title: Interleukin-6 (IL-6) released by macrophages induces IL-6 secretion in the  human colon cancer HT-29 cell line.
abstract: The level of interleukin-6 (IL-6) is correlated with prognosis and liver metastasis in colon cancer. However, the relationship between macrophage-derived and tumor-derived IL-6 in colon cancer remains unclear. We harvested the macrophage supernatant and studied the IL-6-inducing ability of the macrophage supernatant on the colon cancer cell line HT-29. The macrophage supernatant effectively induced IL-6 secretion of colon cancer cells in vitro. The macrophage supernatant and recombinant IL-6 neutralized with anti-IL-6 or ant-gp130 antibodies dramatically decreased the IL-6-induction ability of cancer cells. IL-6-induction occurred through phosphorylation of STAT3. We analyzed the surgical specimens of 126 patients with colon cancer using an immunohistochemical staining method and demonstrated the colocalization of macrophages and the expression of IL-6 in colon cancer patients. These results indicate that macrophages in tumor infiltrates could release IL-6, which in turn conditions colon cancer cells, causing them to secrete IL-6 themselves via phosphorylation of STAT3.
authors.affiliation: Division of Hemato-oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Keelung, Taiwan.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Li
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Hsieh
authors.forename: Rei-Ping
authors.initials: RP
authors.lastname: Tang
authors.forename: Shuen-Keui
authors.initials: SK
authors.lastname: Liao
authors.forename: Kun-Yun
authors.initials: KY
authors.lastname: Yeh
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000096:biosynthesis / Q000276:immunology; D015214:Antigens, Differentiation, Myelomonocytic / Q000096:biosynthesis / Q000276:immunology; D003110:Colonic Neoplasms / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D017077:Culture Media, Conditioned; D050822:Cytokine Receptor gp130 / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019073:HT29 Cells; D006801:Humans; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000276:immunology* / Q000378:metabolism; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D010766:Phosphorylation; D050796:STAT3 Transcription Factor / Q000276:immunology / Q000378:metabolism*; D000097382:CD68 Molecule
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D017077:Culture Media, Conditioned; D050822:Cytokine Receptor gp130; D015850:Interleukin-6; D050796:STAT3 Transcription Factor; C067980:CD68 antigen, human; D000097382:CD68 Molecule