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1.
Nucleic Acids Res ; 51(19): 10484-10505, 2023 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-37697435

RESUMO

Breast cancer linked with BRCA1/2 mutations commonly recur and resist current therapies, including PARP inhibitors. Given the lack of effective targeted therapies for BRCA1-mutant cancers, we sought to identify novel targets to selectively kill these cancers. Here, we report that loss of RNF8 significantly protects Brca1-mutant mice against mammary tumorigenesis. RNF8 deficiency in human BRCA1-mutant breast cancer cells was found to promote R-loop accumulation and replication fork instability, leading to increased DNA damage, senescence, and synthetic lethality. Mechanistically, RNF8 interacts with XRN2, which is crucial for transcription termination and R-loop resolution. We report that RNF8 ubiquitylates XRN2 to facilitate its recruitment to R-loop-prone genomic loci and that RNF8 deficiency in BRCA1-mutant breast cancer cells decreases XRN2 occupancy at R-loop-prone sites, thereby promoting R-loop accumulation, transcription-replication collisions, excessive genomic instability, and cancer cell death. Collectively, our work identifies a synthetic lethal interaction between RNF8 and BRCA1, which is mediated by a pathological accumulation of R-loops.


Assuntos
Proteína BRCA1 , Neoplasias da Mama , Animais , Feminino , Humanos , Camundongos , Proteína BRCA1/metabolismo , Proteína BRCA2/genética , Neoplasias da Mama/genética , Dano ao DNA , Proteínas de Ligação a DNA/metabolismo , Exorribonucleases/metabolismo , Instabilidade Genômica , Recidiva Local de Neoplasia , Estruturas R-Loop , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
2.
Hum Mutat ; 42(11): 1488-1502, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34420246

RESUMO

Germline pathogenic variants in BRCA1 confer a high risk of developing breast and ovarian cancer. The BRCA1 exon 11 (formally exon 10) is one of the largest exons and codes for the nuclear localization signals of the corresponding gene product. This exon can be partially or entirely skipped during pre-mRNA splicing, leading to three major in-frame isoforms that are detectable in most cell types and tissue, and in normal and cancer settings. However, it is unclear whether the splicing imbalance of this exon is associated with cancer risk. Here we identify a common genetic variant in intron 10, rs5820483 (NC_000017.11:g.43095106_43095108dup), which is associated with exon 11 isoform expression and alternative splicing, and with the risk of breast cancer, but not ovarian cancer, in BRCA1 pathogenic variant carriers. The identification of this genetic effect was confirmed by analogous observations in mouse cells and tissue in which a loxP sequence was inserted in the syntenic intronic region. The prediction that the rs5820483 minor allele variant would create a binding site for the splicing silencer hnRNP A1 was confirmed by pull-down assays. Our data suggest that perturbation of BRCA1 exon 11 splicing modifies the breast cancer risk conferred by pathogenic variants of this gene.


Assuntos
Neoplasias da Mama/genética , Éxons , Genes BRCA1 , Triagem de Portadores Genéticos , Predisposição Genética para Doença , Splicing de RNA , Feminino , Humanos , Íntrons
3.
Genome Res ; 26(6): 732-44, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27197215

RESUMO

Alternative splicing is regulated by multiple RNA-binding proteins and influences the expression of most eukaryotic genes. However, the role of this process in human disease, and particularly in cancer, is only starting to be unveiled. We systematically analyzed mutation, copy number, and gene expression patterns of 1348 RNA-binding protein (RBP) genes in 11 solid tumor types, together with alternative splicing changes in these tumors and the enrichment of binding motifs in the alternatively spliced sequences. Our comprehensive study reveals widespread alterations in the expression of RBP genes, as well as novel mutations and copy number variations in association with multiple alternative splicing changes in cancer drivers and oncogenic pathways. Remarkably, the altered splicing patterns in several tumor types recapitulate those of undifferentiated cells. These patterns are predicted to be mainly controlled by MBNL1 and involve multiple cancer drivers, including the mitotic gene NUMA1 We show that NUMA1 alternative splicing induces enhanced cell proliferation and centrosome amplification in nontumorigenic mammary epithelial cells. Our study uncovers novel splicing networks that potentially contribute to cancer development and progression.


