Browsing by MeSH term "Tumor Suppressor Protein p53"
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Publication A cell-based screen identifies ATR inhibitors with synthetic lethal properties for cancer-associated mutations.(Nature Publishing Group, 2011-06) Toledo, Luis I; Murga, Matilde; Zur, Rafal; Soria, Rebeca; Rodriguez, Antonio; Martinez, Sonia; Oyarzabal, Julen; Pastor, Joaquin; Bischoff, James R; Fernandez-Capetillo, Oscar; European Molecular Biology Organization; Fundación Pfizer; Instituto de Salud Carlos III; Ministerio de Ciencia (España)Oncogene activation has been shown to generate replication-born DNA damage, also known as replicative stress. The primary responder to replicative stress is not Ataxia-Telangiectasia Mutated (ATM) but rather the kinase ATM and Rad3-related (ATR). One limitation for the study of ATR is the lack of potent inhibitors. We here describe a cell-based screening strategy that has allowed us to identify compounds with ATR inhibitory activity in the nanomolar range. Pharmacological inhibition of ATR generates replicative stress, leading to chromosomal breakage in the presence of conditions that stall replication forks. Moreover, ATR inhibition is particularly toxic for p53-deficient cells, this toxicity being exacerbated by replicative stress-generating conditions such as the overexpression of cyclin E. Notably, one of the compounds we identified is NVP-BEZ235, a dual phosphatidylinositol-3-OH kinase (PI3K) and mTOR inhibitor that is being tested for cancer chemotherapy but that we now show is also very potent against ATM, ATR and the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs).Publication A mouse model of ATR-Seckel shows embryonic replicative stress and accelerated aging.(Nature Publishing Group, 2009-08) Murga, Matilde; Bunting, Samuel; Montaña, Maria F; Soria, Rebeca; Mulero, Francisca; Cañamero, Marta; Lee, Youngsoo; McKinnon, Peter J; Nussenzweig, Andre; Fernandez-Capetillo, Oscar; European Molecular Biology Organization; Ministerio de Ciencia y Competitividad (España); Unión Europea. Comisión Europea. European Research Council (ERC)Although DNA damage is considered a driving force for aging, the nature of the damage that arises endogenously remains unclear. Replicative stress, a source of endogenous DNA damage, is prevented primarily by the ATR kinase. We have developed a mouse model of Seckel syndrome characterized by a severe deficiency in ATR. Seckel mice show high levels of replicative stress during embryogenesis, when proliferation is widespread, but this is reduced to marginal amounts in postnatal life. In spite of this decrease, adult Seckel mice show accelerated aging, which is further aggravated in the absence of p53. Together, these results support a model whereby replicative stress, particularly in utero, contributes to the onset of aging in postnatal life, and this is balanced by the replicative stress-limiting role of the checkpoint proteins ATR and p53.Publication A p53-dependent response limits the viability of mammalian haploid cells.(National Academy of Sciences, 2017-08-29) Olbrich, Teresa; Mayor-Ruiz, Cristina; Vega-Sendino, Maria; Gomez, Carmen; Ortega, Sagrario; Ruiz, Sergio; Fernandez-Capetillo, Oscar; Boehringer Ingelheim Fonds; Fundación La Caixa; Botín Foundation; Ministerio de Economía, Industria y Competitividad (España)The recent development of haploid cell lines has facilitated forward genetic screenings in mammalian cells. These lines include near-haploid human cell lines isolated from a patient with chronic myelogenous leukemia (KBM7 and HAP1), as well as haploid embryonic stem cells derived from several organisms. In all cases, haploidy was shown to be an unstable state, so that cultures of mammalian haploid cells rapidly become enriched in diploids. Here we show that the observed diploidization is due to a proliferative disadvantage of haploid cells compared with diploid cells. Accordingly, single-cell-sorted haploid mammalian cells maintain the haploid state for prolonged periods, owing to the absence of competing diploids. Although the duration of interphase is similar in haploid and diploid cells, haploid cells spend longer in mitosis, indicative of problems in chromosome segregation. In agreement with this, a substantial proportion of the haploids die at or shortly after the last mitosis through activation of a p53-dependent cytotoxic response. Finally, we show that p53 deletion stabilizes haploidy in human HAP1 cells and haploid mouse embryonic stem cells. We propose that, similar to aneuploidy or tetraploidy, haploidy triggers a p53-dependent response that limits the fitness of mammalian cells.Publication A p53-mediated DNA damage response limits reprogramming to ensure iPS cell genomic integrity.