RESUMO
Cellular senescence is a stress-response mechanism implicated in various physiological processes, diseases, and aging. Current detection approaches have partially addressed the issue of senescent cell identification in clinical specimens. Effective methodologies enabling precise isolation or live tracking of senescent cells are still lacking. In-depth analysis of truly senescent cells is, therefore, an extremely challenging task. We report (1) the synthesis and validation of a fluorophore-conjugated, Sudan Black-B analog (GLF16), suitable for in vivo and in vitro analysis of senescence by fluorescence microscopy and flow cytometry and (2) the development and application of a GLF16-carrying micelle vector facilitating GLF16 uptake by living senescent cells in vivo and in vitro. The compound and the applied methodology render isolation of senescent cells an easy, rapid, and precise process. Straightforward nanocarrier-mediated GLF16 delivery in live senescent cells comprises a unique tool for characterization of senescence at an unprecedented depth.
Assuntos
Senescência Celular , Indicadores e Reagentes , Citometria de FluxoRESUMO
Oncogene-induced senescence (OIS) is an inherent and important tumor suppressor mechanism. However, if not removed timely via immune surveillance, senescent cells also have detrimental effects. Although this has mostly been attributed to the senescence-associated secretory phenotype (SASP) of these cells, we recently proposed that "escape" from the senescent state is another unfavorable outcome. The mechanism underlying this phenomenon remains elusive. Here, we exploit genomic and functional data from a prototypical human epithelial cell model carrying an inducible CDC6 oncogene to identify an early-acquired recurrent chromosomal inversion that harbors a locus encoding the circadian transcription factor BHLHE40. This inversion alone suffices for BHLHE40 activation upon CDC6 induction and driving cell cycle re-entry of senescent cells, and malignant transformation. Ectopic overexpression of BHLHE40 prevented induction of CDC6-triggered senescence. We provide strong evidence in support of replication stress-induced genomic instability being a causative factor underlying "escape" from oncogene-induced senescence.
Assuntos
Senescência Celular , Inversão Cromossômica , Cromossomos/ultraestrutura , Transição Epitelial-Mesenquimal , Neoplasias/genética , Oncogenes , Recombinação Genética , Animais , Brônquios/metabolismo , Sistemas CRISPR-Cas , Ciclo Celular , Transformação Celular Neoplásica , Ritmo Circadiano , Biologia Computacional , Células Epiteliais/metabolismo , Citometria de Fluxo , Genômica , Humanos , Cariotipagem , Camundongos , Camundongos SCID , Neoplasias/metabolismo , Fenótipo , Ligação Proteica , Domínios Proteicos , Fenótipo Secretor Associado à SenescênciaRESUMO
RASSF1A promoter methylation has been correlated with tumor dedifferentiation and aggressive oncogenic behavior. Nevertheless, the underlying mechanism of RASSF1A-dependent tumor dedifferentiation remains elusive. Here, we show that RASSF1A directly uncouples the NOTCH-HES1 axis, a key suppressor of differentiation. Interestingly, the crosstalk of RASSF1A with HES1 occurs independently from the signaling route connecting RASSF1A with the Hippo pathway. At the molecular level, we demonstrate that RASSF1A acts as a scaffold essential for the SUMO-targeted E3 ligase SNURF/RNF4 to target HES1 for degradation. The reciprocal relationship between RASSF1A and HES1 is evident across a wide range of human tumors, highlighting the clinical significance of the identified pathway. We show that HES1 upregulation in a RASSF1A-depleted environment renders cells non-responsive to the downstream effects of γ-secretase inhibitors (GSIs) which restrict signaling at the level of the NOTCH receptor. Taken together, we report a mechanism through which RASSF1A exerts autonomous regulation of the critical Notch effector HES1, thus classifying RASSF1A expression as an integral determinant of the clinical effectiveness of Notch inhibitors.
