Investigating tumor radiation response heterogeneity using single-cell sequencing

Tumor cell radioresistance is a major challenge in radiotherapy. By contrast, radiation response heterogeneity of tumor cells is poorly understood. Here, we performed scRNA-seq and scATAC-seq of 6 Gy γ-ray treated human lung adenocarcinoma cells to dissect cellular radiation response heterogeneity from perspective of transcriptional and regulatory cell states. Notably, we observed heterogeneous radioresponsiveness in purified lung adenocarcinoma cells by qualified cellular radiation response based on transcriptional landscape. There was DNA repair and apoptosis related transcriptional cell state appeared post-irradiation. We identified gene markers in this radiation-associated cell state and screened promising targets for LUAD radiosensitization based on 107 transcriptomic data of radiotherapy treated LUAD patients from TCGA database. Besides, transcriptional cell states transition was obvious accompanied with radiation-induced cell cycle arrest in which cell-cell communication was a potential regulatory mechanism. Finally, we identified radiation-associated regulatory cell state and analyzed the regulatory network of key transcriptional factors in cellular radiation response. scRNA-seq of unpurified and purified A549 cells; scRNA-seq of purified A549 cells (control) and 6 Gy γ-ray treated purified A549 cells at 2 h (IR_2h) and 6 h (IR_6h) post-irradiation, scATAC-seq of purified A549 cells (control) and 6 Gy γ-ray treated purified A549 cells at immediate (IR_immediate) and 2 h (IR_2h) post-irradiation.