title: Integrin α6β4 Promotes Autocrine Epidermal Growth Factor Receptor (EGFR) Signaling to Stimulate Migration and Invasion toward Hepatocyte Growth Factor (HGF).
abstract: Integrin α6β4 is up-regulated in pancreatic adenocarcinomas where it contributes to carcinoma cell invasion by altering the transcriptome. In this study, we found that integrin α6β4 up-regulates several genes in the epidermal growth factor receptor (EGFR) pathway, including amphiregulin (AREG), epiregulin (EREG), and ectodomain cleavage protease MMP1, which is mediated by promoter demethylation and NFAT5. The correlation of these genes with integrin α6β4 was confirmed in The Cancer Genome Atlas Pancreatic Cancer Database. Based on previous observations that integrin α6β4 cooperates with c-Met in pancreatic cancers, we examined the impact of EGFR signaling on hepatocyte growth factor (HGF)-stimulated migration and invasion. We found that AREG and EREG were required for autocrine EGFR signaling, as knocking down either ligand inhibited HGF-mediated migration and invasion. We further determined that HGF induced secretion of AREG, which is dependent on integrin-growth factor signaling pathways, including MAPK, PI3K, and PKC. Moreover, matrix metalloproteinase activity and integrin α6β4 signaling were required for AREG secretion. Blocking EGFR signaling with EGFR-specific antibodies or an EGFR tyrosine kinase inhibitor hindered HGF-stimulated pancreatic carcinoma cell chemotaxis and invasive growth in three-dimensional culture. Finally, we found that EGFR was phosphorylated in response to HGF stimulation that is dependent on EGFR kinase activity; however, c-Met phosphorylation in response to HGF was unaffected by EGFR signaling. Taken together, these data illustrate that integrin α6β4 stimulates invasion by promoting autocrine EGFR signaling through transcriptional up-regulation of key EGFR family members and by facilitating HGF-stimulated EGFR ligand secretion. These signaling events, in turn, promote pancreatic carcinoma migration and invasion.
authors.affiliation: Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40506-0509; Departments of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40506-0509.
authors.forename: Brittany L
authors.initials: BL
authors.lastname: Carpenter
authors.affiliation: Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40506-0509; Departments of Toxicology and Cancer Biology, University of Kentucky, Lexington, Kentucky 40506-0509.
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.affiliation: Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40506-0509.
authors.forename: Teresa
authors.initials: T
authors.lastname: Knifley
authors.affiliation: Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40506-0509.
authors.forename: Kelley A
authors.initials: KA
authors.lastname: Davis
authors.affiliation: Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40506-0509.
authors.forename: Susan M W
authors.initials: SMW
authors.lastname: Harrison
authors.affiliation: Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40506-0509; Departments of Pathology and Laboratory Medicine, University of Kentucky, Lexington, Kentucky 40506-0509.
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Stewart
authors.affiliation: Markey Cancer Center, University of Kentucky, Lexington, Kentucky 40506-0509; Departments of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40506-0509. Electronic address: kloconnor@uky.edu.
authors.forename: Kathleen L
authors.initials: KL
authors.lastname: O'Connor
mesh_terms: D066258:Amphiregulin; D045744:Cell Line, Tumor; D002465:Cell Movement; D066255:EGF Family of Proteins / Q000235:genetics / Q000378:metabolism; D066260:Epiregulin / Q000235:genetics / Q000378:metabolism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D017228:Hepatocyte Growth Factor / Q000378:metabolism*; D006801:Humans; D039161:Integrin alpha6beta4 / Q000235:genetics / Q000378:metabolism*; D020781:Matrix Metalloproteinase 1 / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D059016:Tumor Microenvironment; D015854:Up-Regulation
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D066255:EGF Family of Proteins; C587880:EREG protein, human; D066260:Epiregulin; C066855:HGF protein, human; D039161:Integrin alpha6beta4; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D017228:Hepatocyte Growth Factor; C512478:EGFR protein, human; D066246:ErbB Receptors; C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1
keywords: pancreatic cancer; protein secretion; receptor protein-tyrosine kinase; receptor protein-tyrosine kinases; receptor regulation; receptor tyrosine kinase; signal transduction