title: Persistent transactivation of EGFR and ErbB2/HER2 by protease-activated receptor-1 promotes breast carcinoma cell invasion.
abstract: Hyperactivation of ErbB signaling is implicated in metastatic breast cancer. However, the mechanisms that cause dysregulated ErbB signaling and promote breast carcinoma cell invasion remain poorly understood. One pathway leading to ErbB activation that remains unexplored in breast carcinoma cell invasion involves transactivation by G-protein-coupled receptors (GPCRs). Protease-activated receptor-1 (PAR1), a GPCR activated by extracellular proteases, is overexpressed in invasive breast cancer. PAR1 is also proposed to function in breast cancer invasion and metastasis, but how PAR1 contributes to these processes is not known. In this study, we report that proteolytic activation of PAR1 by thrombin induces persistent transactivation of EGFR and ErbB2/HER2 in invasive breast carcinoma, but not in normal mammary epithelial cells. PAR1-stimulated EGFR and ErbB2 transactivation leads to prolonged extracellular signal-regulated kinase-1 and -2 signaling and promotes breast carcinoma cell invasion. We also show that PAR1 signaling through Galpha(i/o) and metalloprotease activity is critical for ErbB transactivation and cellular invasion. Finally, we demonstrate that PAR1 expression in invasive breast carcinoma is essential for tumor growth in vivo assessed by mammary fat pad xenografts. These studies reveal a critical role for PAR1, a receptor activated by tumor-generated proteases, in hyperactivation of ErbB signaling that promotes breast carcinoma cell invasion.
authors: Department of Pharmacology, Lineberger Comprehensive Cancer Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
authors: P
authors: P
authors: Arora
authors: B D
authors: BD
authors: Cuevas
authors: A
authors: A
authors: Russo
authors: G L
authors: GL
authors: Johnson
authors: J
authors: J
authors: Trejo
mesh_terms: D051722:ADAM Proteins / Q000502:physiology; D000072198:ADAM17 Protein; D000818:Animals; D001943:Breast Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D066246:ErbB Receptors / Q000235:genetics* / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D005260:Female; D005347:Fibroblasts / Q000502:physiology; D044385:GTP-Binding Protein alpha Subunits / Q000502:physiology; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D009361:Neoplasm Invasiveness; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D044463:Receptor, PAR-1 / Q000502:physiology*; D015398:Signal Transduction; D013917:Thrombin / Q000494:pharmacology; D015533:Transcriptional Activation
chemical_list: D051722:ADAM Proteins; D000072198:ADAM17 Protein; D066246:ErbB Receptors; D048049:Extracellular Signal-Regulated MAP Kinases; D044385:GTP-Binding Protein alpha Subunits; D018719:Erb-b2 Receptor Tyrosine Kinases; D044463:Receptor, PAR-1; D013917:Thrombin