RESUMEN
During the repair of interstrand crosslinks (ICLs) a DNA double-strand break (DSB) is generated. The Fanconi anemia (FA) core complex, which is recruited to ICLs, promotes high-fidelity repair of this DSB by homologous recombination (HR). However, whether the FA core complex also promotes HR at ICL-independent DSBs, for example induced by ionizing irradiation or nucleases, remains controversial. Here, we identified the FA core complex members FANCL and Ube2T as HR-promoting factors in a CRISPR/Cas9-based screen. Using isogenic cell line models, we further demonstrated an HR-promoting function of FANCL and Ube2T, and of their ubiquitination substrate FANCD2. We show that FANCL and Ube2T localize at DSBs in a FANCM-dependent manner, and are required for the DSB accumulation of FANCD2. Mechanistically, we demonstrate that FANCL ubiquitin ligase activity is required for the accumulation of CtIP at DSBs, thereby promoting end resection and Rad51 loading. Together, these data demonstrate a dual genome maintenance function of the FA core complex and FANCD2 in promoting repair of both ICLs and DSBs.
Asunto(s)
Roturas del ADN de Doble Cadena , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi , Proteína del Grupo de Complementación L de la Anemia de Fanconi , Recombinación Homóloga , Enzimas Ubiquitina-Conjugadoras , Humanos , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación L de la Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación L de la Anemia de Fanconi/genética , Enzimas Ubiquitina-Conjugadoras/metabolismo , Enzimas Ubiquitina-Conjugadoras/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Proteínas Portadoras/metabolismo , Proteínas Portadoras/genética , Sistemas CRISPR-Cas , Ubiquitinación , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Endodesoxirribonucleasas/metabolismo , Endodesoxirribonucleasas/genética , Células HEK293 , Reparación del ADN por Recombinación , Reparación del ADN , Reparación del ADN por Unión de Extremidades , ADN HelicasasRESUMEN
Histone lysine methyltransferase 2D (KMT2D) is the most frequently mutated epigenetic modifier in head and neck squamous cell carcinoma (HNSCC). However, the role of KMT2D in HNSCC tumorigenesis and whether its mutations confer any therapeutic vulnerabilities remain unknown. Here we show that KMT2D deficiency promotes HNSCC growth through increasing glycolysis. Additionally, KMT2D loss decreases the expression of Fanconi Anemia (FA)/BRCA pathway genes under glycolytic inhibition. Mechanistically, glycolytic inhibition facilitates the occupancy of KMT2D to the promoter/enhancer regions of FA genes. KMT2D loss reprograms the epigenomic landscapes of FA genes by transiting their promoter/enhancer states from active to inactive under glycolytic inhibition. Therefore, combining the glycolysis inhibitor 2-DG with DNA crosslinking agents or poly (ADP-ribose) polymerase (PARP) inhibitors preferentially inhibits tumor growth of KMT2D-deficient mouse HNSCC and patient-derived xenografts (PDXs) harboring KMT2D-inactivating mutations. These findings provide an epigenomic basis for developing targeted therapies for HNSCC patients with KMT2D-inactivating mutations.
Asunto(s)
Glucólisis , Carcinoma de Células Escamosas de Cabeza y Cuello , Animales , Humanos , Ratones , Glucólisis/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Línea Celular Tumoral , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/deficiencia , Proteína BRCA2/genética , Proteína BRCA2/metabolismo , Proteína BRCA2/deficiencia , N-Metiltransferasa de Histona-Lisina/metabolismo , N-Metiltransferasa de Histona-Lisina/genética , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/metabolismo , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/patología , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Regulación Neoplásica de la Expresión Génica , Ensayos Antitumor por Modelo de Xenoinjerto , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Femenino , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Transducción de Señal , Regiones Promotoras Genéticas/genética , Proteína de la Leucemia Mieloide-LinfoideRESUMEN
Fanconi anemia (FA) is a hereditary disorder characterized by a deficiency in the repair of DNA interstrand crosslinks and the response to replication stress. Endogenous DNA damage, most likely caused by aldehydes, severely affects hematopoietic stem cells in FA, resulting in progressive bone marrow failure and the development of leukemia. Recent studies revealed that expression levels of SLFN11 affect the replication stress response and are a strong determinant in cell killing by DNA-damaging cancer chemotherapy. Because SLFN11 is highly expressed in the hematopoietic system, we speculated that SLFN11 may have a significant role in FA pathophysiology. Indeed, we found that DNA damage sensitivity in FA cells is significantly mitigated by the loss of SLFN11 expression. Mechanistically, we demonstrated that SLFN11 destabilizes the nascent DNA strands upon replication fork stalling. In this review, we summarize our work regarding an interplay between SLFN11 and the FA pathway, and the role of SLFN11 in the response to replication stress.