Assuntos
Receptores Notch , Transdução de Sinais , Fatores de Transcrição HES-1 , Proteínas Supressoras de Tumor , Humanos , Proteínas Nucleares/metabolismo , Receptores Notch/genética , Receptores Notch/metabolismo , Fatores de Transcrição HES-1/genética , Fatores de Transcrição HES-1/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
The currently available anti-cancer therapies, such as gamma-radiation and chemotherapeutic agents, induce cell death and cellular senescence not only in cancer cells but also in the adjacent normal tissue. New anti-tumor approaches focus on limiting the side effects on normal cells. In this frame, the potential anti-tumor properties of Pulsed Electromagnetic Fields (PEMFs) through the irradiation of breast cancer epithelial cells (MCF-7 and MDA-MB-231) and normal fibroblasts (FF95) were investigated. PEMFs had a frequency of 8 Hz, full-square wave type and magnetic flux density of 0.011 T and were applied twice daily for 5 days. The data collected showcase that PEMF application decreases the proliferation rate and viability of breast cancer cells while having the opposite effect on normal fibroblasts. Moreover, PEMF irradiation induces cell death and cellular senescence only in breast cancer cells without any effect in the non-cancerous cells. These findings suggest PEMF irradiation as a novel, non-invasive anti-cancer strategy that, when combined with senolytic drugs, may eliminate both cancer and the remaining senescent cells, while simultaneously avoiding the side effects of the current treatments.
Assuntos
Neoplasias da Mama , Campos Eletromagnéticos , Humanos , Feminino , Morte Celular , Senescência Celular , FibroblastosRESUMO
Helicobacter pylori (H. pylori) infection induces DNA Double-Strand Breaks (DSBs) and consequently activates the DNA Damage Response pathway (DDR) and senescence in gastric epithelium. We studied DDR activation and senescence before and after the eradication of the pathogen. Gastric antral and corpus biopsies of 61 patients with H. pylori infection, prior to and after eradication treatment, were analyzed by means of immunohistochemistry/immunofluorescence for DDR marker (γH2AΧ, phosporylated ataxia telangiectasia-mutated (pATM), p53-binding protein (53BP1) and p53) expression. Samples were also evaluated for Ki67 (proliferation index), cleaved caspase-3 (apoptotic index) and GL13 staining (cellular senescence). Ten H. pylori (-) dyspeptic patients served as controls. All patients were re-endoscoped in 72-1361 days (mean value 434 days), and tissue samples were processed in the same manner. The eradication of the microorganism, in human gastric mucosa, downregulates γH2AΧ expression in both the antrum and corpus (p = 0.00019 and p = 0.00081 respectively). The expression of pATM, p53 and 53BP1 is also reduced after eradication. Proliferation and apoptotic indices were reduced, albeit not significantly, after pathogen clearance. Moreover, cellular senescence is increased in H. pylori-infected mucosa and remains unaffected after eradication. Interestingly, senescence was statistically increased in areas of intestinal metaplasia (IM) compared with adjacent non-metaplastic mucosa (p < 0.001). In conclusion, H. pylori infection triggers DSBs, DDR and senescence in the gastric epithelium. Pathogen eradication reverses the DDR activation but not senescence. Increased senescent cells may favor IM persistence, thus potentially contributing to gastric carcinogenesis.
Assuntos
Helicobacter pylori , Humanos , Proteína Supressora de Tumor p53/genética , Mucosa Gástrica , Reparo do DNA , EpitélioRESUMO
Background and Objectives: The presence and contribution of senescent cells in premalignant lesions is well documented, but not in germ cell neoplasia in situ. The purpose of this study is to identify the presence of senescent cells in pre-malignant testicular conditions and in different histological types of testicular cancer. Materials and Methods: Thirty patients who underwent orchiectomy due to testicular tumors were included. Formalin-fixed paraffin-embedded (FFPE) testicular tissue for each patient was available. Sections from these specimens were examined by immunohistochemical analysis with the following markers: GL13 for cellular senescence, p21WAF1/Cip1 for cell cycle arrest, and Ki67 for cell proliferation. Results: Thirteen (43.3%) suffered from seminoma with a mean total proportion of GCNIS senescence of 20.81 ± 6.81%. In the group of embryonal testicular tumors, nine (30%) patients were included, with an average rate of 6.64 ± 5.42% of senescent cells in GCNIS. One (3.3%) patient suffered from chondrosarcoma in which 7.9% of GL13+ cells were detected in GCNIS. Four (13.4%) patients suffered from teratoma and three (10%) from yolk sac tumors, while GCNIS senescence was detected in a range of 4.43 ± 1.78% and 3.76 ± 1.37%, respectively. Conclusions: Cellular senescence was detected in both germ cell neoplasia in situ and testicular cancer, but was more prevalent within the premalignant lesions.
