Single-cell sequencing reveals effects of chemotherapy on the immune landscape and TCR/BCR clonal expansion in a relapsed ovarian cancer patient

Cancer recurrence and chemoresistance are the leading causes of death in high-grade serous ovarian cancer (HGSOC) patients. However, the unique role of the immune environment in tumor progression for relapsed chemo-resistant patients remains elusive. In single-cell resolution, we characterized a comprehensive multi-dimensional cellular and immunological atlas from tumor, ascites, and peripheral blood of a chemo-resistant patient at different stages of treatment. Our results highlight a role in recurrence and chemoresistance of the immunosuppressive microenvironment in ascites, including MDSC-like myeloid and hypo-metabolic gamma delta T cells, and of peripheral CD8(+) effector T cells with chemotherapy-induced senescent/exhaustive. Importantly, paired TCR/BCR sequencing demonstrated relative conservation of TCR clonal expansion in hyper-expanded CD8(+) T cells and extensive BCR clonal expansion without usage bias of V(D)J genes after chemotherapy. Thus, our study suggests strategies for ameliorating chemotherapy-induced immune impairment to improve the clinical outcome of HGSOC.

Automated summary

This study characterizes the immune environment in tumor progression of relapsed chemo-resistant ovarian cancer patients at single-cell resolution. The immunosuppressive microenvironment in ascites, including myeloid and gamma delta T cells, as well as peripheral CD8(+) T cells with chemotherapy-induced senescence/exhaustion, play important roles in recurrence and chemoresistance. TCR/BCR sequencing demonstrates the conservation of TCR clonal expansion in hyper-expanded CD8(+) T cells and extensive BCR clonal expansion without usage bias of V(D)J genes after chemotherapy.