Assuntos
Processamento Alternativo , Neoplasias/genética , Transcriptoma , Motivos de Aminoácidos , Sítios de Ligação , Proliferação de Células , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Genoma Humano , Humanos , Mutação , Neoplasias/metabolismo , Fatores de Processamento de RNA/fisiologia
5.
Breast Cancer Res Treat ; 156(1): 195-201, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26951504

RESUMO

Molecular evidence has linked the pathophysiology of lymphangioleiomyomatosis (LAM) to that of metastatic breast cancer. Following on this observation, we assessed the association between LAM and subsequent breast cancer. An epidemiological study was carried out using three LAM country cohorts, from Japan, Spain, and the United Kingdom. The number of incident breast cancer cases observed in these cohorts was compared with the number expected on the basis of the country-specific incidence rates for the period 2000-2014. Immunohistochemical studies and exome sequence analysis were performed in two and one tumors, respectively. All cohorts revealed breast cancer standardized incidence ratios (SIRs) ≥ 2.25. The combined analysis of all cases or restricted to pre-menopausal age groups revealed significantly higher incidence of breast cancer: SIR = 2.81, 95 % confidence interval (CI) = 1.32-5.57, P = 0.009; and SIR = 4.88, 95 % CI = 2.29-9.99, P = 0.0007, respectively. Immunohistochemical analyses showed positivity for known markers of lung metastatic potential. This study suggests the existence of increased breast cancer risk among LAM patients. Prospective studies may be warranted to corroborate this result, which may be particularly relevant for pre-menopausal women with LAM.


Assuntos
Neoplasias da Mama/epidemiologia , Linfangioleiomiomatose/complicações , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Feminino , Humanos , Incidência , Japão/epidemiologia , Linfangioleiomiomatose/genética , Linfangioleiomiomatose/metabolismo , Metástase Neoplásica , Análise de Sequência de DNA , Espanha/epidemiologia , Reino Unido/epidemiologia
6.
J Biol Chem ; 288(29): 21096-21104, 2013 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-23760262

RESUMO

PCAF and GCN5 acetylate cyclin A at specific lysine residues targeting it for degradation at mitosis. We report here that histone deacetylase 3 (HDAC3) directly interacts with and deacetylates cyclin A. HDAC3 interacts with a domain included in the first 171 aa of cyclin A, a region involved in the regulation of its stability. In cells, overexpression of HDAC3 reduced cyclin A acetylation whereas the knocking down of HDAC3 increased its acetylation. Moreover, reduction of HDAC3 levels induced a decrease of cyclin A that can be reversed by proteasome inhibitors. These results indicate that HDAC3 is able to regulate cyclin A degradation during mitosis via proteasome. Interestingly, HDAC3 is abruptly degraded at mitosis also via proteasome thus facilitating cyclin A acetylation by PCAF/GCN5, which will target cyclin A for degradation. Because cyclin A is crucial for S phase progression and mitosis entry, the knock down of HDAC3 affects cell cycle progression specifically at both, S phase and G2/M transition. In summary we propose here that HDAC3 regulates cyclin A stability by counteracting the action of the acetylases PCAF/GCN5.