Asunto(s)
Daño del ADN , Replicación del ADN , Anemia de Fanconi , Proteínas Nucleares , Anemia de Fanconi/metabolismo , Anemia de Fanconi/genética , Humanos , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Animales , Reparación del ADN , Proteínas del Grupo de Complementación de la Anemia de Fanconi/metabolismo , Proteínas del Grupo de Complementación de la Anemia de Fanconi/genéticaRESUMEN
Fanconi anemia (FA) is an inherited disorder of DNA repair due to mutation in one of 20+ interrelated genes that repair intrastrand DNA crosslinks and rescue collapsed or stalled replication forks. The most common hematologic abnormality in FA is anemia, but progression to bone marrow failure (BMF), clonal hematopoiesis, or acute myeloid leukemia may also occur. In prior studies, we found that Fanconi DNA repair is required for successful emergency granulopoiesis; the process for rapid neutrophil production during the innate immune response. Specifically, Fancc-/- mice did not develop neutrophilia in response to emergency granulopoiesis stimuli, but instead exhibited apoptosis of bone marrow hematopoietic stem cells and differentiating neutrophils. Repeated emergency granulopoiesis challenges induced BMF in most Fancc-/- mice, with acute myeloid leukemia in survivors. In contrast, we found equivalent neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice and WT mice, without BMF. Since termination of emergency granulopoiesis is triggered by accumulation of bone marrow neutrophils, we hypothesize neutrophilia protects Fancc-/-Tp53+/- bone marrow from the stress of a sustained inflammation that is experienced by Fancc-/- mice. In the current work, we found that blocking neutrophil accumulation during emergency granulopoiesis led to BMF in Fancc-/-Tp53+/- mice, consistent with this hypothesis. Blocking neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice (but not WT) impaired cell cycle checkpoint activity, also found in Fancc-/- mice. Mechanisms for loss of cell cycle checkpoints during infectious disease challenges may define molecular markers of FA progression, or suggest therapeutic targets for bone marrow protection in this disorder.
Asunto(s)
Proteína del Grupo de Complementación C de la Anemia de Fanconi , Anemia de Fanconi , Células Madre Hematopoyéticas , Ratones Noqueados , Neutrófilos , Animales , Anemia de Fanconi/patología , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Neutrófilos/metabolismo , Neutrófilos/patología , Ratones , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/patología , Proteína del Grupo de Complementación C de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación C de la Anemia de Fanconi/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/genética , Hematopoyesis , Ratones Endogámicos C57BL , Médula Ósea/metabolismo , Médula Ósea/patologíaRESUMEN
The twenty-three Fanconi anemia (FA) proteins cooperate in the FA/BRCA pathway to repair DNA interstrand cross-links (ICLs). The cell division cycle and apoptosis regulator 1 (CCAR1) protein is also a regulator of ICL repair, though its possible function in the FA/BRCA pathway remains unknown. Here, we demonstrate that CCAR1 plays a unique upstream role in the FA/BRCA pathway and is required for FANCA protein expression in human cells. Interestingly, CCAR1 co-immunoprecipitates with FANCA pre-mRNA and is required for FANCA mRNA processing. Loss of CCAR1 results in retention of a poison exon in the FANCA transcript, thereby leading to reduced FANCA protein expression. A unique domain of CCAR1, the EF hand domain, is required for interaction with the U2AF heterodimer of the spliceosome and for excision of the poison exon. Taken together, CCAR1 is a splicing modulator required for normal splicing of the FANCA mRNA and other mRNAs involved in various cellular pathways.
