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1.
Mol Cell ; 58(5): 794-803, 2015 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-25982117

RESUMEN

G protein-coupled receptors (GPCRs) comprise the largest family of cell surface receptors, regulate a wide range of physiological processes, and are the major targets of pharmaceutical drugs. Canonical signaling from GPCRs is relayed to intracellular effector proteins by trimeric G proteins, composed of α, ß, and γ subunits (Gαßγ). Here, we report that G protein ß subunits (Gß) bind to DDB1 and that Gß2 targets GRK2 for ubiquitylation by the DDB1-CUL4A-ROC1 ubiquitin ligase. Activation of GPCR results in PKA-mediated phosphorylation of DDB1 at Ser645 and its dissociation from Gß2, leading to increase of GRK2 protein. Deletion of Cul4a results in cardiac hypertrophy in male mice that can be partially rescued by the deletion of one Grk2 allele. These results reveal a non-canonical function of the Gß protein as a ubiquitin ligase component and a mechanism of feedback regulation of GPCR signaling.


Asunto(s)
Quinasa 2 del Receptor Acoplado a Proteína-G/metabolismo , Subunidades beta de la Proteína de Unión al GTP/fisiología , Proteínas Nucleares/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinación , Animales , Proteínas de Unión al ADN/metabolismo , Femenino , Células HEK293 , Humanos , Masculino , Ratones Noqueados , Estabilidad Proteica , Proteolisis , Ratas , Ratas Wistar , Transducción de Señal
2.
Carcinogenesis ; 39(3): 318-326, 2018 03 08.
Artículo en Inglés | MEDLINE | ID: mdl-29228217

RESUMEN

Arf, a well-established tumor suppressor, is either mutated or downregulated in a wide array of cancers. However, its role in hepatocellular carcinoma (HCC) progression is controversial. Conflicting observations have been published regarding its expression in HCC. In this study, we provide clear genetic evidence demonstrating a protective role of p19Arf in hepatocarcinogenesis. Using Ras-induced mouse model, we show that p19Arf deficiency accelerates progression of aggressive HCC in vivo. To investigate the role of p14ARF in human liver cancers, we analyzed its expression in human HCC using immunohistochemistry (IHC). We observe lack of nucleolar p14ARF in 43.02% of human HCC samples and that low expression of p14ARF strongly correlates with the early onset of HCC. Importantly, cirrhotic livers that did not progress to HCC harbor higher expression of the p14ARF protein in hepatocytes compared with that in cirrhotic livers with HCC. These results are significant because they suggest that nucleolar p14ARF can be used as early prognostic marker in chronic liver disease to reliably identify patients with high risk for developing liver cancer. Currently, there is no effective systemic therapy for advanced liver cancer; hence, more efficient patient screening and early detection of HCC would significantly contribute to the eradication of this devastating disease.


Asunto(s)
Carcinoma Hepatocelular/patología , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Genes ras/genética , Neoplasias Hepáticas/patología , Proteína p14ARF Supresora de Tumor/genética , Adulto , Anciano , Anciano de 80 o más Años , Animales , Carcinoma Hepatocelular/genética , Progresión de la Enfermedad , Femenino , Humanos , Cirrosis Hepática/genética , Cirrosis Hepática/patología , Neoplasias Hepáticas/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Persona de Mediana Edad
3.
J Hepatol ; 63(2): 429-36, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25828473

RESUMEN

BACKGROUND & AIMS: Overexpression of FoxM1 correlates with poor prognosis in hepatocellular carcinoma (HCC). Moreover, the Ras-signaling pathway is found to be ubiquitously activated in HCC through epigenetic silencing of the Ras-regulators. We investigated the roles of FoxM1 in Ras-driven HCC, and on HCC cells with stem-like features. METHODS: We employed a transgenic mouse model that expresses the oncogenic Ras in the liver. That strain was crossed with a strain that harbor floxed alleles of FoxM1 and the MxCre gene that allows conditional deletion of FoxM1. FoxM1 alleles were deleted after development of HCC, and the effects on the tumors were analyzed. Also, FoxM1 siRNA was used in human HCC cell lines to determine its role in the survival of the HCC cells with stem cell features. RESULTS: Ras-driven tumors overexpress FoxM1. Deletion of FoxM1 inhibits HCC progression. There was increased accumulation of reactive oxygen species (ROS) in the FoxM1 deleted HCC cells. Moreover, FoxM1 deletion caused a disproportionate loss of the CD44+ and EpCAM+ HCC cells in the tumors. We show that FoxM1 directly activates expression of CD44 in human HCC cells. Moreover, the human HCC cells with stem cell features are addicted to FoxM1 for ROS-regulation and survival. CONCLUSION: Our results provide genetic evidence for an essential role of FoxM1 in the progression of Ras-driven HCC. In addition, FoxM1 is required for the expression of CD44 in HCC cells. Moreover, FoxM1 plays a critical role in the survival of the HCC cells with stem cell features by regulating ROS.


