title: Tumoricidal activity of interferon-r activated peripheral monocytes in colorectal cancer patients.
abstract: Peripheral blood monocytes obtained from 8 colorectal cancer patients and 6 normal controls were incubated in vitro with interferon-r (IFN-r) in the presence of bacterial lipopolysaccharide (LPS). The cytotoxic properties of the monocyte were determined subsequent to the interaction with radiolabeled autologous, allogeneic, as well as cultured colorectal cancer cells. Monocytes from normal controls and all colorectal cancer patients were activated in vitro to become tumoricidal; monocytes lysed tumorigenic cells but not nontumorigenic cells. Activators of protein kinase C (e.g. phorbol esters, PMA) and Ca2+ ionophores (A23187) when added alone did not effect the activation state of the monocyte. Whereas, PMA and A23187 cooperatively reproduced the ability of IFN-r to prime monocytes for tumoricidal activity. In the presence of PMA, A23187, and EGTA, the addition of excessive Ca2+ was sufficient for priming, whereas the addition of excessive Mg2+ was much less efficient. Priming by IFN-r, however, was not blocked by EGTA. An efflux of Ca2+ from preloaded monocytes was significantly increased by A23187 and by IFN-r. Quin-2/AM, an intracellular chelator of Ca2+, blocked priming by IFN-r. The results suggest that priming of monocytes for tumoricidal function by IFN-r may be involved in the activation of protein kinase C and mobilization of intracellular Ca2+.
authors.affiliation: Department of Surgery and Pediatrics, College of Medicine, National Taiwan University, Taipei, R.O.C.
authors.forename: K J
authors.initials: KJ
authors.lastname: Chang
authors.forename: C S
authors.initials: CS
authors.lastname: Lee
authors.forename: S M
authors.initials: SM
authors.lastname: Wang
authors.forename: K H
authors.initials: KH
authors.lastname: Hsieh
authors.forename: K M
authors.initials: KM
authors.lastname: Chen
mesh_terms: D000368:Aged; D000634:Aminoquinolines / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D015179:Colorectal Neoplasms / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007372:Interferons / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000276:immunology; D008262:Macrophage Activation; D008297:Male; D008875:Middle Aged; D016260:Monocytes, Activated Killer / Q000276:immunology* / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D000634:Aminoquinolines; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D000001:Calcimycin; C035738:Quin2-acetoxymethyl ester; D007372:Interferons; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium