Breast cancer cells-derived Von Willebrand Factor promotes VEGF-A-related angiogenesis through PI3K/Akt-miR-205-5p signaling pathway.

The metastasis and angiogenesis of breast cancer has always been a difficult problem for treatment. It has recently been discovered that Von Willebrand Factor (vWF), in addition to hemostasis, also plays a role in tumor metastasis and angiogenesis. We noticed that besides endothelial cells, breast cancer cells (MDA-MB-231 and MCF-7) could also express vWF. In vitro experiments showed that knocking down vWF inhibited breast cancer cell metastasis. And we found that overexpression of vWF significantly promoted VEGF-A-dependent vascular proliferation in vitro by activating the PI3K/Akt signaling pathway. Further studies indicated that inhibition of PI3K/Akt signaling pathway up-regulated the expression of miR-205-5p, and miR-205-5p could bind to the 3'UTR region of VEGF-A to hinder the production of VEGF-A. Furthermore, when a spontaneous lung metastasis model was established in Balb/c female mice, knockdown of vWF in 4 T1 cells resulted in a decrease in tumor blood vessel density and effectively inhibited lung metastasis, accompanied by a decrease in the expression level of VEGF-A and an increase in the expression level of miR-205-5p. In summary, our findings provide experimental evidence that overexpression of vWF in breast cancer cells down-regulates the expression of miR-205-5p and up-regulates the expression of VEGF-A through the PI3K/Akt signaling pathway, thereby promoting tumor angiogenesis and metastasis.