Synthesis of 6,8,9 poly-substituted purine analogue libraries as pro-apoptotic inducers of human leukemic lymphocytes and DAPK-1 inhibitors

Abstract

A 18-member library of 6,8,9-poly-substituted purines was prepared from pyrimidines, primary alcohols, and N,N-dimethylamides under basic conditions via a novel one-pot synthetic pathway controlled by amide sizes and the novel analogues were tested against two leukemia cell lines: Jurkat (acute T cell leukemia) and K562 (chronic erythroleukemia) cells. Compounds having a benzoxy group at C6 position of the aromatic ring exhibited antiproliferative activity in Jurkat cells whereas all compounds induced a lower effect on K562 cells. Analysis of cell cycle, Annexin-V staining, and cleavage of initiator caspases assays showed that the active purine analogues induce cell death by apoptosis. Based on these results, a new purine derivative was synthesized, 6-benzyloxy-9-tert-butyl-8-phenyl-9H-purine (6d), which displayed the highest activity of the series against Jurkat cell lines. Finally, (33)P-radiolabeled kinase assays using 96 recombinant human kinases known to be involved in apoptotic events were performed. Just one of the kinases tested, DAPK-1, was inhibited 50% or more by the phenotypic hits at 10 μM, suggesting that the inhibition of this target could be responsible for the induction of cell death by apoptosis. In agreement with the phenotypic results, the most active antiproliferative agent, 6d, displayed also the lowest IC50 value against recombinant DAPK1 (2.5 μM), further supporting the potential role of this protein on the observed functional response. DAPK-1 inhibition led by 6d together with its pro-apoptotic properties against the Jurkat line makes it an interesting candidate to further investigate the role of DAPK1 kinase in triggering apoptosis in cancer cells, a role which is attracting recent interest.

Novel Functions of Death-Associated Protein Kinases through Mitogen-Activated Protein Kinase-Related Signals

“…Eighteen analogs exhibiting anti-proliferative and pro-apoptotic properties on an acute T cell leukemia cell line were obtained [ 105 ]. These analogs have a benzyloxy group at the C6 position and 9-tert-butyl-6-(benzyloxy)-8-phenyl-9 H -purine (6d).…”

Reconstitution of the Ataxia-Telangiectasia Cellular Phenotype With Lentiviral Vectors

“…Cells were irradiated with 4 Gy, cultured for 18 h and cell cycle profiles were determined by flow cytometry after Propidium Iodide staining as described elsewhere ( 34 ) using a BD FACSCanto II flow cytometer (Becton Dickinson, San Jose, CA).…”

Diabetes in Patients with Ataxia telangiectasia: A National Cohort Study

“…Due to better care, life expectancy of A-T patients has emerged over the last decades (44). Especially in the light of new treatment options such as bone marrow transplantation (45)(46)(47), dexamethasone treatment (48)(49)(50) and gene therapy (51)(52)(53) disease facets with manifestation in the later disease course should be screened and treated. According to our data, diabetes screening is indicated starting for the age of 12 years.…”