Asunto(s)
Carcinogénesis/genética , Carcinoma Hepatocelular/genética , Factores de Transcripción Forkhead/genética , Regulación Neoplásica de la Expresión Génica , Neoplasias Hepáticas/genética , Células Madre/patología , Proteínas ras/genética , Animales , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Proliferación Celular , Progresión de la Enfermedad , Proteína Forkhead Box M1 , Factores de Transcripción Forkhead/biosíntesis , Humanos , Inmunohistoquímica , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Pronóstico , Transducción de Señal , Células Madre/metabolismo , Proteínas ras/biosíntesis
4.
J Biol Chem ; 287(5): 3019-28, 2012 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-22167187

RESUMEN

Exposure to ultraviolet rays (UV) in sunlight is the main cause of skin cancer. Here, we show that the p53-induced genes DDB2 and p21 are down-regulated in skin cancer, and in the mouse model they functionally cooperate to prevent UV-induced skin cancer. Our previous studies demonstrated an antagonistic role of DDB2 and p21 in nucleotide excision repair and apoptosis. Surprisingly, we find that the loss of p21 restores nucleotide excision repair and apoptosis in Ddb2(-/-) mice, but it does not protect from UV-mediated skin carcinogenesis. In contrast, Ddb2(-/-)p21(-/-) mice are significantly more susceptible to UV-induced skin cancer than the Ddb2(-/-) or the p21(-/-) mice. We provide evidence that p21 deletion in the Ddb2(-/-) background causes a strong increase in cell proliferation. The increased proliferation in the Ddb2(-/-)p21(-/-) background is related to a severe deficiency in UV-induced premature senescence. Also, the oncogenic pro-proliferation transcription factor FOXM1 is overexpressed in the p21(-/-) background. Our results show that the anti-proliferative and the pro-senescence pathways of DDB2 and p21 are critical protection mechanisms against skin malignancies.


Asunto(s)
Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Neoplasias Inducidas por Radiación/metabolismo , Neoplasias Cutáneas/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Rayos Ultravioleta/efectos adversos , Animales , Proliferación Celular/efectos de la radiación , Senescencia Celular/genética , Senescencia Celular/efectos de la radiación , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Reparación del ADN/genética , Reparación del ADN/efectos de la radiación , Proteínas de Unión al ADN , Proteína Forkhead Box M1 , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Eliminación de Gen , Ratones , Ratones Noqueados , Neoplasias Inducidas por Radiación/genética , Neoplasias Inducidas por Radiación/patología , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Proteína p53 Supresora de Tumor/genética
5.
EMBO J ; 28(19): 2908-18, 2009 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-19696738

RESUMEN

The transcription factor FoxM1 is over-expressed in most human malignancies. Although it is evident that FoxM1 has critical functions in tumour development and progression, the mechanisms by which FoxM1 participates in those processes are not understood. Here, we describe an essential role of FoxM1 in the regulation of oxidative stress that contributes to malignant transformation and tumour cell survival. We identify a negative feedback loop involving FoxM1 that regulates reactive oxygen species (ROS) in proliferating cells. We show that induction of FoxM1 by oncogenic Ras requires ROS. Elevated FoxM1, in turn, downregulates ROS levels by stimulating expression of ROS scavenger genes, such as MnSOD, catalase and PRDX3. FoxM1 depletion sensitizes cells to oxidative stress and increases oncogene-induced premature senescence. Moreover, tumour cells expressing activated AKT1 are 'addicted' to FoxM1, as they require continuous presence of FoxM1 for survival. Together, our results identify FoxM1 as a key regulator of ROS in dividing cells, and provide insights into the mechanism how tumour cells use FoxM1 to control oxidative stress to escape premature senescence and apoptosis.


Asunto(s)
Transformación Celular Neoplásica/metabolismo , Factores de Transcripción Forkhead/metabolismo , Estrés Oxidativo , Animales , Línea Celular Tumoral , Transformación Celular Neoplásica/genética , Proteína Forkhead Box M1 , Factores de Transcripción Forkhead/genética , Regulación Neoplásica de la Expresión Génica , Genes ras , Humanos , Ratones , Ratones Endogámicos C57BL , Células 3T3 NIH , Osteosarcoma/metabolismo , Proteínas Proto-Oncogénicas c-akt/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , Especies Reactivas de Oxígeno/metabolismo
6.
J Biomed Sci ; 20: 12, 2013 Feb 27.
Artículo en Inglés | MEDLINE | ID: mdl-23441825

