Effect of Programmed Death-Ligand 1 in Cancer-Associated Fibroblasts on Advanced Laryngeal Squamous Cell Carcinoma

Abstract

This study aimed to explore the effect of programmed death-ligand 1 (PD-L1) in cancer-associated fibroblasts (CAFs) on advanced laryngeal squamous cell carcinoma (LSCC). The expression of PD-L1 in advanced LSCC tumor tissues was observed in 83 patients with LSCC by immunofluorescence microscopy and compared with that in normal laryngeal mucosa. The CAFs of LSCC and normal fibroblasts (NFs) were isolated, cultured, purified, and examined by fluorescence. The expression of PD-L1 in purified CAFs and NFs was measured by flow cytometry. The expression of PD-L1 in CAFs was downregulated through small interferring RNA (siRNA) transfection. The proliferation and migration capacities of CAFs were observed using proliferation and scratch tests, respectively. The proliferation of HEP-2 cells and T cells was measured after cocultured with CAFs. The secretion of interleukins IL-2 and IL-10 was detected using enzyme-linked immuno sorbent assay (ELISA). PD-L1 was expressed in 62 of 83 cases of the advanced LSCC tumor tissues. Also, CAFs expressed more PD-L1 compared with NFs. The proliferation and migration capacities of CAFs were significantly lower after transfection with PD-L1-siRNA. The proliferation rate of HEP-2 cells cocultured with CAFs decreased in PD-L1-siRNA-transfected cells. However, the proliferation rate of T cells increased in transfected cells. The ELISA results showed that the secretion of IL-2 increased and that of IL-10 decreased in PD-L1-siRNA-transfected cells. The expression of PD-L1 in CAFs of advanced LSCC was higher than that in NFs. The downregulation of PD-L1 reduced the proliferation and migration of CAFs and HEP-2 cells but enhanced the proliferation and pro-inflammatory function of T cells in the coculture experiment.