Figure 1.

HER2 signaling pathways in cancer cell and cardiac myocyte. (A) In cancer cells, the HER2 signaling pathway is activated via different mechanisms. Trastuzumab and lapatinib block HER2 signaling at different levels. (B) In cardiac myocytes, HER2 signaling is involved in pro-survival pathways, which can be blocked by HER2-targeted therapies. HER2: human epidermal receptor 2; ErbB4: erythroblastic leukemia viral oncogene B receptors; NRG-1: neuregulin-1 ligand; TK: tyrosine kinase; MAP-RAS-ERK: mitogen-activated protein kinase-rate sarcoma virus oncogene-extracellular signal-regulated kinase; PI3K-AKT: phosphatidylinositol 3-kinase-protein kinase B; JAK-STAT: Janus kinase-signal transducer and activator of transcription protein; Top-2B: topoisomerase-2 beta isoform; DOX: doxorubicin; ROS: reactive oxygen species