Kinase assays

The assays were performed at room temperature using 20 nM IDO and 2 mM D-Trp in the presence of 20 mM ascorbate, 3.5 μM methylene blue and 0.2 mg/mL catalase in 50 mM potassium phosphate buffer (pH 6.5). The initial reaction rates were recorded by continuously following the absorbance increase at 321 nm due to the formation of N’-formlylkynurenine.

Cell lines

HeLa cells and human T cells

Preparation method

The solubility of this compound in DMSO is >15.7mg/mL. 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.

Reacting condition

0.001~2 μM

Applications

IDO1 induction significantly suppressed T-cell proliferation in coculture systems, and the suppression was effectively reversed by INCB024360. IDO1 also increases IFN-γ production, and reduces conversion to regulatory T (Treg)–like cells.

Animal models

C57BL/6 mice bearing IDO1-expressing PAN02 pancreatic carcinomas

Dosage form

25 and 100 mg/kg, orally, twice a day for 25 days

Application

The growth of tumors in syngeneic immunocompetent C57BL/6 mice was inhibited in a dose-dependent fashion.

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.

INCB024360 is a potent and selective inhibitor of IDO1 with IC50 value of 10 nM. [1]
IDO means indoleamine-pyrrole 2, 3-dioxygenase. IDO is an enzyme which is encoded by the IDO1 gene. IDO is the rate-limiting and first enzyme of tryptophan which is one amino acid of human catabolism through kynurenine pathway. The decrease of L-tryptophan can cause halted growth of T cells as well as microbes. IDO belongs to immunomodulatory enzyme. It is produced by some activated macrophages and immunoregulatory cells. IDO is overexpressed in a wide range of cancer cells such as lung, prostatic, pancreatic, colorectal cancer. It is indentified to help cancer cells to escape the immune system by reducing the level of L-tryptophan in the microenvironment of cells.[2]
In Hela cells, INCB024360 selectively inhibits the activity of human IDO1 with IC50 values of about 10nM. On the other hand INCB024360demonstrates little inhibition activity against human IDO1 or TDO (tryptophan 2, 3-dioxygenase). In coculture systems of human dendritic cells with allogeneic lymphocytes, INCB024360 inhibit T-cell proliferation and cytokine production and influence the viability of NK cells. INCB024360 also increase CD86 expression and promote activation T cells by DCs.
In mice bearing IDO1-expressing PAN02 pancreatic tumour, ICB024360 significantly inhibit tumour growth in lymphocyte-dependent manner.[1] INCB024360 decreased plasma kynurenine levels by inhibiting the activity of IDO1 at 50 mg/kg in native C57BL/6 mice. INCB024360 also inhibit tumor growth at 100mg/kg in CT26 tumor bearing mice.[3]
References:
[1].    Liu X, Shin N, Koblish HK, Yang G, Wang Q, Wang K, Leffet L, Hansbury MJ, Thomas B, Rupar M et al: Selective inhibition of IDO1 effectively regulates mediators of antitumor immunity. Blood, 115(17):3520-3530.
[2].    Uyttenhove C, Pilotte L, Theate I, Stroobant V, Colau D, Parmentier N, Boon T, Van den Eynde BJ: Evidence for a tumoral immune resistance mechanism based on tryptophan degradation by indoleamine 2,3-dioxygenase. Nat Med 2003, 9(10):1269-1274.
[3].    Koblish HK, Hansbury MJ, Bowman KJ, Yang G, Neilan CL, Haley PJ, Burn TC, Waeltz P, Sparks RB, Yue EW et al: Hydroxyamidine inhibitors of indoleamine-2,3-dioxygenase potently suppress systemic tryptophan catabolism and the growth of IDO-expressing tumors. Mol Cancer Ther, 9(2):489-498.