Asunto(s)
Proteínas Reguladoras de la Apoptosis , Proteínas de Ciclo Celular , Proteína del Grupo de Complementación A de la Anemia de Fanconi , Anemia de Fanconi , Empalme del ARN , Factor de Empalme U2AF , Humanos , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Proteína BRCA2/metabolismo , Proteína BRCA2/genética , Reparación del ADN , Endodesoxirribonucleasas , Exones , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación A de la Anemia de Fanconi/metabolismo , Células HEK293 , Células HeLa , Unión Proteica , Precursores del ARN/metabolismo , Precursores del ARN/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transducción de Señal , Empalmosomas/metabolismo , Empalmosomas/genética , Factor de Empalme U2AF/metabolismo , Factor de Empalme U2AF/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismoRESUMEN
In this issue of Molecular Cell, Harada et al.1 and Karasu et al.2 identify CCAR1 as a novel regulator of the Fanconi anemia/BRCA DNA repair pathway via modulating the splicing of the mRNA encoding FANCA.
Asunto(s)
Reparación del ADN , Empalme del ARN , Humanos , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación A de la Anemia de Fanconi/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismoRESUMEN
DNA repair is directly performed by hundreds of core factors and indirectly regulated by thousands of others. We massively expanded a CRISPR inhibition and Cas9-editing screening system to discover factors indirectly modulating homology-directed repair (HDR) in the context of â¼18,000 individual gene knockdowns. We focused on CCAR1, a poorly understood gene that we found the depletion of reduced both HDR and interstrand crosslink repair, phenocopying the loss of the Fanconi anemia pathway. CCAR1 loss abrogated FANCA protein without substantial reduction in the level of its mRNA or that of other FA genes. We instead found that CCAR1 prevents inclusion of a poison exon in FANCA. Transcriptomic analysis revealed that the CCAR1 splicing modulatory activity is not limited to FANCA, and it instead regulates widespread changes in alternative splicing that would damage coding sequences in mouse and human cells. CCAR1 therefore has an unanticipated function as a splicing fidelity factor.
Asunto(s)
Empalme Alternativo , Proteína del Grupo de Complementación A de la Anemia de Fanconi , Humanos , Animales , Ratones , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación A de la Anemia de Fanconi/metabolismo , Reparación del ADN por Recombinación , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Células HEK293 , Exones , Sistemas CRISPR-Cas , Reparación del ADN , Células HeLa , Daño del ADNRESUMEN
Genomic instability is not only a hallmark of senescent cells but also a key factor driving cellular senescence, and replication stress is the main source of genomic instability. Defective prelamin A processing caused by lamin A/C (LMNA) or zinc metallopeptidase STE24 (ZMPSTE24) gene mutations results in premature aging. Although previous studies have shown that dysregulated lamin A interferes with DNA replication and causes replication stress, the relationship between lamin A dysfunction and replication stress remains largely unknown. Here, an increase in baseline replication stress and genomic instability is found in prelamin A-expressing cells. Moreover, prelamin A confers hypersensitivity of cells to exogenous replication stress, resulting in decreased cell survival and exacerbated genomic instability. These effects occur because prelamin A promotes MRE11-mediated resection of stalled replication forks. Fanconi anemia (FA) proteins, which play important roles in replication fork maintenance, are downregulated by prelamin A in a retinoblastoma (RB)/E2F-dependent manner. Additionally, prelamin A inhibits the activation of the FA pathway upon replication stress. More importantly, FA pathway downregulation is an upstream event of p53-p21 axis activation during the induction of prelamin A expression. Overall, these findings highlight the critical role of FA pathway dysfunction in driving replication stress-induced genomic instability and cellular senescence in prelamin A-expressing cells.
Asunto(s)
Replicación del ADN , Inestabilidad Genómica , Lamina Tipo A , Inestabilidad Genómica/genética , Lamina Tipo A/genética , Lamina Tipo A/metabolismo , Humanos , Replicación del ADN/genética , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Senescencia Celular/genéticaRESUMEN
Fanconi anemia (FA) is an autosomal or X-linked human disease, characterized by bone marrow failure, cancer susceptibility and various developmental abnormalities. So far, at least 22 FA genes (FANCA-W) have been identified. Germline inactivation of any one of these FA genes causes FA symptoms. Proteins encoded by FA genes are involved in the Fanconi anemia pathway, which is known for its roles in DNA inter-strand crosslinks (ICLs) repair. Besides, its roles in genome maintenance upon replication stress has also been reported. Post-translational modifications (PTMs) of FA proteins, particularly phosphorylation and ubiquitination, emerge as critical determinants in the activation of the FA pathway during ICL repair or replication stress response. Consequent inactivation of the FA pathway engenders heightened chromosomal instability, thereby constituting a genetic susceptibility conducive to cancer predisposition and the exacerbation of tumorigenesis. In this review, we have combined recent structural analysis of FA proteins and summarized knowledge on the functions of different PTMs in regulating FA pathways, and discuss potential contributions stemming from mutations at PTMs to the genesis and progression of tumorigenesis.
