Single cell analysis to study the longitudinal changes in systemic tumor immune environment in cervical cancer after radiochemotherapy.

Abstract

e17530 Background: Chemoradiation is the mainstay treatment for cervical cancer, which affects not only tumor immune microenvironment (TIME) but may also the systemic tumor immune microenvironment (STIE). Improved understanding of STIE beyond the tumor may enhance improving treatment strategies for cervical cancer. With these motivations, we applied single-cell RNA-sequencing (SCRNA-seq) to investigate longitudinal dynamics of a comprehensive set of immune cells in cervical cancer patients receiving chemoradiation (RCT). Methods: Two patients diagnosed with cervical squamous cell carcinoma at a locally advanced stage and received 45Gy/25f, with concurrent cisplatin, were enrolled. Peripheral blood was collected for SCRNA-seq using the 10× Genomics. Fresh blood samples were obtained at baseline 1-week, 2-week, 3-week, 5-week (end of external beam radiotherapy) and after Chemoradiation. Seurat 4.0 was used to cluster and annotate cell clusters. Results: A total of 90862 cells were clustered into 3 main subsets, including NK&T, B, and myeloid subsets. Then NK&T subset was extracted and further annotated into 10 clusters, including CD8+T naive, CD8+T effector, CD8+T effector memory, mucosal-associated invariant T (MAIT), cycling CD8+T, CD4Tem, CD4+T naive/central memory, regulatory T (Treg), natural killer (NK), and NKT cells. After plotting the dynamic changes of different cell types, MAIT and cycling CD8+T cell steadily increased with time or RT dose accumulation, suggesting that RCT could induce their proliferation. MAIT highly expressed CD69 and CXCR4 much like CD8+T effector memory cell, and cycling CD8+T cell expressed CX3CR1 like CD8+T effector cell. Besides, pseudotime analysis revealed that the differentiation process started from naive CD8+T cell towards cycling CD8+T cell passing through effector memory CD8+T cell, and effector CD8+T cell. In this process, the transcriptionally distinct MAIT cell belong to a different branch of the Pseudotime trajectory compared to the rest of the T cells, albeit mapping close to effector memory CD8+T cell, in line with their shared phenotypic identity. Enrichment was employed to explore their function and MAIT was enriched with genes involving cytokine-cytokine receptor interaction. Moreover, MAIT cell with increased antigen process and presentation function was note, and PD-1 checkpoint pathway was up-regulated during RCT. Conclusions: Chemoradiation induced the accumulation of MAIT cell which has increased antigen process and presentation features and cycling CD8+T cell with a higher PD-1 checkpoint pathway gene expression signature. Taken together, we provide insight into the peripheral immune remodeling induced by RCT, which will help optimize and improve treatment strategies for cervical cancer. Clinical trial information: NCT05061342 .