title: The vacuolar-ATPase modulates matrix metalloproteinase isoforms in human pancreatic cancer.
abstract: The vacuolar-ATPase (v-ATPase) is a proton transporter found on many intracellular organelles and the plasma membrane (PM). The v-ATPase on PMs of cancer cells may contribute to their invasive properties in vitro. Its relevance to human cancer tissues remains unclear. We investigated whether the expression and cellular localization of v-ATPase corresponded to the stage of human pancreatic cancer, and its effect on matrix metalloproteinase (MMP) activation in vitro. The intensity of v-ATPase staining increased significantly across the range of pancreatic histology from normal ducts to pancreatic intraepithelial neoplasms (PanIN), and finally pancreatic ductal adenocarcinoma (PDAC). Low-grade PanIN lesions displayed polarized staining confined to the basal aspect of the cell in the majority (86%) of fields examined. High-grade PanIN lesions and PDAC showed intense and diffuse v-ATPase localization. In pancreatic cancer cells, PM-associated v-ATPase colocalized with cortactin, a component of the leading edge that helps direct MMP release. Blockade of the v-ATPase with concanamycin or short-hairpin RNA targeting the V₁E subunit reduced MMP-9 activity; this effect was greatest in cells with prominent PM-associated v-ATPase. In cells with detectable MMP-2 activities, however, treatment with concanamycin markedly increased MMP-2's most activated forms. V-ATPase blockade inhibited functional migration and invasion in those cells with predominantly MMP-9 activity. These results indicate that human PDAC specimens show loss of v-ATPase polarity and increased expression that correlates with increasing invasive potential. Thus, v-ATPase selectively modulates specific MMPs that may be linked to an invasive cancer phenotype.
authors.affiliation: Department of Medicine, Section of Digestive Diseases, VA CT Research, VA CT Healthcare System, Yale University School of Medicine, West Haven, CT 06516, USA. chuhan.chung@yale.edu
authors.forename: Chuhan
authors.initials: C
authors.lastname: Chung
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Mader
authors.forename: John C
authors.initials: JC
authors.lastname: Schmitz
authors.forename: Jorunn
authors.initials: J
authors.lastname: Atladottir
authors.forename: Phillip
authors.initials: P
authors.lastname: Fitchev
authors.forename: Mona L
authors.initials: ML
authors.lastname: Cornwell
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Koleske
authors.forename: Susan E
authors.initials: SE
authors.lastname: Crawford
authors.forename: Fred
authors.initials: F
authors.lastname: Gorelick
mesh_terms: D045744:Cell Line, Tumor; D004789:Enzyme Activation; D055785:Gene Knockdown Techniques; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism*; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000201:enzymology* / Q000473:pathology; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D020782:Matrix Metalloproteinases; D025262:Vacuolar Proton-Translocating ATPases