(Nature Publishing Group, 2009-08-27) Marión, Rosa M; Strati, Katerina; Li, Han; Murga, Matilde; Blanco, Raquel; Ortega Jimenez, Sagrario; Fernandez-Capetillo, Oscar; Serrano, Manuel; Blasco, MA; Asociación Española Contra el Cáncer; Unión Europea. Comisión Europea. European Research Council (ERC); Comunidad de Madrid (España); Körber European Science Prize; Ministerio de Ciencia e Innovación (España)The reprogramming of differentiated cells to pluripotent cells (induced pluripotent stem (iPS) cells) is known to be an inefficient process. We recently reported that cells with short telomeres cannot be reprogrammed to iPS cells despite their normal proliferation rates, probably reflecting the existence of 'reprogramming barriers' that abort the reprogramming of cells with uncapped telomeres. Here we show that p53 (also known as Trp53 in mice and TP53 in humans) is critically involved in preventing the reprogramming of cells carrying various types of DNA damage, including short telomeres, DNA repair deficiencies, or exogenously inflicted DNA damage. Reprogramming in the presence of pre-existing, but tolerated, DNA damage is aborted by the activation of a DNA damage response and p53-dependent apoptosis. Abrogation of p53 allows efficient reprogramming in the face of DNA damage and the generation of iPS cells carrying persistent DNA damage and chromosomal aberrations. These observations indicate that during reprogramming cells increase their intolerance to different types of DNA damage and that p53 is critical in preventing the generation of human and mouse pluripotent cells from suboptimal parental cells.Publication Actionable cancer vulnerability due to translational arrest, p53 aggregation and ribosome biogenesis stress evoked by the disulfiram metabolite CuET.(Nature Publishing Group, 2023-07) Kanellis, Dimitris C; Zisi, Asimina; Skrott, Zdenek; Lemmens, Bennie; Espinoza, Jaime A; Kosar, Martin; Björkman, Andrea; Li, Xuexin; Arampatzis, Stefanos; Bartkova, Jirina; Andújar-Sánchez, Miguel; Fernandez-Capetillo, Oscar; Mistrik, Martin; Lindström, Mikael S; Bartek, JiriDrug repurposing is a versatile strategy to improve current therapies. Disulfiram has long been used in the treatment of alcohol dependency and multiple clinical trials to evaluate its clinical value in oncology are ongoing. We have recently reported that the disulfiram metabolite diethyldithiocarbamate, when combined with copper (CuET), targets the NPL4 adapter of the p97VCP segregase to suppress the growth of a spectrum of cancer cell lines and xenograft models in vivo. CuET induces proteotoxic stress and genotoxic effects, however important issues concerning the full range of the CuET-evoked tumor cell phenotypes, their temporal order, and mechanistic basis have remained largely unexplored. Here, we have addressed these outstanding questions and show that in diverse human cancer cell models, CuET causes a very early translational arrest through the integrated stress response (ISR), later followed by features of nucleolar stress. Furthermore, we report that CuET entraps p53 in NPL4-rich aggregates leading to elevated p53 protein and its functional inhibition, consistent with the possibility of CuET-triggered cell death being p53-independent. Our transcriptomics profiling revealed activation of pro-survival adaptive pathways of ribosomal biogenesis (RiBi) and autophagy upon prolonged exposure to CuET, indicating potential feedback responses to CuET treatment. The latter concept was validated here by simultaneous pharmacological inhibition of RiBi and/or autophagy that further enhanced CuET's tumor cytotoxicity, using both cell culture and zebrafish in vivo preclinical models. Overall, these findings expand the mechanistic repertoire of CuET's anti-cancer activity, inform about the temporal order of responses and identify an unorthodox new mechanism of targeting p53. Our results are discussed in light of cancer-associated endogenous stresses as exploitable tumor vulnerabilities and may inspire future clinical applications of CuET in oncology, including combinatorial treatments and focus on potential advantages of using certain validated drug metabolites, rather than old, approved drugs with their, often complex, metabolic profiles.Publication ATR signaling can drive cells into senescence in the absence of DNA breaks.