title: Reactivation of p53 mutants by prima-1 [corrected] in thyroid cancer cells.
abstract: Most undifferentiated thyroid carcinomas express p53 mutants and thereafter, are very resistant to chemotherapy. p53 reactivation and induction of massive apoptosis (Prima-1) is a compound restoring the tumor-suppressor activity of p53 mutants. We tested the effect of Prima-1 in thyroid cancer cells harboring p53 mutations. Increasing doses of Prima-1 reduced viability of thyroid cancer cells at a variable extent (range 20-80%). Prima-1 up-regulated p53 target genes (p21(WAF1) , BCL2-associated X protein (Bax), and murine double minute 2 (MDM2)), in BC-PAP and Hth-74 cells (expressing D259Y/K286E and K286E p53 mutants) but had no effect in SW1736 (p53 null) and TPC-1 (expressing wild-type p53) thyroid cancer cells. Prima-1 also increased the cytotoxic effects of either doxorubicin or cisplatin in thyroid cancer cells, including the chemo-resistant 8305C, Hth-74 and BC-PAP cells. Moreover, real-time PCR and Western blot indicated that Prima-1 increases the mRNA of thyroid-specific differentiation markers in thyroid cancer cells. Fluorescence-activated cell sorting analysis revealed that Prima-1 effect on thyroid cancer cells occurs via the enhancement of both cell cycle arrest and apoptosis. Small interfering RNA experiments indicated that Prima-1 effect is mediated by p53 mutants but not by the p53 paralog p73. Moreover, in C-643 thyroid cancer cells, forced to ectopically express wild-type p53, Prima-1 prevented the dominant negative effect of double K248Q/K286E p53 mutant. Finally, co-IP experiments indicated that in Hth-74 cells Prima-1 prevents the ability of p53 mutants to sequestrate the p53 paralog TAp73. These in vitro studies imply that p53 mutant reactivation by small compounds may become a novel anticancer therapy in undifferentiated thyroid carcinomas.
authors.affiliation: Department of Clinical and Molecular Biomedicine, University of Catania, Catania, Italy.
authors.forename: Rosa Linda
authors.initials: RL
authors.lastname: Messina
authors.forename: Mariangela
authors.initials: M
authors.lastname: Sanfilippo
authors.forename: Veronica
authors.initials: V
authors.lastname: Vella
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pandini
authors.forename: Paolo
authors.initials: P
authors.lastname: Vigneri
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Nicolosi
authors.forename: Fiorenza
authors.initials: F
authors.lastname: Gianì
authors.forename: Riccardo
authors.initials: R
authors.lastname: Vigneri
authors.forename: Francesco
authors.initials: F
authors.lastname: Frasca
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D017209:Apoptosis; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D016158:Genes, p53; D006801:Humans; D008565:Membrane Proteins / Q000494:pharmacology*; D051379:Mice; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D009687:Nuclear Proteins / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000235:genetics*; D014162:Transfection; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C446290:PRIMA1 protein, human; C000606460:TP73 protein, human; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins