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Project description:The tumor suppressor gene TP53 is mutated in approximately half of all human tumors. Of those, around 10% are nonsense mutations that produce truncated and inactive p53 protein. Induction of translational readthrough is a promising approach for rescuing full-length p53 and thereby eliminate tumor cells with nonsense mutant TP53. To find novel nonsense mutant TP53 readthrough-inducing compounds with a tolerable toxicity profile, we performed an in silico screening of data at the National Cancer Institute database and identified 5-Fluorouracil (5-FU). We show here that 5-FU induces full-length p53 in human tumor cells carrying R213X nonsense mutant TP53 and that this activity is mediated by its metabolite 5-Fluorouridine (FUr). Ribo-seq analysis validated induction of translational readthrough by FUr. We also show that FUr is incorporated into RNA where it potentially allows base pairing of Arg tRNA at the R213X UGA premature termination codon. Full-length p53 rescued by FUr is transcriptionally active and triggers p53-dependent cell death. Moreover, treatment with 5-FU or FUr restores full-length p53 expression in TP53 R213X mutant human tumor xenografts in vivo. Our results suggest that induction of readthrough by 5-FU/FUr could contribute to therapeutic efficacy in patients with TP53 nonsense mutant tumors.
2022-12-01 | GSE196709 | GEO
Project description:The tumor suppressor gene TP53 is mutated in approximately half of all human tumors. Of those, around 10% are nonsense mutations that produce truncated and inactive p53 protein. Induction of translational readthrough is a promising approach for rescuing full-length p53 and thereby eliminate tumor cells with nonsense mutant TP53. To find novel nonsense mutant TP53 readthrough-inducing compounds with a tolerable toxicity profile, we performed an in silico screening of data at the National Cancer Institute database and identified 5-Fluorouracil (5-FU). We show here that 5-FU induces full-length p53 in human tumor cells carrying R213X nonsense mutant TP53 and that this activity is mediated by its metabolite 5-Fluorouridine (FUr). Ribo-seq analysis validated induction of translational readthrough by FUr. We also show that FUr is incorporated into RNA where it potentially allows base pairing of Arg tRNA at the R213X UGA premature termination codon. Full-length p53 rescued by FUr is transcriptionally active and triggers p53-dependent cell death. Moreover, treatment with 5-FU or FUr restores full-length p53 expression in TP53 R213X mutant human tumor xenografts in vivo. Our results suggest that induction of readthrough by 5-FU/FUr could contribute to therapeutic efficacy in patients with TP53 nonsense mutant tumors.
2022-12-01 | GSE196710 | GEO
Project description:5-Fluorouridine restores functional full-length p53 in TP53 nonsense mutant human tumor cells
| PRJNA806945 | ENA
Project description:5-Fluorouridine restores functional full-length p53 in TP53 nonsense mutant human tumor cells (Ribo-Seq)
| PRJNA806946 | ENA
Project description:5-Fluorouridine restores functional full-length p53 in TP53 nonsense mutant human tumor cells (RNA-Seq)
| PRJNA806948 | ENA
Project description:BackgroundThe mechanisms that can restore biological activity of mutant p53 are an area of high interest given that mutant p53 expression is observed in one third of prostate cancer. Here we demonstrate that Id4, an HLH transcriptional regulator and a tumor suppressor, can restore the mutant p53 transcriptional activity in prostate cancer cells.MethodsId4 was over-expressed in prostate cancer cell line DU145 harboring mutant p53 (P223L and V274F) and silenced in LNCaP cells with wild type p53. The cells were used to quantitate apoptosis, p53 localization, p53 DNA binding and transcriptional activity. Immuno-precipitation/-blot studies were performed to demonstrate interactions between Id4, p53 and CBP/p300 and acetylation of specific lysine residues within p53.ResultsEctopic expression of Id4 in DU145 cells resulted in increased apoptosis and expression of BAX, PUMA and p21, the transcriptional targets of p53. Mutant p53 gained DNA binding and transcriptional activity in the presence of Id4 in DU145 cells. Conversely, loss of Id4 in LNCaP cells abrogated wild type p53 DNA binding and transactivation potential. Gain of Id4 resulted in increased acetylation of mutant p53 whereas loss of Id4 lead to decreased acetylation in DU145 and LNCaP cells respectively. Id4 dependent acetylation of p53 was in part due to a physical interaction between Id4, p53 and acetyl-transferase CBP/p300.ConclusionsTaken together, our results suggest that Id4 regulates the activity of wild type and mutant p53. Id4 promoted the assembly of a macromolecular complex involving CBP/P300 that resulted in acetylation of p53 at K373, a critical post-translational modification required for its biological activity.