(Cold Spring Harbor Laboratory Press, 2008-02-01) Toledo, Luis I; Murga, Matilde; Gutierrez-Martinez, Paula; Soria, Rebeca; Fernandez-Capetillo, OscarThe ATR kinase is a key transducer of "replicative stress," the type of genomic damage that has been postulated to be induced by oncogenes. Here we describe a cellular system in which we can unleash ATR activity at will, in the absence of any actual damage or additional signaling pathways triggered by DNA breaks. We demonstrate that activating ATR is sufficient to promote cell cycle arrest and, if persistent, triggers p53-dependent but Ink4a/ARF-independent senescence. Moreover, we show that an ectopic activation of ATR leads to a G1/S arrest in ATM-/- cells, providing the first evidence of functional complementation of ATM deficiency by ATR. Our system provides a novel platform for the study of the specific functions of ATR signaling and adds evidence for the tumor-suppressive potential of the DNA damage response.Publication Clasp2 ensures mitotic fidelity and prevents differentiation of epidermal keratinocytes(The Company of Biologists, 2017-02-15) Shahbazi, Marta N; Peña-Jiménez, Daniel; Antonucci, Francesca; Drosten, Matthias; Perez-Moreno, Mirna Alicia; Ministerio de Economía y Competitividad (España)Epidermal homeostasis is tightly controlled by a balancing act of self-renewal or terminal differentiation of proliferating basal keratinocytes. An increase in DNA content as a consequence of a mitotic block is a recognized mechanism underlying keratinocyte differentiation, but the molecular mechanisms involved in this process are not yet fully understood. Using cultured primary keratinocytes, here we report that the expression of the mammalian microtubule and kinetochore-associated protein Clasp2 is intimately associated with the basal proliferative makeup of keratinocytes, and its deficiency leads to premature differentiation. Clasp2-deficient keratinocytes exhibit increased centrosomal numbers and numerous mitotic alterations, including multipolar spindles and chromosomal misalignments that overall result in mitotic stress and a high DNA content. Such mitotic block prompts premature keratinocyte differentiation in a p53-dependent manner in the absence of cell death. Our findings reveal a new role for Clasp2 in governing keratinocyte undifferentiated features and highlight the presence of surveillance mechanisms that prevent cell cycle entry in cells that have alterations in the DNA content.Publication Combined MEK and PI3K/p110β Inhibition as a Novel Targeted Therapy for Malignant Mesothelioma Displaying Sarcomatoid Features.(American Association for Cancer Research (AACR), 2020-02-15) Marqués, Miriam; Tranchant, Robin; Risa-Ebrí, Blanca; Suárez-Solís, María L; Fernández, Luis C; Carrillo-de-Santa-Pau, Enrique; Del Pozo, Natalia; Martínez de Villarreal, Jaime; Meiller, Clément; Allory, Yves; Blum, Yuna; Pirker, Christine; Hegedus, Balazs; Barry, Simon T; Carnero, Amancio; Berger, Walter; Jean, Didier; Real Arribas, Francisco; Ministerio de Ciencia, Innovación y Universidades (España); Institut National de la Santé et de la Recherche Médicale (Francia); Instituto de Salud Carlos III; American Association For Cancer ResearchAmong malignant mesotheliomas (MM), the sarcomatoid subtype is associated with higher chemoresistance and worst survival. Due to its low incidence, there has been little progress in the knowledge of the molecular mechanisms associated with sarcomatoid MM, which might help to define novel therapeutic targets. In this work, we show that loss of PTEN expression is frequent in human sarcomatoid MM and PTEN expression levels are lower in sarcomatoid MM than in the biphasic and epithelioid subtypes. Combined Pten and Trp53 deletion in mouse mesothelium led to nonepithelioid MM development. In Pten;Trp53-null mice developing MM, the Gαi2-coupled receptor subunit activated MEK/ERK and PI3K, resulting in aggressive, immune-suppressed tumors. Combined inhibition of MEK and p110β/PI3K reduced mouse tumor cell growth in vitro. Therapeutic inhibition of MEK and p110β/PI3K using selumetinib (AZD6244, ARRY-142886) and AZD8186, two drugs that are currently in clinical trials, increased the survival of Pten;Trp53-null mice