Supplementary MaterialsFigure S1: Individual GC microenvironment induces PD-L1 expression on neutrophils. STAT3 and p-STAT3 in neutrophils treated with BGC-CM for 12 hours was determined by western blot. (B and C) Rabbit Polyclonal to RPS6KB2 Protein and gene levels of PD-L1 on neutrophils pre-treated with or LDN193189 kinase activity assay without JAK-STAT3 inhibitor WP1066 followed by exposure to BGC-CM were determined by flow cytometry (B) and qRT-PCR (C). (D) The expression of STAT3 and p-STAT3 in neutrophils with NTCS and TTCS for 12 hours was determined by Western blot. (E and F) Flow cytometric (E) and qRT-PCR analyses (F) of PD-L1 expression in neutrophils exposed to NTCS and TTCS with or without WP1066. Ctrl: neutrophils treated with exosome-depleted RPMI-1640 medium. * 0.05, ** 0.01, *** 0.001. # 0.05, 0.01, 0.001. Image_2.TIF (284K) GUID:?0D45FC87-77F5-4ABB-92E3-35D36BEE8EB2 Physique S3: Neutrophils activated by GC microenvironment suppress T cell immunity through PD-L1. (A and B) Human peripheral CD3+ T cells were co-cultured with (A) BGC-CM or (B) TTCS treated neutrophils in the presence or absence of PD-L1 antibody. (a, b, c) The expression of activation marker (CD69), production of IFN-, and proliferation of T cells were determined by flow cytometry ( 0.05, ** 0.01, *** 0.001. # 0.05, 0.01, 0.001. Image_3.TIF (781K) GUID:?C757781B-F522-42CD-9D1F-49E9A0CB7FD7 Data Availability StatementThe datasets generated for this study are available on request to the corresponding author. Abstract Neutrophils are prominent components of solid tumors and display distinct phenotypes in various tumor milieu. We’ve previously proven that tumor extracellular vesicles (EVs) could induce pro-tumor activation of neutrophils; nevertheless, the function of tumor EV-elicited neutrophils in tumor immunity continues to be unclear. Herein, we reported that gastric cancers cell-derived EVs (GC-EVs) induced the appearance of designed death-ligand 1 (PD-L1) on neutrophils. GC-EVs carried high-mobility group container-1 (HMGB1) to activate indication transducer and activator of transcription 3 (STAT3) and upregulate PD-L1 gene appearance in neutrophils. Blocking STAT3 silencing and pathway HMGB1 reversed GC-EV-induced PD-L1 expression on neutrophils. GC-EV-elicited neutrophils suppressed T cell proliferation, activation, and function secretion of CCL17 to impair antitumor immunity (13). Lately, neutrophils have already been reported to suppress intraluminal NK cell-mediated tumor cell clearance (14). Hence, additional research from the function of neutrophil in tumor immunity shall provide brand-new approaches for GC therapy. Extracellular vesicles (EVs) are little lipid bilayer membrane vesicles and regarded as an important system for cellular communication, allowing cells to exchange genetic materials and signal molecules. EVs are involved in multiple physiological and pathological processes (15). Increasing evidence suggest that tumor-derived EVs reshape immune cells to help escape immune surveillance (16, 17). We have previously shown that GC cell-derived EVs could induce neutrophils N2 polarization, which in turn promotes tumor cell proliferation, migration, and invasion (18, 19). However, the function of tumor EV-elicited neutrophils in tumor immunity has not been well-characterized. In this study, we reported that tumor EVs could induce PD-L1 expression on neutrophils. Tumor EV-delivered high-mobility group box-1 (HMGB1) activated transmission transducer and activator of transcription (STAT)3 pathway in neutrophils to upregulate PD-L1 gene expression. Tumor EV-elicited neutrophils suppressed the proliferation, activation, and function of T cells in a PD-L1-dependent manner. These findings suggest that tumor EVs could reeducate neutrophils to produce an immunosuppressive microenvironment for GC progression. Materials and Methods Patients and Specimens New gastric tumor and non-tumor (at least 5 cm away from the tumor site) tissues were obtained from patients with GC who underwent surgical resection at the Affiliated People’s Hospital of Jiangsu University or college. None of these patients experienced received chemotherapy or radiotherapy before surgery. Patients with infectious diseases, autoimmune disease, or multi-primary cancers were excluded. The study was approved by the ethics committee of Jiangsu University or college. Written informed consent was obtained from all patients. Cell Culture and Preparation of Conditioned Medium Human GC cell collection BGC-823 was purchased from LDN193189 kinase activity assay your Institute of Biochemistry and Cell Biology at the Chinese Academy of Sciences (Shanghai, China). Cells were LDN193189 kinase activity assay cultured in RPMI-1640 medium, supplemented with 10% fetal bovine serum (FBS; Invitrogen, Carlsbad, CA, USA) at 37C in humidified air flow with 5% CO2. When cells reached 80% confluence, they were changed to exosome-depleted medium and cultured for another 24 h to obtain conditioned medium (BGC-CM). Tumor tissue conditioned supernatants (TTCS) and non-tumor tissue conditioned supernatants (NTCS) were prepared by plating tumor or non-tumor gastric tissues in 1 ml exosome-depleted RPMI-1640 medium. Carrying out a 24-h incubation, all mass media were gathered, respectively, centrifuged to eliminate cell particles, and kept at ?80C in aliquots..