RESUMEN

BACKGROUND: Several studies have demonstrated a fundamental role for the HLA in the susceptibility of, or protection to, type 1 diabetes mellitus (T1DM). However, this has not been adequately studied in Asian Indian populations. To assess the frequency of HLA class II (DPA1, DPB1, DQA1, DQB1 and DRB1) associated to susceptibility or protection toT1DM in a Bengali population of India with diabetes. RESULTS: Single nucleotide polymorphism study. The HLA genotyping was performed by a polymerase chain reaction followed by their HLA-DP, DQ, and DRB1 genotypes and haplotypes by sequencing method. The results are studied by Plink software. The χ2 tests were used for the inferential statistics. To our knowledge, this study is the first of a kind which has attempted to check the HLA association with T1DM by SNPs analysis. The study recruited 151 patients with T1DM and same number of ethno-linguistic, sex matched non-diabetic controls. The present study found a significant SNP rs7990 of HLA-DQA1 (p = 0.009) negative correlation, again indicating that risk from HLA is considerably more with T1DM. CONCLUSIONS: This study demonstrates that the HLA class-II alleles play a major role in genetic basis of T1DM.


Asunto(s)
Diabetes Mellitus Tipo 1/genética , Antígenos HLA-DP/genética , Cadenas alfa de HLA-DQ/genética , Cadenas HLA-DRB1/genética , Adulto , Alelos , Diabetes Mellitus Tipo 1/patología , Femenino , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Genotipo , Haplotipos , Humanos , India , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple
7.
J Pediatr Endocrinol Metab ; 36(1): 4-18, 2023 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-36424806

RESUMEN

OBJECTIVES: 46, XY difference/disorder of sex development (DSD) is a relatively uncommon group of heterogeneous disorders with varying degree of underandrogenization of male genitalia. Such patients should be approached systematically to reach an aetiological diagnosis. However, we lack, at present, a clinical practice guideline on diagnostic approach in 46, XY DSD from this part of the globe. Moreover, debate persists regarding the timing and cut-offs of different hormonal tests, performed in these cases. The consensus committee consisting of 34 highly experienced endocrinologists with interest and experience in managing DSD discussed and drafted a consensus statement on the diagnostic approach to 46, XY DSD focussing on relevant history, clinical examination, biochemical evaluation, imaging and genetic analysis. CONTENT: The consensus was guided by systematic reviews of existing literature followed by discussion. An initial draft was prepared and distributed among the members. The members provided their scientific inputs, and all the relevant suggestions were incorporated. The final draft was approved by the committee members. SUMMARY: The diagnostic approach in 46, XY DSD should be multidisciplinary although coordinated by an experienced endocrinologist. We recommend formal Karyotyping, even if Y chromosome material has been detected by other methods. Meticulous history taking and thorough head-to-toe examination should initially be performed with focus on external genitalia, including location of gonads. Decision regarding hormonal and other biochemical investigations should be made according to the age and interpreted according to age-appropriate norms Although LC-MS/MS is the preferred mode of steroid hormone measurements, immunoassays, which are widely available and less expensive, are acceptable alternatives. All patients with 46, XY DSD should undergo abdominopelvic ultrasonography by a trained radiologist. MRI of the abdomen and/or laparoscopy may be used to demonstrate the Mullerian structure and/or to localize the gonads. Genetic studies, which include copy number variation (CNV) or molecular testing of a candidate gene or next generation sequencing then should be ordered in a stepwise manner depending on the clinical, biochemical, hormonal, and radiological findings. OUTLOOK: The members of the committee believe that patients with 46, XY DSD need to be approached systematically. The proposed diagnostic algorithm, provided in the consensus statement, is cost effective and when supplemented with appropriate genetic studies, may help to reach an aetiological diagnosis in majority of such cases.


Asunto(s)
Trastorno del Desarrollo Sexual 46,XY , Trastornos del Desarrollo Sexual , Humanos , Masculino , Trastornos del Desarrollo Sexual/diagnóstico , Trastornos del Desarrollo Sexual/genética , Cromatografía Liquida , Variaciones en el Número de Copia de ADN , Espectrometría de Masas en Tándem , Trastorno del Desarrollo Sexual 46,XY/genética
8.
Am J Respir Cell Mol Biol ; 46(4): 431-6, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22033266

RESUMEN

Pulmonary arterial hypertension (PAH) is a devastating disease, and no effective treatments are available. Hypoxia-induced pulmonary artery remodeling, including smooth muscle cell proliferation, contributes to PAH, but the exact mechanisms underlying this abnormal process are largely undefined. The forkhead box M1 (FoxM1) transcription factor regulates cancer cell growth by modulating gene expression critical for cell cycle progression. Here, we report for the first time, to the best of our knowledge, a novel function of FoxM1 in the hypoxia-stimulated proliferation of human pulmonary artery smooth muscle cells (HPASMCs). Exposure to hypoxia caused a marked up-regulation of FoxM1 gene expression, mainly at the transcription level, and this induction correlated with HPASMC cell proliferation. The knockdown of FoxM1 inhibited the hypoxia-stimulated proliferation of HPASMCs. We found that the knockdown of HIF-2α, but not HIF-1α, diminished FoxM1 induction in response to hypoxia. However, the knockdown of FoxM1 did not alter expression levels of HIF-2α or HIF-1α, suggesting that HIF-2α is an upstream regulator of FoxM1. Furthermore, the knockdown of FoxM1 prevented the hypoxia-induced expression of aurora A kinase and cyclin D1. Collectively, our results suggest that hypoxia induces FoxM1 gene expression in an HIF-2α-dependent pathway, thereby promoting HPASMC proliferation.


