Fingolimod (FTY720) HCl

The inhibitory effect of S1P is revered by various concentrations of FTY720, with IC50 effect of 173 nM. In addition, FTY720 (10 nM) alone exerts no effect on the expression of co-stimulatory molecules. FTY720 reverses the increased expression of HLA-I induced by S1P for both the percentages of cells and the MFI, upon comparing the effect of S1P to the effect of combining S1P with FTY720. ^[1] Medium and high-dose FTY720-P also enhances the levels of TGF-β1. TGF-β1 and Foxp3 mRNA expression are upregulated in the high-dose FTY720-P group. The proliferation of effector T cells is suppressed significantly in the medium and high-dose FTY720-P group at a Treg/Teff cell ratio of 1:1. At a ratio of 1:1, the proliferation of effector T cells is also suppressed in the high-dose FTY720 group. ^[2]

FTY720 is effective in Ph⁺ but not Ph^- ALL xenografts using an early disease model. FTY720 produces a significant reduction in disease burden in the Ph⁺ ALL xenografts using an early disease model. Ph⁺ human ALL xenografts responds to FTY720 with an 80 % reduction in overall disease if treatment has been initiated early on. In contrast, treatment of mice with FTY720 does not result in reduced leukemia compared to controls using four separate human Ph^- ALL xenografts. ^[3]

• Cell lines

  Immature DCs

• Concentrations

  10 nM

• Incubation Time

  4 hours

• Method

  Immature DCs are left intact or are incubated with 2 μM S1P, 10 nM FTY720, 10 nM SEW2871 or the combinations of S1P with these drugs for 4 hours. As a control 1 μg/mL LPS is used. The cells are washed and incubated in a 96-well plate (v-bottom, 2 × 10⁵ cells per well), washed again and resuspended in PBS buffer containing 0.1% sodium azide. They are labeled with 1 μg/mL FITC-conjugated mouse anti-human CD80, 1 μg/mL FITC-conjugated mouse anti-human CD83, 1 μg/mL FITC-conjugated mouse anti-human CD86, 1 μg/mL FITC-conjugated mouse anti-human HLA-class I, 1 μg/mL FITC-conjugated mouse anti-human HLA-DR, 1 μg/mL FITC-conjugated mouse anti-human HLA-E, or 1 μg/mL FITC-conjugated mouse IgG as a control. The cells are washed twice, and examined in the flow cytometer. Markers are set according to the isotype control FITC-conjugated mouse IgG. To stain NK cells with antibodies for various NK cell activating receptors, they are either left untreated or incubated with 2 μM S1P for 4 hours, washed and stained with 1 μg/mL PE-conjugated mouse anti-human NKp30 (CD337), 1 μg/mL PE-conjugated mouse anti-human NKp44 (CD336), 1 μg/mL PE-conjugated mouse anti-human NKG2D (CD314), or as a control 1 μg/mL PE-conjugated mouse IgG1, for 45 min at 4 °C. NK cells are also stained with 1 μg/mL FITC-conjugated anti-killer inhibitory receptor (KIR)/CD158 antibody which recognizes KIR2DL2, KIR2DL3, KIR2DS2 and KIR2DS4, and as a control with FITC-conjugated mouse IgG. The cells are washed twice, and examined in the flow cytometer. Markers are set according to the isotype control PE-conjugated or FITC-conjugated mouse IgG.

• Animal Models

  NOD/SCIDγc^−/− mice bearing ALL cells.

• Dosages

  5 mg/kg/day, 10 mg/kg/day

• Administration

  Administered via i.p.