Analysis of gene expression in SKBR3 cells isolated from xenograft tumors in mice treated with radioinducible TNF producing CAR-T cells

To overcome these limitations, we developed a strategy that integrates the spatial precision of ionizing radiation with the biological specificity of CAR T cells. We identified radiation-induced genes from irradiated intratumoral T cells and engineered synthetic radio inducible promoters to drive expression of a prototype effector, TNF.

Human CAR T cells expressing this construct (riTNF CAR T) secreted high levels of TNF upon irradiation, independently of antigen engagement. In in vivo models of HER2⁺ and FRα⁺ human xenograft tumors, the combination of riTNF CAR T cells with local irradiation resulted in significantly greater tumor regression than either treatment alone or the combination of standard CAR T cells with irradiation. To study the antitumoral mechanisms involved in treatment with riTNF CAR-T cells, we sorted cancer cells from xenograft tumors after treatment and analyzed changes in gene expression caused by riTNF CAR-T therapy vs control treatments.