Single-cell transcriptomic analysis of immune-checkpoint resistance in hepatocellular carcinoma
Refereed conference paper presented and published in conference proceedings


摘要Background: Binding of programmed death-ligand 1 (PD-L1) to its receptor programmed death 1 (PD-1) on activated T cells inhibits anti-tumor immunity by counteracting T cell-activating signals. Although use of immune-checkpoint inhibitors (ICI) targeting the PD-1/PD-L1 has yielded impressive results in cancer patients, resistance to these therapies has increasingly been observed, especially in hepatocellular carcinoma (HCC).
Materials and Methods: We generated a novel anti-PD-L1 treatment resistant mouse hepatoma cell Hepa1-6 (PD-L1R) by 6-generation of in vivo selection. To dissect tumor cell-intrinsic genes/pathways that correlate with resistance, we performed single-cell RNA-sequencing (scRNA-seq) from anti-PD-L1-treated tumors generated from parental or PD-L1R Hepa1-6 cells, as well as the corresponding bulk RNA-sequencing (RNA-seq) of cell lines. Expression level of target genes on cancer cell lines and tumors was detected by QPCR, western blot and immunohistochemical analysis. To investigate the tumor cell-extrinsic factors for resistance, we profiled the myeloid and lymphoid immune populations by multi-color flow cytometry.
Results: The t-distributed stochastic neighbor embedding (t-SNE) plot of scRNA-seq analysis showed vast difference in the transcriptional patterns between anti-PD-L1-responsive and resistant tumors. We found significant enrichment of key signaling pathways in the differentially-expressed genes, which could be verified in both mRNA and protein levels using bulk RNA-seq, QPCR, Western and immunohistochemical analyses. Flow cytometry analysis showed that ICI resistance was associated with lower anti-tumor CD8+ T cells but higher exhausted T cells, intermediate Th17 cells, myeloid-derived suppressor cells and T regulatory cells in the tumor microenvironment.
Conclusions: Our findings suggest that immune-checkpoint resistance in HCC may be controlled by both tumor cell evolution as well as the educated immunosuppression. Detailed investigation on the crosstalk between tumor cells and its microenvironment is ongoing. Further validation of the mechanism in clinical samples will provide insights in overcoming anti-PD-L1 resistance for the HCC patients.
著者Zhewen XIONG, Jingying ZHOU, Jianquan CAO, Yu FENG, Xuezhen ZENG, Alfred Sze-Lok CHENG
會議名稱CSH-Asia Conference: Advances in Cancer Immunology

上次更新時間 2020-14-05 於 16:41