Figure 2.

Leptin-Leptin ObR axis was required for activation of IL-8, STAT3, ERK1/2, AKT in breast cancer cells. Serum-starved MCF-7 and SK-BR-3 cells were treated with different concentrations of leptin from 20 ng/ml to 200 ng/ml for 24 h or treated with 100 ng/ml leptin for different time from 0 h to 48 h. Q-PCR and Western blotting analysisdemonstrated leptin facilitated IL8 mRNA or protein of MCF-7 and SK-BR-3 cells with dose (A, C) and time-dependent (B, D) manner. The effect reached to peak level after MCF-7 and SK-BR-3 cells were treated with 100 ng/ml leptin for 24 h.(E) Serum-starved MCF-7 and SK-BR-3 cells were treated with 100 ng/ml leptin for various time intervals from 0h to 24 h. Westren blotting analysis was performed to detect the levels of phosphorylared and total STAT3, ERK1/2, AKT. (F) Antibodies against ObR (4 μg/ml) addition to MCF-7 and SK-BR-3 cells prior to leptin exposure absolutely abolished the expression of phosphorylation STAT3 and AKT (P < 0.05), while no changes was observed in phosphotylation ERK1/2. The specific antibody also down- regulated secretion of IL-8 from breast cancer cells that were treated with leptin (P < 0.05).

Figure 2.

(Continued)