除了免疫抑制作用外，过继治疗前的细胞抑制剂调节（例如嵌合抗原受体 (CAR) T 细胞）可能在肿瘤微环境的减灭和重塑中发挥作用。我们在体外研究了三硫丹和氟达拉滨对表达间皮素（MSLN）的卵巢癌细胞的杀伤功效和影响，以及对靶向 MSLN 的 CAR T 细胞的影响。 Treosulfan和氟达拉滨对SKOV3和OVCAR4细胞具有协同杀伤作用。当 SKOV3 细胞表达 MSLN 以及在缺氧条件下测试 OVCAR4 细胞时，对三硫丹和氟达拉滨组合的敏感性增加，而 SKOV3 和 OVCAR4 细胞的 MSLN 细胞表面表达在三硫丹或氟达拉滨暴露后没有改变。暴露于三硫丹或氟达拉滨 (10 µM) 既不会影响 MSLN-CAR T 细胞脱颗粒、MSLN OVCAR3 细胞攻击时细胞因子的产生，也不会诱导线粒体缺陷。三硫丹和氟达拉滨的组合可降低 MSLN-CAR T 细胞在常氧条件下的抗肿瘤杀伤能力，但不会降低缺氧条件下的抗肿瘤杀伤能力。总之，即使在缺氧条件下，三硫丹和氟达拉滨也能杀死 MSLN   卵巢癌细胞而不改变 MSLN-CAR T 细胞功能（在低细胞抑制剂浓度下），我们的数据支持在 MSLN-CAR T 细胞之前使用三硫丹和氟达拉滨作为调理药物疗法。© 2024。作者。

In addition to their immunosuppressive effect, cytostatics conditioning prior to adoptive therapy such as chimeric antigen receptor (CAR) T cells may play a role in debulking and remodeling the tumor microenvironment. We investigated in vitro the killing efficacy and impact of treosulfan and fludarabine on ovarian cancer cells expressing mesothelin (MSLN) and effect on MSLN-targeting CAR T cells. Treosulfan and fludarabine had a synergetic effect on killing of SKOV3 and OVCAR4 cells. Sensitivity to the combination of treosulfan and fludarabine was increased when SKOV3 cells expressed MSLN and when OVCAR4 cells were tested in hypoxia, while MSLN cells surface expression by SKOV3 and OVCAR4 cells was not altered after treosulfan or fludarabine exposure. Exposure to treosulfan or fludarabine (10 µM) neither impacted MSLN-CAR T cells degranulation, cytokines production upon challenge with MSLN + OVCAR3 cells, nor induced mitochondrial defects. Combination of treosulfan and fludarabine decreased MSLN-CAR T cells anti-tumor killing in normoxia but not hypoxia. In conclusion, treosulfan and fludarabine killed MSLN + ovarian cancer cells without altering MSLN-CAR T cells functions (at low cytostatics concentration) even in hypoxic conditions, and our data support the use of treosulfan and fludarabine as conditioning drugs prior to MSLN-CAR T cell therapy.© 2024. The Author(s).