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1.
Cell ; 176(3): 505-519.e22, 2019 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-30612738

RESUMEN

Genomic instability can be a hallmark of both human genetic disease and cancer. We identify a deleterious UBQLN4 mutation in families with an autosomal recessive syndrome reminiscent of genome instability disorders. UBQLN4 deficiency leads to increased sensitivity to genotoxic stress and delayed DNA double-strand break (DSB) repair. The proteasomal shuttle factor UBQLN4 is phosphorylated by ATM and interacts with ubiquitylated MRE11 to mediate early steps of homologous recombination-mediated DSB repair (HRR). Loss of UBQLN4 leads to chromatin retention of MRE11, promoting non-physiological HRR activity in vitro and in vivo. Conversely, UBQLN4 overexpression represses HRR and favors non-homologous end joining. Moreover, we find UBQLN4 overexpressed in aggressive tumors. In line with an HRR defect in these tumors, UBQLN4 overexpression is associated with PARP1 inhibitor sensitivity. UBQLN4 therefore curtails HRR activity through removal of MRE11 from damaged chromatin and thus offers a therapeutic window for PARP1 inhibitor treatment in UBQLN4-overexpressing tumors.


Asunto(s)
Proteínas Portadoras/genética , Proteínas Nucleares/genética , Proteínas Portadoras/metabolismo , Cromatina/metabolismo , ADN , Roturas del ADN de Doble Cadena , Daño del ADN/genética , Reparación del ADN por Unión de Extremidades , Proteínas de Unión al ADN/metabolismo , Femenino , Inestabilidad Genómica , Mutación de Línea Germinal , Recombinación Homóloga , Humanos , Proteína Homóloga de MRE11/genética , Proteína Homóloga de MRE11/metabolismo , Masculino , Neoplasias/genética , Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Cultivo Primario de Células , Reparación del ADN por Recombinación
2.
Cell ; 162(1): 146-59, 2015 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-26140595

RESUMEN

KRAS is one of the most frequently mutated oncogenes in human cancer. Despite substantial efforts, no clinically applicable strategy has yet been developed to effectively treat KRAS-mutant tumors. Here, we perform a cell-line-based screen and identify strong synergistic interactions between cell-cycle checkpoint-abrogating Chk1- and MK2 inhibitors, specifically in KRAS- and BRAF-driven cells. Mechanistically, we show that KRAS-mutant cancer displays intrinsic genotoxic stress, leading to tonic Chk1- and MK2 activity. We demonstrate that simultaneous Chk1- and MK2 inhibition leads to mitotic catastrophe in KRAS-mutant cells. This actionable synergistic interaction is validated using xenograft models, as well as distinct Kras- or Braf-driven autochthonous murine cancer models. Lastly, we show that combined checkpoint inhibition induces apoptotic cell death in KRAS- or BRAF-mutant tumor cells directly isolated from patients. These results strongly recommend simultaneous Chk1- and MK2 inhibition as a therapeutic strategy for the treatment of KRAS- or BRAF-driven cancers.


Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Sinergismo Farmacológico , Inhibidores Enzimáticos/farmacología , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/metabolismo , Proteínas ras/metabolismo , Adenocarcinoma/metabolismo , Adenocarcinoma del Pulmón , Animales , Puntos de Control del Ciclo Celular , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Daño del ADN , Modelos Animales de Enfermedad , Xenoinjertos , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Ratones , Trasplante de Neoplasias , Proteínas Proto-Oncogénicas B-raf/metabolismo , Proteínas Proto-Oncogénicas p21(ras) , Células Tumorales Cultivadas
3.
Blood ; 143(6): 522-534, 2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-37946299