Assuntos
Ciclina A1/metabolismo , Histona Desacetilases/metabolismo , Acetilação , Células HeLa , Humanos , Mitose , Modelos Biológicos , Complexo de Endopeptidases do Proteassoma/metabolismo , Ligação Proteica , Estabilidade Proteica , Proteólise , Fase S
7.
Mol Cancer ; 13: 237, 2014 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-25331979

RESUMO

BACKGROUND: Tumor cell subpopulations can either compete with each other for nutrients and physical space within the tumor niche, or co-operate for enhanced survival, or replicative or metastatic capacities. Recently, we have described co-operative interactions between two clonal subpopulations derived from the PC-3 prostate cancer cell line, in which the invasiveness of a cancer stem cell (CSC)-enriched subpopulation (PC-3M, or M) is enhanced by a non-CSC subpopulation (PC-3S, or S), resulting in their accelerated metastatic dissemination. METHODS: M and S secretomes were compared by SILAC (Stable Isotope Labeling by Aminoacids in Cell Culture). Invasive potential in vitro of M cells was analyzed by Transwell-Matrigel assays. M cells were co-injected with S cells in the dorsal prostate of immunodeficient mice and monitored by bioluminescence for tumor growth and metastatic dissemination. SPARC levels were determined by immunohistochemistry and real-time RT-PCR in tumors and by ELISA in plasma from patients with metastatic or non-metastatic prostate cancer. RESULTS: Comparative secretome analysis yielded 213 proteins differentially secreted between M and S cells. Of these, the protein most abundantly secreted in S relative to M cells was SPARC. Immunodepletion of SPARC inhibited the enhanced invasiveness of M induced by S conditioned medium. Knock down of SPARC in S cells abrogated the capacity of its conditioned medium to enhance the in vitro invasiveness of M cells and compromised their potential to boost the metastatic behavior of M cells in vivo. In most primary human prostate cancer samples, SPARC was expressed in the epithelial tumoral compartment of metastatic cases. CONCLUSIONS: The matricellular protein SPARC, secreted by a prostate cancer clonal tumor cell subpopulation displaying non-CSC properties, is a critical mediator of paracrine effects exerted on a distinct tumor cell subpopulation enriched in CSC. This paracrine interaction results in an enhanced metastatic behavior of the CSC-enriched tumor subpopulation. SPARC is expressed in the neoplastic cells of primary prostate cancer samples from metastatic cases, and could thus constitute a tumor progression biomarker and a therapeutic target in advanced prostate cancer.


Assuntos
Metástase Linfática/patologia , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Osteonectina/metabolismo , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Epitélio/efeitos dos fármacos , Epitélio/patologia , Espaço Extracelular/metabolismo , Humanos , Masculino , Invasividade Neoplásica
8.
Genome Med ; 16(1): 21, 2024 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-38308367

RESUMO

BACKGROUND: The immune system has a central role in preventing carcinogenesis. Alteration of systemic immune cell levels may increase cancer risk. However, the extent to which common genetic variation influences blood traits and cancer risk remains largely undetermined. Here, we identify pleiotropic variants and predict their underlying molecular and cellular alterations. METHODS: Multivariate Cox regression was used to evaluate associations between blood traits and cancer diagnosis in cases in the UK Biobank. Shared genetic variants were identified from the summary statistics of the genome-wide association studies of 27 blood traits and 27 cancer types and subtypes, applying the conditional/conjunctional false-discovery rate approach. Analysis of genomic positions, expression quantitative trait loci, enhancers, regulatory marks, functionally defined gene sets, and bulk- and single-cell expression profiles predicted the biological impact of pleiotropic variants. Plasma small RNAs were sequenced to assess association with cancer diagnosis. RESULTS: The study identified 4093 common genetic variants, involving 1248 gene loci, that contributed to blood-cancer pleiotropism. Genomic hotspots of pleiotropism include chromosomal regions 5p15-TERT and 6p21-HLA. Genes whose products are involved in regulating telomere length are found to be enriched in pleiotropic variants. Pleiotropic gene candidates are frequently linked to transcriptional programs that regulate hematopoiesis and define progenitor cell states of immune system development. Perturbation of the myeloid lineage is indicated by pleiotropic associations with defined master regulators and cell alterations. Eosinophil count is inversely associated with cancer risk. A high frequency of pleiotropic associations is also centered on the regulation of small noncoding Y-RNAs. Predicted pleiotropic Y-RNAs show specific regulatory marks and are overabundant in the normal tissue and blood of cancer patients. Analysis of plasma small RNAs in women who developed breast cancer indicates there is an overabundance of Y-RNA preceding neoplasm diagnosis. CONCLUSIONS: This study reveals extensive pleiotropism between blood traits and cancer risk. Pleiotropism is linked to factors and processes involved in hematopoietic development and immune system function, including components of the major histocompatibility complexes, and regulators of telomere length and myeloid lineage. Deregulation of Y-RNAs is also associated with pleiotropism. Overexpression of these elements might indicate increased cancer risk.


