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AG-490 is a JAK-2 specific inhibitor, which inhibits phosphorylation of EGFR and signal transducer and activator of transcription 3 [STAT-3], and subsequently reduce invasion and adhesion potential of malignant cells.

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AG490 inhibits the activation of Stat-3 by selectively blocking JAK2. AG490 is used to selectively inhibit JAK/Stat-3 activation. At a dose of 10 μM, Stat-3 phosphorylation is decreased by >95% and cell viability is maintained. AG490 at a dose of 10 μM results in >95% decrease in pStat-3 in EGF-stimulated A431 cells with no effect on Stat-3 mass. AG-490 is a potent inhibitor of the JAK3/STAT, JAK3/AP-1, and JAK3/MAPK pathways and their cellular consequences. AG-490 abolishes IL-2-inducible [³H]thymidine incorporation in a dose-dependent manner, displaying an IC₅₀ of 25 μM. AG-490 potently inhibits IL-2-mediated proliferation in T cells, results distinct from previous studies that showed this agent induced apoptosis in ALL cells while exerting apparently no effects on the growth of mitogen-stimulated normal T cells

Regulation and mechanism of leptin on lipid metabolism in ovarian follicle cells from yellow catfish Pelteobagrus fulvidraco.
Zhang LH;Tan XY;Wu K;Zhuo MQ;Song YF;Chen QL Gen Comp Endocrinol. 2015 Oct 1;222:116-23. doi: 10.1016/j.ygcen.2015.06.008. Epub 2015 Jun 25.
The present study was conducted to determine the effect of leptin on lipid metabolism in ovarian follicle cells of yellow catfish Pelteobagrus fulvidraco. For that purpose, primary ovarian follicle cells were isolated from yellow catfish, cultured and subjected to different treatments (control, 0.1% DMSO, 500ng/ml leptin, 500ng/ml leptin plus 100μM wortmannin, 500ng/ml leptin plus 50nM AG490, respectively) for 48h. Intracellular triglyceride (TG) content, the activities (CPT I, FAS, G6PD, and 6PGD) and/or expression level of several enzymes (CPT I, FAS, G6PD, 6PGD, ACCa and ACCb), as well as the mRNA expression of transcription factors (PPARα, PPARγ and SREBP-1) involved in lipid metabolism were determined. Recombinant human leptin (rt-hLEP) incubation significantly reduced intracellular TG content, activities and mRNA levels of FAS, G6PD and 6PGD, SREBP-1 and PPARγ, but enhanced activity and mRNA level of CPT I, PPARα and ACCa. Specific inhibitors AG490 and wortmannin of JAK-STAT and IRS-PI3K signaling pathways prevented leptin-induced changes, indicating that JAK-STAT and IRS-PI3K signaling pathways were involved in the process of leptin-induced changes of lipid metabolism. Based on these observations above, for the first time, our study indicated that leptin reduced lipid deposition by activating lipolysis and suppressing lipogenesis in ovarian follicles of yellow catfish, and both JAK-STAT and IRS-PI3K signaling pathways were involved in the changes of leptin-induced lipid metabolism.