without major toxicity. This drug combination effectively reduced the proliferation of primary cultures of human pleural (Pl) MM, implicating nonepithelioid histology and high vimentin, AKT1/2, and Gαi2 expression levels as predictive markers of response to combined MEK and p110β/PI3K inhibition. Our findings provide a rationale for the use of selumetinib and AZD8186 in patients with MM with sarcomatoid features. This constitutes a novel targeted therapy for a poor prognosis and frequently chemoresistant group of patients with MM, for whom therapeutic options are currently lacking. SIGNIFICANCE: Mesothelioma is highly aggressive; its sarcomatoid variants have worse prognosis. Building on a genetic mouse model, a novel combination therapy is uncovered that is relevant to human tumors.Publication Complete Regression of Advanced Pancreatic Ductal Adenocarcinomas upon Combined Inhibition of EGFR and C-RAF.(Cell Press, 2019-04-15) Blasco, María Teresa; Navas, Carolina; Martín-Serrano, Guillermo; Martín-Díaz, Laura; Li, Jing; Morales-Cacho, Lucia; Esteban-Burgos, Laura; Perales-Patón, Javier; Bousquet-Mur, Emilie; Castellano, Eva; Jacob, Harrys K C; Cabras, Lavinia; Sainz, Bruno; Dusetti, Nelson; Iovanna, Juan; Sánchez-Bueno, Francisco; Hidalgo, Manuel; Khiabanian, Hossein; Rabadán, Raul; Graña Castro, Osvaldo; Lechuga C, Lechuga CG; Djurec M, Djurec M; Musteanu, Mónica; Drosten, Matthias; Ortega Jimenez, Sagrario; Mulero, Francisca; Guerra, Carmen; Barbacid, Mariano; Al-Shahrour, Fatima; Unión Europea. Comisión Europea. European Research Council (ERC); Unión Europea. Comisión Europea; Asociación Española Contra el Cáncer; Ligue Nationale Contre le Cancer (Francia); United States Department of Health and Human Services; Deutsche Forschungsgemeinschaft (Alemania); Ministerio de Ciencia e Innovación (España); Fundación La Caixa; Ministerio de Economía, Industria y Competitividad (España); Fundación AXAFive-year survival for pancreatic ductal adenocarcinoma (PDAC) patients remains below 7% due to the lack of effective treatments. Here, we report that combined ablation of EGFR and c-RAF expression results in complete regression of a significant percentage of PDAC tumors driven by Kras/Trp53 mutations in genetically engineered mice. Moreover, systemic elimination of these targets induces toxicities that are well tolerated. Response to this targeted therapy correlates with transcriptional profiles that resemble those observed in human PDACs. Finally, inhibition of EGFR and c-RAF expression effectively blocked tumor progression in nine independent patient-derived xenografts carrying KRAS and TP53 mutations. These results open the door to the development of targeted therapies for PDAC patients.Publication Definitive evidence for Club cells as progenitors for mutant Kras/Trp53-deficient lung cancer.(Wiley, 2021-11-01) Rosigkeit, Sebastian; Kruchem, Marie; Thies, Dorothe; Kreft, Andreas; Eichler, Emma; Boegel, Sebastian; Jansky, Sandrine; Siegl, Dominik; Kaps, Leonard; Pickert, Geethanjali; Haehnel, Patricia; Kindler, Thomas; Hartwig, Udo F; Guerra, Carmen; Barbacid, Mariano; Schuppan, Detlef; Bockamp, Ernesto; German Research Foundation (DFG); ERAPerMed; Stiftung Rheinland-Pfalz fur InnovationAccumulating evidence suggests that both the nature of oncogenic lesions and the cell-of-origin can strongly influence cancer histopathology, tumor aggressiveness and response to therapy. Although oncogenic Kras expression and loss of Trp53 tumor suppressor gene function have been demonstrated to initiate murine lung adenocarcinomas (LUADs) in alveolar type II (AT2) cells, clear evidence that Club cells, representing the second major subset of lung epithelial cells, can also act as cells-of-origin for LUAD is lacking. Equally, the exact anatomic location of Club cells that are susceptible to Kras transformation and the resulting tumor histotype remains to be established. Here, we provide definitive evidence for Club cells as progenitors for LUAD. Using in vivo lineage tracing, we find that a subset of Kras12V -expressing and Trp53-deficient Club cells act as precursors for LUAD and we define the stepwise trajectory of Club cell-initiated tumors leading to lineage marker conversion and aggressive LUAD. Our results establish Club cells as cells-of-origin for LUAD and demonstrate that Club cell-initiated tumors have the potential to develop aggressive LUAD.Publication Early differential responses elicited by BRAFV600E in adult mouse models.