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. 2021 Jan 1;41(1):62–78. doi: 10.1002/cac2.12117

FIGURE 6.

FIGURE 6

PD‐L1 3’‐UTR is probably required for the EGFR‐P38 MAPK‐miR‐675‐5p axis‐enhanced stability of PD‐L1 mRNA. (A) SMMC‐7721 and HepG2 cells were transfected with firefly luciferase reporter constructs containing the PD‐L1 3’‐UTR fragment (pGL3‐PD‐L1 3’‐UTR) or control vectors (pGL3‐Vector) for 24 h, and then co‐stimulated with or without EGF (20 ng/mL) for another 24 h. Next, the cellular luciferase activity was determined by dual‐luciferase reporter assay system. (B) Cells pre‐transfected with pGL3‐PD‐L1 3’‐UTR were further treated with SB203580 (10 μmol/L) or DMSO for 6 h, and then co‐stimulated with or without EGF (20 ng/mL) for an additional 24 h. Next, the cellular luciferase activity was determined by dual‐luciferase reporter assay system. (C) Cells pre‐transfected with pGL3‐PD‐L1 3’‐UTR were further treated with mimics of miR‐675‐5p or control mimics for 24 h, and then co‐stimulated with or without EGF (20 ng/mL) for an additional 24 h. Next, the cellular luciferase activity was determined by dual‐luciferase reporter assay system. * P ≤ 0.05, ** P ≤ 0.01, *** P ≤ 0.001. Abbreviations: EGFR, epidermal growth factor receptor; EGF, epidermal growth factor; PD‐L1, programmed death‐ligand 1; HLA‐ABC, human leukocyte antigen class‐A, B, C; MAPK, mitogen‐activated protein kinase; 3’‐UTR, 3'‐untranslated region; DMSO, dimethylsulfoxide; miRNA, micro RNA.