Flavonoids inhibit VEGF/bFGF‐induced angiogenesis in vitro by inhibiting the matrix‐degrading proteases

Abstract

Flavonoids have been proposed to act as chemopreventive agents in numerous epidemiological studies and have been shown to inhibit angiogenesis and proliferation of tumor cells and endothelial cells in vitro. Angiogenesis requires tightly controlled extracellular matrix degradation mediated by extracellular proteolytic enzymes including matrix metalloproteinases (MMPs) and serine proteases, in particular, the urokinase-type plasminogen activator (uPA)-plasmin system. In this study, we have investigated the antiangiogenic mechanism of the flavonoids, genistein, apigenin, and 3-hydroxyflavone in a human umbilical vein endothelial cell (HUVEC) model. The stimulation of serum-starved HUVECs with vascular endothelial growth factor/basic fibroblast growth factor (VEGF/bFGF) caused marked increase in MMP-1 production and induced the pro-MMP-2 activation accompanied by the increase in MT1-MMP expression. However, pretreatment with flavonoids before VEGF/bFGF stimulation completely abolished the VEGF/bFGF-stimulated increase in MMP-1 and MT1-MMP expression and pro-MMP-2 activation. Genistein blocked VEGF/bFGF-stimulated increase in TIMP-1 expression and decrease in TIMP-2 expression. Apigenin and 3-hydroxyflavone further decreased TIMP-1 expression below basal level and completely abolished TIMP-2 expression. VEGF and bFGF stimulation also significantly induced uPA expression, most strikingly the level of 33 kDa uPA, and increased the expression of PA inhibitor (PAI)-1. Genistein, apigenin, and 3-hydroxyflavone effectively blocked the generation of 33 kDa uPA, and further decreased the activity of the 55 kDa uPA and the expression of PAI-1 below the basal level. In conclusion, these data suggest that genistein, apigenin, and 3-hydroxyflavone inhibit in vitro angiogenesis, in part via preventing VEGF/bFGF-induced MMP-1 and uPA expression and the activation of pro-MMP-2, and via modulating their inhibitors, TIMP-1 and -2, and PAI-1.

Apigenin and cancer chemoprevention: Progress, potential and promise (Review)

“…Other important targets of apigenin include heat shock proteins (60), telomerase (65), fatty acid synthase (66), matrix metalloproteinases (67), and aryl hydrocarbon receptor activity (68) HER2/neu (69), all of which have relevance to cancer development and progression.…”

Apigenin suppresses the senescence-associated secretory phenotype and paracrine effects on breast cancer cells

“…Apigenin belongs to the flavone subclass of flavonoids (Kim 2003, Osada et al 2004) and is abundant in a variety of fruits, vegetables, and herbs. It often exists in food sources as a glycoside, which improves its solubility and bioavailability (Ross and Kasum 2002).…”

“…It often exists in food sources as a glycoside, which improves its solubility and bioavailability (Ross and Kasum 2002). Like other flavonoids, apigenin has a variety of biological activities, including the ability to inhibit proliferation and induce apoptosis in several cancer cell lines (Reiners et al 1999, Gupta et al 2001, Way et al 2004, Brusselmans et al 2005, as well as an ability to inhibit angiogenesis (Kim 2003, Osada et al 2004). Targets of apigenin that could contribute to these anticancer activities include heat shock proteins (Osada et al 2004), fatty acid synthase (Brusselmans et al 2005), the aryl hydrocarbon receptor (Reiners et al 1999), HER2/neu (Way et al 2004), and matrix metalloproteinases (Kim 2003).…”

“…Like other flavonoids, apigenin has a variety of biological activities, including the ability to inhibit proliferation and induce apoptosis in several cancer cell lines (Reiners et al 1999, Gupta et al 2001, Way et al 2004, Brusselmans et al 2005, as well as an ability to inhibit angiogenesis (Kim 2003, Osada et al 2004). Targets of apigenin that could contribute to these anticancer activities include heat shock proteins (Osada et al 2004), fatty acid synthase (Brusselmans et al 2005), the aryl hydrocarbon receptor (Reiners et al 1999), HER2/neu (Way et al 2004), and matrix metalloproteinases (Kim 2003). Apigenin can also reduce markers of inflammation in response to lipopolysaccharides, TNF-α, and allergens and was shown to suppress activities of the inflammatory mediators cyclooxygenase and NF-κB (Liang et al 1999, Ruiz and Haller 2006, Li et al 2010, Kang et al 2011, Duarte et al 2013.…”

Low‐energy laser irradiation increases endothelial cell proliferation, migration, and eNOS gene expression possibly via PI3K signal pathway

“…These signal pathways culminate in the expression of matrix enzymes [25], inhibition of apoptosis [26], and regulation of NO synthase [27]. VEGF induces angiogenesis by stimulating endothelial cell proliferation and migration primarily through the receptor tyrosine kinase VEGF receptor 2 (Flk/KDR) [28].…”