Asunto(s)
Proteínas del Grupo de Complementación de la Anemia de Fanconi , Procesamiento Proteico-Postraduccional , Humanos , Proteínas del Grupo de Complementación de la Anemia de Fanconi/metabolismo , Proteínas del Grupo de Complementación de la Anemia de Fanconi/genética , Carcinogénesis/metabolismo , Carcinogénesis/genética , Anemia de Fanconi/metabolismo , Anemia de Fanconi/genética , Animales , Reparación del ADNRESUMEN
Fanconi Anemia (FA) pathway resolves DNA interstrand cross links (ICL). The FA pathway was initially recognized in vertebrates, but was later confirmed in other animals and speculated in fungi. FA proteins FANCM, FANCL and FANCJ are present in Saccharomyces cerevisiae but, their mechanism of interaction to resolve ICL is still unclear. Unlike Dikarya, early diverging fungi (EDF) possess more traits shared with animals. We traced the evolutionary history of the FA pathway across Opisthokonta. We scanned complete proteomes for FA-related homologs to establish their taxonomic distribution and analyzed their phylogenetic trees. We checked transcription profiles of FA genes to test if they respond to environmental conditions and their genomic localizations for potential co-localization. We identified fungal homologs of the activation and ID complexes, 5 out of 8 core proteins, all of the endonucleases, and deubiquitination proteins. All fungi lack FANCC, FANCF and FANCG proteins responsible for post-replication repair and chromosome stability in animals. The observed taxonomic distribution can be attributed to a gradual degradation of the FA pathway from EDF to Dikarya. One of the key differences is that EDF have the ID complex recruiting endonucleases to the site of ICL. Moreover, 21 out of 32 identified FA genes are upregulated in response to different growth conditions. Several FA genes are co-localized in fungal genomes which also could facilitate co-expression. Our results indicate that a minimal FA pathway might still be functional in Mucoromycota with a gradual loss of components in Dikarya ancestors.
Asunto(s)
Filogenia , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteínas del Grupo de Complementación de la Anemia de Fanconi/metabolismo , Proteínas del Grupo de Complementación de la Anemia de Fanconi/genética , Hongos/genética , Hongos/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Evolución Molecular , Reparación del ADNRESUMEN
Demand-adjusted and cell type specific rates of protein synthesis represent an important safeguard for fate and function of long-term hematopoietic stem cells. Here, we identify increased protein synthesis rates in the fetal hematopoietic stem cell pool at the onset of hematopoietic failure in Fanconi Anemia, a prototypical DNA repair disorder that manifests with bone marrow failure. Mechanistically, the accumulation of misfolded proteins in Fancd2-/- fetal liver hematopoietic stem cells converges on endoplasmic reticulum stress, which in turn constrains midgestational expansion. Restoration of protein folding by the chemical chaperone tauroursodeoxycholic acid, a hydrophilic bile salt, prevents accumulation of unfolded proteins and rescues Fancd2-/- fetal liver long-term hematopoietic stem cell numbers. We find that proteostasis deregulation itself is driven by excess sterile inflammatory activity in hematopoietic and stromal cells within the fetal liver, and dampened Type I interferon signaling similarly restores fetal Fancd2-/- long-term hematopoietic stem cells to wild type-equivalent numbers. Our study reveals the origin and pathophysiological trigger that gives rise to Fanconi anemia hematopoietic stem cell pool deficits. More broadly, we show that fetal protein homeostasis serves as a physiological rheostat for hematopoietic stem cell fate and function.
Asunto(s)
Anemia de Fanconi , Humanos , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteostasis , Células Madre Hematopoyéticas/metabolismo , Ciclo Celular , Feto/metabolismo , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/metabolismoRESUMEN
Fanconi anemia (FA) is characterized by congenital abnormalities, bone marrow failure, and cancer susceptibility. The central FA protein complex FANCI/FANCD2 (ID2) is activated by monoubiquitination and recruits DNA repair proteins for interstrand crosslink (ICL) repair and replication fork protection. Defects in the FA pathway lead to R-loop accumulation, which contributes to genomic instability. Here, we report that the splicing factor SRSF1 and FANCD2 interact physically and act together to suppress R-loop formation via mRNA export regulation. We show that SRSF1 stimulates FANCD2 monoubiquitination in an RNA-dependent fashion. In turn, FANCD2 monoubiquitination proves crucial for the assembly of the SRSF1-NXF1 nuclear export complex and mRNA export. Importantly, several SRSF1 cancer-associated mutants fail to interact with FANCD2, leading to inefficient FANCD2 monoubiquitination, decreased mRNA export, and R-loop accumulation. We propose a model wherein SRSF1 and FANCD2 interaction links DNA damage response to the avoidance of pathogenic R-loops via regulation of mRNA export.
