title: Guanine nucleotide depletion triggers cell cycle arrest and apoptosis in human neuroblastoma cell lines.
abstract: Mycophenolic acid (MPA) specifically inhibits inosine-5'-monophosphate dehydrogenase, the first committed step toward GMP biosynthesis. In its morpholinoethyl ester pro-drug form it is one of the most promising immunosuppressive drugs recently developed. The aim of the present study was to investigate the in vitro effects of MPA, at concentrations readily attainable during immunosuppressive therapy, on 3 human neuroblastoma cell lines (LAN5, SHEP and IMR32). Mycophenolic acid (0.1-10 microM) caused a decrease of intracellular levels of guanine nucleotides, a G(1) arrest and a time- and dose-dependent death by apoptosis. These effects, associated with an up-regulation of p53, p21 and bax, a shuttling of p53 protein into the nucleus and a down-regulation of bcl-2, survivin and p27 protein, were reversed by the simultaneous addition of guanine or guanosine and were more evident using nondialysed serum containing hypoxanthine. These results suggest that in neuroblastoma cell lines clinically attainable concentrations of mycophenolic acid deplete guanine nucleotide pools triggering G(1) arrest and apoptosis through p53-mediated pathways, indicating a potential role of its morpholinoethyl ester pro-drug in the management of patients with neuroectodermal tumors.
authors.affiliation: Department of Experimental Medicine and Pathology, University of Rome La Sapienza, Via Regina Elena 324, 00161 Rome, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Messina
authors.forename: Paola
authors.initials: P
authors.lastname: Gazzaniga
authors.forename: Vanna
authors.initials: V
authors.lastname: Micheli
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Guaglianone
authors.forename: Silvia
authors.initials: S
authors.lastname: Barbato
authors.forename: Stefania
authors.initials: S
authors.lastname: Morrone
authors.forename: Luigi
authors.initials: L
authors.lastname: Frati
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Aglianò
authors.forename: Alessandro
authors.initials: A
authors.lastname: Giacomello
mesh_terms: D017209:Apoptosis; D015153:Blotting, Western; D002453:Cell Cycle; D002455:Cell Division; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D005434:Flow Cytometry; D016193:G1 Phase; D015972:Gene Expression Regulation, Neoplastic; D006150:Guanine Nucleotides / Q000737:chemistry / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D019271:Hypoxanthine / Q000378:metabolism; D007150:Immunohistochemistry; D007166:Immunosuppressive Agents / Q000494:pharmacology; D051034:Inhibitor of Apoptosis Proteins; D008840:Microfilament Proteins / Q000096:biosynthesis; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis; D009124:Muscle Proteins; D009173:Mycophenolic Acid / Q000494:pharmacology; D009363:Neoplasm Proteins; D009447:Neuroblastoma / Q000473:pathology*; D011355:Prodrugs / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D016283:Proto-Oncogene Proteins p21(ras) / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000077022:Survivin; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; C107489:BIRC5 protein, human; D006150:Guanine Nucleotides; D007166:Immunosuppressive Agents; D051034:Inhibitor of Apoptosis Proteins; D008840:Microfilament Proteins; D008869:Microtubule-Associated Proteins; D009124:Muscle Proteins; D009363:Neoplasm Proteins; D011355:Prodrugs; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D000077022:Survivin; C058992:Tagln protein, mouse; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D006153:Guanosine Diphosphate; D019271:Hypoxanthine; D006160:Guanosine Triphosphate; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); D009173:Mycophenolic Acid