Fig. 6

METTL3-expressing CRC Cells Recruits M2-type macrophage Via Secreting CXCL2. a Chromatin immunoprecipitation sequence data show that Snail might directly bind to Cxcl2 proximal promoters. b (Left) Schematic representation of CXCL2 promoter organization, and the luciferase reporter constructs pGL-CXCL2 (1606 bp: − 1606 to + 104 bp, 942 bp: − 942 to + 104 bp, 457 bp: − 457 to + 104 bp). TSS: transcriptional start site, E1: exon1, and Luc: luciferase. The green bars indicate E-boxes (CANNTG), which are the binding sites of Snail. (Right) Relative luciferase activities are shown. c ELISA to analyze the expression of CXCL2 in sh-NC/sh-SNAIL RKO cells (left), and the expression of CXCL2 in sh-NC/sh-SNAIL RKO cells (right), treated with or without BAY11-7082 (NF-κB inhibitor) at 10 μM for 24 h. d M2-type macrophage were seeded in the top chamber of the transwell containing 100 mL 1640 medium with or without CXCR2 inhibitor (SB265610, 10 mM). On the other hand, the bottom chamber contained 600 mL of CRC cell conditioned medium (no fetal bovine serum) with or without recombinant CXCL2 protein (1 ng/mL). After 4-h incubation, cells that have completely migrated to the bottom chamber were counted. e Immunofluorescence analysis of CD163 protein expression in colorectal in nude mice specimen. f Immunofluorescence analysis of CD163 protein expression in colorectal in situ carcinoma and pulmonary metastatic carcinoma. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001