Hwang Kyung-Sun, Cho Won-Kyung, Yoo Jinsang, Seong Young Rim, Kim Bum-Kyeng, Kim Samyong, Im Dong-Soo
Cell Biology Laboratory/Gene Therapy Research Unit, Korea Research Institute of Bioscience and Biotechnology, Yusong, Daejeon, Republic of Korea.
Cancer Gene Ther. 2004 Jun;11(6):397-407. doi: 10.1038/sj.cgt.7700711.
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.
我们在此报告，使用编码白细胞介素（IL）-18突变体的重组腺病毒进行基因转移可在体内诱导强大的抗肿瘤活性。IL-18的前体形式（ProIL-18）由半胱天冬酶-1加工以产生生物活性IL-18，但其被半胱天冬酶-3（CPP32）切割则产生无活性形式。为制备具有有效抗肿瘤活性的IL-18分子，构建了分别在成熟IL-18 cDNA的5'端带有小鼠粒细胞-巨噬细胞（GM）-集落刺激因子（CSF）信号序列的小鼠IL-18突变体（GMmIL-18）和带有胰蛋白酶前原导肽序列（PPT）且不被半胱天冬酶-3切割的人IL-18突变体（PPThIL-18CPP32-）。携带GMmIL-18或PPThIL-18CPP32-的腺病毒载体产生生物活性IL-18。在肾细胞腺癌（Renca）荷瘤小鼠中，Ad.GMmIL-18比编码未成熟IL-18的Ad.mProIL-18具有更强的抗肿瘤作用。在用Ad.GMmIL-18治疗的Renca荷瘤小鼠中检测到肿瘤特异性细胞毒性T淋巴细胞、Th1细胞因子的诱导以及增强的自然杀伤（NK）细胞活性。免疫组织学分析显示，CD4 +和CD8 + T细胞大量浸润到用Ad.GMmIL-18治疗的小鼠肿瘤中。与编码未成熟IL-18的Ad.hProIL-18相比，Ad.PPThIL-18CPP32-显著抑制了T细胞功能缺陷的裸鼠中Huh-7人肝癌肿瘤的生长。用Ad.PPThIL-18CPP32-治疗的裸鼠含有细胞毒性增加的NK细胞。结果表明，肿瘤中成熟IL-18的释放是实现包括肿瘤特异性细胞免疫和增强的NK细胞介导细胞毒性在内的抗肿瘤作用所必需的。这些经过优化设计的IL-18突变体可能有助于提高野生型IL-18的抗肿瘤效力。
