Induction of SDF-1 expression in human gastric carcinoma cell line TSGH 9201 and AGS cells by resistin stimulation. TSGH 9201 and AGS cells were treated with vehicle and resistin treatment. RNA samples were isolated at the indicated time periods or doses. All bar graphs represent folds of control cells (CL) and normalized to 18S rRNA by real-time PCR analysis (A, C). Human SDF-1 protein secretion was determined by ELISA analyses (B, D). Cells were stimulated with 25 ng/mL resistin for the times indicated (A, B), or induced at various doses for 4 h (C) or 6 h (D). RNA levels were quantified with the control being set at 100%. The experiments were performed in triplicate, and data are presented as means ± SD. The symbol *indicates means that are significantly different when compared to the control group (CL) of TSGH 9201 with P < 0.05, respectively.