]1.Treatment with Ki8751 could significantly reduced breast cancer cell proliferation,and enhanced cancer cell apoptosis.2.Confocal microscopic and flow cytometric analyses showed that Ki8751 treatment robustly increased mitochondrial mass of both cancer cells,and western blot indicated that Ki8751 treatment markedly upregulated the expression of mitochondrial transcription factor A(TFAM).Flow cytometric analyses showed that Ki8751 treatment can provoke reactive oxygen species(ROS)production.3.VEGFR2 knockdown by shRNAs showed similar effects to those of Ki8751,confirming the specificity of Ki8751 treatment.Furthermore,Ki8751 treatment down-regulated the phosphorylation AKT(p-AKT)and phosphorylation peroxisome proliferator-activated receptor y coactivator 1?(p-PGC1?),both AKT and PGC1?without significant change,up-regulated expression of mitochondrial transcription factor A(TFAM)and subsequently induced mitochondrial biogenesis[Conclusion]In conclusion,our present study indicated that Ki8751 may exert anti-tumor potential via enhance Akt-PGC1 ?-TFAM signaling mediated mitochondrial biogenesis,ROS production and cell apoptosis.