Inhibitory effects of Physalis angulata on tumor metastasis and angiogenesis

The methanolic extracts of Physalis angulata (PA extracts) have the potential for anti-angiogenic effects through the inhibition of neo-angiogenesis in the chick chorioallantoic membrane in vivo. Physalis angulata is well-known in traditional Chinese medicine as a ingredient for various herbal formulation; also, it has been shown to exhibit anti-cancer and anti-inflammatory effects. In this study, the ability of P. angulata to inhibit tumor metastasis and angiogenesis was investigated. Anti-proliferative activity of ethyl acetate extracts of P. angulata (PA extracts), was determined against human oral squamous carcinoma (HSC-3) and human umbilical vein endothelial cells (HUVECs) by trypan blue exclusion method. Wound-healing migration, trans-well invasion, Western blotting and chick chorioallantoic membrane assay were carried out to determine the anti-metastatic and anti-angiogenic effects of PA extracts in vitro and in vivo. We demonstrated that at sub-cytotoxic concentrations of PA extracts (5–15 μg/mL) markedly inhibited the migration and invasion of highly metastatic HSC-3 cells as shown by wound-healing repair assay and trans-well assay. Gelatin zymography assay showed that PA extracts suppressed the activity of matrix metalloproteinase (MMP)-9 and -2, and urokinase plasminogen activator (u-PA) in HSC-3 cells. In addition, Western blot analysis confirmed that PA extracts significantly decreased MMP-2 and u-PA protein expression in HSC-3 cells. Notably, PA extracts significantly augmented the expression of their endogenous inhibitors, including tissue inhibitors of MMP (TIMP-1 and -2), and plasminogen activator inhibitors (PAI-1 and -2). Further investigations revealed that non-cytotoxic concentration of PA extracts (5–15 μg/mL) inhibited vascular endothelial growth factor (VEGF)-induced proliferation, and migration/invasion of HUVECs in vitro. PA extracts also suppressed the activity of MMP-9, but not MMP-2, in HUVECs. Further, we observed, PA extracts strongly suppressed neovessel formation in the chorioallantoic membrane of chick embryos in vivo. These results strongly support an anti-metastatic and anti-angiogenic activity of P. angulata that may contribute to the development of better chemopreventive agent for cancer and inflammation.