Cell experiment:

In brief, approximately 2×103 cells are plated into microtiterplate wells in 100 mL RPMI-1640 growth media with indicated concentrations of TG101209. The relative growth of cells is quantified at 24-hour intervals using Cell Proliferation Kit II (XTT) as per manufacturer's guidelines. After incubation, 20 mL of XTT is added to the wells and allowed to incubate for 4-6 hours. The colored formazan product is measured spectrophotometrically at 450 nm with correction at 650 nm, and IC50 values are determined using the GraphPad Prism 4.0 software. Data are subjected to a non-linear regression-fit analysis and IC50 values are determined as the concentration that inhibits proliferation by 50%. All experiments are done in triplicate and the results normalized to growth of untreated cells.

Animal experiment:

Severe combined immunodeficiency (SCID) mice are intravenously injected with 10 times 106 sorted GFP-positive BaF/3 cells expressing JAK2V617F (Ba/F3-V617F-GFP). TG101209 is administered by oral gavage at the indicated doses beginning day +3 after tumor cell infusion and ending on day +20. On day +11 following tumor cell injection, 1 mL blood is collected by terminal cardiac bleeding from the mouse that receives vehicle, and 0.1 mL of blood is collected by non-lethal retro-orbital collection from each of the three six-mouse groups dosed with 10, 30 or 100 mg/kg b.i.d. (twice daily) of TG101209, and samples pooled within the dose groups. Blood mononuclear cells are isolated by a Ficoll cushion centrifugation method (600 RCF and 30 min). The isolated cells are subjected to FACS analysis to determine the percentage of GFP-positive tumor cells (that is, Ba/F3-V617F-GFP cells).

TG101209, a small-molecule identified by structure based design, is a selective inhibitor of janus kinase 2 (Jak2) that potently inhibits Jak/Stat pathway in multiple myeloma (MM) cell lines, such as cell harboring JAK2V617F or MPLW515L/K mutations which are commonly associated with polycythemia vera (PV) and primary myelofibrosis (PMF) respectively. According to results of multiple studies, it has revealed that TG101209 exhibits a dose and time dependent cyctoxicity, which is associated with inhibited cell cycle progrgression and induced apoptosis, in a wild range of MM cell lines through suppressing the expression of pJak2, pStat3 and Bcl-xl and inducing the overexpression of pErk and pAkt.

Reference

[1].Ramakrishnan V, Kimlinger T, Haug J, Timm M, Wellik L, Halling T, Pardanani A, Tefferi A, Rajkumar SV, Kumar S. TG101209, a novel JAK2 inhibitor, has significant in vitro activity in multiple myeloma and displays preferential cytotoxicity for CD45+ myeloma cells. Am J Hematol. 2010;85(9):675-686.