Assuntos
Estudo de Associação Genômica Ampla , Neoplasias , Humanos , Feminino , Fenótipo , Locos de Características Quantitativas , Pleiotropia Genética , Neoplasias/genética , Polimorfismo de Nucleotídeo Único , Predisposição Genética para Doença
9.
Exp Cell Res ; 318(18): 2365-76, 2012 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-22814251

RESUMO

The induction of DNA double-strand breaks (DSBs) elicits a plethora of responses that redirect many cellular functions to the vital task of repairing the injury, collectively known as the DNA damage response (DDR). We have found that, in the absence of DNA damage, the DSB repair factors RNF8 and BRCA1 are associated with the nucleolus. Shortly after exposure of cells to γ-radiation, RNF8 and BRCA1 translocated from the nucleolus to damage foci, a traffic that was reverted several hours after the damage. RNF8 interacted through its FHA domain with the ribosomal protein RPSA, and knockdown of RPSA caused a depletion of nucleolar RNF8 and BRCA1, suggesting that the interaction of RNF8 with RPSA is critical for the nucleolar localization of these DDR factors. Knockdown of RPSA or RNF8 impaired bulk protein translation, as did γ-irradiation, the latter being partially countered by overexpression of exogenous RNF8. Our results suggest that RNF8 and BRCA1 are anchored to the nucleolus through reversible interactions with RPSA and that, in addition to its known functions in DDR, RNF8 may play a role in protein synthesis, possibly linking the nucleolar exit of this factor to the attenuation of protein synthesis in response to DNA damage.


Assuntos
Proteína BRCA1/metabolismo , Nucléolo Celular/metabolismo , Dano ao DNA , Proteínas de Ligação a DNA/metabolismo , Proteína BRCA1/genética , Proteínas de Ligação a DNA/genética , Células HEK293 , Células HeLa , Humanos , Receptores de Laminina/genética , Receptores de Laminina/metabolismo , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Ubiquitina-Proteína Ligases
10.
Arch Esp Urol ; 66(5): 475-86, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23793765

RESUMO

Tumors constitute complex ecosystems with multiple interactions among neoplastic cells displaying various phenotypes and functions and where the tumoral niche is built with an active participation of the host environment that also impacts the malignant progression of the tumor cells. Irrespective of the cell of origin of prostate adenocarcinoma, mounting evidences support the existence of a hierarchy within neoplastic prostate cells that contributes to the heterogeneity of these tumors. At the origin of this hierarchy are small populations of tumor cells with high self-renewal potential and also capable of generating progeny tumor cells that lose self-renewal properties as they acquire more differentiated phenotypes. These cancer stem cells (CSC) depend on active gene networks that confer them with their self-renewal capacity through symmetrical divisions whereas they can also undergo asymmetrical division and differentiation either as stochastic events or in response to environmental cues. Although new experimental evidences indicate that this is can be a reversible process, thus blurring the distinction between CSCs and non-CSCs, the former are considered as the drivers of tumor growth and evolution, and thus a prime target for therapeutic intervention. Of particular importance in prostate cancer, CSCs may constitute the repository population of androgen-insensitive and chemotherapy-resistant tumor cells responsible for castration-resistant and chemotherapy-insensitive tumors, thus their identification and quantification in primary and metastatic neoplasms could play important roles in the management of this disease.