Asunto(s)
Anemia de Fanconi , Neoplasias , Humanos , Estructuras R-Loop , Transporte Activo de Núcleo Celular , Anemia de Fanconi/metabolismo , Proteínas del Grupo de Complementación de la Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/metabolismo , Ubiquitinación , Reparación del ADN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Daño del ADN , Factores de Empalme Serina-Arginina/genética , Factores de Empalme Serina-Arginina/metabolismoRESUMEN
Monoubiquitination of FANCD2 is a central step in the activation of the Fanconi anemia (FA) pathway after DNA damage. Defects in the FA pathway centered around FANCD2 not only lead to genomic instability but also induce tumorigenesis. At present, few studies have investigated FANCD2 in tumors, and no pan-cancer research on FANCD2 has been conducted. We conducted a comprehensive analysis of the role of FANCD2 in cancer using public databases and other published studies. Moreover, we evaluated the role of FANCD2 in the proliferation, migration and invasion of lung adenocarcinoma cells through in vitro and in vivo experiments, and explored the role of FANCD2 in cisplatin chemoresistance. We investigated the regulatory effect of FANCD2 on the cell cycle of lung adenocarcinoma cells by flow cytometry, and verified this effect by western blotting. FANCD2 expression is elevated in most TCGA tumors and shows a strong positive correlation with poor prognosis in tumor patients. In addition, FANCD2 expression shows strong correlations with immune infiltration, immune checkpoints, the tumor mutation burden (TMB), and microsatellite instability (MSI), which are immune-related features, suggesting that it may be a potential target of tumor immunotherapy. We further found that FANCD2 significantly promotes the proliferation, invasion, and migration abilities of lung adenocarcinoma cells and that its ability to promote cancer cell proliferation may be achieved by modulating the cell cycle. The findings indicate that FANCD2 is a potential biomarker and therapeutic target in cancer treatment by analyzing the oncogenic role of FANCD2 in different tumors.
Asunto(s)
Carcinogénesis , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi , Neoplasias , Humanos , Adenocarcinoma del Pulmón/genética , Adenocarcinoma del Pulmón/patología , Carcinogénesis/genética , Daño del ADN , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/metabolismo , Neoplasias/genética , Neoplasias/patologíaRESUMEN
BACKGROUND: ATM and ATR are two critical factors to regulate DNA damage response (DDR), and their mutations were frequently observed in different types of cancer, including non-small cell lung cancer (NSCLC). Given that the majority of identified ATM/ATR mutations were variants of uncertain significance, the clinical/molecular features of pathogenic ATM/ATR aberrations have not been comprehensively investigated in NSCLC. METHODS: Next-generation sequencing (NGS) analyses were conducted to investigate the molecular features in 191 NSCLC patients who harbored pathogenic/likely pathogenic ATM/ATR mutations and 308 NSCLC patients who did not have any types of ATM/ATR variants. The results were validated using an external cohort of 2727 NSCLC patients (including 48 with ATM/ATR pathogenic mutations). RESULTS: Most pathogenic ATM/ATR genetic alterations were frameshift and nonsense mutations that disrupt critical domains of the two proteins. ATM/ATR-mutated patients had significantly higher tumor mutational burdens (TMB; P < 0.001) and microsatellite instabilities (MSI; P = 0.023), but not chromosomal instabilities, than those without any ATM/ATR variations. In particular, KRAS mutations were significantly enriched in ATM-mutated patients (P = 0.014), whereas BRCA2 mutations (P = 0.014), TP53 mutations (P = 0.014), and ZNF703 amplification (P = 0.008) were enriched in ATR-mutated patients. Notably, patients with ATM/ATR pathogenic genetic alterations were likely to be accompanied by mutations in Fanconi anemia (FA) and homologous recombination (HR) pathways, which were confirmed using both the study (P < 0.001) and validation (P < 0.001) cohorts. Furthermore, the co-occurrence of FA/HR aberrations could contribute to increased TMB and MSI, and patients with both ATM/ATR and FA/HR mutations tended to have worse overall survival. CONCLUSIONS: Our results demonstrated the unique clinical and molecular features of pathogenic ATM/ATR mutations in NSCLC, which helps better understand the cancerous involvement of these DDR regulators, as well as directing targeted therapies and/or immunotherapies to treat ATM/ATR-mutated NSCLC, especially those with co-existing FA/HR aberrations.