Single-Cell Analysis Reveals the Alteration of Immune Checkpoint Molecules Induced by Radiochemotherapy in Cervical Cancer Microenvironment

Radiochemotherapy (RCT) could alter the function, activation state, and distribution of immune cells in tumor microenvironment (TME). This study aimed to decipher the alteration of immune checkpoint molecules induced by RCT in the TME of cervical cancer by single-cell RNA sequencing (scRNA-seq).We analyzed the alterations of immune checkpoint molecules in the TME using scRNA-seq data of 32,116 cells from 3 pairs of tumor biopsies of cervical cancer patients pre- and post-RCT. Uniform Manifold Approximation and Projection was applied to demonstrate the heterogeneity of cell subclusters and differences in the distribution of immune checkpoint molecules. The Wilcoxon rank sum test was used to compare the expression level of the immune checkpoint molecules pre- and post-RCT.VSIR was mainly expressed on cancer-associated fibroblasts and myeloid cells, of which the level can be reduced by RCT (both P < 0.05). RCT also inhibited the expression of co-inhibitory molecules, such as HAVCR2, TIGIT, CD244, and CD160 on CD4+ T, CD8+ T, and NK cells (all P < 0.05). The expression level of co-inhibitory molecules, LAG3, and co-stimulatory molecules, TNFRSF9 on CD8+ and CD4+ T cells were reduced post-RCT (all P < 0.05). Nonetheless, the expression level of co-stimulatory molecules CD28 was significantly increased on CD4+ and CD8+ T cells post-RCT (all P < 0.05). Intriguingly, the expression level of TNFRSF18 was increased on CD8+ T cells post-RCT while it was reduced on NK cells post-RCT (both P < 0.05).This study unveils that RCT could induce complex alteration of the expression of immune checkpoint molecules on immune cells as well as stromal cells, which may help further understand the mechanism of anti-tumor effect of RCT and optimize treatment strategies.