Assuntos
Células-Tronco Neoplásicas/patologia , Neoplasias da Próstata/patologia , Adulto , Animais , Resistencia a Medicamentos Antineoplásicos , Humanos , Masculino , Orquiectomia , Neoplasias da Próstata/genética , Neoplasias da Próstata/cirurgia , Células-Tronco/fisiologia
11.
Nat Commun ; 13(1): 1895, 2022 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-35393420

RESUMO

Breast cancer risk for carriers of BRCA1 pathological variants is modified by genetic factors. Genetic variation in HMMR may contribute to this effect. However, the impact of risk modifiers on cancer biology remains undetermined and the biological basis of increased risk is poorly understood. Here, we depict an interplay of molecular, cellular, and tissue microenvironment alterations that increase BRCA1-associated breast cancer risk. Analysis of genome-wide association results suggests that diverse biological processes, including links to BRCA1-HMMR profiles, influence risk. HMMR overexpression in mouse mammary epithelium increases Brca1-mutant tumorigenesis by modulating the cancer cell phenotype and tumor microenvironment. Elevated HMMR activates AURKA and reduces ARPC2 localization in the mitotic cell cortex, which is correlated with micronucleation and activation of cGAS-STING and non-canonical NF-κB signaling. The initial tumorigenic events are genomic instability, epithelial-to-mesenchymal transition, and tissue infiltration of tumor-associated macrophages. The findings reveal a biological foundation for increased risk of BRCA1-associated breast cancer.


Assuntos
Proteína BRCA1 , Neoplasias da Mama , Proteínas da Matriz Extracelular , Receptores de Hialuronatos , Complexo 2-3 de Proteínas Relacionadas à Actina/genética , Animais , Proteína BRCA1/genética , Neoplasias da Mama/patologia , Carcinogênese/genética , Proteínas da Matriz Extracelular/genética , Feminino , Estudo de Associação Genômica Ampla , Heterozigoto , Humanos , Receptores de Hialuronatos/genética , Camundongos , Microambiente Tumoral/genética
12.
ERJ Open Res ; 8(1)2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35083324

RESUMO

INTRODUCTION: Lymphangioleiomyomatosis (LAM) is a rare low-grade metastasising disease characterised by cystic lung destruction. The genetic basis of LAM remains incompletely determined, and the disease cell-of-origin is uncertain. We analysed the possibility of a shared genetic basis between LAM and cancer, and LAM and pulmonary function. METHODS: The results of genome-wide association studies of LAM, 17 cancer types and spirometry measures (forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), FEV1/FVC ratio and peak expiratory flow (PEF)) were analysed for genetic correlations, shared genetic variants and causality. Genomic and transcriptomic data were examined, and immunodetection assays were performed to evaluate pleiotropic genes. RESULTS: There were no significant overall genetic correlations between LAM and cancer, but LAM correlated negatively with FVC and PEF, and a trend in the same direction was observed for FEV1. 22 shared genetic variants were uncovered between LAM and pulmonary function, while seven shared variants were identified between LAM and cancer. The LAM-pulmonary function shared genetics identified four pleiotropic genes previously recognised in LAM single-cell transcriptomes: ADAM12, BNC2, NR2F2 and SP5. We had previously associated NR2F2 variants with LAM, and we identified its functional partner NR3C1 as another pleotropic factor. NR3C1 expression was confirmed in LAM lung lesions. Another candidate pleiotropic factor, CNTN2, was found more abundant in plasma of LAM patients than that of healthy women. CONCLUSIONS: This study suggests the existence of a common genetic aetiology between LAM and pulmonary function.