Assuntos
Senescência Celular , Neoplasias Embrionárias de Células Germinativas , Neoplasias Testiculares , Humanos , Masculino , Neoplasias Testiculares/patologia , Neoplasias Testiculares/cirurgia , Senescência Celular/fisiologia , Adulto , Neoplasias Embrionárias de Células Germinativas/patologia , Neoplasias Embrionárias de Células Germinativas/cirurgia , Pessoa de Meia-Idade , Orquiectomia , Imuno-HistoquímicaRESUMO
BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection of the respiratory system can progress to a multisystemic disease with aberrant inflammatory response. Cellular senescence promotes chronic inflammation, named senescence-associated secretory phenotype (SASP). We investigated whether coronavirus disease 2019 (COVID-19) is associated with cellular senescence and SASP. METHODS: Autopsy lung tissue samples from 11 COVID-19 patients and 43 age-matched non-COVID-19 controls with similar comorbidities were analysed by immunohistochemistry for SARS-CoV-2, markers of senescence and key SASP cytokines. Virally induced senescence was functionally recapitulated in vitro, by infecting epithelial Vero-E6 cells and a three-dimensional alveosphere system of alveolar type 2 (AT2) cells with SARS-CoV-2 strains isolated from COVID-19 patients. RESULTS: SARS-CoV-2 was detected by immunocytochemistry and electron microscopy predominantly in AT2 cells. Infected AT2 cells expressed angiotensin-converting enzyme 2 and exhibited increased senescence (p16INK4A and SenTraGor positivity) and interleukin (IL)-1ß and IL-6 expression. In vitro, infection of Vero-E6 cells with SARS-CoV-2 induced senescence (SenTraGor), DNA damage (γ-H2AX) and increased cytokine (IL-1ß, IL-6, CXCL8) and apolipoprotein B mRNA-editing (APOBEC) enzyme expression. Next-generation sequencing analysis of progenies obtained from infected/senescent Vero-E6 cells demonstrated APOBEC-mediated SARS-CoV-2 mutations. Dissemination of the SARS-CoV-2-infection and senescence was confirmed in extrapulmonary sites (kidney and liver) of a COVID-19 patient. CONCLUSIONS: We demonstrate that in severe COVID-19, AT2 cells infected by SARS-CoV-2 exhibit senescence and a proinflammatory phenotype. In vitro, SARS-CoV-2 infection induces senescence and inflammation. Importantly, infected senescent cells may act as a source of SARS-CoV-2 mutagenesis mediated by APOBEC enzymes. Therefore, SARS-CoV-2-induced senescence may be an important molecular mechanism of severe COVID-19, disease persistence and mutagenesis.
Assuntos
COVID-19 , SARS-CoV-2 , Senescência Celular , Citocinas/metabolismo , Humanos , Inflamação , Interleucina-6 , Pulmão/metabolismo , Mutagênese , FenótipoRESUMO
Autophagy is a catabolic process that preserves cellular homeostasis. Its exact role during carcinogenesis is not completely defined. Specifically in head and neck cancer, such information from clinical settings that comprise the whole spectrum of human carcinogenesis is very limited. Towards this direction, we examined the in situ status of the autophagy-related factors, Beclin-1, microtubule-associated protein 1 light chain 3, member B (LC3B) and sequestosome 1/p62 (p62) in clinical material covering all histopathological stages of human head and neck carcinogenesis. This material is unique as each panel of lesions is derived from the same patient and moreover we have previously assessed it for the DNA damage response (DDR) activation status. Since Beclin-1, LC3B and p62 reflect the nucleation, elongation and degradation stages of autophagy, respectively, their combined immunohistochemical (IHC) expression profiles could grossly mirror the autophagic flux. This experimental approach was further corroborated by ultrastructural analysis, applying transmission electron microscopy (TEM). The observed Beclin-1/LC3B/p62 IHC patterns, obtained from serial sections analysis, along with TEM findings are suggestive of a declined authophagic activity in preneoplastic lesions that was restored in full blown cancers. Correlating these findings with DDR status in the same pathological stages are indicative of: (i) an antitumor function of autophagy in support to that of DDR, possibly through energy deprivation in preneoplastic stages, thus preventing incipient cancer cells from evolving; and (ii) a tumor-supporting role in the cancerous stage.
