Title:Cancer-associated Fibroblast-derived Extracellular Vesicles Mediate
Immune Escape of Bladder Cancer via PD-L1/PD-1 Expression
Volume: 23
Issue: 11
Author(s): Rui Feng, Zhongxing Li, Guangcheng Ge, Chenghao Wang, Yuejun Jia and Jun Ouyang*
Affiliation:
- Department of Urology, The First Affiliated Hospital of Soochow University, Suzhou, 215006, Jiangsu, P.R. China
Keywords:
Bladder cancer, cancer-associated fibroblasts, extracellular vesicles, PD-L1, PD-1, immune escape, T24 cells, CD8+ T cells.
Abstract:
Objective: Bladder cancer (BCa) is a malignant urological tumor with a high prevalence
and poor prognosis. Extracellular vesicles (EVs) are increasingly becoming current
hotspots owing to their involvement in cancer progression. This paper probed into the action of
cancer-associated fibroblast-derived EVs (CAF-EVs) in the immune escape of BCa.
Methods: CAFs were identified by immunofluorescence. EVs were extracted from CAFs via
ultracentrifugation and later characterized. BCa cells (T24 cell line) were co-cultured with CD8+
T cells and then treated with CAF-EVs. The uptake of EVs by T24 cells was examined by confocal
laser microscopy. T24 cell apoptosis and invasion were assessed using flow cytometry and
invasion assay. CD8+ T cell proliferation was evaluated using CFSE staining. The levels of cytokines
(IFN-γ, IL-2, and TNF-α) were measured by ELISA. PD-L1 and PD-1 levels were determined
utilizing RT-qPCR and flow cytometry. BCa mouse models were established to identify
the effect of CAF-EVs on BCa progression in vivo.
Results: CAF-EVs decreased apoptosis and enhanced invasion of T24 cells, reduced proliferation
of CD8+ T cells, and diminished levels of IFN-γ, IL-2, and TNF-α secreted by CD8+ T cells.
CAF-EVs promoted the immune escape of T24 cells by carrying PD-L1. Downregulation of PDL1
expression in T24 cells or EVs partially counteracted the promotion of CAF-EVs on immune
escape by reducing the binding of PD-L1 and PD-1. Additionally, CAF-EVs raised tumor volume
and weight, upregulated PD-L1 expression, and weakened CD8+ T cell infiltration in BCa mice.
Conclusion: CAF-EVs facilitate the immune escape of BCa by upregulating PD-L1/PD-1.