The Role Of JAK2∕STAT3 Signaling Pathway In Leptin Promoting The Proliferation Of Human Endometrial Cancer Cells

Objective: To explore the role of JAK/STAT3 signaling pathway in leptin promoting the proliferation of human endometrial cancer cells.Methods: The expression of leptin receptor (OB-Rb) in Ishikawa cells were detected by fluoroimmunoassay. The cells after serum starvation were treated by leptin with various concentrations (0, 10, 50, 100, 150ng/ml) for different times (6, 12, 24h). The effect of leptin treatment on cell proliferation was examined by MTT assay. Meanwhile, JAK2's selective inhibitor AG490 with various concentrations (10, 50, 100μmol/L) was used to block STAT3's phosphorylation, and then the proliferation of Ishikawa cells promoted by leptin was also studied. Ishikawa cells were treated with 100ng/ml leptin for various time periods (0,20,40,60min), the level of STAT3 phosphorylation was examined by Western blot.Results: Fluoroimmunoassay showed the presence of leptin receptor OB-Rb in Ishikawa cells. Leptin stimulated the proliferation of Ishikawa cells in a time- and dose- dependent manner, and the effect was maximum at 100ng/ml for 24h treatment, there was no diference between 100ng/ml and 150ng/ml(P>0.05). AG490 significantly reduced the proliferation stimulation of Ishikawa cells by leptin in a dose- dependent manner. STAT3 phosphorylation was significantly increase stimulated by leptin in Ishikawa cells and lasted for 60min at least.Conclusion: It is suggested that leptin may promotes the proliferation in endometrial cancer cells by activating JAK2/STAT3 signaling pathway.