ABSTRACT
For advanced pulmonary metastases or melanoma, radiotherapy combined with immune checkpoint inhibitor can block the immunosuppression pathway, enhance the antitumor immune response, and significantly improve survival. Stereotactic body radiation therapy ( SBRT ) delivers a large dose of radiation to the tumor target with high precision while sparing irradiation of the surrounding normal tissues. It is suggested that SBRT could be the most appropriate radiotherapy modality to be combined with immunotherapy since it induces the expression of a series of cytokines and immune molecules and is more likely to cause intense immune response and exert an abscopal effect than conventional radiotherapy. Previous studies have explored that total dose and fractionation seem to be important parameters for determining the immune response;the timing of radiation with immunotherapy significantly influences the outcome, and tumor infiltrating lymphocytes, the expression level of programmed death-ligand 1, and mismatch repair defect may be important predicators of the outcome. With appropriate radiotherapy dose and fractionation, the optimal timing of radiation with immunotherapy, and effective predictive markers, a combination of SBRT and immunotherapy may eliminate advanced malignancies while activating the systemic immune response to exert an abscopal effect.
ABSTRACT
For advanced pulmonary metastases or melanoma, radiotherapy combined with immune checkpoint inhibitor can block the immunosuppression pathway, enhance the antitumor immune response, and significantly improve survival. Stereotactic body radiation therapy ( SBRT ) delivers a large dose of radiation to the tumor target with high precision while sparing irradiation of the surrounding normal tissues. It is suggested that SBRT could be the most appropriate radiotherapy modality to be combined with immunotherapy since it induces the expression of a series of cytokines and immune molecules and is more likely to cause intense immune response and exert an abscopal effect than conventional radiotherapy. Previous studies have explored that total dose and fractionation seem to be important parameters for determining the immune response;the timing of radiation with immunotherapy significantly influences the outcome, and tumor infiltrating lymphocytes, the expression level of programmed death-ligand 1, and mismatch repair defect may be important predicators of the outcome. With appropriate radiotherapy dose and fractionation, the optimal timing of radiation with immunotherapy, and effective predictive markers, a combination of SBRT and immunotherapy may eliminate advanced malignancies while activating the systemic immune response to exert an abscopal effect.
ABSTRACT
Objective To investigate whether or not adaptive response of the 2BS and A549 cells induced by low dose irradiation.Moreover,to analyze the relationship between the adaptive response and cells cycle regulation. Methods 1.The dose-survival curves of A549 and 2BS cells were figured by colony formation and typan blue cell staining.2.Flow cytometry was used to analyze the cell cycle after the different doses irradiation. Results 1. The adaptive response induced in 2BS cells by low dose,while it was not induced in A549 cells.2.G2 phase arrest of 2BS cells after 75mGy X-ray plus 4Gy 60Co γ-ray irradiation appeared in 30 minutes,and cell cycle recovered in 24 hours. Conclusion The adaptive response of 2BS cell could be induced by low dose irradiation,and there was close relationship between the adaptive responses and the regulation of cell cycle.