13.
Nucleic Acids Res ; 37(21): 7072-84, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19773423

RESUMO

Cyclin dependent kinases (cdks) regulate cell cycle progression and transcription. We report here that the transcriptional co-activator PCAF directly interacts with cdk2. This interaction is mainly produced during S and G(2)/M phases of the cell cycle. As a consequence of this association, PCAF inhibits the activity of cyclin/cdk2 complexes. This effect is specific for cdk2 because PCAF does not inhibit either cyclin D3/cdk6 or cyclin B/cdk1 activities. The inhibition is neither competitive with ATP, nor with the substrate histone H1 suggesting that somehow PCAF disturbs cyclin/cdk2 complexes. We also demonstrate that overexpression of PCAF in the cells inhibits cdk2 activity and arrests cell cycle progression at S and G(2)/M. This blockade is dependent on cdk2 because it is rescued by the simultaneous overexpression of this kinase. Moreover, we also observed that PCAF acetylates cdk2 at lysine 33. As this lysine is essential for the interaction with ATP, acetylation of this residue inhibits cdk2 activity. Thus, we report here that PCAF inhibits cyclin/cdk2 activity by two different mechanisms: (i) by somehow affecting cyclin/cdk2 interaction and (ii) by acetylating K33 at the catalytic pocket of cdk2. These findings identify a previously unknown mechanism that regulates cdk2 activity.


Assuntos
Quinase 2 Dependente de Ciclina/metabolismo , Fatores de Transcrição de p300-CBP/metabolismo , Acetilação , Animais , Ciclo Celular , Linhagem Celular , Ciclina A/antagonistas & inibidores , Ciclina A/metabolismo , Quinase 2 Dependente de Ciclina/antagonistas & inibidores , Camundongos , Transativadores/antagonistas & inibidores , Transativadores/metabolismo
14.
Mol Cancer Res ; 19(11): 1840-1853, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34312290

RESUMO

Lymphangioleiomyomatosis (LAM) is a rare, low-grade metastasizing disease characterized by cystic lung destruction. LAM can exhibit extensive heterogeneity at the molecular, cellular, and tissue levels. However, the molecular similarities and differences among LAM cells and tissue, and their connection to cancer features are not fully understood. By integrating complementary gene and protein LAM signatures, and single-cell and bulk tissue transcriptome profiles, we show sources of disease heterogeneity, and how they correspond to cancer molecular portraits. Subsets of LAM diseased cells differ with respect to gene expression profiles related to hormones, metabolism, proliferation, and stemness. Phenotypic diseased cell differences are identified by evaluating lumican (LUM) proteoglycan and YB1 transcription factor expression in LAM lung lesions. The RUNX1 and IRF1 transcription factors are predicted to regulate LAM cell signatures, and both regulators are expressed in LAM lung lesions, with differences between spindle-like and epithelioid LAM cells. The cancer single-cell transcriptome profiles most similar to those of LAM cells include a breast cancer mesenchymal cell model and lines derived from pleural mesotheliomas. Heterogeneity is also found in LAM lung tissue, where it is mainly determined by immune system factors. Variable expression of the multifunctional innate immunity protein LCN2 is linked to disease heterogeneity. This protein is found to be more abundant in blood plasma from LAM patients than from healthy women. IMPLICATIONS: This study identifies LAM molecular and cellular features, master regulators, cancer similarities, and potential causes of disease heterogeneity.


Assuntos
Biomarcadores Tumorais/metabolismo , Linfangioleiomiomatose/genética , Transcriptoma/genética , Feminino , Humanos
15.
J Clin Invest ; 131(3)2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33529165

