Cell therapies such as chimeric-antigen receptor (CAR) T-cells and NK cells are cutting-edge methods for treating cancer and other diseases. There is high interest in optimizing drug treatment regimens to best work together with emerging cell therapies, such as targeting epigenetic enzymes to stimulate recognition of tumor cells by immune cells. Herein, we uncover new mechanisms of the histone demethylase LSD1, and various inhibitors targeting unique domains of LSD1, in the function of NK cells grown for cell therapy. Catalytic inhibitors (tranylcypromine and the structural derivatives GSK LSD1 and RN-1) can irreversibly block the demethylase activity of LSD1, while scaffolding inhibitors (SP-2509 and clinical successor SP-2577, also known as seclidemstat) disrupt epigenetic complexes that include LSD1. Relevant combinations of LSD1 inhibitors with cell therapy infusions and immune checkpoint blockade have shown efficacy in pre-clinical solid tumor models, reinforcing a need to understand how these drugs would impact T- and NK cells. We find that scaffolding LSD1 inhibitors potently reduce oxidative phosphorylation and glycolysis of NK cells, and higher doses induce mitochondrial reactive oxygen species and depletion of the antioxidant glutathione. These effects are unique to scaffolding inhibitors compared to catalytic, to NK cells compared to T-cells, and importantly, can fully ablate the lytic capacity of NK cells. Supplementation with biologically achievable levels of glutathione rescues NK cell cytolytic function but not NK cell metabolism. Our results suggest glutathione supplementation may reverse NK cell activity suppression in patients treated with seclidemstat.

嵌合抗原受体（CAR）T细胞和NK细胞等细胞疗法是治疗癌症和其他疾病的前沿方法。对优化药物治疗方案以使其与新兴细胞疗法（例如靶向表观遗传酶以刺激免疫细胞识别肿瘤细胞）的最佳配合产生了极大的兴趣。在这里，我们揭示了组蛋白脱甲基酶LSD1的新机制，以及针对LSD1独特域的各种抑制剂，它们在为细胞治疗而生长的NK细胞中发挥了作用。催化抑制剂（反式环丙胺及其结构衍生物GSK LSD1和RN-1）可以不可逆地阻断LSD1的脱甲基酶活性，而脚手架抑制剂（SP-2509和临床后继剂SP-2577，也称为seclidemstat）破坏包括LSD1的表观遗传复合物。LSD1抑制剂与细胞疗法输注和免疫检查点阻断的相关组合已在临床前实体瘤模型中显示出功效，从而加强了对了解这些药物如何影响T细胞和NK细胞的需求。我们发现脚手架LSD1抑制剂有效地减少NK细胞的氧化磷酸化和糖酵解，并更高剂量诱导线粒体活性氧种类和抗氧化剂谷胱甘肽的消耗。与催化作用相比，这些作用对于支架抑制剂是独特的，与T细胞相比，对NK细胞是独特的，并且重要的是，可以完全消除NK细胞的裂解能力。补充具有生物学上可达到的水平的谷胱甘肽可以挽救NK细胞的细胞溶解功能，但不能挽救NK细胞的代谢。