Betacellulin induces angiogenesis through activation of mitogen-activated protein kinase and phosphatidylinositol 3′-kinase in endothelial cells

Betacellulin (BTC) is a member of the epidermal growth factor (EGF) family, and it acts through EGF receptors. We asked whether BTC could be an angiogenic factor. Using human umbilical vein endothelial cells (HUVECs), we examined the effect of BTC on kinases and angiogenic processes. BTC induced ERK1/2 and Akt phosphorylation in a dose- and time-dependent manner. BTC induced phosphorylation of all three EGF receptors present on HUVECs: ErbB2, ErbB3, and ErbB4. Pretreatment with effective concentrations of ErbB1 inhibitor did not suppress BTC-induced kinase phosphorylation. BTC, EGF, VEGF (all at 10 ng/ml) produced similar increases in DNA synthesis. BTC, EGF, and VEGF all significantly increased endothelial cell migration. In addition, BTC promoted survival in a dose-dependent manner, and its effect was inhibited by pretreatment with PtdIns 3'-kinase inhibitor wortmannin or MEK1/2 inhibitor PD98059. Both BTC and EGF produced similar increases in tube formation in collagen gels. BTC-induced tube formation was suppressed by PD98059, wortmannin, and LY294002. In the mouse Matrigel plug assay, BTC (100 ng/ml) promoted neovessel formation, and its effect was suppressed by a combination of wortmannin and PD98059. Taken together, these data show that BTC exerts potent angiogenic activity through activation of EGF receptors, mitogen-activated protein kinase, and PtdIns 3'-kinase/Akt in endothelial cells.