Figure 7.

Increased ARG1 expression in HLA-DR⁻CD33⁺MDSCs induced by exosomal miR-107-mediated PTEN suppression and PI3K pathway activation.

Notes: (A) MDSCs were co-transfected with WT PTEN-3ʹUTR or mutant PTEN-3ʹUTR together with miR-107 mimic. PTEN protein expression was then determined by Western blot. (B) ARG1 mRNA expression in co-transfected MDSCs determined by RT-qPCR. (C) Relative % of ARG1-positive cells within HLA-DR⁻, HLA-DR⁻CD11b⁺ or HLA-DR⁻CD33⁺MDSC population determined by flow cytometry after co-transfection with WT or mutant PTEN-3ʹUTR and miR-107 mimic. (D) mRNA expression of PI3K, AKT, mTOR, and NF-kB in co-transfected MDSCs. (E) PI3K, AKT, mTOR, NF-kB, p-AKT, p-mTOR and p65 subunit of NF-kB protein expression was determined by Western blot. (F) Quantification of protein expression in (E). (G) PTEN or scrambled siRNAs were transfected into the MDSCs, and PTEN protein expression was determined by Western blot. (H) Quantification of protein expression in (G). (I) Relative ARG1 mRNA expression in MDSCs transfected with PTEN or scrambled siRNAs. (J–K) Relative % of ARG1-positive cells within HLA-DR⁻, HLA-DR⁻CD11b⁺ or HLA-DR⁻CD33⁺MDSC population after transfection with PTEN or scrambled siRNAs. (L) mRNA expression of PI3K, AKT, mTOR and NF-kB in MDSCs transfected with PTEN or scrambled siRNAs. (M) PI3K, AKT, mTOR, NF-kB, p-AKT, p-mTOR and p65 subunit of NF-kB protein expression in MDSCs transfected with PTEN or scrambled siRNAs. (N) Quantification of protein expression in (M). *P<0.05; **P<0.01.

Abbreviations: n.s., not significant; RT-qPCR, real-time quantitative PCR.