Fig. 4

STAT3 mediates the ERp57 regulating ILF3. a SW839 cells were transfected shSTAT3 or A498 were cells transfected with STAT3 overexpression vector pWP-STAT3. ILF3 mRNA level was measured by qRT-PCR. *P < 0.05, **P < 0.01 vs. corresponding control. b SW839 cells were transfected shSTAT3 or shERp57 respectively or co-transfected them together. A498 cells were transfected with shSTAT3 or pWPI-ERp57 respectively or co-transfected them together. qRT-PCR detected ILF3 mRNA level. *P < 0.05 vs. corresponding control. Western blot performed to detect ERp57, STAT3, ILF3 and Cyclin E1 protein level. c SW839 cells were transfected shSTAT3 and shERp57 respectively or transfected them together. Cell proliferation was measured by BrdU stain. Scale bar = 20 μm. Right panel showed analysis for BrdU positive cell number. *P < 0.05 vs corresponding control. d A498 cells were transfected with pWPI-ERp57 or empty vector and then cell lysates were immunoprecipitated with antibody against ERp57. Western blot detected ERp57 and STAT3 protein level in lysates. e A498 were treated as (d), PLA analysis was used to test the interaction between ERp57 and STAT3. Analysis of number of PLA positive cells. *P < 0.05 vs. empty vector. f Potential binding site of STAT3 in ILF3 promotor. g ChIP-qPCR was used to test STAT3 and ERp57 binding to the ILF3 promoter region in 293A cells. *P < 0.05, **P < 0.01 vs. IgG. h ILF3 promoter-luciferase reporter were co-transfected with pWPI-ERp57 or co-transfected pWPI-ERp57 combination of shSTAT3 vector into 293A cells, and then luciferase reporter assays were performed. *P < 0.05 vs. corresponding control