Macrophage-derived cathepsin L promotes epithelial-mesenchymal transition and M2 polarization in gastric cancer

Figure 4 Cathepsin L + macrophages exert orienting effects on polarization. A: Multiplied immunohistochemistry (mIHC) analysis of cathepsin L (CTSL), CD68, and CDD163 in human gastric tumor sections; scale bar, 20 μm; B: Correlation analysis between CTSL and macrophage markers (CD68 or CD163) via Pearson’s R value measured by Image J; |R| ≤ 1; C and D: Representative mIHC images stained for CTSL, CD68, and CD163 in the tumor margin and bulk of human gastric tissues; magnification, 20 ×, 80 ×; E: Immunofluorescence analysis of CD163 and CD86 expression in shCTSL-transfected or shNC-transfected THP-1 cells; scale bar, 20 μm; F: Quantitative real-time polymerase chain reaction analysis of mRNAs extracted from shCTSL-treated or shNC-treated macrophages induced into the M0/M1/M2 state in vitro; the results revealed increased M1 and decreased M2 marker mRNA levels in shCTSL-treated macrophages. The error bars represent the SD; ^cP < 0.001; ^bP < 0.01; ^aP < 0.05 according to one-way analysis of variance. CTSL: Cathepsin L; DAPI: 4',6-diamidino-2-phenylindole; TNF-α: Tumor necrosis factor-α; IL: Interleukin; Arg-1: Arginase 1.