Human IL18-IL2 fusion protein as a potential antitumor reagent by enhancing NK cell cytotoxicity and IFN-γ production.
OBJECTIVE
To obtain a human IL18-IL2 fusion protein by genetic engineering methods and investigate its antitumor activity and mechanism in tumor-bearing mouse models.


METHODS
Human IL-18, IL-2 and the fusion gene IL18-IL2 were obtained by PCR, inserted into pBV220 vector and expressed in BL21 (DE3) by 42 °C heat induction. Purified proteins were analyzed by SDS-PAGE and Western blot. The biological activity of IL18-IL2 was first determined by its ability to augment IFN-γ production in PBMCs. Then tumor-bearing mouse models of mouse Lewis lung carcinoma (LLC), human large cell lung carcinoma (NCI-H460) and human colorectal carcinoma (HCT-116) were established to investigate the antitumor activity and mechanism of IL18-IL2.


RESULTS
IL18-IL2 was confirmed by Western blot, and its molecular weight was about 34.5 kDa. IL18-IL2 could significantly enhance production of IFN-γ in PBMCs in vitro and induce significant tumor regression in tumor-bearing mouse models of LLC, NCI-H460 and HCT-116 than that of IL-18 and IL-2 separately or combination using. In the mice bearing HCT-116 and LLC, IFN-γ concentrations and natural killer cell cytotoxicity were highly enhanced by IL18-IL2. Anti asialo GM1 could reduce natural killer cell cytotoxicity, production of IFN-γ, and regression of LLC tumor aroused by IL18-IL2.


CONCLUSIONS
These results suggested the IL18-IL2 fusion protein showed a synergetic effect on tumor regression, which was related to the great ability of IL18-IL2 in enhancing IFN-γ production and natural killer cell cytotoxicity. The fusion protein was a potential antitumor reagent in cancer immunotherapy.
School of Pharmacy, Yantai University, Yantai 264005, China. guangyingdu@126.com
Guangying
G
Du
Liang
L
Ye
Guoying
G
Zhang
Qiuju
Q
Dong
Kun
K
Liu
Jingwei
J
Tian
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001483:Base Sequence; D018827:Carcinoma, Lewis Lung / Q000188:drug therapy / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D005822:Genetic Vectors; D045325:HCT116 Cells; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000276:immunology; D020382:Interleukin-18 / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*
D000970:Antineoplastic Agents; C508594:IL2 protein, human; D020382:Interleukin-18; D007376:Interleukin-2; D011993:Recombinant Fusion Proteins; D007371:Interferon-gamma