RESUMO

Germline mutations in BRCA1 and BRCA2 (BRCA1/2) genes considerably increase breast and ovarian cancer risk. Given that tumors with these mutations have elevated genomic instability, they exhibit relative vulnerability to certain chemotherapies and targeted treatments based on poly (ADP-ribose) polymerase (PARP) inhibition. However, the molecular mechanisms that influence cancer risk and therapeutic benefit or resistance remain only partially understood. BRCA1 and BRCA2 have also been implicated in the suppression of R-loops, triple-stranded nucleic acid structures composed of a DNA:RNA hybrid and a displaced ssDNA strand. Here, we report that loss of RNF168, an E3 ubiquitin ligase and DNA double-strand break (DSB) responder, remarkably protected Brca1-mutant mice against mammary tumorigenesis. We demonstrate that RNF168 deficiency resulted in accumulation of R-loops in BRCA1/2-mutant breast and ovarian cancer cells, leading to DSBs, senescence, and subsequent cell death. Using interactome assays, we identified RNF168 interaction with DHX9, a helicase involved in the resolution and removal of R-loops. Mechanistically, RNF168 directly ubiquitylated DHX9 to facilitate its recruitment to R-loop-prone genomic loci. Consequently, loss of RNF168 impaired DHX9 recruitment to R-loops, thereby abrogating its ability to resolve R-loops. The data presented in this study highlight a dependence of BRCA1/2-defective tumors on factors that suppress R-loops and reveal a fundamental RNF168-mediated molecular mechanism that governs cancer development and vulnerability.


Assuntos
Proteína BRCA1/deficiência , Proteína BRCA2/deficiência , DNA de Neoplasias/metabolismo , Instabilidade Genômica , Neoplasias Mamárias Animais/metabolismo , Neoplasias Ovarianas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , DNA de Neoplasias/genética , Feminino , Loci Gênicos , Humanos , Neoplasias Mamárias Animais/genética , Camundongos , Camundongos Knockout , Neoplasias Ovarianas/genética , Ubiquitina-Proteína Ligases/genética
16.
EMBO Mol Med ; 13(9): e13929, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34378323

RESUMO

Inhibition of mTOR is the standard of care for lymphangioleiomyomatosis (LAM). However, this therapy has variable tolerability and some patients show progressive decline of lung function despite treatment. LAM diagnosis and monitoring can also be challenging due to the heterogeneity of symptoms and insufficiency of non-invasive tests. Here, we propose monoamine-derived biomarkers that provide preclinical evidence for novel therapeutic approaches. The major histamine-derived metabolite methylimidazoleacetic acid (MIAA) is relatively more abundant in LAM plasma, and MIAA values are independent of VEGF-D. Higher levels of histamine are associated with poorer lung function and greater disease burden. Molecular and cellular analyses, and metabolic profiling confirmed active histamine signaling and metabolism. LAM tumorigenesis is reduced using approved drugs targeting monoamine oxidases A/B (clorgyline and rasagiline) or histamine H1 receptor (loratadine), and loratadine synergizes with rapamycin. Depletion of Maoa or Hrh1 expression, and administration of an L-histidine analog, or a low L-histidine diet, also reduce LAM tumorigenesis. These findings extend our knowledge of LAM biology and suggest possible ways of improving disease management.


Assuntos
Neoplasias Pulmonares , Linfangioleiomiomatose , Biomarcadores , Histamina , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Linfangioleiomiomatose/tratamento farmacológico , Transdução de Sinais
17.
Biochem Soc Trans ; 38(Pt 1): 83-6, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20074040

RESUMO

Cyclin A must be degraded at prometaphase in order to allow mitosis progression. Nevertheless, the signals that trigger cyclin A degradation at mitosis have been largely elusive. In the present paper, we review the status of cyclin A degradation in the light of recent evidence indicating that acetylation plays a role in cyclin A stability. The emerging model proposes that the acetyltransferase PCAF [p300/CREB (cAMP-response-element-binding protein)-binding protein-associated factor] [perhaps also its homologue GCN5 (general control non-derepressible 5)] acetylates cyclin A at Lys(54), Lys(68), Lys(95) and Lys(112) during mitosis, leading to its ubiquitylation by the anaphase-promoting factor/cyclosome and its subsequent degradation via proteasome. Interestingly, these four lysine residues in cyclin A also participate in the regulation of cyclin A-Cdk (cyclin-dependent kinase) activity by modulating its interaction with Cdks.