Assuntos
Autofagia/fisiologia , Neoplasias de Cabeça e Pescoço/metabolismo , Imuno-Histoquímica/métodos , Autofagia/genética , Proteína Beclina-1/genética , Proteína Beclina-1/metabolismo , Dano ao DNA/genética , Dano ao DNA/fisiologia , Neoplasias de Cabeça e Pescoço/genética , HumanosRESUMO
Common fragile sites (CFSs) are regions of the genome with a predisposition to DNA double-strand breaks in response to intrinsic (oncogenic) or extrinsic replication stress. CFS breakage is a common feature in carcinogenesis from its earliest stages. Given that a number of oncogenes and tumor suppressors are located within CFSs, a question that emerges is whether fragility in these regions is only a structural "passive" incident or an event with a profound biological effect. Furthermore, there is sparse evidence that other elements, like non-coding RNAs, are positioned with them. By analyzing data from various libraries, like miRbase and ENCODE, we show a prevalence of various cancer-related genes, miRNAs, and regulatory binding sites, such as CTCF within CFSs. We propose that CFSs are not only susceptible structural domains, but highly organized "functional" entities that when targeted, severe repercussion for cell homeostasis occurs.
Assuntos
Sítios Frágeis do Cromossomo , Neoplasias/genética , Oncogenes , Animais , Reparo do DNA , Replicação do DNA , Humanos , MicroRNAs/genéticaRESUMO
PURPOSE: The aim of this experimental study is to investigate the correlation between the presence of senescent cells and the tumor size, the lymphovascular invasion (LVI), the invasion of rete testis (RTI), the preoperative tumor markers or pathological stage in patients who underwent orchiectomy for malignant purposes. METHODS: This experimental study included patients with a history of radical orchiectomy performed from January 2011 to January 2019. The testicular tissue specimens underwent an immunohistopathological process for the detection of the presence of cellular senescence. Besides, the tumor size, the histopathological type, the pathological stage of the tumor and the presence of Lymphovascular (LVI) or rete testis (RTI) invasions were also recorded. Additionally, the preoperative serum levels of alpha-fetoprotein, beta-human chorionic gonadotropin and lactate dehydrogenase were recorded. After the completion of immunohistochemical analysis, the rate of senescent cells in each specimen was also recorded. RESULTS: The mean senescent cell rate was estimated to be 14.11±11.32% and 15.46±10.58% in patients with presence of LVI or absence of LVI, respectively (p=0.46). The mean senescent cell rate was calculated at 18.13±12.26% and 12.56±9.38% (p=0.096) in patients with presence of RTI or absence of RTI, respectively. The mean senescent cell rate in the pT1 group was calculated at 14.58 ± 9.82%, while in T2 and T3 groups the mean senescent cell rate was estimated to be 15.22 ± 12.03% and 15.35 ± 14.21%, respectively (p=0.98). A statistically significant correlation was detected between the senescence rate and the tumor size (Pearson score 0.40, p=0.027) and between the rate of senescent cells and the preoperative level of lactate dehydrogenase (LDH) (Pearson score -0.53, p=0.002). CONCLUSIONS: The presence of cellular senescence was correlated with the extent of the testicular tumor in terms of tumor size as well as the preoperative level of the LDH serum marker.
Assuntos
Neoplasias Embrionárias de Células Germinativas , Neoplasias Testiculares , Masculino , Humanos , Neoplasias Testiculares/patologia , Orquiectomia , Senescência Celular , Lactato DesidrogenasesRESUMO
Identification and isolation of senescent cells is challenging, rendering their detailed analysis an unmet need. We describe a precise one-step protocol to fluorescently label senescent cells, for flow cytometry and fluorescence microscopy, implementing a fluorophore-conjugated Sudan Black-B analog, GLF16. Also, a micelle-based approach allows identification of senescent cells in vivo and in vitro, enabling live-cell sorting for downstream analyses and live in vivo tracking. Our protocols are applicable to cellular systems, tissues, or animal models where senescence is present. For complete details on the use and execution of this protocol, please refer to Magkouta et al.1.