Asunto(s)
Factores de Transcripción Forkhead/metabolismo , Hipoxia/metabolismo , Miocitos del Músculo Liso/fisiología , Arteria Pulmonar/citología , Aurora Quinasas , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Hipoxia de la Célula , Proliferación Celular , Células Cultivadas , Ciclina B/genética , Ciclina B/metabolismo , Ciclina D1/genética , Ciclina D1/metabolismo , Hipertensión Pulmonar Primaria Familiar , Proteína Forkhead Box M1 , Factores de Transcripción Forkhead/genética , Expresión Génica , Humanos , Hipertensión Pulmonar/metabolismo , Hipertensión Pulmonar/patología , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Miocitos del Músculo Liso/citología , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Arteria Pulmonar/metabolismo
9.
Dev Biol ; 352(2): 278-87, 2011 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-21291880

RESUMEN

The mammalian Cul4 genes, Cul4A and Cul4B, encode the scaffold components of the cullin-based E3 ubiquitin ligases. The two Cul4 genes are functionally redundant. Recent study indicated that mice expressing a truncated CUL4A that fails to interact with its functional partner ROC1 exhibit no developmental phenotype. We generated a Cul4A-/- strain lacking exons 4-8 that does not express any detectable truncated protein. In this strain, the male mice are infertile and exhibit severe deficiencies in spermatogenesis. The primary spermatocytes are deficient in progression through late prophase I, a time point when expression of the X-linked Cul4B gene is silenced due to meiotic sex chromosome inactivation. Testes of the Cul4A-/- mice exhibit extensive apoptosis. Interestingly, the pachytene spermatocytes exhibit persistent double stranded breaks, suggesting a deficiency in homologous recombination. Also, we find that CUL4A localizes to the double stranded breaks generated in pre-pachytene spermatocytes. The observations identify a novel function of CUL4A in meiotic recombination and demonstrate an essential role of CUL4A in spermatogenesis.


Asunto(s)
Proteínas Cullin/fisiología , Fertilidad/fisiología , Espermatogénesis/fisiología , Animales , Apoptosis , Secuencia de Bases , Proteínas Cullin/genética , Roturas del ADN de Doble Cadena , Cartilla de ADN/genética , Reparación del ADN/genética , Reparación del ADN/fisiología , Fertilidad/genética , Masculino , Meiosis/genética , Meiosis/fisiología , Profase Meiótica I/genética , Profase Meiótica I/fisiología , Ratones , Ratones Noqueados , Recombinación Genética , Espermatocitos/citología , Espermatocitos/fisiología , Espermatogénesis/genética , Testículo/anomalías
10.
Proc Natl Acad Sci U S A ; 106(26): 10690-5, 2009 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-19541625

RESUMEN

The xeroderma pigmentosum complementation group E (XP-E) gene product damaged-DNA binding protein 2 (DDB2) plays important roles in nucleotide excision repair (NER). Previously, we showed that DDB2 participates in NER by regulating the level of p21(Waf1/Cip1). Here we show that the p21(Waf1/Cip1) -regulatory function of DDB2 plays a central role in defining the response (apoptosis or arrest) to DNA damage. The DDB2-deficient cells are resistant to apoptosis in response to a variety of DNA-damaging agents, despite activation of p53 and the pro-apoptotic genes. Instead, these cells undergo cell cycle arrest. Also, the DDB2-deficient cells are resistant to E2F1-induced apoptosis. The resistance to apoptosis of the DDB2-deficient cells is caused by an increased accumulation of p21(Waf1/Cip1) after DNA damage. We provide evidence that DDB2 targets p21(Waf1/Cip1) for proteolysis. The resistance to apoptosis in DDB2-deficient cells also involves Mdm2 in a manner that is distinct from the p53-regulatory activity of Mdm2. Our results provide evidence for a new regulatory loop involving the NER protein DDB2, Mdm2, and p21(Waf1/Cip1) that is critical in deciding cell fate (apoptosis or arrest) upon DNA damage.


