Leukemia & Lymphoma 2012-10-01

Multifaceted actions of 8-amino-adenosine kill BCR-ABL positive cells.

Rathi N Pillai, Lisa S Chen, Mary L Ayres, Billie J Nowak, Michael W Thomas, Elizabeth J Shpall, Michael J Keating, Varsha Gandhi

Index: Leuk. Lymphoma 53(10) , 2024-32, (2012)

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Abstract

Survival of chronic myelogenous leukemia (CML) cells is dependent on BCR-ABL kinase, the activity of which is contingent on the level of BCR-ABL protein and the availability of adenosine triphosphate (ATP). We hypothesized that 8-amino-adenosine (8-amino-Ado)-mediated reduction in cellular ATP level and inhibition of mRNA synthesis leading to a decrease in protein level would result in a multifaceted targeting of BCR-ABL. Using K562 cells, we demonstrated that there was a dose- and time-dependent increase in 8-amino-ATP accompanied by a > 95% decline in the endogenous ATP pool. In parallel, 8-amino-Ado inhibited RNA synthesis and resulted in a depletion of BCR-ABL transcript. Consistent with this, BCR-ABL and ABL protein levels were also decreased. These effects were associated with the initiation of cell death as visualized by poly(ADP-ribose) polymerase (PARP) cleavage, decreased clonogenicity and greater than additive interaction with imatinib. In imatinib-sensitive and -resistant KBM5 cells, 8-amino-Ado treatment augmented the imatinib effect on growth inhibition.