| 1. |
- Bersani, Cinzia, et al.
(författare)
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Genome-wide identification of Wig-1 mRNA targets by RIP-Seq analysis
- 2016
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Ingår i: Oncotarget. - : Impact Journals LLC. - 1949-2553. ; 7:2, s. 1895-1911
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Tidskriftsartikel (refereegranskat)abstract
- RNA-binding proteins (RBPs) play important roles in the regulation of gene expression through a variety of post-transcriptional mechanisms. The p53-induced RBP Wig-1 (Zmat3) binds RNA through its zinc finger domains and enhances stability of p53 and N-Myc mRNAs and decreases stability of FAS mRNA. To identify novel Wig-1-bound RNAs, we performed RNA-immunoprecipitation followed by high-throughput sequencing (RIP-Seq) in HCT116 and Saos-2 cells. We identified 286 Wig-1-bound mRNAs common between the two cell lines. Sequence analysis revealed that AU-rich elements (AREs) are highly enriched in the 3'UTR of these Wig-1-bound mRNAs. Network enrichment analysis showed that Wig-1 preferentially binds mRNAs involved in cell cycle regulation. Moreover, we identified a 2D Wig-1 binding motif in HIF1A mRNA. Our findings confirm that Wig-1 is an ARE-BP that regulates cell cycle-related processes and provide a novel view of how Wig-1 may bind mRNA through a putative structural motif. We also significantly extend the repertoire of Wig-1 target mRNAs. Since Wig-1 is a transcriptional target of the tumor suppressor p53, these results have implications for our understanding of p53-dependent stress responses and tumor suppression.
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| 2. |
- Doffe, Flora, et al.
(författare)
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Identification and functional characterization of new missense SNPs in the coding region of the TP53 gene
- 2021
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Ingår i: Cell Death and Differentiation. - : Springer Science and Business Media LLC. - 1350-9047 .- 1476-5403. ; 28:5, s. 1477-1492
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Tidskriftsartikel (refereegranskat)abstract
- Infrequent and rare genetic variants in the human population vastly outnumber common ones. Although they may contribute significantly to the genetic basis of a disease, these seldom-encountered variants may also be miss-identified as pathogenic if no correct references are available. Somatic and germline TP53 variants are associated with multiple neoplastic diseases, and thus have come to serve as a paradigm for genetic analyses in this setting. We searched 14 independent, globally distributed datasets and recovered TP53 SNPs from 202,767 cancer-free individuals. In our analyses, 19 new missense TP53 SNPs, including five novel variants specific to the Asian population, were recurrently identified in multiple datasets. Using a combination of in silico, functional, structural, and genetic approaches, we showed that none of these variants displayed loss of function compared to the normal TP53 gene. In addition, classification using ACMG criteria suggested that they are all benign. Considered together, our data reveal that the TP53 coding region shows far more polymorphism than previously thought and present high ethnic diversity. They furthermore underline the importance of correctly assessing novel variants in all variant-calling pipelines associated with genetic diagnoses for cancer.
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| 3. |
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| 4. |
- Kharaziha, Pedram, et al.
(författare)
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Functional characterization of novel germline TP53 variants in Swedish families
- 2019
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Ingår i: Clinical Genetics. - : Wiley. - 0009-9163 .- 1399-0004. ; 96:3, s. 216-225
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Tidskriftsartikel (refereegranskat)abstract
- Pathogenic germline TP53 variants predispose to a wide range of early onset cancers, often recognized as the Li-Fraumeni syndrome (LFS). They are also identified in 1% of families with hereditary breast cancer (HrBC) that do not fulfill the criteria for LFS. In this study, we present a total of 24 different TP53 variants identified in 31 Swedish families with LFS or HrBC. Ten of these variants, nine exonic and one splice, have previously not been described as germline pathogenic variants. The nine exonic variants were functionally characterized and demonstrated partial transactivation activity compared to wild-type p53. Some show nuclear localization similar to wild-type p53 while others possess cytoplasmic or perinuclear localization. The four frameshift variants (W91Gfs*32, L111 Wfs*12, S227 Lfs*20 and S240Kfs*25) had negligible, while F134 L and T231del had low level of p53 activity. The L111 Wfs*12 and T231del variants are also deficient for induction of apoptosis. The missense variant R110C retain p53 effects and the nonsense E349* shows at least partial transcription factor activity but has reduced ability to trigger apoptosis. This is the first functional characterization of novel germline TP53 pathogenic or likely pathogenic variants in the Swedish cohort as an attempt to understand its association with LFS and HrBC, respectively.
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| 5. |
- Lehmann, Sören, et al.
