Uchibori Ryosuke, Teruya Takeshi, Ido Hiroyuki, Ohmine Ken, Sehara Yoshihide, Urabe Masashi, Mizukami Hiroaki, Mineno Junichi, Ozawa Keiya
Division of Immuno-Gene and Cell Therapy, Jichi Medical University, Shimotsuke, Japan.
Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Japan.
Mol Ther Oncolytics. 2018 Dec 1;12:16-25. doi: 10.1016/j.omto.2018.11.003. eCollection 2019 Mar 29.
Adoptive transfer of T cells expressing a chimeric antigen receptor (CAR) is a promising cell-based anticancer therapy. Although clinical studies of this approach show therapeutic efficacy, additional genetic modification is necessary to enhance the efficacy and safety of CAR-T cells. For example, production of an antitumor cytokine from CAR-T cells can potentially enhance their tumor-killing activity, but there are concerns that constitutive expression of anticancer molecules will cause systemic side effects. Therefore, it is important that exogenous gene expression is confined to the tumor locality. Here, we aimed to develop an inducible promoter driven by activation signals from a CAR. Transgene expression in T cells transduced with the CD19-targeted CAR and an inducible promoter, including inducible reporter genes (CAR-T/iReporter), was only induced strongly by co-culture with CD19-positive target cells. CAR-T/iReporter cells also showed redirected cytolysis toward CD19-positive, but not CD19-negative, tumor cells. Overall, our study indicated that the inducible promoter was selectively driven by activation signals from the CAR, and transduction with the inducible promoter did not affect original effector activities including interleukin-2 and interferon-γ production and the antitumor activity of CAR-redirected cytotoxic T lymphocytes. Moreover, this inducible promoter permits visualization and quantification of the activation status in CAR-T cells.
过继转移表达嵌合抗原受体（CAR）的T细胞是一种很有前景的基于细胞的抗癌疗法。尽管这种方法的临床研究显示出治疗效果，但仍需要进行额外的基因改造以提高CAR-T细胞的疗效和安全性。例如，CAR-T细胞产生抗肿瘤细胞因子可能会增强其杀瘤活性，但人们担心抗癌分子的组成性表达会引起全身性副作用。因此，将外源基因表达限制在肿瘤局部非常重要。在此，我们旨在开发一种由CAR的激活信号驱动的诱导型启动子。用靶向CD19的CAR和诱导型启动子转导的T细胞中的转基因表达，包括诱导型报告基因（CAR-T/iReporter），仅在与CD19阳性靶细胞共培养时强烈诱导。CAR-T/iReporter细胞也显示出对CD19阳性而非CD19阴性肿瘤细胞的重定向细胞溶解作用。总体而言，我们的研究表明，诱导型启动子由CAR的激活信号选择性驱动，并且用诱导型启动子转导不影响包括白细胞介素-2和干扰素-γ产生以及CAR重定向细胞毒性T淋巴细胞的抗肿瘤活性在内的原始效应子活性。此外，这种诱导型启动子允许可视化和量化CAR-T细胞中的激活状态。