(Nature Publishing Group, 2022-02-10) Bosso, Giuseppe; Lanuza-Gracia, Pablo; Piñeiro-Hermida, Sergio; Yilmaz, Merve; Serrano, Rosa; Blasco, MA; Comunidad de Madrid (España); Agencia Estatal de Investigación (España); World Cancer Research Fund International; Unión Europea. Comisión Europea. European Research Council (ERC); Botín FoundationThe BRAF gene is frequently mutated in cancer. The most common genetic mutation is a single nucleotide transition which gives rise to a constitutively active BRAF kinase (BRAFV600E) which in turn sustains continuous cell proliferation. The study of BRAFV600E murine models has been mainly focused on the role of BRAFV600E in tumor development but little is known on the early molecular impact of BRAFV600E expression in vivo. Here, we study the immediate effects of acute ubiquitous BRAFV600E activation in vivo. We find that BRAFV600E elicits a rapid DNA damage response in the liver, spleen, lungs but not in thyroids. This DNA damage response does not occur at telomeres and is accompanied by activation of the senescence marker p21CIP1 only in lungs but not in liver or spleen. Moreover, in lungs, BRAFV600E provokes an acute inflammatory state with a tissue-specific recruitment of neutrophils in the alveolar parenchyma and macrophages in bronchi/bronchioles, as well as bronchial/bronchiolar epithelium transdifferentiation and development of adenomas. Furthermore, whereas in non-tumor alveolar type II (ATIIs) pneumocytes, acute BRAFV600E induction elicits rapid p53-independent p21CIP1 activation, adenoma ATIIs express p53 without resulting in p21CIP1 gene activation. Conversely, albeit in Club cells BRAFV600E-mediated proliferative cue is more exacerbated compared to that occurring in ATIIs, such oncogenic stimulus culminates with p21CIP1-mediated cell cycle arrest and apoptosis. Our findings indicate that acute BRAFV600E expression drives an immediate induction of DNA damage response in vivo. More importantly, it also results in rapid differential responses of cell cycle and senescence-associated proteins in lung epithelia, thus revealing the early molecular changes emerging in BRAFV600E-challenged cells during tumorigenesis in vivo.Publication Early induction of senescence and immortalization in PGC-1α-deficient mouse embryonic fibroblasts(Elsevier, 2019) Prieto, Ignacio; Zambrano, Alberto; Laso, Javier; Aranda, Ana; Samper, Enrique; Monsalve, María; Ministerio de Economía, Industria y Competitividad (España); Unión Europea. Fondo Europeo de Desarrollo Regional (FEDER/ERDF); Unión Europea. Comisión Europea. H2020; Instituto de Salud Carlos IIIOxidative stress is known to induce early replicative senescence. Senescence has been proposed to work as a barrier to immortalization and tumor development. Here, we aimed to evaluate the impact of the loss of peroxisome proliferator activated receptor γ co-activator 1α (PGC-1α), a master regulator of oxidative metabolism and mitochondrial reactive oxygen species (ROS) generation, on replicative senescence and immortalization in mouse embryonic fibroblasts (MEFs). We found that primary MEFs lacking PGC-1α showed higher levels of ROS than wild-type MEFs at all cell passages tested. The elevated production of ROS was associated with higher levels of oxidative DNA damage and the increased formation of DNA double-strand breaks. Evaluation of the induction of DNA repair systems in response to γ-radiation indicated that the loss of PGC-1α also resulted in a small but significant reduction in their activity. DNA damage induced the early activation of senescence markers, including an increase in the number of β-galactosidase-positive cells, the induction of p53 phosphorylation, and the increase in p16 and p19 protein. These changes were, however, not sufficient to reduce proliferation rates of PGC-1α-deficient MEFs at any cell passage tested. Moreover, PGC-1α-deficient cells escaped replicative senescence. PGC-1α plays an important role in the control of cellular senescence and immortalization.Publication EGF receptor signaling is essential for k-ras oncogene-driven pancreatic ductal adenocarcinoma.