Asunto(s)
Apoptosis/fisiología , Ciclo Celular/fisiología , Daño del ADN/fisiología , Proteínas de Unión al ADN/metabolismo , Aclarubicina/farmacología , Animales , Antineoplásicos/farmacología , Western Blotting , Células Cultivadas , Cisplatino/farmacología , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Reparación del ADN , Proteínas de Unión al ADN/genética , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Fibroblastos/efectos de la radiación , Citometría de Flujo , Células HeLa , Humanos , Etiquetado Corte-Fin in Situ , Ratones , Ratones Noqueados , Proteínas Proto-Oncogénicas c-mdm2/genética , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteína p53 Supresora de Tumor/genética , Proteína p53 Supresora de Tumor/metabolismo , Rayos Ultravioleta
11.
Int J Mol Sci ; 13(9): 11012-11026, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23109835

RESUMEN

Premature senescence induced by DNA damage or oncogene is a critical mechanism of tumor suppression. Reactive oxygen species (ROS) have been implicated in the induction of premature senescence response. Several pathological disorders such as cancer, aging and age related neurological abnormalities have been linked to ROS deregulation. Here, we discuss how Damaged DNA binding Protein-2 (DDB2), a nucleotide excision repair protein, plays an important role in ROS regulation by epigenetically repressing the antioxidant genes MnSOD and Catalase. We further revisit a model in which DDB2 plays an instrumental role in DNA damage induced ROS accumulation, ROS induced premature senescence and inhibition of skin tumorigenesis.


Asunto(s)
Envejecimiento Prematuro/genética , Senescencia Celular/genética , Daño del ADN/genética , Proteínas de Unión al ADN/genética , Especies Reactivas de Oxígeno/metabolismo , Animales , Apoptosis/genética , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Catalasa/biosíntesis , Catalasa/genética , Transformación Celular Neoplásica , Proteínas Cullin/metabolismo , Reparación del ADN/genética , Proteínas de Unión al ADN/metabolismo , Humanos , Ratones , Transducción de Señal/genética , Neoplasias Cutáneas/patología , Superóxido Dismutasa/biosíntesis , Superóxido Dismutasa/genética , Xerodermia Pigmentosa/genética
12.
Oncogene ; 41(30): 3778-3790, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35761036

RESUMEN

Hepatocellular carcinoma (HCC) is one of the deadliest cancers. The retinoblastoma protein (RB1), a regulator of cell proliferation, is functionally inactivated in HCC by CYCLIN D/E-mediated phosphorylation. However, the mechanism of RB1-inactivation is unclear because only small percentages of HCCs exhibit amplification of CYCLIN D/E or mutations in the CDK-inhibitory genes. We show that FOXM1, which is overexpressed and critical for HCC, plays essential roles in inactivating RB1 and suppressing RB1-induced senescence of the HCC cells. Mechanistically, FOXM1 binds RB1 and DNMT3B to repress the expression of FOXO1, leading to a decrease in the levels of the CDK-inhibitors, creating an environment for phosphorylation and inactivation of RB1. Consistent with that, inhibition of FOXM1 causes increased expression of FOXO1 with consequent activation of RB1, leading to senescence of the HCC cells, in vitro and in vivo. Also, repression-deficient mutants of FOXM1 induce senescence that is blocked by depletion of RB1 or FOXO1. We provide evidence that human HCCs rely upon this FOXM1-FOXO1 axis for phosphorylation and inactivation of RB1. The observations demonstrate the existence of a new autoregulatory loop of RB1-inactivation in HCC involving a FOXM1-FOXO1 axis that is required for phosphorylation of RB1 and for aggressive progression of HCC.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Proliferación Celular/genética , Senescencia Celular , Ciclina D/metabolismo , Proteína Forkhead Box M1/genética , Proteína Forkhead Box M1/metabolismo , Proteína Forkhead Box O1/genética , Proteína Forkhead Box O1/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Hepáticas/patología , Proteínas de Unión a Retinoblastoma/genética , Proteínas de Unión a Retinoblastoma/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo
13.
Cancer Res ; 82(13): 2458-2471, 2022 07 05.
Artículo en Inglés | MEDLINE | ID: mdl-35583996

RESUMEN

The transcription factor Forkhead box M1 (FoxM1) is overexpressed in breast cancers and correlates with poor prognosis. Mechanistically, FoxM1 associates with CBP to activate transcription and with Rb to repress transcription. Although the activating function of FoxM1 in breast cancer has been well documented, the significance of its repressive activity is poorly understood. Using CRISPR-Cas9 engineering, we generated a mouse model that expresses FoxM1-harboring point mutations that block binding to Rb while retaining its ability to bind CBP. Unlike FoxM1-null mice, mice harboring Rb-binding mutant FoxM1 did not exhibit significant developmental defects. The mutant mouse line developed PyMT-driven mammary tumors that were deficient in lung metastasis, which was tumor cell-intrinsic. Single-cell RNA-seq of the tumors revealed a deficiency in prometastatic tumor cells and an expansion of differentiated alveolar type tumor cells, and further investigation identified that loss of the FoxM1/Rb interaction caused enhancement of the mammary alveolar differentiation program. The FoxM1 mutant tumors also showed increased Pten expression, and FoxM1/Rb was found to activate Akt signaling by repressing Pten. In human breast cancers, expression of FoxM1 negatively correlated with Pten mRNA. Furthermore, the lack of tumor-infiltrating cells in FoxM1 mutant tumors appeared related to decreases in pro-metastatic tumor cells that express factors required for infiltration. These observations demonstrate that the FoxM1/Rb-regulated transcriptome is critical for the plasticity of breast cancer cells that drive metastasis, identifying a prometastatic role of Rb when bound to FoxM1. SIGNIFICANCE: This work provides new insights into how the interaction between FoxM1 and Rb facilitates the evolution of metastatic breast cancer cells by altering the transcriptome.


