1, 4-bis (4-(1H-benzo[d]imidazol-2-yl-phenyl)) piperazine (BIPP) induces apoptosis in leukemia cells Free

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The agent, 1, 4-bis (4-(1H-benzo[d]imidazol-2-yl-phenyl)) piperazine (BIPP) is a newly synthesized piperazine derivative. Piperazines are normally used as anti-helmintic or antibiotic agents for treatment of parasitic worm or microbial infections. The increased solubility, stability, and potency of delivery that the piperazine base provides have led us to believe that it may also be a novel anticancer agent. We have compared the effect of BIPP on two leukemia cell lines (U937, monocytic leukemia and K562, erythroleukemia) against the HDAC inhibitor sodium butyrate. We provide evidence that BIPP induces an apoptotic response by inducing Annexin V binding, caspase activation, loss of mitochondrial membrane potential (MMP), and decrease in ATP levels. In addition, we investigated whether like butyrate; BIPP causes leukemia cell death via intrinsic or extrinsic apoptotic pathways. Using several techniques, we have shown that BIPP induces dose-responsive cell death in U937 and K562 leukemia cell lines by intrinsic apoptosis mechanisms. Maximum apoptotic effect of BIPP on cell viability was observed between 3.2 and12.8 uM while butyrate elicited its maximum effect at 10 to 25 mM. We performed caspase enzymatic assays in cells treated with varying doses of BIPP using untreated cells as negative control. We noted that BIPP induces differential dose-response activation of caspases 3, 8 and 9. Again, the optimum activation of these caspases was attained at 3.2 to 12.8 uM of BIPP. Caspase activation profiles induced by BIPP were similar to those caused by butyrate in that both differentially activate caspases 3, 8 ad 9 in these cells. However, BIPP failed to activate caspase 2 and had an inhibitory effect on caspase 10. The differential response seen in initiator caspase activity (caspases-2, -8, -10) combined with the increased activity of effector caspases (caspases-3 and -9) and the loss of MMP suggest and intrinsic mechanism in the initiation of apoptosis and that BIPP causes leukemia cell death by these intrinsic apoptotic mechanisms. Also, our data suggests that BIPP triggers induction of leukemia cell death and that this drug could be considered as a potential therapeutic agent for human monocytic and erythroblastic leukemia. NHLBI T32 and SCORE grants