Morelloflavone, a biflavonoid, inhibits tumor angiogenesis by targeting rho GTPases and extracellular signal-regulated kinase signaling pathways.

Abstract

Morelloflavone, a biflavonoid extracted from Garcinia dulcis, has shown antioxidative, antiviral, and anti-inflammatory properties. However, the function and the mechanism of this compound in cancer treatment and tumor angiogenesis have not been elucidated to date. In this study, we postulated that morelloflavone might have the ability to inhibit angiogenesis, the pivotal step in tumor growth, invasiveness, and metastasis. We showed that morelloflavone could inhibit vascular endothelial growth factor (VEGF)-induced cell proliferation, migration, invasion, and capillary-like tube formation of primary cultured human umbilical vascular endothelial cells in a dose-dependent manner. Morelloflavone effectively inhibited microvessel sprouting of endothelial cells in the mouse aortic ring assay and the formation of new blood microvessels induced by VEGF in the mouse Matrigel plug assay. Furthermore, morelloflavone inhibited tumor growth and tumor angiogenesis of prostate cancer cells (PC-3) in xenograft mouse tumor model in vivo, suggesting that morelloflavone inhibited tumorigenesis by targeting angiogenesis. To understand the underlying mechanism of morelloflavone on the inhibitory effect of tumor growth and angiogenesis, we showed that morelloflavone could inhibit the activation of both RhoA and Rac1 GTPases but have little effect on the activation of Cdc42 GTPase. Additionally, morelloflavone inhibited the phosphorylation and activation of Raf/mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase/ERK pathway kinases without affecting VEGF receptor 2 activity. Together, our results indicate that morelloflavone exerts antiangiogenic action by targeting the activation of Rho-GTPases and ERK signaling pathways. These findings are the first to reveal the novel functions of morelloflavone in tumor angiogenesis and its molecular basis for the anticancer action.

• Authors: Xiufeng Pang, Tingfang Yi, Zhengfang Yi, Sung Gook Cho, Weijing Qu, Decha Pinkaew, Ken Fujise, Mingyao Liu
• Journal: Cancer research (Cancer Res) Vol. 69 Issue 2 Pg. 518-25 (Jan 15 2009) ISSN: 1538-7445 [Electronic] United States
• PMID: 19147565 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Angiogenesis Inhibitors
• Biflavonoids
• Vascular Endothelial Growth Factor A
• morelloflavone
• Vascular Endothelial Growth Factor Receptor-2
• Extracellular Signal-Regulated MAP Kinases
• rho GTP-Binding Proteins

Topics

• Angiogenesis Inhibitors (pharmacology)
• Animals
• Biflavonoids (pharmacology)
• Cell Growth Processes (drug effects)
• Cell Movement (drug effects)
• Endothelial Cells (cytology, drug effects)
• Extracellular Signal-Regulated MAP Kinases (antagonists & inhibitors, metabolism)
• Humans
• MAP Kinase Signaling System (drug effects)
• Male
• Mice
• Mice, SCID
• Neovascularization, Pathologic (drug therapy, enzymology)
• Prostatic Neoplasms (drug therapy, pathology)
• Signal Transduction (drug effects)
• Vascular Endothelial Growth Factor A (antagonists & inhibitors)
• Vascular Endothelial Growth Factor Receptor-2 (metabolism)
• Xenograft Model Antitumor Assays
• rho GTP-Binding Proteins (antagonists & inhibitors, metabolism)