Knock-down of Chi3L1 inhibits cell migration and proliferation in human lung cancer cell lines A549 and H460. (A) Cancer cell migration was measured by trans-well migration assays of A549 and H460 cells treated with siChi3L1 or siControl. *, p<0.05. (B) Trans-well migration assays of A549 and H460 cells treated with rhChi3L1 protein. *, p<0.05. (C) Cell proliferation was measured by MTT assay of A549 and H460 cells treated with siChi3L1. *, p<0.05. (D) Cell proliferation was measured by MTT assay of A549 and H460 cells treated with rhChi3L1. *, p<0.05. (E) Expressions of Chi3L1, MMP-9, MMP-13, PCNA, and VEGF after siChi3L1 treatment were analyzed by Western blotting. (F) Expressions of Chi3L1, MMP-9, MMP-13, PCNA, and VEGF after rhChi3L1 treatment were analyzed by Western blotting. All experiments were prepared in duplicate and repeated three times. Values below the Western blot indicate densitometry analysis using ImageJ software.