Just as expected, rapamycin inhibited phosphoryla tion of each p70S6K and 4E BP1, Dex alone had no result on p p70S6K and p 4E BP1. Nonetheless, when combined use of these two drugs, a synergistic inhibition of mTOR signaling was detected by de phosphorylation of p70S6K and 4E BP1, These effects advised that inhibition from the mTOR signaling pathway may well potentiate the cytotoxic effect of Dex. Precisely the same results had been obtained in the two Jurkat and CEM C1 15 cells, Rapamycin and Dex arrest T ALL cells in G0 G1 phase in the cell cycle The primary function of rapamycin will be to induce cell cycle arrest, Movement cytometric analysis showed that 48 h deal with ment with rapamycin plainly induced G0 G1 arrest in all 4 cell lines of T ALL. In GC delicate cell line, CEM C7 14, Dex itself, can induce G0 G1 arrest, and co treat ment with rapamycin improved the G0 G1 phase somewhat, from 67% to 70%, p 0. 05.
But in GC resistant cell lines, rapamycin augmented the result of G0 G1 arrest significantly, from 45% to 58% in CEM C1 15 cells, 50% to 65% in Jurkat cells, and 57% to 75% in Molt 4 cells, p 0. 05, To assess the molecular basis underlying cell cycle arrest, NVP-BKM120 1202777-78-3 we investigated the expression of cell cycle regu latory proteins. As shown in Figure 3B, the two rapamycin and Dex could induce up regulation of cyclin depen dent kinase inhibitors of p21 and p27, and a synergistic result of induction was detected when applying these two drugs with each other. Rapamycin did not definitely influence the expression of cyclin A, whereas dexametha sone induced cyclin A expession. Rapamycin prevented dexamethasone induced expression of cyclin A. Cyclin D1 amounts have been diminished when handled with rapamycin or dexamethasone alone, or in mixture. In contrast with Dex, rapamycin had a stronger impact on down reg ulation of cyclin D1.
Rapamycin sensitizes T ALL cells to Dex induced apoptosis Cell cycle arrest could not describe the magic result on development Wnt-C59 1243243-89-1 inhibition of Dex when co handled with rapamy cin. The main mechanism of Dex while in the treatment of lymphoid malignancies should be to induce apoptotic cell death. We made use of Annexin V PI staining to find out the early stage of apoptosis. Dex, used alone at one uM, had no apoptotic result on Jurkat and Molt four cells, and there was only a minimal result on CEM C1 15 cells at 48 h and also a modest impact on CEM C7 14 cells at 24 h, p 0. 05. Rapamycin, utilized at ten nM, also had no obvious apoptosis inducing impact on all four cell lines, though at this con centration, major cell cycle arrest at G1 phase occurred, Nonetheless, when mixed Dex with rapamycin, a remarkable raise in cell apoptosis was ensued in all four cell lines, In contrast with Rap group, the combination deal with ment group of cells elevated the apoptotic fee from 3% to 20% in CEM C7 14 at 24 h, p 0.0