Optimal radiation dose to induce an abscopal effect by combining carbon-ion radiotherapy and anti-CTLA4 antibody

ATP11B triggers the infiltration of T cells into GBM and intensifies anti-GBM immunity by upregulating and externalizing S1PR1

BACKGROUND

Insufficient T-cell infiltration in tumours causes immune checkpoint inhibitor (ICI) resistance in glioblastoma (GBM) patients. The aim of this study was to demonstrate a preferable way to facilitate T-cell infiltration and improve the therapeutic effects of ICIs in GBM.

METHODS

Flow cytometry, western blot and immunofluorescence staining were used to detect the effects of ATP11B upregulation on S1PR1 expression and distribution, T-cell infiltration and differentiation. A coculture system and an intracranial GBM model were established to explore the anti-GBM potential of ATP11B/S1PR1 signaling through systemic administration of CD3-DSPE-PEG2K-NHS/ATP11B nanoparticles to specifically deliver ATP11B overexpressing plasmids to T cells.

RESULTS

S1PR1 deficiency in T cells caused T-cell lymphopenia and systemic immunosuppression in GBM, whereas ATP11B overexpression induced the upregulation and externalization of S1PR1 on T-cell membranes, thus increasing the ability of T cells to eliminate GBM cells. In intracranial GBM models, an ATP11B overexpression plasmid was specifically delivered to T cells in the peripheral blood, bone marrow and spleen, then triggering the infiltration of T cells deeply into the GBM and reversing systemic immunosuppression, ultimately enhancing the therapeutic outcomes of ICIs.

CONCLUSIONS

The upregulation and externalization of S1PR1 on T cells mediated by ATP11B overexpression may be promising immunotherapeutic alternatives for GBM treatment.

Physical parameters and biological factors affect the abscopal effect of combining radiotherapy with immunotherapy: an update on preclinical works

In the process of radiotherapy for cancer patients, there is an extremely low probability phenomenon that the distal tumor/metastasis away from the irradiation field undergoes regression after localized radiation therapy, which is called the abscopal effect. Enhancing the incidence of this phenomenon possesses profound significance for the investigation of metastatic cancer treatment. Currently, the underlying mechanisms of the abscopal effect remain unclear. Radiation-induced immunogenic cell death is considered one of the potential mechanisms for the abscopal effect. From this perspective, we explored how physical parameters and biological factors influence this process. Differences between patients with respect to physical factors and intrinsic biological factors that activate the immune response (acquired factors) may affect the induction of the abscopal effect.