Browsing by Subject "P53"

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  • Laine, Anni; Nagelli, Srikar G.; Farrington, Caroline; Butt, Umar; Cvrljevic, Anna N.; Vainonen, Julia P.; Feringa, Femke M.; Gronroos, Tove J.; Gautam, Prson; Khan, Sofia; Sihto, Harri; Qiao, Xi; Pavic, Karolina; Connolly, Denise C.; Kronqvist, Pauliina; Elo, Laura L.; Maurer, Jochen; Wennerberg, Krister; Medema, Rene H.; Joensuu, Heikki; Peuhu, Emilia; de Visser, Karin; Narla, Goutham; Westermarck, Jukka (2021)
    Basal-like breast cancers (BLBC) are characterized by defects in homologous recombination (HR), deficient mitotic checkpoint, and high-proliferation activity. Here, we discover CIP2A as a candidate driver of BLBC. CIP2A was essential for DNA damage-induced initiation of mouse BLBC-like mammary tumors and for survival of HR-defective BLBC cells. CIP2A was dispensable for normal mammary gland development and for unperturbed mitosis, but selectively essential for mitotic progression of DNA damaged cells. A direct interaction between CIP2A and a DNA repair scaffold protein TopBP1 was identified, and CIP2A inhibition resulted in enhanced DNA damage-induced TopBP1 and RAD51 recruitment to chromatin in mammary epithelial cells. In addition to its role in tumor initiation, and survival of BRCA-deficient cells, CIP2A also drove proliferative MYC and E2F1 signaling in basal-like triple-negative breast cancer (BL-TNBC) cells. Clinically, high CIP2A expression was associated with poor patient prognosis in BL-TNBCs but not in other breast cancer subtypes. Small-molecule reactivators of PP2A (SMAP) inhibited CIP2A transcription, phenocopied the CIP2A-deficient DNA damage response (DDR), and inhibited growth of patient-derived BLBC xenograft. In summary, these results demonstrate that CIP2A directly interacts with TopBP1 and coordinates DNAdamage-induced mitotic checkpoint and proliferation, thereby driving BLBC initiation and progression. SMAPs could serve as a surrogate therapeutic strategy to inhibit the oncogenic activity of CIP2A in BLBCs. Significance: These results identify CIP2A as a nongenetic driver and therapeutic target in basal-like breast cancer that regulates DNA damage-induced G2-M checkpoint and proliferative signaling.
  • Bauleth-Ramos, Tomás; Feijão, Tália; Gonçalves, André; Shahbazi, Mohammad-Ali; Liu, Zehua; Barrias, Cristina; Oliveira, Maria Jose; L. Granja, Pedro; Santos, Hélder A.; Sarmento, Bruno (2020)
    Colorectal cancer (CRC) is the third most common and the second deadliest type of cancer worldwide, urging the development of more comprehensive models and of more efficient treatments. Although the combination of nanotechnology with chemo- and immuno-therapy has represented a promising treatment approach, its translation to the clinic has been hampered by the absence of cellular models that can provide reliable and predictive knowledge about the in vivo efficiency of the formulation. Herein, a 3D model based on CRC multicellular tumor spheroids (MCTS) model was developed by combining epithelial colon cancer cells (HCT116), human intestinal fibroblasts and monocytes. The developed MCTS 3D model mimicked several tumor features with cells undergoing spatial organization and producing extracellular matrix, forming a mass of tissue with a necrotic core. Furthermore, monocytes were differentiated into macrophages with an anti-inflammatory, pro-tumor M2-like phenotype. For a combined chemoimmunotherapy effect, spermine-modified acetalated dextran nanoparticles (NPs) loaded with the chemotherapeutic Nutlin-3a (Nut3a) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were produced and tested in 2D cultures and in the MCTS 3D model. NPs were successfully taken-up by the cells in 2D, but in a significant less extent in the 3D model. However, these NPs were able to induce an anti-proliferative effect both in the 2D and in the 3D models. Moreover, Nut3a was able to partially shift the polarization of the macrophages present in the MCTS 3D model towards an anti-tumor M1-like phenotype. Overall, the developed MCTS 3D model showed to recapitulate key features of tumors, while representing a valuable model to assess the effect of combinatorial nano-therapeutic strategies in CRC. In addition, the developed NPs could represent a promising approach for CRC treatment.
