增强 CAR-T 细胞代谢以克服脑肿瘤微环境中的缺氧状态

The efficacy of chimeric antigen receptor T cell (CAR-T) therapy has been limited against brain tumors to date. CAR-T cells infiltrating syngeneic intracerebral SB28 EGFRvIII gliomas revealed impaired mitochondrial ATP production and a markedly hypoxic status compared with ones migrating to subcutaneous tumors.

Drug screenings to improve metabolic states of T cells under hypoxic conditions led us to evaluate the combination of the AMPK activator metformin and the mTOR inhibitor rapamycin (Met+Rap). Met+Rap-pretreated mouse CAR-T cells showed activated PPAR- coactivator 1 (PGC-1 ) through mTOR inhibition and AMPK activation, and a higher level of mitochondrial spare respiratory capacity than those pretreated with individual drugs or without pretreatment.

Moreover, Met+Rap-pretreated CAR-T cells demonstrated persistent and effective antiglioma cytotoxic activities in the hypoxic condition.

Furthermore, a single intravenous infusion of Met+Rap-pretreated CAR-T cells significantly extended the survival of mice bearing intracerebral SB28 EGFRvIII gliomas. Mass cytometric analyses highlighted increased glioma-infiltrating CAR-T cells in the Met+Rap group, with fewer Ly6c+CD11b+ monocytic myeloid-derived suppressor cells in the tumors.

Finally, human CAR-T cells pretreated with Met+Rap recapitulated the observations with murine CAR-T cells, demonstrating improved functions under in vitro hypoxic conditions.

These findings advocate for translational and clinical exploration of Met+Rap-pretreated CAR-T cells in human trials.