Table 1.
Preclinical and clinical studies addressing the mechanisms CAR T-cell killing.
| Reference | Experiments | Results | |
|---|---|---|---|
| Perforin/granzymes | Davenport et al., 2015 (25) | Imaging killing assay coculturing HER2 CAR T with HER2-expressing tumor cells | Confocal microscopy showing PI blush after CAR T-targeted cell contact, suggesting the formation of perforin pores |
| Koehler et al., 2007 (26) | Cytotoxic assay coculture CEA CAR T with CEA-expressing colon carcinoma cell lines | Granzyme B secretion by CAR T cells in the presence of targeted antigen | |
| Kumaresan et al., 2014 (27) | Dectin-1 CAR cocultured with Aspergillus hyphae | Threefold upregulation of CD107a and secretion of perforin/granzyme B | |
| Darcy et al., 2000 (28) | Chrome release assay coculturing CEA CAR T with CEA-expressing colon carcinoma cell lines | Chrome-release abolished when using perforin-deficient CAR T cells | |
| Mamonkin et al., 2015 (29) | Cytotoxic assay coculture CD5 CAR T with Jurkat cells Perforin/granzyme blocking by EGTA |
Decreased cytotoxicity upon perforin/granzyme blockade | |
| Haynes et al., 2002 (30) | In vivo CEA-expressing colon carcinomas growth monitoring after CEA CAR adoptive transfer | Antitumoral efficacy decreased with perforin-deficient CAR T cells | |
| Ishii et al., 2020 (31) | Treatment with CD19 CAR T cells of leukemia-bearing mice | Antitumoral efficacy decreased with perforin-deficient CAR T cells | |
| Li et al., 2020 (32) | Glypican 3 CAR T treatment for orthotopic hepatocellular carcinoma in mice | Perforin and granzyme B-mediated apoptosis and tumor eradication | |
| Death receptors | Mamonkin et al., 2015 (29) | Cytotoxic assay coculture CD5 CAR T with Jurkat cells Anti-FasL blocking antibodies |
Decreased cytotoxicity upon FasL blockade |
| Upadhyay et al., 2020 (11) | Cytotoxic assay coculture CD19 CAR T cells with CD19+ or CD19− lymphoma cells Adoptive transfer of CD19 CAR T cells in CD19+ or CD19+/CD19− lymphomas bearing mice |
Fas deficiency moderately decreased CD19 CAR T-cell cytotoxicity against CD19+ lymphoma cells and nearly abolished CD19 CAR T-cell bystander cytotoxicity against CD19− lymphoma cells CD19 CAR T prolonged survival of both CD19+ and CD19+/CD19− lymphoma-bearing mice FasL blockade impaired on-target and bystander CD19 CAR T-cell efficacy in vivo |
|
| Darcy et al., 1998 (43) | Cytotoxic assay coculture CEA CAR T with CEA-expressing colon carcinoma cell lines | Decreased cytotoxicity with Fas-deficient CEA-expressing target cells | |
| DeSelm et al., 2018 (44) | Sialyl Lewis-A (sLeA) CAR adoptive transfer on sLeA+ and sLeA− heterogeneous tumor-bearing mice | Low-dose radiation sensitizes both on-target and bystander tumor cell killing by CAR T-cell via the TRAIL axis | |
| Hong et al., 2018 (45) | Cytotoxic assay coculture CD30 CAR T with CD30+ and CD30− tumor cells | Fas/FasL-dependent killing of CD30− tumor cells if CAR T cells were preactivated with CD30+ tumor cells | |
| Singh et al., 2020 (47) | Unbiased genome-wide loss-of-function screen in B-ALL cell lines under CD19 CAR T-cell pressure | Disruption of genes associated with proapoptotic death receptor signaling pathway (FADD, BID, CASP8, and TNFRSF10B) confers resistance to CAR-T cell killing Knockout of antiapoptotic genes (CFLAR, TRAF2, and BIRC2) led to an increased susceptibility to CAR-T killing |
|
| Dufva et al., 2020 (48) | Unbiased genome-wide loss-of-function screen in B-ALL and DLBCL cells under CD19 CAR T cells pressure associated with high-throughput drug screening | Death receptor signaling (FADD, TNFRSF10B) is a key mediator of CAR T-cell cytotoxicity Increased CAR T-cell cytotoxicity in presence of SMAC mimetics and IAP antagonists |
|
| Cytokines | Kumaresan et al., 2014 (27) | Dectin-1 CAR cocultured with Aspergillus hyphae | IFNγ production when exposed to their target antigen |
| Haynes et al., 2002 (30) | In vivo CEA-expressing colon carcinomas growth monitoring after CEA CAR adoptive transfer | Antitumoral efficacy decreased with IFNγ deficient CAR T | |
| Ishii et al., 2020 (31) | Treatment with CD19 CAR T cells of leukemia-bearing mice | Antileukemia activity despite the absence of perforin Compensatory overexpression of IFNγ IFNγ blockade decreased antileukemia activity |
|
| Arenas et al., 2021 (71) | HER2-driven cell lines and patient-derived xenografts treated with HER2 CAR T cells | Antitumoral efficacy decreased with IFNγ deficient CAR T, notably through the downregulation of JAK2 |