Single-cell spatial analysis with Xenium reveals anti-tumour responses of CXCL13 + T and CXCL9+ cells after radiotherapy combined with anti-PD-L1 therapy

Abstract Background The standard treatment for unresectable non-small cell lung cancer (NSCLC) is anti-PD-L1 therapy combined with chemoradiotherapy (anti-PD-L1-CRT). Although some patients achieve complete cancer eradication and cure, more than half of patients retain persistent cancer cells. Our research aimed to unravel the nuanced mechanisms involved in both immune attack and evasion induced by anti-PD-L1-CRT with single cell spatial transcriptome. Methods Xenium is a cutting-edge single-cell spatial analysis tool that enables pathology-based and single-cell analyses while preserving spatial information. In our study, we used Xenium to identify the tumour microenvironment (TME), immune dynamics, and residual cancer cells at the single-cell level following treatment with anti-PD-L1-CRT. Results Posttreatment alterations included a significant increase in CXCL9 + cells and CXCL13 + T cells, particularly around tumour cells. Additionally, we discovered that CXCL13 + T cells directly impact cancer cells in the posttreatment environment. Moreover, we identified clusters of immune-cold cancer cells posttreatment, revealing their activation of DNA repair pathways and high proliferative capacity. The novel spatial analysis tool Xenium enabled identification of the immune environment at the single-cell level following treatment with anti-PD-L1-CRT, elucidating its characteristics. Conclusions These findings suggest potential advancements in developing new treatments to improve posttreatment immune responses and address resistance challenges.