Asunto(s)
Neoplasias de la Mama , Proteína Forkhead Box M1/metabolismo , Factores de Transcripción Forkhead , Animales , Neoplasias de la Mama/patología , Diferenciación Celular/genética , Línea Celular Tumoral , Femenino , Proteína Forkhead Box M1/genética , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Regulación Neoplásica de la Expresión Génica , Humanos , Ratones , Transducción de Señal , Transcripción Genética
14.
Hepatology ; 51(3): 922-31, 2010 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-20058312

RESUMEN

UNLABELLED: In this study, we determined the role of the nuclear factor-kappaB (NF-kappaB) subunit c-Rel in liver injury and regeneration. In response to toxic injury of the liver, c-Rel null (c-rel(-/-)) mice displayed a defect in the neutrophilic inflammatory response, associated with impaired induction of RANTES (Regulated upon Activation, Normal T-cell Expressed, and Secreted; also known as CCL5). The subsequent fibrogenic/wound-healing response to both chronic carbon tetrachloride and bile duct ligation induced injury was also impaired and this was associated with deficiencies in the expression of fibrogenic genes, collagen I and alpha-smooth muscle actin, by hepatic stellate cells. We additionally report that c-Rel is required for the normal proliferative regeneration of hepatocytes in response to toxic injury and partial hepatectomy. Absence of c-Rel was associated with blunted and delayed induction of forkhead box M1 (FoxM1) and its downstream targets cyclin B1 and Cdc25C. Furthermore, isolated c-rel(-/-) hepatocytes expressed reduced levels of FoxM1 and a reduced rate of basal and epidermal growth factor-induced DNA synthesis. Chromatin immunoprecipitation revealed that c-Rel binding to the FoxM1 promoter is induced in the regenerating liver. CONCLUSION: c-Rel has multiple functions in the control of liver homeostasis and regeneration and is a transcriptional regulator of FoxM1 and compensatory hepatocyte proliferation.


Asunto(s)
Hepatitis/etiología , Hepatocitos/citología , FN-kappa B/fisiología , Cicatrización de Heridas/fisiología , Animales , Proliferación Celular , Regeneración Hepática , Masculino , Ratones , Ratones Endogámicos C57BL
15.
EMBO Rep ; 10(9): 1036-42, 2009 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-19644500

RESUMEN

The tumour suppressor ARF (alternative reading frame), which is mutated or silenced in various tumours, has a crucial role in tumour surveillance to suppress unwarranted cell growth and proliferation. ARF has also been linked to the DNA-damage-induced response of p53 because of its ability to inhibit murine double minute 2 (MDM2). Here, however, we provide genetic evidence for a role of ARF in nucleotide excision repair (NER) that is independent of p53. Cells lacking ARF are deficient in NER. Expression of ARF restores the repair activity, which coincides with increased expression of the damaged-DNA recognition protein xeroderma pigmentosum, complementation group C (XPC). We provide evidence that, by disrupting the interaction between E2F transcription factor 4 (E2F4) and DRTF polypeptide 1 (DP1), ARF reduces the interaction of the E2F4-p130 repressor complex with the promoter of XPC to ensure high-level expression of XPC. Together, our results point to an important 'care-taker'-type tumour-suppression function for ARF in NER through the increased expression of XPC.


Asunto(s)
Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Reparación del ADN , Proteínas de Unión al ADN/metabolismo , ADN/metabolismo , Factor de Transcripción E2F4/metabolismo , Animales , Secuencia de Bases , Línea Celular , Inhibidor p16 de la Quinasa Dependiente de Ciclina/deficiencia , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Proteínas de Unión al ADN/genética , Regulación de la Expresión Génica , Ratones , Ratones Noqueados , Unión Proteica , Proteínas Proto-Oncogénicas c-mdm2/deficiencia , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Dímeros de Pirimidina/metabolismo , Proteína p53 Supresora de Tumor/deficiencia , Proteína p53 Supresora de Tumor/metabolismo
16.
J Biol Chem ; 284(44): 30695-707, 2009 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-19737929