(Cell Press, 2012-09-11) Navas, Carolina; Hernández-Porras, Isabel; Schuhmacher, Alberto J; Sibilia, Maria; Guerra, Carmen; Barbacid, Mariano; Unión Europea. Comisión Europea. European Research Council (ERC); Ministerio de Economía y Competitividad (España); Fundacion de la Mutua Madrilena del Automovil; Instituto de Salud Carlos III; Fundacion Ramon Areces; Austrian Federal Government's GEN-AU program "Austro-mouse"Clinical evidence indicates that mutation/activation of EGF receptors (EGFRs) is mutually exclusive with the�presence of K-RAS oncogenes in lung and colon tumors. We have validated these observations using genetically engineered mouse models. However, development of pancreatic ductal adenocarcinomas driven by K-Ras oncogenes are totally dependent on EGFR signaling. Similar results were obtained using human pancreatic tumor cell lines. EGFRs were also essential even in the context of pancreatic injury and absence of p16Ink4a/p19Arf. Only loss of p53 made pancreatic tumors independent of EGFR signaling. Additional inhibition of PI3K and STAT3 effectively prevented proliferation of explants derived from these p53-defective pancreatic tumors. These findings may provide the bases for more rational approaches to treat pancreatic tumors in the clinic.Publication Haploinsufficiency for BRCA1 leads to cell-type-specific genomic instability and premature senescence(Nature Publishing Group, 2015-06-24) Sedic, Maja; Skibinski, Adam; Brown, Nelson; Gallardo, Mercedes; Mulligan, Peter; Martinez Rodriguez, Paula; Keller, Patricia J; Glover, Eugene; Richardson, Andrea L; Cowan, Janet; Toland, Amanda E; Ravichandran, Krithika; Riethman, Harold; Naber, Stephen P; Näär, Anders M; Blasco, MA; Hinds, Philip W; Kuperwasser, Charlotte; Raymond and Beverly Sackler Foundation; Breast Cancer Research Foundation; Silvian Foundation; NIH - National Cancer Institute (NCI) (Estados Unidos); Unión Europea. Comisión Europea. European Research Council (ERC); Ministerio de Economía y Competitividad (España); Fundación AXA; Botín Foundation; Fundación Lilly; Comunidad de Madrid (España)Although BRCA1 function is essential for maintaining genomic integrity in all cell types, it is unclear why increased risk of cancer in individuals harbouring deleterious mutations in BRCA1 is restricted to only a select few tissues. Here we show that human mammary epithelial cells (HMECs) from BRCA1-mutation carriers (BRCA1(mut/+)) exhibit increased genomic instability and rapid telomere erosion in the absence of tumour-suppressor loss. Furthermore, we uncover a novel form of haploinsufficiency-induced senescence (HIS) specific to epithelial cells, which is triggered by pRb pathway activation rather than p53 induction. HIS and telomere erosion in HMECs correlate with misregulation of SIRT1 leading to increased levels of acetylated pRb as well as acetylated H4K16 both globally and at telomeric regions. These results identify a novel form of cellular senescence and provide a potential molecular basis for the rapid cell- and tissue- specific predisposition of breast cancer development associated with BRCA1 haploinsufficiency.Publication In-depth proteomics characterization of ∆Np73 effectors identifies key proteins with diagnostic potential implicated in lymphangiogenesis, vasculogenesis and metastasis in colorectal cancer(Wiley, 2022-07) Garranzo-Asensio, Maria; Rodríguez-Cobos, Javier; San Millán, Coral; Poves, Carmen; Fernández-Aceñero, María Jesús; Pastor-Morate, Daniel; Viñal, David; Montero-Calle, Ana Maria; Solis-Fernandez, Guillermo; Ceron, María-Ángeles; Gámez-Chiachio, Manuel; Rodríguez, Nuria; Guzmán-Aránguez, Ana; Barderas Manchado, Rodrigo; Domínguez, Gemma; Instituto de Salud Carlos III; Unión Europea. Fondo Europeo de Desarrollo Regional (FEDER/ERDF); Roche; Comunidad de Madrid (España); Unión Europea. Fondo Social Europeo (ESF/FSE); Research Foundation - Flanders; Ministerio de Educación, Cultura y Deporte (España); Ministerio de Asuntos Económicos y Transformación Digital (España)Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related death worldwide. Alterations in proteins of the p53-family are a common event in CRC. ΔNp73, a p53-family member, shows oncogenic properties and its effectors are largely unknown. We performed an in-depth proteomics characterization of transcriptional control by ∆Np73 of the secretome of human colon cancer cells and validated its clinical potential. The secretome was analyzed using high-density antibody microarrays and stable isotopic metabolic labeling. Validation was performed by semiquantitative PCR, ELISA, dot-blot and western blot analysis. Evaluation of selected effectors was carried out using 60 plasma samples from CRC patients, individuals carrying premalignant