Adenovirus-mediated interleukin-18 mutant in vivo gene transfer inhibits tumor growth through the induction of T cell immunity and activation of natural killer cell cytotoxicity.
We report here that gene transfer using recombinant adenoviruses encoding interleukin (IL)-18 mutants induces potent antitumor activity in vivo. The precursor form of IL-18 (ProIL-18) is processed by caspase-1 to produce bioactive IL-18, but its cleavage by caspase-3 (CPP32) produces an inactive form. To prepare IL-18 molecules with an effective antitumor activity, a murine IL-18 mutant with the signal sequence of murine granulocyte-macrophage (GM)- colony stimulating factor (CSF) at the 5'-end of mature IL-18 cDNA (GMmIL-18) and human IL-18 mutant with the prepro leader sequence of trypsin (PPT), which is not cleaved by caspase-3 (PPThIL-18CPP32-), respectively, were constructed. Adenovirus vectors carrying GMmIL-18 or PPThIL-18CPP32- produced bioactive IL-18. Ad.GMmIL-18 had a more potent antitumor effect than Ad.mProIL-18 encoding immature IL-18 in renal cell adenocarcinoma (Renca) tumor-bearing mice. Tumor-specific cytotoxic T lymphocytes, the induction of Th1 cytokines, and an augmented natural killer (NK) cell activity were detected in Renca tumor-bearing mice treated with Ad.GMmIL-18. An immunohistological analysis revealed that CD4+ and CD8+ T cells abundantly infiltrated into tumors of mice treated with Ad.GMmIL-18. Huh-7 human hepatoma tumor growth in nude mice with a defect of T cell function was significantly inhibited by Ad.PPThIL-18CPP32- compared with Ad.hProIL-18 encoding immature IL-18. Nude mice treated with Ad.PPThIL-18CPP32- contained NK cells with increased cytotoxicity. The results suggest that the release of mature IL-18 in tumors is required for achieving an antitumor effect including tumor-specific cellular immunity and augmented NK cell-mediated cytotoxicity. These optimally designed IL-18 mutants could be useful for improving the antitumor effectiveness of wild-type IL-18.
Hwang
Kyung-Sun
KS
Cell Biology Laboratory/Gene Therapy Research Unit, Korea Research Institute of Bioscience and Biotechnology, Yusong, Daejeon, Republic of Korea.
Cho
Won-Kyung
WK
Yoo
Jinsang
J
Seong
Young Rim
YR
Kim
Bum-Kyeng
BK
Kim
Samyong
S
Im
Dong-Soo
DS
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D003470:Culture Media / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D018014:Gene Transfer Techniques; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D007371:Interferon-gamma / Q000378:metabolism; D020382:Interleukin-18 / Q000235:genetics*; D007376:Interleukin-2 / Q000378:metabolism; D007680:Kidney Neoplasms / Q000628:therapy; D007694:Killer Cells, Natural / Q000378:metabolism; D008113:Liver Neoplasms / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008957:Models, Genetic; D009154:Mutation; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D013997:Time Factors; D014162:Transfection
D003470:Culture Media; D018076:DNA, Complementary; D020382:Interleukin-18; D007376:Interleukin-2; D049452:Green Fluorescent Proteins; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor