title: Antiapoptotic effects of roscovitine on camptothecin-induced DNA damage in neuroblastoma cells.
abstract: In the present study dopaminergic neuroblastoma B65 cells were exposed to Camptothecin (CPT) (0.5-10 μM), either alone or in the presence of roscovitine (ROSC). The results show that CPT induces apoptosis through the activation of ataxia telangiectasia mutated (ATM)-induced cell-cycle alteration in neuroblastoma B65 cells. The apoptotic process is mediated through the activation of cystein proteases, namely calpain/caspases. However, whereas a pan-caspase inhibitor, zVADfmk, inhibited CPT-mediated apoptosis, a calpain inhibitor, calpeptin, did not prevent cell death. Interestingly, CPT also induces CDK5 activation and ROSC (25 μM) blocked CDK5, ATM activation and apoptosis (as measured by caspase-3 activation). By contrast, selective inhibition of ATM, by KU55933, and non-selective inhibition, by caffeine, did not prevent CPT-mediated apoptosis. Thus, we conclude that CDK5 is activated in response to DNA damage and that CDK5 inhibition prevents ATM and p53ser15 activation. However, pharmacological inhibition of ATM using KU55933 and caffeine suggests that ATM inhibition by ROSC is not the only mechanism that might explain the anti-apoptotic effects of this drug in this apoptosis model. Our findings have a potential clinical implication, suggesting that combinatory drugs in the treatment of cancer activation should be administered with caution.
authors.affiliation: Centros de Investigación Biomédica en Red Enfermedades Neurodegenerativas, Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Institut de Biomedicina, Universitat de Barcelona, Nucli Universitari de Pedralbes, Spain.
authors.forename: Javier G
authors.initials: JG
authors.lastname: Pizarro
authors.forename: Jaume
authors.initials: J
authors.lastname: Folch
authors.forename: Felix
authors.initials: F
authors.lastname: Junyent
authors.forename: Ester
authors.initials: E
authors.lastname: Verdaguer
authors.forename: Carme
authors.initials: C
authors.lastname: Auladell
authors.forename: Carlos
authors.initials: C
authors.lastname: Beas-Zarate
authors.forename: Mercè
authors.initials: M
authors.lastname: Pallàs
authors.forename: Antoni
authors.initials: A
authors.lastname: Camins
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D064007:Ataxia Telangiectasia Mutated Proteins; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism; D002166:Camptothecin / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D045744:Cell Line, Tumor; D051360:Cyclin-Dependent Kinase 5 / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects*; D004268:DNA-Binding Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D004151:Dipeptides / Q000494:pharmacology; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011687:Purines / Q000494:pharmacology*; D011753:Pyrones / Q000494:pharmacology; D000077546:Roscovitine; D025521:Tumor Suppressor Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C495818:2-morpholin-4-yl-6-thianthren-1-yl-pyran-4-one; D000590:Amino Acid Chloromethyl Ketones; D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D004151:Dipeptides; D009025:Morpholines; D011687:Purines; D011753:Pyrones; D025521:Tumor Suppressor Proteins; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D000077546:Roscovitine; C071482:calpeptin; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D051360:Cyclin-Dependent Kinase 5; D017346:Protein Serine-Threonine Kinases; D002154:Calpain; D002166:Camptothecin