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Anemia de Fanconi , Neoplasias Pulmonares , Humanos , Carcinoma de Pulmón de Células no Pequeñas/genética , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Neoplasias Pulmonares/genética , Mutación/genética , Pronóstico , Recombinación Homóloga/genética , Proteínas Portadoras/genética , Proteínas de la Ataxia Telangiectasia Mutada/genética , Proteínas de la Ataxia Telangiectasia Mutada/metabolismoRESUMEN
BACKGROUND: Individuals diagnosed with Fanconi anemia (FA), an uncommon disorder characterized by chromosomal instability affecting the FA signaling pathway, exhibit heightened vulnerability to the onset of myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML). METHODS: Herein, we employed diverse bioinformatics and statistical analyses to investigate the potential associations between the expression/mutation patterns of FA pathway genes and MDS/AML. RESULTS: The study included 4295 samples, comprising 3235 AML and 1024 MDS from our and nine other online cohorts. We investigated the distinct proportion of race, age, French-American-British, and gender factors. Compared to the FA wild-type group, we observed a decrease in the expression of FNACD2, FANCI, and RAD51C in the FA mutation group. The FA mutation group exhibited a more favorable clinical overall survival prognosis. We developed a random forest classifier and a decision tree based on FA gene expression for cytogenetic risk assessment. Furthermore, we created an FA-related Nomogram to predict survival rates in AML patients. CONCLUSIONS: This investigation facilitates a deeper understanding of the functional links between FA and MDS/AML.
Asunto(s)
Anemia de Fanconi , Leucemia Mieloide Aguda , Síndromes Mielodisplásicos , Humanos , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Síndromes Mielodisplásicos/genética , Leucemia Mieloide Aguda/genética , Mutación , Pronóstico , Transducción de Señal/genéticaRESUMEN
Fanconi anemia (FA) is a rare genetic disease caused by a defect in DNA repair pathway for DNA interstrand crosslinks. These crosslinks can potentially impede the progression of the DNA replication fork, consequently leading to DNA double-strand breaks. Heterozygous RAD51-Q242R mutation has been reported to cause FA-like symptoms. However, the molecular defect of RAD51 underlying the disease is largely unknown. In this study, we conducted a biochemical analysis of RAD51-Q242R protein, revealing notable deficiencies in its DNA-dependent ATPase activity and its ATP-dependent regulation of DNA-binding activity. Interestingly, although RAD51-Q242R exhibited the filament instability and lacked the ability to form displacement loop, it efficiently stimulated the formation of displacement loops mediated by wild-type RAD51. These findings facilitate understanding of the biochemical properties of the mutant protein and how RAD51 works in the FA patient cells.
Asunto(s)
Adenosina Trifosfatasas , Reparación del ADN , Anemia de Fanconi , Recombinasa Rad51 , Humanos , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , ADN/metabolismo , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Mutación , Recombinasa Rad51/genética , Recombinasa Rad51/metabolismoRESUMEN
BACKGROUND/AIM: Patients with radiation sensitive Fanconi anemia (FA) are presenting with cancers of the oral cavity, oropharynx, and other anatomic locations. MATERIALS AND METHODS: Animal models for cancer in FA mice used orthotopic tumors from wild type mice. We derived a cancer cell line from Fanca-/- mice by topical application of the chemical carcinogen dimethyl benzanthracene (DMBA). RESULTS: A Fanca-/- mouse rhabdomyosarcoma was derived from a Fanca-/- (129/Sv) mouse. The in vitro clonogenic survival of the Fanca-/- clone 6 cancer cell line was consistent with the FA genotype. Transplanted tumors demonstrated hypoxic centers surrounded by senescent cells. CONCLUSION: This Fanca-/- mouse syngeneic cancer should provide a valuable resource for discovery and development of new normal tissue radioprotectors for patients with FA and cancer.
