Inhibitory effect of cryptotanshinone on angiogenesis and Wnt/β-catenin signaling pathway in human umbilical vein endothelial cells.

Objective: To investigate the anti-angiogenic effect of cryptotanshinone (CPT) on human umbilical vein endothelial cells (HUVECs) and the effect of CPT on Wnt/β-catenin signaling pathway.

Methods: HUVECs were incubated with 0, 2.5, 5, 10, and 20 μ mol/L CPT for detecting cell viability with dimethyl thiazolyl-2,5-diphenyltetrazolium bromide (MTT) assay. Then, HUVECs were incubated with 0, 2.5, 5, and 10 μ mol/L CPT for detecting endothelial cell migration, invasion, and tubular-like structure formation with wound healing, transwell invasion and matrigel tube formation assays, respectively. To gain insight into CPT-mediated signaling, the effects of CPT on T-cell factor/lymphocyte enhancer factor (TCF/LEF) transcription factors were detected by the Dual-luciferase reporter assay. Next, the nuclear expression of β-catenin was evaluated using Western blot and immunochemistry. Finally, vascular endothelial growth factor (VEGF) and cyclin D1, downstream proteins of the Wnt pathway were examined with Western blot.

Results: CPT dose-dependently suppressed endothelial cell viability, migration, invasion, and tubular-like structure formation. In particular, CPT blocked β-catenindependent transcription in HUVECs in a dose-dependent manner. In Western bolt, 10 μ mol/L CPT decreased expression of β-catenin in nucleus of HUVECs (P<0.01). In immunohistochemistry, β-catenin was more potent in response to LiCl (an activator of the pathway) treatment. However, the signals were weaker in the nucleus of the CPT (10 μ mol/L) group, compared to the positive control. Also, VEGF and cyclin D1 were both eliminated by CPT in 5 and 10 μ mol/L doses (P<0.05).

Conclusion: Our study supported the role of CPT as an angiogenic inhibitor, which may impact on the Wnt/β-catenin signaling pathway.