colorectal lesions and colonoscopy-negative controls. In total, 51 dysregulated proteins were observed showing at least 1.5-foldchange in expression. We found an important association between the overexpression of ∆Np73 and effectors related to lymphangiogenesis, vasculogenesis and metastasis, such as brain-derived neurotrophic factor (BDNF) and the putative aminoacyl tRNA synthase complex-interacting multifunctional protein 1 (EMAP-II)-vascular endothelial growth factor C-vascular endothelial growth factor receptor 3 axis. We further demonstrated the usefulness of BDNF as a potential CRC biomarker able to discriminate between CRC patients and premalignant individuals from controls with high sensitivity and specificity.Publication mTORC1 Inactivation Promotes Colitis-Induced Colorectal Cancer but Protects from APC Loss-Dependent Tumorigenesis.(Cell Press, 2018-01-09) Brandt, Marta; Grazioso, Tatiana P; Fawal, Mohamad-Ali; Tummala, Krishna S; Torres-Ruiz, Raul; Rodriguez Perales, Sandra; Perna, Cristian; Djouder, Nabil; Fundación La Caixa; Ministerio de Ciencia y Competitividad (España); Olga Torres Foundation (FOT); European Union (EU)Dietary habits that can induce inflammatory bowel disease (IBD) are major colorectal cancer (CRC) risk factors, but mechanisms linking nutrients, IBD, and CRC are unknown. Using human data and mouse models, we show that mTORC1 inactivation-induced chromosomal instability impairs intestinal crypt proliferation and regeneration, CDK4/6 dependently. This triggers interleukin (IL)-6-associated reparative inflammation, inducing crypt hyper-proliferation, wound healing, and CRC. Blocking IL-6 signaling or reactivating mTORC1 reduces inflammation-induced CRC, so mTORC1 activation suppresses tumorigenesis in IBD. Conversely, mTORC1 inactivation is beneficial in APC loss-dependent CRC. Thus, IL-6 blockers or protein-rich-diet-linked mTORC1 activation may prevent IBD-associated CRC. However, abolishing mTORC1 can mitigate CRC in predisposed patients with APC mutations. Our work reveals mTORC1 oncogenic and tumor-suppressive roles in intestinal epithelium and avenues to optimized and personalized therapeutic regimens for CRC.Publication Mutant p53 induces SIRT3/MnSOD axis to moderate ROS production in melanoma cells(Elsevier, 2020-01-15) Torrens-Mas, Margalida; Cordani, Marco; Mullappilly, Nidula; Pacchiana, Raffaella; Riganti, Chiara; Palmieri, Marta; Pons, Daniel-Gabriel; Roca, Pilar; Oliver, Jordi; Donadelli, MassimoThe TP53 tumor suppressor gene is the most frequently altered gene in tumors and mutant p53 isoforms can acquire oncogenic properties referred to as gain-of-function (GOF). In this study, we used wild-type (A375) and mutant p53 (MeWo) melanoma cell lines to assess the regulation of the mitochondrial antioxidant manganese superoxide dismutase (MnSOD) by mutant p53. The effects of mutant p53 were evaluated by qPCR, immunoblotting, enzyme activity assay, cell proliferation assay, reactive oxygen species (ROS) assay after cellular transfection. We demonstrate that mutant p53 induces MnSOD expression, which is recovered by the ROS scavenger N-acetyl-l-cysteine. This suggests MnSOD induction as a defense mechanism of melanoma cells to counterbalance the pro-oxidant conditions induced by mutant p53. We also demonstrate that mutant p53 induces the expression of Sirtuin3 (SIRT3), a major mitochondrial NAD+-dependent deacetylase, stimulating MnSOD deacetylation and enzymatic activity. Indeed, the restoration of SIRT3 reverses MnSOD activity decrease by mutant p53 knock-down. Finally, MnSOD knock-down further enhances mutant p53-mediated ROS increase, counteracting mutp53-dependent cell hyperproliferation. This indicates that SIRT3 and MnSOD act to maintain ROS levels controlled to promote cell proliferation and survival, providing new therapeutic opportunities to be further considered for clinical studies in cancer patients bearing mutant TP53 gene.Publication p21Cip1 plays a critical role in the physiological adaptation to fasting through activation of PPARα(Nature Publishing Group, 2016-10) Lopez-Guadamillas, Elena; Fernandez-Marcos, Pablo J; Pantoja, Cristina; Muñoz-Martin, Maribel; Martinez Garcia, Maria Dolores; Gómez-López, Gonzalo; Campos Olivas, Ramon; Valverde, Angela M; Serrano Marugan, Manuel; Ministerio de Ciencia e Innovación (España); Asociación Española Contra el Cáncer; Unión Europea. Comisión Europea. European Research Council (ERC); Comunidad