Construction of a recombinant human GM-CSF/MCAF fusion protein and study on itsin vitro andin vivo antitumor effects
A novel cytokine fusion protein was constructed by fusing granulocyte macrophage colony stimulating factor (GM-CSF) with monocyte chemotactic activating factor (MCAF), which acts as a factor directing effector cells (monocytes) to a target site. The recombinant human GM-CSF/MCAF fusion protein could sustain the growth of GMCSF-dependent cell line TF1 and was chemotactic for monocytes. Thein vitro antitumor effect showed that rhGM-CSF/MCAF could activate monocytes to inhibit the growth of several human tumor cell lines, including a promyelocyte leukemia cell line HL-60, a lung adenocarcinoma cell line A549, a hepatoma cell line SMMC-7721 and a melanoma cell line Bowes. Furthermore, the cytotoxicity of monocytes activated by rhGM-CSF/MCAF against HL-60 and A549 was greater than that activated by GM-CSF or MCAF alone, even greater than that activated by a combination of GM-CSF and MCAF, suggesting that the fusion protein has synergistic or enhanced effects. Thein vivo antitumor effect indicated that rhGM-CSF/MCAF had marked antitumor effect against A549 tumor in nude mice and even completely suppressed tumor formation. rhGM-CSF/MCAF was significantly more effective in inhibiting tumor growth than rhGM-CSF. Histological analysis showed that tumor site injected with rhGM-CSF/MCAF was infiltrated by a large number of monocytes while a sparse infiltration of monocytes was observed at the tumor site injected with rhGM-CSF or normal saline, suggesting that the antitumor effect of rhGM-CSF/MCAF was mediated by the recruitment of a large number of monocytes to the tumor site.
KeywordsGM-CSF MCAF gene cloning fusion protein antitumor
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- 2.Zhao, C. H., Tang, P. H., Wang, J. X.et a1., Characterization of a recombinant human fusion protein IL6/IL-2 (CH925),Chin. J. Exp. Hematol., 1994, 2: 29.Google Scholar
- 5.Sambrook, J., Fritsch, E.F., Maniatis, T.,Molecular Cloning: A Laboratory Manual, New York: Cold Spring Harbor Laboratory Press. 1989.Google Scholar
- 7.Wu, J. G.,Applied Clinic Immunological Detection (in Chinese), Nanjing: Jiangsu Science and Technology Press, 1989, 133.Google Scholar
- 10.Ye, Q. N., Su, G. F., Yuan, Y.et al., The PCR, cloning and sequencing of human monocyte chemoattractant protein-1 (MCP-1) gene,Chin. J. Micro. Immunol. (in Chinese), 1994, 14: 29.Google Scholar
- 12.Nakano, Y., Kasahara, T., Mukaida, N.et al., Protection against lethal bacterial infection in mice by monocyte-chemotactic and-activating factor,Infcct. Immun., 1994, 62: 377.Google Scholar
- 15.Ragnhamnar, P., Frodin, J. E., Trotta, P. P.et al., Cytotoxicity of white blood cells activated by granulocytemacrophage colony-stimulating factor and macrophage-colony-stimulating factor against tumor cells in the presence of various monoclonal antibodies,Cancer Immunol. Immunother., 1994, 39: 254.CrossRefGoogle Scholar