Efficacy of CAR T cell therapy in large tumors relies upon stromal targeting by IFNγ
Menée à l'aide d'un modèle murin , cette étude met en évidence des mécanismes, liés au microenvironnement tumoral, suggérant l'intérêt d'un traitement à base de lymphocytes T, modifiés pour exprimer un récepteur d'antigène chimérique, dans les tumeurs solides
Adoptive T cell therapy using chimeric antigen receptor-modified T cells (CAR-T therapy) has shown dramatic efficacy in patients with circulating lymphoma. However, eradication of solid tumors with CAR-T therapy has not been reported yet to be efficacious. In solid tumors, stroma destruction, due to MHC-restricted cross-presentation of tumor antigens to T cells, may be essential. However, CAR-Ts recognize antigens in an MHC-independent manner on cancer cells but not stroma cells. In this report, we show how CAR-Ts can be engineered to eradicate large established tumors with provision of a suitable CD28 costimulatory signal. In a HER-2-dependent tumor model, tumor rejection by HER-2-specific CAR-Ts was associated with sustained influx and proliferation of the adoptively transferred T cells. Interestingly, tumor rejection did not involve NK cells, but was associated instead with a marked increase in the level of M1 macrophages and a requirement for IFNγ receptor expression on tumor stroma cells. Our results argue that CAR-T therapy is capable of eradicating solid tumors through a combination of antigen-independent stroma destruction and antigen-specific tumor cell targeting.