Induction of monocyte chemoattractant protein-1 by nicotine in pancreatic ductal adenocarcinoma cells: Role of osteopontin

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)-I 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 polymerase chain reaction and enzyme-linked immunosorbent assay Luciferase-labeled promoter studies evaluated the effects of nicotine and OPN on MCP-I transcription Intracellular and tissue colocalization of OPN and MCP-I 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-I 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 unlit higher expression levels of OPN in the tissue from patients with invasive PDA Conclusion. Our data suggest that cigarette smoking and nicotine may contribute to PDA nil lamination by inducing MCP-I and provide a novel insight into a unique role for OPN in mediating these effects. (Surgery 2010,148 298-309.)