Assuntos
Senescência Celular , Corantes Fluorescentes , Animais , Separação Celular , Citometria de Fluxo , Modelos AnimaisRESUMO
Intercellular adhesion molecule-1 (ICAM-1), a cell adhesion molecule with a key role in inflammation and immunosurveillance, has been implicated in carcinogenesis by facilitating instability of the tumor environment. The K469E single nucleotide polymorphism (SNP) (G>A) affects the ICAM-1 mRNA splicing pattern; the alternatively spliced isoform (ICAM-1-S) lacks transmembrane and intracellular domain, which affects the structural and signal transduction properties. Moreover, the expression of ICAM-1 is transcriptionally regulated by p53, and this SNP has been shown to be related with apoptosis. PCR-RFLP analysis was used to assess the K469E SNP status comparatively in 203 non-small cell lung cancer patients and 175 healthy sex-matched controls. This SNP was examined in relation to tumor kinetic parameters (Ki-67 immunohistochemical evaluation and Tdt-mediated dUTP nick end labeling assay), p53 immunohistochemistry status, and clinicopathological data in patients with operable stages. Both the genotype and allele frequency did not differ significantly between patients and controls. However, patients with the AG/AA genotypes had worse survival (39 vs 45 months, p = 0.036) and tended to be present in advanced stages (p = 0.057). Moreover, the AG/AA genotypes exerted a synergistic effect with aberrant p53 on tumor progression, while the GG genotype retained a better apoptotic index. The AG/AA genotypes correlated with worse survival and advanced stages probably due to defective immunosurveillance and apoptosis. These genetic backgrounds may confer a selective advantage for dissemination of tumor cells with high metastatic potential compared to GG genotype.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/mortalidade , Molécula 1 de Adesão Intercelular/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/mortalidade , Polimorfismo de Nucleotídeo Único , Adulto , Idoso , Idoso de 80 Anos ou mais , Alelos , Carcinoma Pulmonar de Células não Pequenas/patologia , Estudos de Casos e Controles , Progressão da Doença , Feminino , Frequência do Gene , Genótipo , Humanos , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Proteína Supressora de Tumor p53/genéticaRESUMO
Oral lichen planus (OLP) is a chronic oral inflammatory disease of unknown etiology. According to reports, 1-2% of OLP patients develop oral squamous cell carcinoma (OSCC) in the long run. While World Health Organization (WHO) classifies OLP as "a potentially malignant disorder," it is still a matter of debate which mechanisms drive OLP to such a condition. The current hypothesis connecting OLP and OSCC is that chronic inflammation results in crucial DNA damage which over time results in cancer development. Initial studies investigating the OLP and OSCC link were mainly retrospective clinical studies. Over the past years, several amount of information has accumulated, mainly from molecular studies on the OLP malignant potential. This article is a critical review of whether OLP has a malignant potential and, therefore, represents a model of preneoplastic inflammation.
Assuntos
Inflamação/patologia , Líquen Plano Bucal/patologia , Lesões Pré-Cancerosas/patologia , Humanos , Modelos BiológicosRESUMO
The etiology of sporadic cardiac myxomas remains elusive. The tendency for these lesions to recur following resection, their immunopathological characteristics, along with their histological and molecular profile, may implicate the presence of an infective agent in this type of tumor. In this study, we investigated the presence of herpes simplex virus (HSV) DNA in a cohort of cardiac myxomas in a tertiary referral centre. Twenty-nine formalin-fixed paraffin-embedded (FFPE) sporadic cardiac myxomas were obtained, 17 of which were shown to be informative. These were compared to 19 macroscopically and microscopically normal heart tissue specimens. The detection of HSV-1 and -2 genomic sequences was achieved with the use of a combined nested PCR-Restriction Fragment Length Polymorphism methodology. The presence of HSV-1 and/or -2 DNA was demonstrated in 6 of 17 (35%) informative sporadic cardiac myxomas, whereas no HSV DNA was detected in normal heart tissues (P < 0.01). The existence of HSV-1/2 DNA in sporadic cardiac myxomas, along with its absence from normal heart tissues, reinforces the possibility that HSV infection might be involved in the development of these lesions. Our findings raise the point of anti-HSV medication postsurgically with a potential benefit in reducing the rate of recurrences.
