title: Induction of monocyte chemoattractant protein-1 by nicotine in pancreatic ductal adenocarcinoma cells: role of osteopontin.
abstract: BACKGROUND
  Cigarette smoke and nicotine are among the leading environmental risk factors for developing pancreatic ductal adenocarcinoma (PDA). We showed recently that nicotine induces osteopontin (OPN), a protein that plays critical roles in inflammation and tumor metastasis. We identified an OPN isoform, OPNc, that is selectively inducible by nicotine and highly expressed in PDA tissue from smokers. In this study, we explored the potential proinflammatory role of nicotine in PDA through studying its effect on the expression of monocyte chemoattractant protein (MCP)-1 and evaluated the role of OPN in mediating these effects.
  
  
  METHODS
  MCP-1 mRNA and protein in PDA cells treated with or without nicotine (3-300 nmol/L) or OPN (0.15-15 nmol/L) were analyzed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Luciferase-labeled promoter studies evaluated the effects of nicotine and OPN on MCP-1 transcription. Intracellular and tissue colocalization of OPN and MCP-1 were examined by immunofluorescence and immunohistochemistry.
  
  
  RESULTS
  Nicotine treatment significantly increased MCP-1 expression in PDA cells. Interestingly, blocking OPN with siRNA or OPN antibody abolished these effects. Transient transfection of the OPNc gene in PDA cells or their treatment with recombinant OPN protein significantly (P < .05) increased MCP-1 mRNA and protein and induced its promoter activity. MCP-1 was found in 60% of invasive PDA lesions, of whom 66% were smokers. MCP-1 colocalized with OPN in PDA cells and in the malignant ducts, and correlated well with higher expression levels of OPN in the tissue from patients with invasive PDA.
  
  
  CONCLUSIONS
  Our data suggest that cigarette smoking and nicotine may contribute to PDA inflammation by inducing MCP-1 and provide a novel insight into a unique role for OPN in mediating these effects.
authors.affiliation: Department of Surgery, Jefferson Pancreatic, Biliary and Related Cancer Center, Philadelphia, PA, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Lazar
authors.forename: Jennifer
authors.initials: J
authors.lastname: Sullivan
authors.forename: Galina
authors.initials: G
authors.lastname: Chipitsyna
authors.forename: Tamer
authors.initials: T
authors.lastname: Aziz
authors.forename: Ahmed F
authors.initials: AF
authors.lastname: Salem
authors.forename: Qiaoke
authors.initials: Q
authors.lastname: Gong
authors.forename: Agnes
authors.initials: A
authors.lastname: Witkiewicz
authors.forename: David T
authors.initials: DT
authors.lastname: Denhardt
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Yeo
authors.forename: Hwyda A
authors.initials: HA
authors.lastname: Arafat
mesh_terms: D021441:Carcinoma, Pancreatic Ductal / Q000209:etiology* / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D009538:Nicotine / Q000633:toxicity*; D053495:Osteopontin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D010190:Pancreatic Neoplasms / Q000209:etiology* / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000494:pharmacology; D012907:Smoking / Q000009:adverse effects; D014162:Transfection
chemical_list: C111835:CCL2 protein, human; D018932:Chemokine CCL2; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D053495:Osteopontin; D009538:Nicotine