title: p53 dependent cell-cycle arrest triggered by chemotherapy in xenografted breast tumors.
abstract: The major long-term prognostic factor for breast cancer patients treated by first-line chemotherapy is response to treatment. We have previously shown that complete responses to high doses epirubicin-cyclophosphamide were observed only in human tumors bearing a TP53 mutation. Three xenografted human breast tumors, 2 of them with a TP53 mutation and one of them without, were studied for their immediate response to this drug association. Cell cycle, cellular senescence and cell death were characterized and quantified on tissue section before and after treatment. The TP53 wild-type tumor showed a strong early induction of senescence-like phenotype with overexpression of SA-beta-gal and p21(CIP1). In contrast both TP53 mutated tumors showed no sign of cell cycle arrest or senescence. Conversely, abnormal mitoses strongly increased, only in TP53 mutated tumors. Thus, in these in vivo models, epirubicin-cyclophosphamide treatment induces senescence-like features in TP53 wild-type tumor, likely accounting for cell cycle arrest and subsequent resistance to treatment. Conversely in TP53 mutated tumors, chemotherapy induces mitotic catastrophe and tumor death, accounting for complete response to this association exclusively in patients with TP53 mutated tumors.
authors.affiliation: INSERM U728, University Institute of Hematology, University Paris 7 Denis Diderot, Paris, France.
authors.forename: Mariana
authors.initials: M
authors.lastname: Varna
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Lehmann-Che
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Turpin
authors.forename: Elizabetha
authors.initials: E
authors.lastname: Marangoni
authors.forename: Morad
authors.initials: M
authors.lastname: El-Bouchtaoui
authors.forename: Marion
authors.initials: M
authors.lastname: Jeanne
authors.forename: Carmen
authors.initials: C
authors.lastname: Grigoriu
authors.forename: Philippe
authors.initials: P
authors.lastname: Ratajczak
authors.forename: Christophe
authors.initials: C
authors.lastname: Leboeuf
authors.forename: Louis-François
authors.initials: LF
authors.lastname: Plassa
authors.forename: Irmine
authors.initials: I
authors.lastname: Ferreira
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Poupon
authors.forename: Anne
authors.initials: A
authors.lastname: Janin
authors.forename: Hugues
authors.initials: H
authors.lastname: de Thé
authors.forename: Philippe
authors.initials: P
authors.lastname: Bertheau
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D002453:Cell Cycle; D016922:Cellular Senescence; D003520:Cyclophosphamide / Q000008:administration & dosage; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm; D015251:Epirubicin / Q000008:administration & dosage; D016158:Genes, p53; D006801:Humans; D015674:Mammary Neoplasms, Animal / Q000235:genetics* / Q000473:pathology*; D051379:Mice; D009154:Mutation; D009368:Neoplasm Transplantation; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D004273:DNA, Neoplasm; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D015251:Epirubicin; D003520:Cyclophosphamide