Inhibitory activities

IC50 values for TG101348 were determined commercially using the InVitrogen kinase profiling service for a 223 kinase screen that included JAK2 and JAK2V617F or Carna Biosciences for the screen of all Janus kinase family members including JAK1 and Tyk2. ATP concentration was set to approximately the Km value for each kinase.

Cell lines

Human erythroleukemic cell line (HEL) with JAK2V617F mutation; Ba/F3 cells

Preparation method

Soluble in DMSO >10 mM. General tips for obtaining a higher concentration: Please warm the tube at 37℃ for 10 minutes and/or shake it in the ultrasonic bath for a while. Stock solution can be stored below -20℃ for several months.

Reaction Conditions

0.1, 0.3, 1, 3, and 10 μM; 72 h.

Applications

In HEL and Ba/F3 cells with JAK2V617F mutation, TG101348 (SAR302503) inhibits cell proliferation with IC50 values of 300 nM and 420 nM, respectively. TG101348 also reduces STAT5 phosphorylation and induces apoptosis in a dose-dependent way.

Animal models

C57Bl/6 mice; C57BL/6 mice intravenously injected with whole bone marrow expressing JAK2V617F.

Dosage form

30, 100, and 200 mg/kg; 0.5, 1, 3, 5, 7, and 24 hr postdose; administrated orally.60 mg/kg, 120 mg/kg; oral gavage twice daily; from day 28 on for 42 days.

Applications

In C57Bl/6 mice, maximum plasma concentrations (Cmax) of TG101348 are 0.68, 3.58, and 4.28 μM at 3 h postdose at doses 30, 100, and 200 mg/kg, respectively. In mice with polycythemia vera induced by JAK2V617F, TG101348 reduces hematocrit by 5.1% and 17.9% at 60 mg/kg and 120 mg/kg, respectively. Also, TG101348 dose-dependently inhibits splenomegaly and polycythemia.

Other notes

Please test the solubility of all compounds indoor, and the actual solubility may slightly differ with the theoretical value. This is caused by an experimental system error and it is normal.

• Planta 253.2 (2021): 1-18. PMID:33439503

Fedratinib (TG-101348) is a selective inhibitor of JAK2 with an IC50 of 3 nM, showing 35- and 334-fold selectivity over JAK1 and JAK3, respectively.

Fedratinib (TG-101348) significantly inhibits JAK2 V617F, Flt3, and Ret with IC50 of 3 nM, 15 nM, and 48 nM, respectively. TG101348 has an IC50 appr 300-fold higher for the closely related JAK3 and is a less potent inhibitor of the JAK1 and TYK2 family members. Fedratinib (TG-101348) inhibits proliferation of a human erythroblast leukemia (HEL) cell line that harbors the JAK2V617F mutation, as well as a murine pro-B cell line expressing human JAK2V617F (Ba/F3 JAK2V617F), with IC50 of 305 nM and 270 nM, respectively. Fedratinib (TG-101348) also inhibits proliferation of parental Ba/F3 cells to a comparable level, with IC50 of appr 420 nM. Fedratinib (TG-101348) treatment reduces STAT5 phosphorylation at concentrations that parallel the concentrations required to inhibit cell proliferation. Fedratinib (TG-101348) induces apoptosis in both HEL and Ba/F3 JAK2V617F cells in a dose-dependent manner. Fedratinib does not show proapoptotic activity in control normal human dermal fibroblasts at concentrations up to 10 μM, and the antiproliferative IC50 against fibroblasts is >5 μM[1]. Fedratinib (TG-101348) treatment decreases GATA-1 expression, which is associated with erythroid-skewing of JAK2V617F+ progenitor differentiation, and inhibits STAT5 as well as GATA S310 phosphorylation[2]. Fedratinib (TG-101348) inhibits the proliferation of HMC-1.1 (KITV560G) cells, with somewhat lower potency than HMC-1.2 (KITD816V, KITV560G) cells, with IC50 of 740 nM and 407 nM, respectively[3].

Fedratinib (TG-101348) has potential for efficacious treatment of JAK2V617F-associated myeloproliferative diseases (MPD). In treated animals, there is a statistically significant reduction in hematocrit and leukocyte count, a dose-dependent reduction/elimination of extramedullary hematopoiesis, and, at least in some instances, evidence for attenuation of myelofibrosis, correlated with surrogate endpoints, including reduction/elimination of JAK2V617F disease burden, suppression of endogenous erythroid colony formation, and in vivo inhibition of JAK-STAT signal transduction. There are no apparent toxicities and no effect on T cell number[1]. Oral administration of Fedratinib (TG-101348) (120 mg/kg) significantly inhibits PV progenitor erythroid differentiation in vivo[2].

References:
[1]. Wernig G, et al. Efficacy of TG101348, a selective JAK2 inhibitor, in treatment of a murine model of JAK2V617F-induced polycythemia vera. Cancer Cell. 2008 Apr;13(4):311-20.
[2]. Geron I, et al. Selective inhibition of JAK2-driven erythroid differentiation of polycythemia vera progenitors. Cancer Cell. 2008 Apr;13(4):321-30.
[3]. Lasho T, et al. Inhibition of JAK-STAT signaling by TG101348: a novel mechanism for inhibition of KITD816V-dependent growth in mast cell leukemia cells. Leukemia. 2010 Jul;24(7):1378-80.
[4]. Mu CF, et al. Codelivery of AP24534 and SAR302503 by Active Bone-Targeted Polymeric Micelles for the Treatment of Therapy-Resistant Chronic Myeloid Leukemia. Mol Pharm. 2017 Jan 3;14(1):274-283.