Abstract
Background
Anti-angiogenesis therapy has increasingly become an important strategy for the treatment of colorectal cancer. Recent studies have shown that tumor microenvironment (TME) promotes tumour angiogenesis. Bufalin is an active compound whose anti-tumor efficacy has been proven by previous studies. However, there are very few studies on the anti-angiogenic effects of bufalin.
Methods
Herein, human umbilical vein endothelial cells (HUVEC) tube formation, migration and adhesion test were used to assess angiogenesis in vitro. Western blot and quantitative PCR were used to detect relevant protein levels and the expressions of mRNAs. Subcutaneous xenograft tumor model and hepatic metastasis model in mice were established to investigate the influence of bufalin on angiogenesis-mediated by TME in vivo.
Results
We found that the angiogenesis mediated by tumor microenvironment cells was significantly inhibited in the present of bufalin. The results demonstrated that the pro-angiogenic gene in HUVEC such as VEGF, PDGFA, E-selectin and P-selectin were downregulated by bufalin, and the downregulation was regulated by inhibiting the STAT3 pathway. Overexpression STAT3 could reverse the inhibitory effect of bufalin on angiogenesis. What is more, few reduction of angiogenesis when bufalin directly acted on tumor microenvironment cells.
Conclusion
Our findings demonstrate that bufalin suppresses tumour microenvironment-mediated angiogenesis by inhibiting the STAT3 signaling pathway of vascular endothelial cells, which reveals that bufalin may be used as a new anti-angiogenic adjuvant therapy medicine in the treatment of colorectal cancer.
AZD1480, a JAK inhibitor, inhibits cell growth and survival of colorectal cancer via modulating the JAK2/STAT3 signaling pathway
