Fig 2: STT3A Expression was Positively Correlated with TGF-ß1 and C-Jun in NPC Tissues, and High STT3A Expression was Associated with a more advanced stage in NPC. (A) Representative pictures of c-Jun and STT3A expression in NPC patients in TGF-ß1-low and high expression groups. Scale bars represented 100µm. (B, C) Pearson correlation analysis of the association between TGF-ß1 and STT3A (r=0.412; p=0.013) and between c-Jun and STT3A (r=0.5859; p=0.0002) in NPC tissues. (D) Comparison of STT3A levels in 36 NPC patients with different clinical stages. **p<0.01.

Fig 3: The CRISPR-Cas9 screen reveals the oligosaccharyltransferase complex as essential to DENV propagation. (A) Depiction of the whole-genome CRISPR screen selecting for knockout cells resistant to dengue virus infection. (B) Diagram of the two OST complexes that contain either STT3A or STT3B. Subunits of the OST complex shown in blue were significantly enriched in the screen. (C) Table of the hits from the screen showing the gene identifier (ID), P value, and false-discovery rate as calculated by MAGeCK analysis.

Fig 4: SB431542 Downregulated Glycosylation of PD-L1 via C-Jun/STT3A Pathway in Vitro and C-Jun was a Direct Transcriptional Regulator of STT3A. (A) Western blot analysis of c-Jun, STT3A and PD-L1 after silencing c-Jun in 5-8F and CNE1 cells. (B) Western blot analysis of STT3A and PD-L1 after silencing STT3A in 5-8F and CNE1 cells. (C) Western blot analysis of c-Jun, STT3A and PD-L1 after overexpressing c-Jun with(out) silencing STT3A in 5-8F and CNE1 cells. (D) Western blot analysis of PD-L1, c-Jun and STT3A in exogenous Flag-PD-L1 expressing 5-8F and CNE1 cells with the treatment of 20µM SB431542. (E) The binding motif of c-Jun from JASPAR database. (F) The CHIP-PCR assay was used to assess the binding of STT3A promoter region. (G) Anti-c-Jun-pulled down chromatins were analyzed by qRT-PCR. (H) A diagram showing the relationship of full-length and mutant STT3A promoters. (I) Dual-luciferase reporter gene assay was performed to indicate the interaction between c-Jun and STT3A. Bars, mean ± SD, *p<0.5, **p<0.01.

Fig 5: Inhibition of TGF-ß1 by SB431542 suppressed T cells activity by inhibiting PD-L1 glycosylation in Vitro. (A, B) The death rate of 5-8F or CNE1 cells co-cultured with Jurkat T cells for 6h. The tumor cells were STT3A-kncokdowned by shRNA or pretreated with SB431542 (20µM) or TM (10µg/ml) for 48h. (C, D) IL-2 production by activated Jurkat T cells co-cultured with 5-8F or CNE1 cells with shSTT3A or pretreated with SB431542 (20µM) or TM (15µg/ml) for 48h. IL-2 secretion was measured by ELISA. Bars, mean ± SD, **p<0.01.