Assuntos
Neoplasias Cardíacas/virologia , Herpes Simples/virologia , Herpesvirus Humano 1/isolamento & purificação , Herpesvirus Humano 2/isolamento & purificação , Mixoma/virologia , Idoso , Estudos de Casos e Controles , DNA Viral/análise , Feminino , Átrios do Coração/patologia , Átrios do Coração/virologia , Neoplasias Cardíacas/química , Neoplasias Cardíacas/patologia , Ventrículos do Coração/patologia , Ventrículos do Coração/virologia , Herpes Simples/patologia , Herpesvirus Humano 1/genética , Herpesvirus Humano 2/genética , Histocitoquímica , Humanos , Masculino , Pessoa de Meia-Idade , Mixoma/química , Mixoma/patologia , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Estatísticas não ParamétricasRESUMO
The use of epidermal growth factor receptor-targeting antibodies in metastatic colorectal cancer has been restricted to patients with wild-type KRAS tumors by the European Medicines Agency since 2008, based on data showing a lack of efficacy and potential harm in patients with mutant KRAS tumors. In an effort to ensure optimal, uniform, and reliable community-based KRAS testing throughout Europe, a KRAS external quality assessment (EQA) scheme was set up. The first large assessment round included 59 laboratories from eight different European countries. For each country, one regional scheme organizer prepared and distributed the samples for the participants of their own country. The samples included unstained sections of 10 invasive colorectal carcinomas with known KRAS mutation status. The samples were centrally validated by one of two reference laboratories. The laboratories were allowed to use their own preferred method for histological evaluation, DNA isolation, and mutation analysis. In this study, we analyze the setup of the KRAS scheme. We analyzed the advantages and disadvantages of the regional scheme organization by analyzing the outcome of genotyping results, analysis of tumor percentage, and written reports. We conclude that only 70% of laboratories correctly identified the KRAS mutational status in all samples. Both the false-positive and false-negative results observed negatively affect patient care. Reports of the KRAS test results often lacked essential information. We aim to further expand this program to more laboratories to provide a robust estimate of the quality of KRAS testing in Europe, and provide the basis for remedial measures and harmonization.
Assuntos
Neoplasias Colorretais/genética , Análise Mutacional de DNA/normas , Genes ras , Laboratórios Hospitalares/normas , Proteínas Proto-Oncogênicas/genética , Garantia da Qualidade dos Cuidados de Saúde , Proteínas ras/genética , Anticorpos , Análise Mutacional de DNA/métodos , Receptores ErbB/imunologia , Europa (Continente) , Testes Genéticos , Genótipo , Humanos , Mutação , Proteínas Proto-Oncogênicas p21(ras) , Controle de QualidadeRESUMO
DNA damage checkpoint genes, such as p53, are frequently mutated in human cancer, but the selective pressure for their inactivation remains elusive. We analysed a panel of human lung hyperplasias, all of which retained wild-type p53 genes and had no signs of gross chromosomal instability, and found signs of a DNA damage response, including histone H2AX and Chk2 phosphorylation, p53 accumulation, focal staining of p53 binding protein 1 (53BP1) and apoptosis. Progression to carcinoma was associated with p53 or 53BP1 inactivation and decreased apoptosis. A DNA damage response was also observed in dysplastic nevi and in human skin xenografts, in which hyperplasia was induced by overexpression of growth factors. Both lung and experimentally-induced skin hyperplasias showed allelic imbalance at loci that are prone to DNA double-strand break formation when DNA replication is compromised (common fragile sites). We propose that, from its earliest stages, cancer development is associated with DNA replication stress, which leads to DNA double-strand breaks, genomic instability and selective pressure for p53 mutations.
