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. 2021 Dec 8;9(12):e002772. doi: 10.1136/jitc-2021-002772

Figure 1.

Figure 1

A significant inverse relationship between PD-L1 and FOXO3 protein expression is discovered in patients with various tumors, and PD-L1 and FOXO3 protein expression in mouse tumor cells are regulated by low-dose SN-38. (A–C) Using immunofluorescence (IF) analysis, we determined the protein expression of PD-L1 and FOXO3 in three different human primary tumor tissues that were tumor tissue microarrays (TMAs) of OvCa, invasive BCa, and HCC specimens. Each tumor TMA slide was incubated with an anti-FOXO3 or ant-PD-L1 antibody (Ab) and followed by an Alexa Fluor 594-conjugated or 488-conjugated secondary Ab and IF analysis was performed using fluorescence confocal microscopy. (D and E) Mouse ID-8 OvCa cells were treated with a dose–response (D) or a time course (E) of SN-38 or DMSO control (0 nM) as indicated. Protein expression in total lysates of treated cells were analyzed by immunoblotting (IB) with anti-PD-L1 and anti-FOXO3 Abs as indicated. GAPDH and β-Actin represent loading controls. (F) ID-8 cells were treated with low-dose SN-38 (10 nM) or DMSO control and analyzed by flow cytometry with indicated Abs or isotype control IgG. BCa, breast cancer; DMSO, dimethylsulfoxide; HCC, hepatocellular carcinoma; OvCa, ovarian cancer; PD-L1, programmed death-ligand 1.