RESUMEN

The Forkhead box M1 (FoxM1) transcription factor is critical for expression of the genes essential for G(1)/S transition and mitotic progression. To explore the cell cycle regulation of FoxM1, we examined the phosphorylation profile of FoxM1. Here, we show that the phosphorylated status and the activity of FoxM1 increase as cells progress from S to G(2)/M phases. Moreover, dephosphorylation of FoxM1 coincides with exit from mitosis. Using mass spectrometry, we have identified a new conserved phosphorylation site (Ser-251) within the forkhead domain of FoxM1. Disruption of Ser-251 inhibits phosphorylation of FoxM1 and dramatically decreases its transcriptional activity. We demonstrate that the Ser-251 residue is required for CDK1-dependent phosphorylation of FoxM1 as well as its interaction with the coactivator CREB-binding protein (CBP). Interestingly, the transcriptional activity of the S251A mutant protein remains responsive to activation by overexpressed Polo-like kinase 1 (PLK1). Cells expressing the S251A mutant exhibit reduced expression of the G(2)/M phase genes and impaired mitotic progression. Our results demonstrate that the transcriptional activity of FoxM1 is controlled in a cell cycle-dependent fashion by temporally regulated phosphorylation and dephosphorylation events, and that the phosphorylation at Ser-251 is critical for the activation of FoxM1.


Asunto(s)
Proteína Quinasa CDC2/metabolismo , Factores de Transcripción Forkhead/metabolismo , Sitios de Unión , Proteína de Unión a CREB/metabolismo , Ciclo Celular , Línea Celular Tumoral , Secuencia Conservada , Proteína Forkhead Box M1 , Humanos , Fosforilación , Serina/metabolismo , Transcripción Genética
17.
Mol Cell Biol ; 27(3): 1007-16, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17101782

RESUMEN

The forkhead box M1 (FoxM1) transcription factor regulates expression of cell cycle genes essential for DNA replication and mitosis during organ repair and cancer progression. Here, we demonstrate that FoxM1-deficient (-/-) mouse embryonic fibroblasts and osteosarcoma U2OS cells depleted in FoxM1 levels by small interfering RNA transfection display increased DNA breaks, as evidenced by immunofluorescence focus staining for phosphospecific histone H2AX. FoxM1-deficient cells also exhibit stimulation of p53 transcriptional activity, as evidenced by increased expression of the p21(cip1) gene. FoxM1-deficient cells display reduced expression of the base excision repair factor X-ray cross-complementing group 1 (XRCC1) and breast cancer-associated gene 2 (BRCA2), the latter of which is involved in homologous recombination repair of DNA double-strand breaks. Furthermore, FoxM1 protein is phosphorylated by checkpoint kinase 2 (Chk2) in response to DNA damage. This phosphorylation of FoxM1 on serine residue 361 caused increased stability of the FoxM1 protein with corresponding increased transcription of XRCC1 and BRCA2 genes, both of which are required for repair of DNA damage. These results identify a novel role for FoxM1 in the transcriptional response during DNA damage/checkpoint signaling and show a novel mechanism by which Chk2 protein regulates expression of DNA repair enzymes.


Asunto(s)
Proteína BRCA2/metabolismo , Reparación del ADN/genética , Proteínas de Unión al ADN/metabolismo , Factores de Transcripción Forkhead/metabolismo , Regulación de la Expresión Génica/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Secuencia de Aminoácidos , Animales , Proteína BRCA2/genética , Quinasa de Punto de Control 2 , Roturas del ADN , Reparación del ADN/efectos de los fármacos , Reparación del ADN/efectos de la radiación , Proteínas de Unión al ADN/genética , Etopósido/farmacología , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/enzimología , Fibroblastos/efectos de la radiación , Proteína Forkhead Box M1 , Factores de Transcripción Forkhead/química , Factores de Transcripción Forkhead/deficiencia , Humanos , Rayos Infrarrojos , Ratones , Datos de Secuencia Molecular , Fosforilación/efectos de los fármacos , Fosforilación/efectos de la radiación , Serina/metabolismo , Transducción de Señal/efectos de los fármacos , Transducción de Señal/efectos de la radiación , Termodinámica , Transcripción Genética/efectos de los fármacos , Transcripción Genética/efectos de la radiación , Proteína p53 Supresora de Tumor/metabolismo , Rayos Ultravioleta , Proteína 1 de Reparación por Escisión del Grupo de Complementación Cruzada de las Lesiones por Rayos X
18.
Oncogene ; 39(8): 1784-1796, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31740787