Assuntos
Ciclo Celular/fisiologia , Ciclina A/metabolismo , Acetilação , Ciclina A/genética , Quinase 2 Dependente de Ciclina/metabolismo , Lisina/metabolismo , Mutação , Ubiquitinação , Fatores de Transcrição de p300-CBP/metabolismo
18.
Cancers (Basel) ; 12(2)2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-32012804

RESUMO

The transcription factor EVI1 plays an oncogenic role in several types of neoplasms by promoting aggressive cancer features. EVI1 contributes to epigenetic regulation and transcriptional control, and its overexpression has been associated with enhanced PI3K-AKT-mTOR signaling in some settings. These observations raise the possibility that EVI1 influences the prognosis and everolimus-based therapy outcome of clear cell renal cell carcinoma (ccRCC). Here, gene expression and protein immunohistochemical studies of ccRCC show that EVI1 overexpression is associated with advanced disease features and with poorer outcome-particularly in the CC-e.3 subtype defined by The Cancer Genome Atlas. Overexpression of an oncogenic EVI1 isoform in RCC cell lines confers substantial resistance to everolimus. The EVI1 rs1344555 genetic variant is associated with poorer survival and greater progression of metastatic ccRCC patients treated with everolimus. This study leads us to propose that evaluation of EVI1 protein or gene expression, and of EVI1 genetic variants may help improve estimates of prognosis and the benefit of everolimus-based therapy in ccRCC.

19.
iScience ; 23(7): 101296, 2020 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-32622267

RESUMO

Proper immune system function hinders cancer development, but little is known about whether genetic variants linked to cancer risk alter immune cells. Here, we report 57 cancer risk loci associated with differences in immune and/or stromal cell contents in the corresponding tissue. Predicted target genes show expression and regulatory associations with immune features. Polygenic risk scores also reveal associations with immune and/or stromal cell contents, and breast cancer scores show consistent results in normal and tumor tissue. SH2B3 links peripheral alterations of several immune cell types to the risk of this malignancy. Pleiotropic SH2B3 variants are associated with breast cancer risk in BRCA1/2 mutation carriers. A retrospective case-cohort study indicates a positive association between blood counts of basophils, leukocytes, and monocytes and age at breast cancer diagnosis. These findings broaden our knowledge of the role of the immune system in cancer and highlight promising prevention strategies for individuals at high risk.

20.
NPJ Syst Biol Appl ; 5: 7, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30854222

RESUMO

In spite of the increasing availability of genomic and transcriptomic data, there is still a gap between the detection of perturbations in gene expression and the understanding of their contribution to the molecular mechanisms that ultimately account for the phenotype studied. Alterations in the metabolism are behind the initiation and progression of many diseases, including cancer. The wealth of available knowledge on metabolic processes can therefore be used to derive mechanistic models that link gene expression perturbations to changes in metabolic activity that provide relevant clues on molecular mechanisms of disease and drug modes of action (MoA). In particular, pathway modules, which recapitulate the main aspects of metabolism, are especially suitable for this type of modeling. We present Metabolizer, a web-based application that offers an intuitive, easy-to-use interactive interface to analyze differences in pathway metabolic module activities that can also be used for class prediction and in silico prediction of knock-out (KO) effects. Moreover, Metabolizer can automatically predict the optimal KO intervention for restoring a diseased phenotype. We provide different types of validations of some of the predictions made by Metabolizer. Metabolizer is a web tool that allows understanding molecular mechanisms of disease or the MoA of drugs within the context of the metabolism by using gene expression measurements. In addition, this tool automatically suggests potential therapeutic targets for individualized therapeutic interventions.


Assuntos
Biologia Computacional/métodos , Descoberta de Drogas/métodos , Redes e Vias Metabólicas/efeitos dos fármacos , Simulação por Computador , Redes Reguladoras de Genes/genética , Humanos , Internet , Redes e Vias Metabólicas/genética , Redes e Vias Metabólicas/fisiologia , Modelos Biológicos , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/metabolismo , Fenótipo , Software , Transcriptoma
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