The mRNA level (A, C) and protein level (B, D) of c-Myc and CyclinD1, Cyclin A, p53 were analyzed by real-time RT-PCR and Western blotting in ISL1 stable overexpression HIT-T15 cells (A and B) and ISL1 knockdown HIT-T15 cells (C and D). The transcriptional activity of ISL1 was analyzed by luciferase reporter assay. ISL1 activated the promoter of c-Myc (E) or CyclinD1 (F) in a dose-dependent manner. The data represent 3 independent experiments, each performed in triplicate. Each bar represents mean ± SD (**p<0.01, *p<0.05, vs. the control).