Fig. 5

Continuous IL-6 activated the DNA damage and genomic instability through RAD51B. a Detection of STAT3, p-STAT3, UBE2D1, p53 and DNA damage marker of p-CHK1 and RPAin IL-6 treated SMMC-7721 cells for 0, 24, 48 and 72 h. b DNA damage and genomic instability was detected in continuous IL-6 (more than 2 months) treated QSG-7701 and SMMC-7721 cells. c γ-H2Ax foci in QSG-7701 and SMMC-7721 cells treated with IL-6(24 h) and continuous IL-6 were determined by immunofluorescence. Nuclei were stained by DAPI. Scale bar, 50um. The number of γ-H2Ax foci positive cells was showed in the right panel and data was collected from three independent experiments. d Protein levels of STAT3, p-STAT3, p-CHK1, RPA and γ-H2Ax in STAT3 overexpressed SMMC-7721 cells. e Protein levels of p-CHK1, RPA and γ-H2Ax in STAT3 silent and control SMMC-7721 cells with continuous IL-6. f Relative expression of RAD51B in continuous IL-6 treated SMMC-7721 and QSG-7701 cells. g Protein level of RAD51B in continuous IL-6 treated and STAT3 overexpressed SMMC-7721 cells. h The relative enrichment of p-STAT3 by real-time analysis at the promoter of RAD51B in ChIP assays. The relative enrichment was normalized to corresponding input (whole cell extracts). The primers were designed according to the predict sites of p-STAT3 in the promoter of RAD51B using programs in the gene-regulation. i Relative expression of RAD51B in STAT3 silent and control SMMC-7721 cells with continuous IL-6. j Protein levels of p-CHK1, RPA and γ-H2Ax in RAD51B overexpressed and silent SMMC-7721 cells. k Protein levels of p-CHK1 and γ-H2Ax in RAD51B overexpressed and control SMMC-7721 cells with continuous IL-6. *p < 0.05,**p < 0.01, ***I < 0.001