title: RNAi knockdown of Hop (Hsp70/Hsp90 organising protein) decreases invasion via MMP-2 down regulation.
abstract: We previously identified Hop as over expressed in invasive pancreatic cancer cell lines and malignant tissues of pancreatic cancer patients, suggesting an important role for Hop in the biology of invasive pancreatic cancer. Hop is a co-chaperone protein that binds to both Hsp70/Hsp90. We hypothesised that by targeting Hop, signalling pathways modulating invasion and client protein stabilisation involving Hsp90-dependent complexes may be altered. In this study, we show that Hop knockdown by small interfering (si)RNA reduces the invasion of pancreatic cancer cells, resulting in decreased expression of the downstream target gene, matrix metalloproteinases-2 (MMP-2). Hop in conditioned media co-immunoprecipitates with MMP-2, implicating a possible extracellular function for Hop. Knockdown of Hop expression also reduced expression levels of Hsp90 client proteins, HER2, Bcr-Abl, c-MET and v-Src. Furthermore, Hop is strongly expressed in high grade PanINs compared to lower PanIN grades, displaying differential localisation in invasive ductal pancreatic cancer, indicating that the localisation of Hop is an important factor in pancreatic tumours. Our data suggests that the attenuation of Hop expression inactivates key signal transduction proteins which may decrease the invasiveness of pancreatic cancer cells possibly through the modulation of Hsp90 activity. Therefore, targeting Hop in pancreatic cancer may constitute a viable strategy for targeted cancer therapy.
authors.affiliation: National Institute for Cellular Biotechnology, Dublin City University, Glasnevin, Dublin 9, Ireland. Naomi.walsh@dcu.ie
authors.forename: Naomi
authors.initials: N
authors.lastname: Walsh
authors.forename: AnneMarie
authors.initials: A
authors.lastname: Larkin
authors.forename: Niall
authors.initials: N
authors.lastname: Swan
authors.forename: Kevin
authors.initials: K
authors.lastname: Conlon
authors.forename: Paul
authors.initials: P
authors.lastname: Dowling
authors.forename: Ray
authors.initials: R
authors.lastname: McDermott
authors.forename: Martin
authors.initials: M
authors.lastname: Clynes
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000378:metabolism* / Q000517:prevention & control / Q000556:secondary; D015153:Blotting, Western; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism* / Q000517:prevention & control / Q000556:secondary; D002448:Cell Adhesion; D002465:Cell Movement; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors; D018832:Molecular Chaperones; D009361:Neoplasm Invasiveness; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control; D034741:RNA, Small Interfering / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D061965:Matrix Metalloproteinase Inhibitors; D018832:Molecular Chaperones; D034741:RNA, Small Interfering; C079373:STIP1 protein, human; D020778:Matrix Metalloproteinase 2