The inhibition of Flt3 ITD induces a G1 cell-cycle arrest and down-regulation of D-cyclins. (A) MV4-11, MOLM13, THP-1, and U937 cells were treated with THRX-165724 (300 nM) or SU14813 (100 nM) for 24 hours. After propidium iodide staining, cell-cycle analysis was performed by flow cytometry. (B) Ribonuclease protection assay. MV4-11 cells were treated with THRX-165724 (300 nM) or with vehicle (DMSO) for 3 hours. Changes in mRNA levels of a set of cyclin genes was determined by ribonuclease protection assay (RPA) P indicates probe). (C) Western blot. MV4-11 cells were treated with THRX-165724 for 0, 1, 2, 4, 8, and 12 hours. Lysates were immunoblotted with the indicated antibodies. Probing with anti-tubulin was used to ensure equal loading. (D) Western blot. MOLM13, MV4-11, U937, and THP-1 cells were treated with THRX-165724 (300 nM) or DMSO (vehicle control) as well as SU14813 (100 nM) or DMSO (vehicle control) for 16 hours. A Western blot was performed with cell lysates probing for cyclin D2, D3, and pRb. Actin served as marker for equal loading.
