Fig. 5

AXL suppression inhibits the polarization of immunosuppressive M2 macrophages via STAT6. A Treatment with TP-0903 reduced AXL, phospho-STAT6, and STAT6 protein expression as determined by Western blotting. B M2 macrophages polarized from AXL-KO THP-1 cells had lower phospho-AXL, AXL, phospho-STAT6, and STAT6 protein expression than those polarized from control THP-1 cells, as determined using Western blotting. C–E STAT6 was knocked down in THP-1 cells using siRNAs, and then THP-1 cells were induced to M2 macrophages. Knockdown of STAT6 in THP-1–polarized M2 macrophages C decreased the CD163⁺CD206⁺ macrophage population as determined by flow cytometry D and decreased the expression of the CD163 and CD206 genes as determined using qRT-PCR E. F STAT6 was overexpressed in M2 macrophages polarized from AXL-KO THP-1 cells as tested using qRT-PCR. G STAT6 overexpression mitigated the inhibitory effect of AXL KO on the expression of M2 macrophage markers and cytokines, including CD163, CD206, CCL17, and CCL18. H The CM from control, AXL-KO, and AXL-KO + STAT6–overexpressing M2 macrophages and fresh media were used as attractants plated in the bottom chamber of transwells to test the migration of SUM149 cells. Migration of SUM149 cells was greater with CM from AXL-KO + STAT6–overexpressing M2 macrophages than with CM from AXL-KO M2 macrophages. All experiments were repeated at least three times. Data were summarized as means ± SD. One-way analysis of variance followed by Dunnett’s multiple comparison test was used to calculate P values. *P < 0.05; **P < 0.01