TY - JOUR AB - Programmed death‑ligand 1 (PD‑L1) plays an essential role in tumor cell escape from anti‑tumor immunity in various types of cancer, including gastric cancer (GC). The present study investigated the intracellular and membrane‑bound expression of PD‑L1 in the GC cell lines MKN1, MKN74, KATO III and OCUM‑1. Furthermore, soluble PD‑L1 (sPD‑L1) level in the supernatant of GC cells and the serum of patients with GC and healthy controls was determined by ELISA. Interferon (IFN)‑γ treatment of cells resulted in increased cytoplasmic expression of PD‑L1 in GC cells in a dose‑dependent manner, except for MKN74 cells; however, there was no association between tumor necrosis factor‑α treatment and enhanced PD‑L1 expression. Concordant with these findings, results from flow cytometry analysis demonstrated that membrane‑bound PD‑L1 expression was also increased following GC cell treatment with IFN‑γ in a dose‑dependent manner. In addition, significant sPD‑L1 overproduction was observed only in the culture supernatant of OCUM‑1 cells. Serum level of sPD‑L1 was significantly increased in patients with GC, in particular in stage IV patients, compared with healthy controls. In conclusion, the present study demonstrated that IFN‑γ treatment increased the intracellular and membrane‑bound PD‑L1 expression in GC cells. In addition, sPD‑L1 was detected not only in the supernatant of GC cells but also in the serum of patients with GC. Further investigation on the underlying mechanism of regulation of PD‑L1 expression and sPD‑L1 production is required. AD - Department of Gastroenterology, Graduate School of Medicine, Chiba University, Chuo‑ku, Chiba 260‑8670, Japan Department of Molecular Virology, Graduate School of Medicine, Chiba University, Chuo‑ku, Chiba 260‑8670, Japan Division of Hematological Malignancy, Institute of Medical Sciences, Tokai University, Isehara, Kanagawa 259‑1193, Japan Department of Frontier Surgery, Graduate School of Medicine, Chiba University, Chuo‑ku, Chiba 260‑8670, Japan AU - Imai,Yushi AU - Chiba,Tetsuhiro AU - Kondo,Takayuki AU - Kanzaki,Hiroaki AU - Kanayama,Kengo  AU - Ao,Junjie  AU - Kojima,Ryuta AU - Kusakabe,Yuko AU - Nakamura,Masato  AU - Saito,Tomoko  AU - Nakagawa,Ryo AU - Suzuki,Eiichiro AU - Nakamoto,Shingo AU - Muroyama,Ryosuke  AU - Tawada,Akinobu AU - Matsumura,Tomoaki AU - Nakagawa,Tomoo  AU - Kato,Jun AU - Kotani,Ai AU - Matsubara,Hisahiro AU - Kato,Naoya DA - 2020/09/01 DO - 10.3892/ol.2020.11757 EP - 2168 IS - 3 JO - Oncol Lett KW - gastric cancer programmed death‑ligand 1 interferon γ PY - 2020 SN - 1792-1074 1792-1082 SP - 2161 ST - Interferon‑γ induced PD‑L1 expression and soluble PD‑L1 production in gastric cancer T2 - Oncology Letters TI - Interferon‑γ induced PD‑L1 expression and soluble PD‑L1 production in gastric cancer UR - https://doi.org/10.3892/ol.2020.11757 VL - 20 ER -