title: Impaired up-regulation of polo-like kinase 2 in B-cell chronic lymphocytic leukaemia lymphocytes resistant to fludarabine and 2-chlorodeoxyadenosine: a potential marker of defective damage response.
abstract: The functional evaluation of ataxia telangiectasia mutated (ATM) and p53 was recently developed in B-cell chronic lymphocytic leukaemia (B-CLL), a disease in which the response to DNA damage is frequently altered. We identified a novel biomarker of chemosensitivity based on the induction of DNA damage by the purine nucleoside analogues (PNA) fludarabine and 2-chlorodeoxyadenosine (CdA). Using genome-wide expression profiling, it was observed that, in chemosensitive samples, PNA predominantly increased the expression of p53-dependent genes, among which PLK2 was the most highly activated at early time points. Conversely, in chemoresistant samples, p53-dependent and PLK2 responses were abolished. Using a quantitative real time polymerase chain reaction, we confirmed that PNA dose- and time-dependently increased PLK2 expression in chemosensitive but not chemoresistant B-CLL samples. Analysis of a larger cohort of B-CLL patients showed that cytotoxicity induced by PNA correlated well with PLK2 mRNA induction. Interestingly, we observed that failure to up-regulate PLK2 following PNA and chemoresistance were not strictly correlated with structural alterations in the TP53 gene. In conclusion, we propose that testing PLK2 activation after a 24-h incubation with PNA could be used to investigate the functional integrity of DNA damage-response pathways in B-CLL cells, and predict clinical sensitivity to these drugs.
authors.affiliation: De Duve Institute, Université catholique de Louvain, Brussels, Belgium.
authors.forename: Emeline
authors.initials: E
authors.lastname: de Viron
authors.forename: Laurent
authors.initials: L
authors.lastname: Knoops
authors.forename: Thierry
authors.initials: T
authors.lastname: Connerotte
authors.forename: Caroline
authors.initials: C
authors.lastname: Smal
authors.forename: Lucienne
authors.initials: L
authors.lastname: Michaux
authors.forename: Pascale
authors.initials: P
authors.lastname: Saussoy
authors.forename: Pascal
authors.initials: P
authors.lastname: Vannuffel
authors.forename: Eline
authors.initials: E
authors.lastname: Beert
authors.forename: Marie-Christiane
authors.initials: MC
authors.lastname: Vekemans
authors.forename: Cédric
authors.initials: C
authors.lastname: Hermans
authors.forename: Françoise
authors.initials: F
authors.lastname: Bontemps
authors.forename: Eric
authors.initials: E
authors.lastname: Van Den Neste
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000494:pharmacology*; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D016923:Cell Death / Q000187:drug effects; D017338:Cladribine / Q000494:pharmacology; D015331:Cohort Studies; D004249:DNA Damage; D004273:DNA, Neoplasm / Q000235:genetics; D019008:Drug Resistance, Neoplasm; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000201:enzymology* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects*; D014740:Vidarabine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D017338:Cladribine; C496126:PLK2 protein, human; D017346:Protein Serine-Threonine Kinases; D014740:Vidarabine; C024352:fludarabine