title: Oncostatin M binds to extracellular matrix in a bioactive conformation: implications for inflammation and metastasis.
abstract: Oncostatin M (OSM) is an interleukin-6-like inflammatory cytokine reported to play a role in a number of pathological processes including cancer. Full-length OSM is expressed as a 26 kDa protein that can be proteolytically processed into 24 kDa and 22 kDa forms via removal of C-terminal peptides. In this study, we examined both the ability of OSM to bind to the extracellular matrix (ECM) and the activity of immobilized OSM on human breast carcinoma cells. OSM was observed to bind to ECM proteins collagen types I and XI, laminin, and fibronectin in a pH-dependent fashion, suggesting a role for electrostatic bonds that involves charged amino acids of both the ECM and OSM. The C-terminal extensions of 24 kDa and 26 kDa OSM, which contains six and thirteen basic amino acids, respectively, enhanced electrostatic binding to ECM at pH 6.5-7.5 when compared to 22 kDa OSM. The highest levels of OSM binding to ECM, though, were observed at acidic pH 5.5, where all forms of OSM bound to ECM proteins to a similar extent. This indicates additional electrostatic binding properties independent of the OSM C-terminal extensions. The reducing agent dithiothreitol also inhibited the binding of OSM to ECM suggesting a role for disulfide bonds in OSM immobilization. OSM immobilized to ECM was protected from cleavage by tumor-associated proteases and maintained activity following incubation at acidic pH for extended periods of time. Importantly, immobilized OSM remained biologically active and was able to induce and sustain the phosphorylation of STAT3 in T47D and ZR-75-1 human breast cancer cells over prolonged periods, as well as increase levels of STAT1 and STAT3 protein expression. Immobilized OSM also induced epithelial-mesenchymal transition-associated morphological changes in T47D cells. Taken together, these data indicate that OSM binds to ECM in a bioactive state that may have important implications for the development of chronic inflammation and tumor metastasis.
authors.affiliation: Department of Biological Sciences, 1910 University Drive, Boise, ID 83725, United States; Biomolecular Research Center, 1910 University Drive, Boise, ID 83725, United States.
authors.forename: Randall E
authors.initials: RE
authors.lastname: Ryan
authors.affiliation: Biomolecular Research Center, 1910 University Drive, Boise, ID 83725, United States; Department of Chemistry and Biochemistry, 1910 University Drive, Boise, ID 83725, United States.
authors.forename: Bryan
authors.initials: B
authors.lastname: Martin
authors.affiliation: Biomolecular Research Center, 1910 University Drive, Boise, ID 83725, United States.
authors.forename: Liliana
authors.initials: L
authors.lastname: Mellor
authors.affiliation: Department of Chemistry and Biochemistry, 1910 University Drive, Boise, ID 83725, United States.
authors.forename: Reed B
authors.initials: RB
authors.lastname: Jacob
authors.affiliation: Department of Biological Sciences, 1910 University Drive, Boise, ID 83725, United States; Biomolecular Research Center, 1910 University Drive, Boise, ID 83725, United States.
authors.forename: Ken
authors.initials: K
authors.lastname: Tawara
authors.affiliation: Biomolecular Research Center, 1910 University Drive, Boise, ID 83725, United States; Department of Chemistry and Biochemistry, 1910 University Drive, Boise, ID 83725, United States.
authors.forename: Owen M
authors.initials: OM
authors.lastname: McDougal
authors.affiliation: Department of Biological Sciences, 1910 University Drive, Boise, ID 83725, United States; Biomolecular Research Center, 1910 University Drive, Boise, ID 83725, United States.
authors.forename: Julia Thom
authors.initials: JT
authors.lastname: Oxford
authors.affiliation: Department of Biological Sciences, 1910 University Drive, Boise, ID 83725, United States; Biomolecular Research Center, 1910 University Drive, Boise, ID 83725, United States. Electronic address: cjorcyk@boisestate.edu.
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Jorcyk
mesh_terms: D001943:Breast Neoplasms; D018920:Coculture Techniques; D024042:Collagen Type I / Q000378:metabolism; D024161:Collagen Type XI / Q000378:metabolism; D004229:Dithiothreitol / Q000494:pharmacology; D058750:Epithelial-Mesenchymal Transition; D005109:Extracellular Matrix / Q000378:metabolism*; D005260:Female; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007249:Inflammation / Q000378:metabolism*; D007797:Laminin / Q000378:metabolism; D009362:Neoplasm Metastasis / Q000503:physiopathology*; D053683:Oncostatin M / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D050794:STAT1 Transcription Factor / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D024042:Collagen Type I; D024161:Collagen Type XI; D005353:Fibronectins; D007797:Laminin; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050796:STAT3 Transcription Factor; D053683:Oncostatin M; D004229:Dithiothreitol
keywords: Cancer; Col11a1; Extracellular matrix; Inflammatory cytokines; Metastasis