(författare)
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Targeting p53 in Vivo : a First-in-Human Study With p53-Targeting Compound APR-246 in Refractory Hematologic Malignancies and Prostate Cancer
- 2012
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Ingår i: Journal of Clinical Oncology. - 0732-183X .- 1527-7755. ; 30:29, s. 3633-3639
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSEAPR-246 (PRIMA-1MET) is a novel drug that restores transcriptional activity of unfolded wild-type or mutant p53. The main aims of this first-in-human trial were to determine maximum-tolerated dose (MTD), safety, dose-limiting toxicities (DLTs), and pharmacokinetics (PK) of APR-246.PATIENTS AND METHODSAPR-246 was administered as a 2-hour intravenous infusion once per day for 4 consecutive days in 22 patients with hematologic malignancies and prostate cancer. Acute myeloid leukemia (AML; n = 7) and prostate cancer (n = 7) were the most frequent diagnoses. Starting dose was 2 mg/kg with dose escalations up to 90 mg/kg.RESULTSMTD was defined as 60 mg/kg. The drug was well tolerated, and the most common adverse effects were fatigue, dizziness, headache, and confusion. DLTs were increased ALT/AST (n = 1), dizziness, confusion, and sensory disturbances (n = 2). PK showed little interindividual variation and were neither dose nor time dependent; terminal half-life was 4 to 5 hours. Tumor cells showed cell cycle arrest, increased apoptosis, and upregulation of p53 target genes in several patients. Global gene expression analysis revealed changes in genes regulating proliferation and cell death. One patient with AML who had a p53 core domain mutation showed a reduction of blast percentage from 46% to 26% in the bone marrow, and one patient with non-Hodgkin's lymphoma with a p53 splice site mutation showed a minor response.CONCLUSION We conclude that APR-246 is safe at predicted therapeutic plasma levels, shows a favorable pharmacokinetic profile, and can induce p53-dependent biologic effects in tumor cells in vivo.
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| 6. |
- Mahmoudi, Salah, et al.
(författare)
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WRAP53 Is Essential for Cajal Body Formation and for Targeting the Survival of Motor Neuron Complex to Cajal Bodies
- 2010
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Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 8:11, s. e1000521-
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Tidskriftsartikel (refereegranskat)abstract
- The WRAP53 gene gives rise to a p53 antisense transcript that regulates p53. This gene also encodes a protein that directs small Cajal body-specific RNAs to Cajal bodies. Cajal bodies are nuclear organelles involved in diverse functions such as processing ribonucleoproteins important for splicing. Here we identify the WRAP53 protein as an essential factor for Cajal body maintenance and for directing the survival of motor neuron (SMN) complex to Cajal bodies. By RNA interference and immunofluorescence we show that Cajal bodies collapse without WRAP53 and that new Cajal bodies cannot be formed. By immunoprecipitation we find that WRAP53 associates with the Cajal body marker coilin, the splicing regulatory protein SMN, and the nuclear import receptor importin beta, and that WRAP53 is essential for complex formation between SMN-coilin and SMN-importin beta. Furthermore, depletion of WRAP53 leads to accumulation of SMN in the cytoplasm and prevents the SMN complex from reaching Cajal bodies. Thus, WRAP53 mediates the interaction between SMN and associated proteins, which is important for nuclear targeting of SMN and the subsequent localization of the SMN complex to Cajal bodies. Moreover, we detect reduced WRAP53-SMN binding in patients with spinal muscular atrophy, which is the leading genetic cause of infant mortality worldwide, caused by mutations in SMN1. This suggests that loss of WRAP53-mediated SMN trafficking contributes to spinal muscular atrophy.
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| 7. |
- Paul, Esbjörn, et al.
(författare)
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Low p14ARF expression in de novo acute myeloid leukemia with normal karyotype is associated with poor survival
- 2009
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Ingår i: Leukemia and Lymphoma. - : Informa UK Limited. - 1042-8194 .- 1029-2403. ; 50:9, s. 1512-1518
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Tidskriftsartikel (refereegranskat)abstract
- The p14ARF protein activates the p53 tumor suppressor by binding to and inhibiting its negative regulator HDM-2. We have studied the prognostic impact of p14ARF in acute myeloid leukemia (AML). Leukemic cells from 57 adult patients with normal karyotype de novo AML were analyzed for p14ARF mRNA expression level using real-time polymerase chain reaction (RT-PCR). We also tested the effect of conventional anti-leukemic drugs and the mutant p53-targeting small molecule PRIMA-1 in vitro. Patients whose cells expressed more p14ARF mRNA than the 75th percentile (0.26) had significantly better survival compared with those expressing lower levels, 61 vs. 30% 3-year survival (p = 0.046). The difference remained significant also when NPM1/FLT3 status was considered. The mean effects of all the tested conventional anti-leukemic drugs were greater in leukemic cell samples expressing p14ARF mRNA >or= 0.26, but the differences were not statistically significant. In contrast, PRIMA-1 had a significantly greater effect on leukemic cell samples with low levels of p14ARF mRNA. We conclude that low levels of p14ARF mRNA in leukemic cells from patients with normal karyotype AML is associated with poor prognosis. Treatment with drugs targeting p53 may be a future possibility to improve outcome for these patients.
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| 8. |
- Punga, Tanel, 1974-
(författare)
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The Interaction of the Adenovirus E1B-55K Protein with a Histone Deacetylase Complex: Its Importance in Regulation of P53 Protein Functions
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The human tumour suppressor protein p53 is an effective inhibitor of cell growth, by inducing cell cycle arrest and apoptosis. However, p53-induced cell growth inhibition can be detrimental for virus multiplication. Therefore, viruses encode for proteins, which can interfere with the functions of the p53 protein. Human adenoviruses encode for a transcription repressor protein named E1B-55K, which inhibits the activity of the p53 protein during a lytic adenovirus infection.In this thesis, we have studied the biochemical characteristics of the E1B-55K protein and how the E1B-55K protein interferes with the function of p53 as a transcription factor.Our data show that the E1B-55K protein interacts with the Sin3 co-repressor complex in adenovirus transformed and in adenovirus infected cells. Furthermore, the E1B-55K protein recruites a histone deacetylase activity, indicating that the E1B-55K protein is associated with a functional chromatin modifying complex. We also show that in addition to repressing p53-activated transcription, E1B-55K could also relieve p53-mediated repression of the survivin and Map4 promoters.Previous results have shown that E1B-55K inhibits p53 as a transcriptional activator of the p21/CDKN1A promoter. Here we show that the E1B-55K protein prevents p53 from inducing histone H3 and H4 acetylation on p21/CDKN1A promoter, which coincided with the inhibition of p21/CDKN1A protein expression. Notably, the Sin3 complex was detected in the vicinity of the p53 binding site on the p21/CDKN1A promoter, suggesting that the E1B-55K protein blocked p53-mediated histone acetylation by recruitment of a histone deacetylase activity. Inhibition of p21/CDKN1A protein expression might be the reason, why the E1B-55K protein alleviates p53-dependent transcriptional repression of the survivin promoter. Finally, we show that oligomerisation of the E1B-55K protein is important for the defined subcellular localization of the protein and for its function as a repressor of p53-activated transcription.
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| 9. |
- Rahman-Roblick, Rubaiyat, et al.
(författare)
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p53 targets identified by protein expression profiling
- 2007
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 104:13, s. 5401-5406
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Tidskriftsartikel (refereegranskat)abstract
- p53 triggers cell cycle arrest and apoptosis through transcriptional regulation of specific target genes. We have investigated the effect of p53 activation on the proteome using 2D gel electrophoresis analysis of mitomycin C-treated HCT116 colon carcinoma cells carrying wild-type p53. Approximately 5,800 protein spots were separated in overlapping narrow-pH-range gel strips, and 115 protein spots showed significant expression changes upon p53 activation. The identity of 55 protein spots was obtained by mass spectrometry. The majority of the identified proteins have no previous connection to p53. The proteins fall into different functional categories, such as mRNA processing, translation, redox regulation, and apoptosis, consistent with the idea that p53 regulates multiple cellular pathways. p53-dependent regulation of five of the up-regulated proteins, eIF5A, hnRNP C1/C2, hnRNP K, lamin A/C, and Nm23-H1, and two of the down-regulated proteins, Prx II and TrpRS, was examined in further detail. Analysis of mRNA expression levels demonstrated both transcription-dependent and transcription-independent regulation among the identified targets. Thus, this study reveals protein targets of p53 and highlights the role of transcription-independent effects for the p53-induced biological response.
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| 10. |
- Zhang, Qiang, et al.
(författare)
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Evolutionary history of the p53 family DNA-binding domain : insights from an Alvinella pompejana homolog
- 2022
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Ingår i: Cell Death and Disease. - : Springer Nature. - 2041-4889. ; 13:3
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Tidskriftsartikel (refereegranskat)abstract
- The extremophile Alvinella pompejana, an annelid worm living on the edge of hydrothermal vents in the Pacific Ocean, is an excellent model system for studying factors that govern protein stability. Low intrinsic stability is a crucial factor for the susceptibility of the transcription factor p53 to inactivating mutations in human cancer. Understanding its molecular basis may facilitate the design of novel therapeutic strategies targeting mutant p53. By analyzing expressed sequence tag (EST) data, we discovered a p53 family gene in A. pompejana. Protein crystallography and biophysical studies showed that it has a p53/p63-like DNA-binding domain (DBD) that is more thermostable than all vertebrate p53 DBDs tested so far, but not as stable as that of human p63. We also identified features associated with its increased thermostability. In addition, the A. pompejana homolog shares DNA-binding properties with human p53 family DBDs, despite its evolutionary distance, consistent with a potential role in maintaining genome integrity. Through extensive structural and phylogenetic analyses, we could further trace key evolutionary events that shaped the structure, stability, and function of the p53 family DBD over time, leading to a potent but vulnerable tumor suppressor in humans.
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