Potent antitumor immunotherapy mediated by IL-18 gene transfection to PAM212 cells

目前考虑的是增加口腔癌患者的数量，尽管手术技术和化疗正在发展。肿瘤基因治疗是治疗口腔癌的新方法之一。获得性免疫反应的启动被认为是局部组织坏死和凋亡的结果，以及常驻巨噬细胞和募集的多形核白细胞释放炎性细胞因子的结果。肿瘤部位释放的细胞因子包括IL-1、IL-6、IL-12和IL-18，以及其他细胞因子和趋化因子。树突状细胞的募集和成熟是诱导免疫反应所必需的。IL-18为干扰素-g-诱导因子，是Th1细胞活化的刺激因子，Th1细胞是肿瘤部位产生干扰素-g的主要细胞。Inf-g上调肿瘤细胞表面MHC I、II类分子的表达。MHC I类是活化的NK细胞和巨噬细胞，并帮助产生CD8+细胞毒T细胞。本研究利用IL-18基因转移至小鼠鳞状细胞癌细胞(PAM212)，将细胞因子转移至肿瘤微环境。IL-18单基因体外转染法对肿瘤细胞的肿瘤消退作用最小，要产生活性形式的IL-18，需要IL-1b转换酶(ICE)裂解细胞间的半胱氨酸残基。因此，本研究进行了IL-18和ICE的双重转染法。肿瘤细胞体外双基因转染法研究，肿瘤消退效果达20%，这与我们的研究方向不符。这些结果可能与基因对PAM212细胞的转导效率有关。我们还给IL-18/PAM212荷瘤小鼠注射了ICE，导致所有动物因毒性而死亡。因此，需要进一步开展鳞状细胞癌基因转染率技术的研究。

Increased number of oral cancer patient is currently consideration, which in Spite of developing operation technique and chemotherapy. Cancer gene therapy is one of new approaches against oral cancer. Initiation of the adaptive immune response is believed to be a result of local necrotic and apoptotic death of tissues and release of inflammatory cytokines by resident macrophages and recruited plymorphonuclear leukocytes. The cytokines released at the tumor site include IL-1, IL-6, IL-12 and IL-18, and other cytokines and chemokines. Dendritic cell recruitment and maturation is required for the induction of immune response. IL-18, INF-g-inducing factor, is a stimulatory factor in activation of Th1 cells that are major INF-g producing cells at tumor site. INF-g is up-regulate MHC class I and II expression on tumor cells. MHC class I is activated NK cells and macrophages and to help generate CD8+ cytotoxic T cells. In this study, IL-18 gene transfer to mouse squamous cell carcinoma cell (PAM212) was used to deliver cytokine to the tumor microenvironment. IL-18 single gene transfection of tumor cell ex vivo resulted in minimum effect of tumor regression, To generate active form of IL-18, it needs to IL-1b converting enzyme (ICE) to cleaved intercellular cysteine residue. Thus, dual transfection of IL-18 and ICE was performed in this study. Dual gene transfection study of tumor cell ex vivo resulted in 20% effect of tumor regression that was out of our respect. The reason of these results may be related to the transfection efficiency of the genes to PAM212 cells. We also injected ICE to IL-18/PAM212 bearing mouse, resulted in death of all animals because of toxicity. Therefore, future study required for develop the technique of transfection efficiency in the squamous cell carcinoma.