c-Jun could transactivate differentiation-associated genes.

<p>(<b>A</b>) A schematic illustration of human cystatin A, involucrin and SPRR3 genes. AP-1 DNA binding sites predicted using bioinformatics software. (<b>B</b>) Down-regulation of c-Jun was frequently detected in the paired ESCC tissues (T) and adjacent nontumor tissues (N) from the same patient by Western blot (left panel). Statistical analysis was performed (right panel). (<b>C</b>) Expression of c-Jun was detected in esophageal cancer cell lines by Western blot. (<b>D</b>) c-Jun can directly bind to the promoters of these genes in vivo. KYSE450 cells were subjected to ChIP with anti-c-Jun or β-actin antibody. Purified DNA was analyzed by PCR. (<b>E</b>) AP-1 transactivation activity was detected by luciferase reporter assay system. KYSE450 cells were transiently cotransfected with pAP-1-luc and pRL-CMV. (<b>F</b>) c-Jun could transactivate differentiation- associated genes. KYSE450 cells were cotransfected with c-Jun and cystatin A, involucrin or SPRR3 promoter constructs. pRL-SV40 Renilla was used for normalization of transfection efficiency. After 48 hours, the luciferase activity was measured. Data shown are Mean ± SD from multiple independent experiments (*: P< 0.05).