title: p53-Independent induction of Fas and apoptosis in leukemic cells by an adenosine derivative, Cl-IB-MECA.
abstract: A(3) adenosine receptor (A(3)AR) agonists have been reported to influence cell death and survival. The effects of an A(3)AR agonist, 1-[2-chloro-6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-beta-D-ribofuranonamide (Cl-IB-MECA), on apoptosis in two human leukemia cell lines, HL-60 and MOLT-4, were investigated. Cl-IB-MECA (> or =30 microM) increased the apoptotic fractions, as determined using fluorescence-activated cell sorting (FACS) analysis, and activated caspase 3 and poly-ADP-ribose-polymerase. Known messengers coupled to A(3)AR (phospholipase C and intracellular calcium) did not seem to play a role in the induction of apoptosis. Neither dantrolene nor BAPTA-AM affected the Cl-IB-MECA-induced apoptosis. Cl-IB-MECA failed to activate phospholipase C in HL-60 cells, while UTP activated it through endogenous P2Y(2) receptors. Induction of apoptosis during a 48hr exposure to Cl-IB-MECA was not prevented by the A(3)AR antagonists [5-propyl-2-ethyl-4-propyl-3-(ethylsulfanylcarbonyl)-6-phenylpyridine-5-carboxylate] (MRS 1220) or N-[9-chloro-2-(2-furanyl)[1,2,4]triazolo[1,5-c]quinazolin-5-yl]benzeneacetamide (MRS 1523). Furthermore, higher concentrations of MRS 1220, which would also antagonize A(1) and A(2A) receptors, were ineffective in preventing the apoptosis. Although Cl-IB-MECA has been shown in other systems to cause apoptosis through an A(3)AR-mediated mechanism, in these cells it appeared to be an adenosine receptor-independent effect, which required prolonged incubation. In both HL-60 and MOLT-4 cells, Cl-IB-MECA induced the expression of Fas, a death receptor. This induction of Fas was not dependent upon p53, because p53 is not expressed in an active form in either HL-60 or MOLT-4 cells. Cl-IB-MECA-induced apoptosis in HL-60 cells was augmented by an agonistic Fas antibody, CH-11, and this increase was suppressed by the antagonistic anti-Fas antibody ZB-4. Therefore, Cl-IB-MECA induced apoptosis via a novel, p53-independent up-regulation of Fas.
authors.affiliation: Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Seong Gon
authors.initials: SG
authors.lastname: Kim
authors.forename: Gnana
authors.initials: G
authors.lastname: Ravi
authors.forename: Carsten
authors.initials: C
authors.lastname: Hoffmann
authors.forename: Yun Jin
authors.initials: YJ
authors.lastname: Jung
authors.forename: Min
authors.initials: M
authors.lastname: Kim
authors.forename: Aishe
authors.initials: A
authors.lastname: Chen
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Jacobson
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D004347:Drug Interactions; D018922:HL-60 Cells; D006801:Humans; D007938:Leukemia / Q000473:pathology; D058915:Purinergic P1 Receptor Antagonists; D043684:Receptor, Adenosine A3; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism*; D019014:fas Receptor / Q000096:biosynthesis* / Q000276:immunology
chemical_list: D000906:Antibodies; D058915:Purinergic P1 Receptor Antagonists; D043684:Receptor, Adenosine A3; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor; D010738:Type C Phospholipases; D000241:Adenosine; D002118:Calcium; C090034:2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide