Fig. 6

FAT4 overexpression inhibits PD-L1 expression and cell membrane localization. A Immunoblotting was used to detect the expression of PD-L1 and STT3A in CTRL or FAT4 overexpression cells. B Immunofluorescence staining for PD-L1 expression in ME180 and U14 cells. CTRL is located mainly on the cell membrane (white arrow). In FAT4 overexpression cells, FAT4 was detected throughout the cytoplasm with the reduced signal at the membrane (red arrows). Data represent mean ± SD. Scale bar = 10 μm. C RT-qPCR analysis of human CD274 and STT3A mRNA in sgFAT4 and CTRL ME180 Cells. D RT-qPCR analysis of mouse Cd274 and Stt3a mRNA in sgFat4 and CTRL U14 Cells. E Flow cytometric analysis of PD-L1⁺ membrane expression in ME180 and U14 cells. F&G ME180 cells were transfected with control vector or Active β-catenin vector for 48 h. Immunoblot analysis (F) and RT-qPCR analysis (G) were performed. H&I (H) Representative images and (I) quantitation of green-fluorescent labeling recombinant human PD-1 Fc protein or recombinant mouse PD-1 Fc protein on CTRL or FAT4 overexpression cells. Scale bar = 10 μm. All error bars are expressed as mean ± SD, ***P < 0.001 and ****P < 0.0001