  • Trokovic, Ras; Weltner, Jere; Noisa, Parinya; Raivio, Taneli; Otonkoski, Timo (2015)
    Somatic cells can be reprogrammed into induced pluripotent stem cells (iPSC) by the forced expression of the transcription factors OCT4, SOX2, KLF4 and c-MYC. Pluripotent reprogramming appears as a slow and inefficient process because of genetic and epigenetic barriers of somatic cells. In this report, we have extended previous observations concerning donor age and passage number of human fibroblasts as critical determinants of the efficiency of iPSC induction. Human fibroblasts from 11 different donors of variable age were reprogrammed by ectopic expression of reprogramming factors. Although all fibroblasts gave rise to iPSC colonies, the reprogramming efficiency correlated negatively and declined rapidly with increasing donor age. In addition, the late passage fibroblasts gave less reprogrammed colonies than the early passage cell counterparts, a finding associated with the cellular senescence-induced upregulation of p21. Knockdown of p21 restored iPSC generation even in long-term passaged fibroblasts of an old donor, highlighting the central role of the p53/p21 pathway in cellular senescence induced by both donor age and culture time. (C) 2015 The Authors. Published by Elsevier B.V.
  • Karinen, Sirkku; Heikkinen, Tuomas; Nevanlinna, Heli; Hautaniemi, Sampsa (2011)
  • Cascone, Annunziata; Bruelle, Celine; Lindholm, Dan; Bernardi, Paolo; Eriksson-Rosenberg, Ove (2012)
  • Makinen, Netta; Aavikko, Mervi; Heikkinen, Tuomas; Taipale, Minna; Taipale, Jussi; Koivisto-Korander, Riitta; Butzow, Ralf; Vahteristo, Pia (2016)
    Uterine leiomyosarcomas (ULMSs) are aggressive smooth muscle tumors associated with poor clinical outcome. Despite previous cytogenetic and molecular studies, their molecular background has remained elusive. To examine somatic variation in ULMS, we performed exome sequencing on 19 tumors. Altogether, 43 genes were mutated in at least two ULMSs. Most frequently mutated genes included tumor protein P53 (TP53; 6/19; 33%), alpha thalassemia/mental retardation syndrome X-linked (ATRX; 5/19; 26%), and mediator complex subunit 12 (MED12; 4/19; 21%). Unlike ATRX mutations, both TP53 and MED12 alterations have repeatedly been associated with ULMSs. All the observed ATRX alterations were either nonsense or frameshift mutations. ATRX protein levels were reliably analyzed by immunohistochemistry in altogether 44 ULMSs, and the majority of tumors (23/44; 52%) showed clearly reduced expression. Loss of ATRX expression has been associated with alternative lengthening of telomeres (ALT), and thus the telomere length was analyzed with telomere-specific fluorescence in situ hybridization. The ALT phenotype was confirmed in all ULMSs showing diminished ATRX expression. Exome data also revealed one nonsense mutation in death-domain associated protein (DAXX), another gene previously associated with ALT, and the tumor showed ALT positivity. In conclusion, exome sequencing revealed that TP53, ATRX, and MED12 are frequently mutated in ULMSs. ALT phenotype was commonly seen in tumors, indicating that ATR inhibitors, which were recently suggested as possible new drugs for ATRX-deficient tumors, could provide a potential novel therapeutic option for ULMS.
  • Maki-Nevala, Satu; Sarhadi, Virinder Kaur; Ronty, Mikko; Kettunen, Eeva; Husgafvel-Pursiainen, Kirsti; Wolff, Henrik; Knuuttila, Aija; Knuutila, Sakari (2016)
    Objectives: Non-small cell lung cancer (NSCLC) is a common cancer with a poor prognosis. The aim of this study was to screen Finnish NSCLC tumor samples for common cancer-related mutations by targeted next generation sequencing and to determine their concurrences and associations with clinical features. Materials and methods: Sequencing libraries were prepared from DNA isolated from formalin-fixed, paraffin-embedded tumor material of 425 patients using the AmpliSeq Colon and Lung panel covering mutational hot spot regions of 22 cancer genes. Sequencing was performed with the Ion Torrent Personal Genome Machine (PGM). Results: Data analysis of the hot spot mutations revealed mutations in 77% of the patients, with 7% having 3 or more mutations reported in the Catalogue of Somatic Mutations in Cancer (COSMIC) database. Two of the most frequently mutated genes were TP53 (46%) and KRAS (25%). KRAS codon 12 mutations were the most recurrently occurring mutations. EGFR mutations were significantly associated with adenocarcinoma, female gender and never/light-smoking history; CTNNB1 mutations with light ex-smokers, PlIC3CA and TP53 mutations with squamous cell carcinoma, and KRAS with adenocarcinoma. TP53 mutations were most prevalent in current smokers and ERBB2, ERBB4, PIK3CA, NRAS, NOTCH1, FBWX7, PTEN and STK11 mutations occurred exclusively in a group of ever-smokers, however the association was not statistically significant. No mutation was found that associated with asbestos exposure. Conclusion: Finnish NSCLC patients have a similar mutation profile as other Western patients, however with a higher frequency of BRAF mutations but a lower frequency of STK11 and ERBB2 mutations. Moreover, TP53 mutations occurred frequently with other gene mutations, most commonly with KRAS, MET, EGFR and PIK3CA mutations. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
  • Louhimo, Riku; Laakso, Marko; Heikkinen, Tuomas; Laitinen, Susanna; Manninen, Pekka; Rogojin, Vladimir; Miettinen, Minna; Blomqvist, Carl; Liu, Jianjun; Nevanlinna, Heli; Hautaniemi, Sampsa (2013)
  • Long, Maeve; McWilliams, Thomas G. (2020)
    Autophagy refers to an essential mechanism that evolved to sustain eukaryotic homeostasis and metabolism during instances of nutrient deprivation. During autophagy, intracellular cargo is encapsulated and delivered to the lysosome for elimination. Loss of basal autophagy in vivo negatively impacts cellular proteostasis, metabolism and tissue integrity. Accordingly, many drug development strategies are focused on modulating autophagic capacity in various pathophysiological states, from cancer to neurodegenerative disease. The role of autophagy in cancer is particularly complicated, as either augmenting or attenuating this process can have variable outcomes on cellular survival, proliferation and transformation. This complexity is compounded by the emergence of several selective autophagy pathways, which act to eliminate damaged or superfluous cellular components in a targeted fashion. The advent of sensitive tools to monitor autophagy pathways in vivo holds promise to clarify their importance in cancer pathophysiology. In this review, we provide an overview of autophagy in cancer biology and outline how the development of tools to study autophagy in vivo could enhance our understanding of its function for translational benefit.
  • Martin-Lopez, Marta; Maeso-Alonso, Laura; Fuertes-Alvarez, Sandra; Balboa, Diego; Rodriguez-Cortez, Virginia; Weltner, Jere; Diez-Prieto, Inmaculada; Davis, Andrew; Wu, Yaning; Otonkoski, Timo; Flores, Elsa R.; Menendez, Pablo; Marques, Margarita M.; Marin, Maria C. (2017)
    The generation of induced pluripotent stem cells (iPSCs) by somatic cell reprogramming holds great potential for modeling human diseases. However, the reprogramming process remains very inefficient and a better understanding of its basic biology is required. The mesenchymal-to-epithelial transition (MET) has been recognized as a crucial step for the successful reprogramming of fibroblasts into iPSCs. It has been reported that the p53 tumor suppressor gene acts as a barrier of this process, while its homolog p63 acts as an enabling factor. In this regard, the information concerning the role of the third homolog, p73, during cell reprogramming is limited. Here, we derive total Trp73 knockout mouse embryonic fibroblasts, with or without Trp53, and examine their reprogramming capacity. We show that p73 is required for effective reprogramming by the Yamanaka factors, even in the absence of p53. Lack of p73 affects the early stages of reprogramming, impairing the MET and resulting in altered maturation and stabilization phases. Accordingly, the obtained p73-deficient iPSCs have a defective epithelial phenotype and alterations in the expression of pluripotency markers. We demonstrate that p73 deficiency impairs the MET, at least in part, by hindering BMP pathway activation. We report that p73 is a positive modulator of the BMP circuit, enhancing its activation by DNp73 repression of the Smad6 promoter. Collectively, these findings provide mechanistic insight into the MET process, proposing p73 as an enhancer of MET during cellular reprogramming.
  • Almangush, Alhadi; Heikkinen, Ilkka; Mäkitie, Antti A.; Coletta, Ricardo D.; Läärä, Esa; Leivo, Ilmo; Salo, Tuula (2017)
    Background: Identifying informative prognostic biomarkers for oral tongue squamous cell carcinoma (OTSCC) is of great importance in order to better predict tumour behaviour and to guide treatment planning. Here, we summarise existing evidence regarding immunohistochemical prognostic biomarkers for OTSCC. Methods: A systematic search of the literature was performed using the databases of Scopus, Ovid Medline, Web of Science and Cochrane Library. All studies which had investigated the prognostic significance of immunohistochemical biomarkers in OTSCC during the period from 1985 to 2015 were retrieved. For the five most often evaluated biomarkers a random-effects meta-analysis on overall survival was performed, including those studies that provided the necessary statistical results. Results: A total of 174 studies conducted during the last three decades were found, and in these 184 biomarkers were evaluated for the prognostication of OTSCC. The five biomarkers most frequently assessed were p53, Ki-67, p16, VEGFs and cyclin D1. In the meta-analyses, the most promising results of the prognostic power for OTSCC were obtained for cyclin D1. For studies of VEGF A and C the results were equivocal, but the pooled analysis of VEGF A separately showed it to be a useful prognosticator for OTSCC. There was no sufficient evidence to support p53, Ki-67 and p16 as prognostic biomarkers for OTSCC. Limitations in the quality of the published studies (e.g., small cohorts, lack of compliance with REMARK guidelines) are widespread. Conclusions: Numerous biomarkers have been presented as useful prognosticators for OTSCC, but the quality of the conduct and reporting of original studies is overall unsatisfactory which does not allow reliable conclusions. The value of two biomarkers (VEGFA and cyclin D1) should be validated in a multicentre study setting following REMARK guidelines.
  • Moore, Henna M.; Bai, Baoyan; Matilainen, Olli; Colis, Laureen; Peltonen, Karita; Laiho, Marikki (2013)
  • Liu, Wei; Lu, Xiangyi; He, Guangyang; Gao, Xiang; Xu, Maonian; Zhang, Jingkai; Li, Meiling; Wang, Lifeng; Li, Zhenjing; Wang, Likui; Luo, Cheng (2013)
  • Wei, Ting; Najmi, Saman M.; Liu, Hester; Peltonen, Karita; Kucerova, Alena; Schneider, David A.; Laiho, Marikki (2018)
    Summary Inhibition of RNA polymerase I (Pol I) is a promising strategy for modern cancer therapy. BMH-21 is a first-in-class small molecule that inhibits Pol I transcription and induces degradation of the enzyme, but how this exceptional response is enforced is not known. Here, we define key elements requisite for the response. We show that Pol I preinitiation factors and polymerase subunits (e.g., RPA135) are required for BMH-21-mediated degradation of RPA194. We further find that Pol I inhibition and induced degradation by BMH-21 are conserved in yeast. Genetic analyses demonstrate that mutations that induce transcription elongation defects in Pol I result in hypersensitivity to BMH-21. Using a fully reconstituted Pol I transcription assay, we show that BMH-21 directly impairs transcription elongation by Pol I, resulting in long-lived polymerase pausing. These studies define a conserved regulatory checkpoint that monitors Pol I transcription and is activated by therapeutic intervention.
  • Ou, Hui-Ling; Kim, Christine S.; Uszkoreit, Simon; Wickström, Sara A.; Schumacher, Björn (2019)
    Genome integrity in primordial germ cells (PGCs) is a prerequisite for fertility and species maintenance. In C. elegans, PGCs require global-genome nucleotide excision repair (GG-NER) to remove UV-induced DNA lesions. Failure to remove the lesions leads to the activation of the C. elegans p53, CEP-1, resulting in mitotic arrest of the PGCs. We show that the eIF4E2 translation initiation factor IFE-4 in somatic gonad precursor (SGP) niche cells regulates the CEP-1/p53-mediated DNA damage response (DDR) in PGCs. We determine that the IFE-4 translation target EGL-15/FGFR regulates the non-cell-autonomous DDR that is mediated via FGF-like signaling. Using hair follicle stem cells as a paradigm, we demonstrate that the eIF4E2-mediated niche cell regulation of the p53 response in stem cells is highly conserved in mammals. We thus reveal that the somatic niche regulates the CEP-1/p53-mediated DNA damage checkpoint in PGCs. Our data suggest that the somatic niche impacts the stability of heritable genomes.
  • Murtola, Teemu J.; Visvanathan, Kala; Artama, Miia; Vainio, Harri; Pukkala, Eero (2014)
  • Demyanenko, Svetlana; Sharifulina, Svetlana (2021)
    Histone deacetylase (HDAC) and histone acetyltransferase (HAT) regulate transcription and the most important functions of cells by acetylating/deacetylating histones and non-histone proteins. These proteins are involved in cell survival and death, replication, DNA repair, the cell cycle, and cell responses to stress and aging. HDAC/HAT balance in cells affects gene expression and cell signaling. There are very few studies on the effects of stroke on non-histone protein acetylation/deacetylation in brain cells. HDAC inhibitors have been shown to be effective in protecting the brain from ischemic damage. However, the role of different HDAC isoforms in the survival and death of brain cells after stroke is still controversial. HAT/HDAC activity depends on the acetylation site and the acetylation/deacetylation of the main proteins (c-Myc, E2F1, p53, ERK1/2, Akt) considered in this review, that are involved in the regulation of cell fate decisions. Our review aims to analyze the possible role of the acetylation/deacetylation of transcription factors and signaling proteins involved in the regulation of survival and death in cerebral ischemia.
  • Munne, Pauliina M.; Gu, Yuexi; Tumiati, Manuela; Gao, Ping; Koopal, Sonja; Uusivirta, Sanna; Sawicki, Janet; Wei, Gong-Hong; Kuznetsov, Sergey G. (2014)