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ABSTRACT: Background
Enhancing the response rate of immunotherapy will aid in the success of cancer treatment. Here, we aimed to explore the combined effect of immunogenic radiotherapy with anti-PD-L1 treatment in immunotherapy-resistant HNSCC mouse models.Methods
The SCC7 and 4MOSC2 cell lines were irradiated in vitro. SCC7-bearing mice were treated with hypofractionated or single-dose radiotherapy followed by anti-PD-L1 therapy. The myeloid-derived suppressive cells (MDSCs) were depleted using an anti-Gr-1 antibody. Human samples were collected to evaluate the immune cell populations and ICD markers.Results
Irradiation increased the release of immunogenic cell death (ICD) markers (calreticulin, HMGB1 and ATP) in SCC7 and 4MOSC2 in a dose-dependent manner. The supernatant from irradiated cells upregulated the expression of PD-L1 in MDSCs. Mice treated with hypofractionated but not single-dose radiotherapy were resistant to tumour rechallenge by triggering ICD, when combined with anti-PD-L1 treatment. The therapeutic efficacy of combination treatment partially relies on MDSCs. The high expression of ICD markers was associated with activation of adaptive immune responses and a positive prognosis in HNSCC patients.Conclusion
These results present a translatable method to substantially improve the antitumor immune response by combining PD-L1 blockade with immunogenic hypofractionated radiotherapy in HNSCC.
SUBMITTER: Mao L
PROVIDER: S-EPMC10206106 | biostudies-literature | 2023 Jun
REPOSITORIES: biostudies-literature
Mao Liang L Zhou Jun-Jie JJ Xiao Yao Y Yang Qi-Chao QC Yang Shao-Chen SC Wang Shuo S Wu Zhi-Zhong ZZ Xiong Hong-Gang HG Yu Hai-Jun HJ Sun Zhi-Jun ZJ
British journal of cancer 20230328 11
<h4>Background</h4>Enhancing the response rate of immunotherapy will aid in the success of cancer treatment. Here, we aimed to explore the combined effect of immunogenic radiotherapy with anti-PD-L1 treatment in immunotherapy-resistant HNSCC mouse models.<h4>Methods</h4>The SCC7 and 4MOSC2 cell lines were irradiated in vitro. SCC7-bearing mice were treated with hypofractionated or single-dose radiotherapy followed by anti-PD-L1 therapy. The myeloid-derived suppressive cells (MDSCs) were depleted ...[more]