Assuntos
Dano ao DNA , Instabilidade Genômica/genética , Lesões Pré-Cancerosas/patologia , Lesões Pré-Cancerosas/prevenção & controle , Desequilíbrio Alélico/genética , Apoptose , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Quinase do Ponto de Checagem 2 , Fragilidade Cromossômica , Dano ao DNA/genética , Replicação do DNA , Progressão da Doença , Ativação Enzimática , Genes p53/genética , Histonas/metabolismo , Humanos , Hiperplasia/enzimologia , Hiperplasia/genética , Hiperplasia/metabolismo , Hiperplasia/patologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Mutação/genética , Fosfoproteínas/metabolismo , Fosforilação , Lesões Pré-Cancerosas/enzimologia , Lesões Pré-Cancerosas/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53RESUMO
Cockayne syndrome (CS) is a DNA repair syndrome characterized by a broad spectrum of clinical manifestations such as neurodegeneration, premature aging, developmental impairment, photosensitivity and other symptoms. Mutations in Cockayne syndrome protein B (CSB) are present in the vast majority of CS patients and in other DNA repair-related pathologies. In the literature, the role of CSB in different DNA repair pathways has been highlighted, however, new CSB functions have been identified in DNA transcription, mitochondrial biology, telomere maintenance and p53 regulation. Herein, we present an overview of identified structural elements and processes that impact on CSB activity and its post-translational modifications, known to balance the different roles of the protein not only during normal conditions but most importantly in stress situations. Moreover, since CSB has been found to be overexpressed in a number of different tumors, its role in cancer is presented and possible therapeutic targeting is discussed.
Assuntos
Síndrome de Cockayne/genética , DNA Helicases/genética , Enzimas Reparadoras do DNA/genética , Neoplasias/genética , Proteínas de Ligação a Poli-ADP-Ribose/genética , Animais , Síndrome de Cockayne/metabolismo , Dano ao DNA , DNA Helicases/química , DNA Helicases/metabolismo , Reparo do DNA , Enzimas Reparadoras do DNA/química , Enzimas Reparadoras do DNA/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Modelos Moleculares , Mutação , Neoplasias/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/química , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Conformação Proteica , Processamento de Proteína Pós-TraducionalRESUMO
Protection of genome integrity is vital for all living organisms, particularly when DNA double-strand breaks (DSBs) occur. Eukaryotes have developed two main pathways, namely Non-Homologous End Joining (NHEJ) and Homologous Recombination (HR), to repair DSBs. While most of the current research is focused on the role of key protein players in the functional regulation of DSB repair pathways, accumulating evidence has uncovered a novel class of regulating factors termed non-coding RNAs. Non-coding RNAs have been found to hold a pivotal role in the activation of DSB repair mechanisms, thereby safeguarding genomic stability. In particular, long non-coding RNAs (lncRNAs) have begun to emerge as new players with vast therapeutic potential. This review summarizes important advances in the field of lncRNAs, including characterization of recently identified lncRNAs, and their implication in DSB repair pathways in the context of tumorigenesis.
Assuntos
Reparo do DNA/genética , Reparo do DNA/fisiologia , RNA Longo não Codificante/fisiologia , Animais , DNA/metabolismo , Quebras de DNA de Cadeia Dupla , Dano ao DNA/fisiologia , Reparo do DNA por Junção de Extremidades/fisiologia , Instabilidade Genômica , Humanos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Reparo de DNA por Recombinação/fisiologiaRESUMO
Circular RNAs (circRNA) comprise a distinct class of non-coding RNAs that are abundantly expressed in the cell. CircRNAs have the capacity to regulate gene expression by interacting with regulatory proteins and/or other classes of RNAs. While a vast number of circRNAs have been discovered, the majority still remains poorly characterized. Particularly, there is no detailed information on the identity and functional role of circRNAs that are transcribed from genes encoding components of the DNA damage response and repair (DDRR) network. In this article, we not only review the available published information on DDRR-related circRNAs, but also conduct a bioinformatic analysis on data obtained from public repositories to uncover deposited, yet uncharacterized circRNAs derived from components of the DDRR network. Finally, we interrogate for potential targets that are regulated by this class of molecules and look into potential functional implications.