Enhancement of natural killer cell-mediated cytotoxicity by coexpression of GM-CSF/B70 in hepatoma.
On investigating the role of granulocyte-macrophage colony-stimulating factor (GM-CSF) and costimulatory molecule, B70, in antitumor immunity, we have found important effects of GM-CSF/B70 coexpression in the interaction with natural killer (NK) cells. We used the pLSN vector system to contain the neomycin-resistant gene and LTR promoter. The pLSNGM-CSF, pLSNB70 and pLSNB70/GM-CSF, pLSN vectors each containing GM-CSF, B70, and B70/GM-CSF cDNA, respectively, were constructed. They were transfected into human hepatocellular carcinoma cell (SK-HEP1), and stable cells (SK-pLSN, SK-GM, SK-B70 and SK-BG) were selected after neomycin treatment. According to enzyme-linked immunosorbent analysis and FACS, we showed that expression of GM-CSF was increased up to 23-fold in SK-GM and SK-BG cells, and also expression of B70 was induced at least 76-97% in SK-B70 and SK-BG cells. Expression of B70 was remarkably increased by autocrine effect of GM-CSF in SK-BG cells. Primary cytolytic ability of GM-CSF and B70 significantly increased almost 4-fold (effector/target ratio, 100:1) in SK-BG cells. In in vivo studies, SK-BG cells showed much less subcutaneous tumor formation in nude mice accompanying increased NK cell proliferation and cytotoxicity. Therefore, these results suggest that combining expression of GM-CSF and B70 may enhance NK-mediated cytotoxicity, and then induce the antitumor immunity in hepatoma transplanted into nude mice.
Kim
K Y
KY
Division of Cancer Research, Department of Biomedical Science, National Institute of Health, #5 Nopbun-dong, Eunpung-ku, 122-701, Seoul, South Korea.
Kang
M A
MA
Nam
M J
MJ
D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D051940:B7-2 Antigen; D002455:Cell Division; D003601:Cytotoxicity Tests, Immunologic; D015316:Genetic Therapy; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008114:Liver Neoplasms, Experimental / Q000276:immunology* / Q000473:pathology / Q000628:therapy; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D012333:RNA, Messenger / Q000096:biosynthesis; D014162:Transfection; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; D051940:B7-2 Antigen; C497964:CD86 protein, human; C497965:Cd86 protein, mouse; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D016178:Granulocyte-Macrophage Colony-Stimulating Factor