RESUMEN

Cancers in the oral/head & neck region (HNSCC) are aggressive due to high incidence of recurrence and distant metastasis. One prominent feature of aggressive HNSCC is the presence of severely hypoxic regions in tumors and activation of hypoxia-inducible factors (HIFs). In this study, we report that the XPE gene product DDB2 (damaged DNA binding protein 2), a nucleotide excision repair protein, is upregulated by hypoxia. Moreover, DDB2 inhibits HIF1α in HNSCC cells. It inhibits HIF1α in both normoxia and hypoxia by reducing mRNA expression. Knockdown of DDB2 enhances the expression of angiogenic markers and promotes tumor growth in a xenograft model. We show that DDB2 binds to an upstream promoter element in the HIF1Α gene and promotes histone H3K9 trimethylation around the binding site by recruiting Suv39h1. Also, we provide evidence that DDB2 has a significant suppressive effect on expression of the endogenous markers of hypoxia that are also prognostic indicators in HNSCC. Together, these results describe a new mechanism of hypoxia regulation that opposes expression of HIF1Α mRNA and the hypoxia-response genes.


Asunto(s)
Proteínas de Unión al ADN/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Hipoxia Tumoral , Línea Celular Tumoral , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Regulación Neoplásica de la Expresión Génica , Técnicas de Silenciamiento del Gen , Humanos , Carcinoma de Células Escamosas de Cabeza y Cuello/genética
19.
Diabetes Ther ; 11(12): 2791-2827, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33025397

RESUMEN

Diabetic kidney disease (DKD) occurs in approximately 20-40% of patients with type 2 diabetes mellitus. Patients with DKD have a higher risk of cardiovascular and all-cause mortality. Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers and antihyperglycemic drugs form the mainstay of DKD management and aim to restrict progression to more severe stages of DKD. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) control hyperglycemia by blocking renal glucose reabsorption in addition to preventing inflammation, thereby improving endothelial function and reducing oxidative stress; consequently, this class of prescription medicines is emerging as an important addition to the therapeutic armamentarium. The EMPA-REG OUTCOME, DECLARE TIMI 58, and CANVAS trials demonstrated the renoprotective effects of SGLT2i, such as restricting decline in glomerular filtration rate, in the progression of albuminuria, and in death due to renal causes. The renoprotection provided by SGLT2i was further confirmed in the CREDENCE study, which showed a 30% reduction in progression of chronic kidney disease, and in the DELIGHT study, which demonstrated a reduction in albuminuria with dapagliflozin compared with placebo (- 21.0%, confidence interval [CI] - 34.1 to - 5.2, p = 0.011). Furthermore, a meta-analysis demonstrated a reduced risk of dialysis, transplantation, or death due to kidney disease (relative risk 0.67; 95% CI 0.52-0.86; p = 0.0019) and a 45% risk reduction in worsening of renal function, end-stage renal disease, or renal death (hazard ratio 0.55, CI 0.48-0.64, p < 0.0001) with SGLT2i, irrespective of baseline estimated glomerular filtration rate. Thus, there is emerging evidence that SGLT2i may be used to curb the mortality and improve the quality of life in patients with DKD. However, clinicians need to effectively select candidates for SGLT2i therapy. In this consensus statement, we have qualitatively synthesized evidence demonstrating the renal effects of SGLT2i and proposed recommendations for optimal use of SGLT2i to effectively manage and delay progression of DKD.

20.
Curr Opin Genet Dev ; 15(1): 42-8, 2005 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15661532

RESUMEN

Recent genetic studies demonstrate that mice deficient in the forkhead box m1b (Foxm1b) transcription factor are highly resistant to developing hepatocellular carcinoma, which is among the most lethal cancers worldwide. In addition, the Foxm1b transcription factor was identified as a novel inhibitory target of the p19ARF tumor suppressor during early stages of liver tumorigenesis, but p19ARF expression is extinguished in hepatic tumors that develop at later stages. Structure-function studies demonstrate that amino acids 26-46 of the p19ARF protein are sufficient to bind Foxm1b and reduce Foxm1b transcriptional activity by targeting it to the nucleolus. A peptide containing amino acids 24-46 of p19ARF, which was modified to enhance cellular uptake, is an effective inhibitor of Foxm1b transcriptional activity and prevents Foxm1b stimulation of anchorage-independent growth of cells on soft agar. Thus, the p19ARF peptide is an effective inhibitor of Foxm1b and represents a potential therapy for hepatocellular carcinoma.


Asunto(s)
Carcinoma Hepatocelular/etiología , Proteínas Nucleares/metabolismo , Factores de Transcripción/metabolismo , Proteína p14ARF Supresora de Tumor/metabolismo , Animales , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Inhibidor p16 de la Quinasa Dependiente de Ciclina , Inhibidor p27 de las Quinasas Dependientes de la Ciclina , Proteína Forkhead Box M1 , Factores de Transcripción Forkhead , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/genética , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Ratones , Proteínas Nucleares/genética , Factores de Transcripción/genética , Proteína p14ARF Supresora de Tumor/genética , Proteínas Supresoras de Tumor/genética , Proteínas Supresoras de Tumor/metabolismo
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