Single-Cell Analysis Reveals Characterization of Infiltrating T Cells in Moderately Differentiated Colorectal Cancer

• Main Authors: Xi Yang, Quan Qi, Yuefen Pan, Qing Zhou, Yinhang Wu, Jing Zhuang, Jiamin Xu, Mingyue Pan, Shuwen Han
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2021-01-01
• Series: Frontiers in Immunology
• Subjects: colon cancer; rectal cancer; single-cell RNA sequencing; tumor-infiltrating T cells; immunotherapy
• Online Access: https://www.frontiersin.org/articles/10.3389/fimmu.2020.620196/full

ObjectiveThis study aimed to characterize the tumor-infiltrating T cells in moderately differentiated colorectal cancer.MethodsUsing single-cell RNA sequencing data of isolated 1632 T cells from tumor tissue and 1252 T cells from the peripheral blood of CRC patients, unsupervised clustering analysis was performed to identify functionally distinct T cell populations, followed by correlations and ligand-receptor interactions across cell types. Finally, differential analysis of the tumor-infiltrating T cells between colon cancer and rectal cancer were carried out.ResultsA total of eight distinct T cell populations were identified from tumor tissue. Tumor-Treg showed a strong correlation with Th17 cells. CD8+TRM was positively correlated with CD8+IEL. Seven distinct T cell populations were identified from peripheral blood. There was a strong correlation between CD4+TN and CD4+blood-TCM. Colon cancer and rectal cancer showed differences in the composition of tumor-infiltrating T cell populations. Tumor-infiltrating CD8+IEL cells were found in rectal cancer but not in colon cancer, while CD8+ TN cells were found in the peripheral blood of colon cancer but not in that of rectal cancer. A larger number of tumor-infiltrating CD8+ Tex (88.94%) cells were found in the colon cancer than in the rectal cancer (11.06%). The T cells of the colon and rectal cancers showed changes in gene expression pattern.ConclusionsWe characterized the T cell populations in the CRC tumor tissue and peripheral blood.