Fig. 3

IGFBPL1 inhibits esophageal cancer cell proliferation and induces cell apoptosis and G1/S phase arrest. a The effect of IGFBPL1 on cell viability was examined by the MTT assay. The growth curves of IGFBPL1 re-expressed and unexpressed KYSE150 and KYSE410 cells, and KYSE510 cells before and after IGFBPL1 gene knockdown, were analyzed. Each experiment was repeated three times. **p < 0.01, ***p < 0.001. b Colony formation assays showed that the number of clones decreased after the expression of IGFBPL1 was restored in KYSE150 and KYSE410 cells, while the number of clones of KYSE510 cells increased after IGFBPL1 knockdown. Each experiment was repeated three times. **p < 0.01, ***p < 0.001. c Flow cytometry results showed that over-expression of IGFBPL1 in KYSE150 and KYSE410 cells induced apoptosis, whereas apoptosis decreased after knockdown of IGFBPL1 in KYSE510 cells. Each experiment was repeated three times. **p < 0.01, ***p < 0.001. d Cell cycle distribution of KYSE150 and KYSE410 cells that had no IGFBPL1 expression or re-expression of IGFBPL1 and KYSE510 before and after knockdown of IGFBPL1. Each experiment was repeated three times. **p < 0.0 1, ***p < 0.001. e IGFBPL1 in KYSE510 cells was knocked down by siRNA. IGFBPL1 expression was examined by Western blot. NC, siRNA for IGFBPL1 negative control; siRNA847 and siRNA482, siRNA for IGFBPL1. f Western blots showed that IGFBPL1 has an effect on the expression levels of caspase-3 and Bcl-2 in KYSE150, KYSE410, and KYSE510 cells. Control, control vector; IGFBPL1, IGFBPL1 expression vector; β-actin, internal control; NC, siRNA negative control; siRNA, siIGFBPL1. g Western blots validated the effect of IGFBPL1 on the protein expression levels of cyclin E1, cyclin A2, and cyclin D1. Control, control vector; IGFBPL1, IGFBPL1 expressing vector; β-actin, internal control; NC, siRNA negative control; siRNA, siIGFBPL1