de Madrid (España); Botín Foundation; Banco Santander; Fundación Ramón Areces; Fundación AXAFasting is a physiological stress that elicits well-known metabolic adaptations, however, little is known about the role of stress-responsive tumor suppressors in fasting. Here, we have examined the expression of several tumor suppressors upon fasting in mice. Interestingly, p21 mRNA is uniquely induced in all the tissues tested, particularly in liver and muscle (>10 fold), and this upregulation is independent of p53. Remarkably, in contrast to wild-type mice, p21-null mice become severely morbid after prolonged fasting. The defective adaptation to fasting of p21-null mice is associated to elevated energy expenditure, accelerated depletion of fat stores, and premature activation of protein catabolism in the muscle. Analysis of the liver transcriptome and cell-based assays revealed that the absence of p21 partially impairs the transcriptional program of PPARα, a key regulator of fasting metabolism. Finally, treatment of p21-null mice with a PPARα agonist substantially protects them from their accelerated loss of fat upon fasting. We conclude that p21 plays a relevant role in fasting adaptation through the positive regulation of PPARα.Publication P53 and BCL-2 family proteins PUMA and NOXA define competitive fitness in pluripotent cell competition.(Public Library of Science (PLOS), 2024-03) Valverde-Lopez, Jose A; Li-Bao, Lin; Sierra, Rocío; Santos, Elisa; Giovinazzo, Giovanna; Díaz-Díaz, Covadonga; Torres, Miguel; Ministerio de Ciencia e Innovación (España); Fundación ProCNIC; Ministerio de Ciencia e Innovación. Centro de Excelencia Severo Ochoa (España)Cell Competition is a process by which neighboring cells compare their fitness. As a result, viable but suboptimal cells are selectively eliminated in the presence of fitter cells. In the early mammalian embryo, epiblast pluripotent cells undergo extensive Cell Competition, which prevents suboptimal cells from contributing to the newly forming organism. While competitive ability is regulated by MYC in the epiblast, the mechanisms that contribute to competitive fitness in this context are largely unknown. Here, we report that P53 and its pro-apoptotic targets PUMA and NOXA regulate apoptosis susceptibility and competitive fitness in pluripotent cells. PUMA is widely expressed specifically in pluripotent cells in vitro and in vivo. We found that P53 regulates MYC levels in pluripotent cells, which connects these two Cell Competition pathways, however, MYC and PUMA/NOXA levels are independently regulated by P53. We propose a model that integrates a bifurcated P53 pathway regulating both MYC and PUMA/NOXA levels and determines competitive fitness.Publication p53 Modulates the Fate of Cardiac Progenitor Cells Ex Vivo and in the Diabetic Heart In Vivo(Elsevier, 2017-01-31) Kannappan, Ramaswamy; Matsuda, Alex; Ferreira-Martins, João; Zhang, Eric; Palano, Giorgia; Czarna, Anna; Cabral-Da-Silva, Mauricio Castro; Bastos-Carvalho, Adriana; Sanada, Fumihiro; Ide, Noriko; Rota, Marcello; Blasco , MA; Serrano Marugan, Manuel; Anversa, Piero; Leri, Annarosa; National Institutes of Health (Estados Unidos); Cardiocentro Ticino Foundationp53 is an important modulator of stem cell fate, but its role in cardiac progenitor cells (CPCs) is unknown. Here, we tested the effects of a single extra-copy of p53 on the function of CPCs in the presence of oxidative stress mediated by doxorubicin in vitro and type-1 diabetes in vivo. CPCs were obtained from super-p53 transgenic mice (p53-tg), in which the additional allele is regulated in a manner similar to the endogenous protein. Old CPCs with increased p53 dosage showed a superior ability to sustain oxidative stress, repair DNA damage and restore cell division. With doxorubicin, a larger fraction of CPCs carrying an extra-copy of the p53 allele recruited γH2A.X reestablishing DNA integrity. Enhanced p53 expression resulted in a superior tolerance to oxidative stress in vivo by providing CPCs with defense mechanisms necessary to survive in the milieu of the diabetic heart; they engrafted in regions of tissue injury and in three days acquired the cardiomyocyte phenotype. The biological advantage provided by the increased dosage of p53 in CPCs suggests that this genetic strategy may be translated to humans to increase cellular engraftment and growth, critical determinants of successful cell therapy for the failing heart.