Department of Pediatric Hematology and Oncology, University Children's Hospital Münster, 48149 Münster, Germany.
Department of Pediatric Hematology and Oncology, University Children's Hospital Münster, 48149 Münster, Germany; Center of Integrated Protein Science Munich (CIPS-M) and Division of Clinical Pharmacology, Department of Medicine IV, University Hospital, Ludwig-Maximilians-Universität München, 80539 Munich, Germany.
Mol Ther. 2019 May 8;27(5):933-946. doi: 10.1016/j.ymthe.2019.02.014. Epub 2019 Feb 23.
Chimeric antigen receptor (CAR) engineering of T cells allows one to specifically target tumor cells via cell surface antigens. A candidate target in Ewing sarcoma is the ganglioside G, but heterogeneic expression limits its value. Here we report that pharmacological inhibition of Enhancer of Zeste Homolog 2 (EZH2) at doses reducing H3K27 trimethylation, but not cell viability, selectively and reversibly induces G surface expression in Ewing sarcoma cells. EZH2 in Ewing sarcoma cells directly binds to the promoter regions of genes encoding for two key enzymes of G biosynthesis, and EZH2 inhibition enhances expression of these genes. G surface expression in Ewing sarcoma cells is not associated with distinct in vitro proliferation, colony formation, chemosensitivity, or in vivo tumorigenicity. Moreover, disruption of G synthesis by gene editing does not affect its in vitro behavior. EZH2 inhibitor treatment sensitizes Ewing sarcoma cells to effective cytolysis by G-specific CAR gene-modified T cells. In conclusion, we report a clinically applicable pharmacological approach for enhancing efficacy of adoptively transferred G-redirected T cells against Ewing sarcoma, by enabling recognition of tumor cells with low or negative target expression.
嵌合抗原受体（CAR）修饰的 T 细胞可以通过细胞表面抗原特异性靶向肿瘤细胞。在尤文肉瘤中，一个候选靶点是神经节苷脂 G，但异质性表达限制了其价值。在这里，我们报告称，在降低 H3K27 三甲基化但不影响细胞活力的剂量下，抑制 Enhancer of Zeste Homolog 2（EZH2）可选择性和可逆性地诱导尤文肉瘤细胞表面 G 表达。EZH2 在尤文肉瘤细胞中直接结合编码 G 生物合成两个关键酶的基因的启动子区域，EZH2 抑制增强这些基因的表达。尤文肉瘤细胞表面 G 表达与体外增殖、集落形成、化疗敏感性或体内致瘤性无关。此外，通过基因编辑破坏 G 合成并不影响其体外行为。EZH2 抑制剂治疗可增强 G 特异性 CAR 基因修饰 T 细胞对尤文肉瘤的有效细胞溶解作用。总之，我们报告了一种临床适用的药理学方法，通过增强对低表达或阴性表达肿瘤细胞的识别，提高过继转移 G 重定向 T 细胞治疗尤文肉瘤的疗效。
