Herceptin Research Today is a free monthly online journal that collates and summarizes the latest research about Herceptin, including details on side-effects, breast cancer, treatment, therapy.

Human epidermal growth factor receptor 2 regulates angiopoietin-2 expression in breast cancer via AKT and mitogen-activated protein kinase pathways.

Niu G, Carter WB

Don and Erika Wallace Comprehensive Breast Program, H. Lee Moffitt Cancer Center, University of South Florida College of Medicine, 12902 Magnolia Drive, Tampa, FL 33612, USA.

Abnormal activation of human epidermal growth factor receptor 2 (HER2; ErbB-2) in breast tumors results in increased metastasis and angiogenesis, as well as reduced survival. Here, we show that angiopoietin-2 (Ang-2) expression correlates with HER2 activity in human breast cancer cell lines. Inhibiting HER2 activity with anti-HER2 monoclonal antibody trastuzumab (Herceptin) or HER2 short interfering RNA in tumor cells down-regulates Ang-2 expression. Consistent with the important roles of AKT and mitogen-activated protein kinase in the HER2 signaling pathway, AKT and ERK mitogen-activated protein kinase (MAPK) kinase activity is necessary for Ang-2 up-regulation by HER2. Moreover, overexpression of HER2 protein up-regulates Ang-2 expression. Heregulin-beta1-induced Ang-2 up-regulation is abrogated when AKT and ERK kinase activity are blocked. Immunohistochemical analysis of HER2 and Ang-2 proteins in human breast carcinomas shows that Ang-2 expression in breast cancer correlates with HER2 expression. These studies provide evidence that the Ang-2 gene is regulated by HER2 activity in breast cancer, and propose an additional mechanism for HER2 contributing to tumor angiogenesis and metastasis.

Published 19 February 2007 in Cancer Res, 67(4): 1487-93.
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