Fundamental study for improvement of cancer immunotherapy based on gene analysis

我们正在使用自体癌症特异性细胞毒性T淋巴细胞(CTL)进行过继免疫治疗。在临床试验中，晚期癌症患者外周血单个核细胞(PBMC)在加入IL-2(100U/ml)和患者照射的肿瘤细胞的情况下培养约14天。培养后，大多数PBMC中识别出包括NK细胞和LAK细胞在内的主要CTL。此外，我们正在使用面向CTL前体的癌症疫苗对晚期或复发的癌症患者进行I/II期试验。对于从这些患者获得的癌症样本，计划在治疗前使用DNA TIP进行基因分析，以确定有效的免疫治疗病例。本研究共收集癌症样本II份，有效病例样本6份，无效病例样本5份。在调节性T细胞分析的基础研究中，培养14天以上的淋巴细胞以CD4+/CD25+T细胞为主。这些调节性T细胞在体外被抗IL-2受体α抗体处理而减少。通过这种处理，转化生长因子-β的产生也被减少。我们对蛋白酶体抑制物(PI)进行了进一步的基础研究，以提高肿瘤免疫治疗的效果。通过PI处理TRAIL受体弱表达的肿瘤细胞，TRAIL受体表达明显增强，TRAIL活性显著提高，因此，必须控制调节性T细胞和TRAIL的活性，以提高肿瘤免疫治疗的临床效果。此外，我们还将继续保存癌症样本，以研究DNA TIP的基因分析。

We are performing adoptive immunotherapy using autologous cancer specific cytotoxic T lymphocytes (CTLs). In this clinical trial, peripheral blood mononuclear cells (PBMC) obtained from advanced cancer patient were cultured for about 14 days under the addition of IL-2 (100U/ml) and patient's irradiated tumor cells. Following the cultivation, predominant CTLs including NK cells and LAK cells were recognized in most PBMC. Further more, we are performing phase I/II trial for advanced or recurrent cancer patients using CTL precursor-oriented cancer vaccine. For cancer samples obtained from these patients, gene analysis using DNA tip was planned to define effective cases of immunotherapy prior to treatment. In this study, II cancer samples were stocked, 6 were effective case samples and 5 were non effective case samples. However we have failed to stock cancer samples in many cases due to no tumor lesion or rejection of gene analysis.In the fundamental studies on regulatory T cell analysis, CD4+/CD25+ T-cells were dominant in cultured lymphocytes more than 14 days. These regulatory T-cells were reduced by in vitro treatment of anti-IL-2 receptor α antibody. By this treatment, production of TGF-β was also reduced. We performed further fundamental study on proteasome inhibitor (PI) to improve the effect of cancer immunotherapy. By the PI treatment of cancer cells with weak expression of TRAIL receptor, TRAIL receptor was markedly expressed and TRAIL activity was significantly improved.From these results, we have to control regulatory T-cell and TRAIL activity to improve the clinical effect of cancer immunotherapy. Further we will continue the storage of cancer samples to investigate gene analysis by DNA tip.