result analysis documented the existence of powerful synergisms at drug concentrations well below the respective IC50 for these drugs in CEM S cells. Eventually, KU 63794, a double ATP aggressive mTORC1/ mTORC2 inhibitor, was successful on CEM S cells and MOLT 4, while CEM and Jurkat Dtc cells exhibited a much higher IC50. Inhibitors of PI3K/Akt/mTOR signaling block cells in the G0/G1 stage of the cell cycle and induce apoptosis To ascertain whether treatment of T ALL cell lines with inhibitors of PI3K/Akt/mTOR signaling could Dovitinib CHIR-258 influence cell cycle progression, MOLT 4 cells were incubated for 24 h with increasing concentrations of the drugs and the cell cycle was examined by means of flow cytometric analysis of propidium iodide stained samples. All the drugs induced a statistically significant G0/G1 block and a concomitant decline in both S and G2/M stages of the cell cycle. The induction of apoptosis was investigated through Annexin V FITC/ PI staining and flow cytometric evaluation in MOLT 4 cells. The drugs that most potently induced apoptosis were KU 63794 and MK 2206. Results Gene expression of the inhibitors on PI3K/Akt/mTOR signaling in T ALL cell lines Western blot analysis demonstrated a concentration dependent decrease in Ser 473 g Akt, indicative of mTORC2 inhibition, after 24 h of therapy with all the inhibitors, in all the cell lines analyzed. Whole Akt levels were unaffected by the drugs, except for NVP BAG956 at the highest concentration employed. S6 ribosomal protein, an mTORC1 downstream substrate, was also effectively dephosphorylated by the inhibitors. An occasion dependent study was also performed and documented that, in CEM R cell lines and in MOLT 4, NVP BAG956, MK 2206, and GDC 0941 dephosphorylated p S6RP, Ser 473 p Akt, and p 4E BP1 already after 6 h of treatment. Inhibitors of PI3K/Akt/mTOR signaling synergize together Then, it was investigated whether MK 2206, GDC 0941, NVP BAG956, KU 63794, and RAD 001 could mutually synergize in T ALL cells. CEM S cells were incubated for 24 h with just one drug alone or with a combination of two drugs at an equal rate. MTT assays were then performed. The less successful mixtures were those consisting order Dasatinib of GDC 0941/KU 63794, GDC 0941/MK 2206, GDC 0941/NVP BAG965, GDC0941/ RAD 001, MK 2206/NVP BAG965. Certainly, with your combined therapies, an antagonism was often detected, and, each time a synergism was observed, the combination index was usually not below 0. 6, showing a weak synergism. In comparison, a solid synergism was observed with MK 2206/KU 63794, MK 2206/RAD 001, NVP BAG956/KU 63794, NVP BAG956/RAD 001, and RAD 001/KU 63794 combinations. More over, we reviewed the results of the RAD 001/KU 63794 mix on cell cycle progression, as those two drugs clearly synergized at 1 uM.