Asunto(s)
Anemia de Fanconi , Neoplasias , Humanos , Ratones , Animales , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Línea Celular , Carcinógenos/toxicidad , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genéticaRESUMEN
Fanconi anemia (FA) is a clinically variable and genetically heterogeneous cancer-predisposing disorder representing the most common bone marrow failure syndrome. It is caused by inactivating predominantly biallelic mutations involving >20 genes encoding proteins with roles in the FA/BRCA DNA repair pathway. Molecular diagnosis of FA is challenging due to the wide spectrum of the contributing gene mutations and structural rearrangements. The assessment of chromosomal fragility after exposure to DNA cross-linking agents is generally required to definitively confirm diagnosis. We assessed peripheral blood genome-wide DNA methylation (DNAm) profiles in 25 subjects with molecularly confirmed clinical diagnosis of FA (FANCA complementation group) using Illumina's Infinium EPIC array. We identified 82 differentially methylated CpG sites that allow to distinguish subjects with FA from healthy individuals and subjects with other genetic disorders, defining an FA-specific DNAm signature. The episignature was validated using a second cohort of subjects with FA involving different complementation groups, documenting broader genetic sensitivity and demonstrating its specificity using the EpiSign Knowledge Database. The episignature properly classified DNA samples obtained from bone marrow aspirates, demonstrating robustness. Using the selected probes, we trained a machine-learning model able to classify EPIC DNAm profiles in molecularly unsolved cases. Finally, we show that the generated episignature includes CpG sites that do not undergo functional selective pressure, allowing diagnosis of FA in individuals with reverted phenotype due to gene conversion. These findings provide a tool to accelerate diagnostic testing in FA and broaden the clinical utility of DNAm profiling in the diagnostic setting.
Asunto(s)
Anemia de Fanconi , Humanos , Anemia de Fanconi/diagnóstico , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteínas del Grupo de Complementación de la Anemia de Fanconi/genética , Proteínas del Grupo de Complementación de la Anemia de Fanconi/metabolismo , Metilación de ADN/genética , Proteínas/genética , ADN/metabolismoRESUMEN
The Fanconi anemia pathway is a key pathway involved in the repair of deoxyribonucleic acidinterstrand crosslinking damage, which chiefly includes the following four modules: lesion recognition, Fanconi anemia core complex recruitment, FANCD2-FANCI complex monoubiquitination, and downstream events (nucleolytic incision, translesion synthesis, and homologous recombination). Mutations or deletions of multiple Fanconi anemia genes in this pathway can damage the interstrand crosslinking repair pathway and disrupt primordial germ cell development and oocyte meiosis, thereby leading to abnormal follicular development. Premature ovarian insufficiency is a gynecological clinical syndrome characterized by amenorrhea and decreased fertility due to decreased oocyte pool, accelerated follicle atresia, and loss of ovarian function in women <40 years old. Furthermore, in recent years, several studies have detected mutations in the Fanconi anemia gene in patients with premature ovarian insufficiency. In addition, some patients with Fanconi anemia exhibit symptoms of premature ovarian insufficiency and infertility. The Fanconi anemia pathway and premature ovarian insufficiency are closely associated.
Asunto(s)
Anemia de Fanconi , Humanos , Femenino , Adulto , Anemia de Fanconi/complicaciones , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Reparación del ADN/genética , Replicación del ADN , Ubiquitinación , Mutación , Daño del ADNRESUMEN
Alcohol contributes to cellular accumulation of acetaldehyde, a primary metabolite of alcohol and a major human carcinogen. Acetaldehyde can form DNA adducts and induce interstrand crosslinks (ICLs) that are repaired by the Fanconi anemia DNA repair pathway (FA pathway). Individuals with deficiency in acetaldehyde detoxification or in the FA pathway have an increased risk of squamous-cell carcinomas (SCCs) including those of the esophagus. In a recent report, we described the molecular basis of acetaldehyde-induced DNA damage in esophageal keratinocytes [1]. We demonstrated that, at physiologically relevant concentrations, acetaldehyde induces DNA damage at the DNA replication fork. This resulted in replication stress, leading to activation of the ATR-Chk1-dependent cell cycle checkpoints. We also reported that the p53 DNA damage response is elevated in response to acetaldehyde and that the FA pathway limits acetaldehyde-induced genomic instability. Here, we highlight these findings and present additional results to discuss the role of the FA pathway and p53 DNA damage response in the protection against genomic instability and esophageal carcinogenesis.