| S-EPMC3866570 | biostudies-literature
Project description:The tumor suppressor gene TP53 is inactivated by mutation in a large fraction of human tumors. Around 10% of TP53 mutations are nonsense mutations that lead to premature termination of translation and expression of truncated unstable and non-functional p53 protein. Aminoglycosides G418 (geneticin) and gentamicin have been shown to induce translational readthrough and expression of full-length p53. However, aminoglycosides have severe side effects that limit their clinical use. Here, we show that combination treatment with a proteasome inhibitor or compounds that disrupt p53-Mdm2 binding can synergistically enhance levels of full-length p53 upon aminoglycoside-induced readthrough of R213X nonsense mutant p53. Full-length p53 expressed upon combination treatment is functionally active as assessed by upregulation of p53 target genes, suppression of cell growth, and induction of cell death. Thus, our results demonstrate that combination treatment with aminoglycosides and compounds that inhibit p53 degradation is synergistic and can provide significantly improved efficacy of readthrough when compared with aminoglycosides alone. This may have implications for future cancer therapy based on reactivation of nonsense mutant TP53.
| S-EPMC5758538 | biostudies-literature
Project description:TP53 nonsense mutations in cancer produce truncated inactive p53 protein. We show that 5-FU metabolite 5-Fluorouridine (FUr) induces full-length p53 in human tumor cells carrying R213X nonsense mutant TP53. Ribosome profiling visualized translational readthrough at the R213X premature stop codon and demonstrated that FUr-induced readthrough is less permissive for canonical stop codon readthrough compared to aminoglycoside G418. FUr is incorporated into mRNA and can potentially base-pair with guanine, allowing insertion of Arg tRNA at the TP53 R213X UGA premature stop codon and translation of full-length wild-type p53. We confirmed that full-length p53 rescued by FUr triggers tumor cell death by apoptosis. FUr also restored full-length p53 in TP53 R213X mutant human tumor xenografts in vivo. Thus, we demonstrate a novel strategy for therapeutic rescue of nonsense mutant TP53 and suggest that FUr should be explored for treatment of patients with TP53 nonsense mutant tumors.
| S-EPMC9700717 | biostudies-literature
Project description:Missense mutations in p53 are severely deleterious and occur in over 50% of all human cancers. The majority of these mutations are located in the inherently unstable DNA-binding domain (DBD), many of which destabilize the domain further and expose its aggregation-prone hydrophobic core, prompting self-assembly of mutant p53 into inactive cytosolic amyloid-like aggregates. Screening an oligopyridylamide library, previously shown to inhibit amyloid formation associated with Alzheimer's disease and type II diabetes, identified a tripyridylamide, ADH-6, that abrogates self-assembly of the aggregation-nucleating subdomain of mutant p53 DBD. Moreover, ADH-6 targets and dissociates mutant p53 aggregates in human cancer cells, which restores p53's transcriptional activity, leading to cell cycle arrest and apoptosis. Notably, ADH-6 treatment effectively shrinks xenografts harboring mutant p53, while exhibiting no toxicity to healthy tissue, thereby substantially prolonging survival. This study demonstrates the successful application of a bona fide small-molecule amyloid inhibitor as a potent anticancer agent.
| S-EPMC8233319 | biostudies-literature
Project description:The p53 protein is frequently mutated in a very large proportion of human tumors, where it seems to acquire gain-of-function activity that facilitates tumor onset and progression. A possible mechanism is the ability of mutant p53 proteins to physically interact with other proteins, including members of the same family, namely p63 and p73, inactivating their function. Assuming that this interaction might occurs at the level of the monomer, to investigate the molecular basis for this interaction, here, we sample the structural flexibility of the wild-type p53 monomeric protein. The results show a strong stability up to 850 ns in the DNA binding domain, with major flexibility in the N-terminal transactivations domains (TAD1 and TAD2) as well as in the C-terminal region (tetramerization domain). Several stable hydrogen bonds have been detected between N-terminal or C-terminal and DNA binding domain, and also between N-terminal and C-terminal. Essential dynamics analysis highlights strongly correlated movements involving TAD1 and the proline-rich region in the N-terminal domain, the tetramerization region in the C-terminal domain; Lys120 in the DNA binding region. The herein presented model is a starting point for further investigation of the whole protein tetramer as well as of its mutants.
| S-EPMC3875683 | biostudies-literature