RESUMEN

ABSTRACT: State-of-the-art response assessment of central nervous system lymphoma (CNSL) by magnetic resonance imaging is challenging and an insufficient predictor of treatment outcomes. Accordingly, the development of novel risk stratification strategies in CNSL is a high unmet medical need. We applied ultrasensitive circulating tumor DNA (ctDNA) sequencing to 146 plasma and cerebrospinal fluid (CSF) samples from 67 patients, aiming to develop an entirely noninvasive dynamic risk model considering clinical and molecular features of CNSL. Our ultrasensitive method allowed for the detection of CNSL-derived mutations in plasma ctDNA with high concordance to CSF and tumor tissue. Undetectable plasma ctDNA at baseline was associated with favorable outcomes. We tracked tumor-specific mutations in plasma-derived ctDNA over time and developed a novel CNSL biomarker based on this information: peripheral residual disease (PRD). Persistence of PRD after treatment was highly predictive of relapse. Integrating established baseline clinical risk factors with assessment of radiographic response and PRD during treatment resulted in the development and independent validation of a novel tool for risk stratification: molecular prognostic index for CNSL (MOP-C). MOP-C proved to be highly predictive of outcomes in patients with CNSL (failure-free survival hazard ratio per risk group of 6.60; 95% confidence interval, 3.12-13.97; P < .0001) and is publicly available at www.mop-c.com. Our results highlight the role of ctDNA sequencing in CNSL. MOP-C has the potential to improve the current standard of clinical risk stratification and radiographic response assessment in patients with CNSL, ultimately paving the way toward individualized treatment.


Asunto(s)
Neoplasias del Sistema Nervioso Central , ADN Tumoral Circulante , Linfoma no Hodgkin , Humanos , ADN Tumoral Circulante/genética , Recurrencia Local de Neoplasia , Neoplasias del Sistema Nervioso Central/diagnóstico , Neoplasias del Sistema Nervioso Central/genética , Neoplasias del Sistema Nervioso Central/terapia , Pronóstico , Biomarcadores de Tumor/genética , Sistema Nervioso Central
4.
Nat Rev Mol Cell Biol ; 14(9): 563-80, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23969844

RESUMEN

Coordinated progression through the cell cycle is a complex challenge for eukaryotic cells. Following genotoxic stress, diverse molecular signals must be integrated to establish checkpoints specific for each cell cycle stage, allowing time for various types of DNA repair. Phospho-Ser/Thr-binding domains have emerged as crucial regulators of cell cycle progression and DNA damage signalling. Such domains include 14-3-3 proteins, WW domains, Polo-box domains (in PLK1), WD40 repeats (including those in the E3 ligase SCF(ßTrCP)), BRCT domains (including those in BRCA1) and FHA domains (such as in CHK2 and MDC1). Progress has been made in our understanding of the motif (or motifs) that these phospho-Ser/Thr-binding domains connect with on their targets and how these interactions influence the cell cycle and DNA damage response.


Asunto(s)
Fosfoserina/química , Fosfotreonina/química , Estructura Terciaria de Proteína , Proteínas/química , Ciclo Celular/genética , Daño del ADN , Reparación del ADN , Humanos , Modelos Moleculares , Fosfoserina/metabolismo , Fosfotreonina/metabolismo , Unión Proteica , Proteínas/genética , Proteínas/metabolismo
5.
Eur J Nucl Med Mol Imaging ; 51(5): 1361-1370, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38114616

RESUMEN

PURPOSE: The emergence of chimeric antigen receptor (CAR) T-cell therapy fundamentally changed the management of individuals with relapsed and refractory large B-cell lymphoma (LBCL). However, real-world data have shown divergent outcomes for the approved products. The present study therefore set out to evaluate potential risk factors in a larger cohort. METHODS: Our analysis set included 88 patients, treated in four German university hospitals and one Italian center, who had undergone 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (PET) before CAR T-cell therapy with tisagenlecleucel or axicabtagene ciloleucel. We first determined the predictive value of conventional risk factors, treatment lines, and response to bridging therapy for progression-free survival (PFS) through forward selection based on Cox regression. In a second step, the additive potential of two common PET parameters was assessed. Their optimal dichotomizing thresholds were calculated individually for each CAR T-cell product. RESULTS: Extra-nodal involvement emerged as the most relevant of the conventional tumor and patient characteristics. Moreover, we found that inclusion of metabolic tumor volume (MTV) further improves outcome prediction. The hazard ratio for a PFS event was 1.68 per unit increase of our proposed risk score (95% confidence interval [1.20, 2.35], P = 0.003), which comprised both extra-nodal disease and lymphoma burden. While the most suitable MTV cut-off among patients receiving tisagenlecleucel was 11 mL, a markedly higher threshold of 259 mL showed optimal predictive performance in those undergoing axicabtagene ciloleucel treatment. CONCLUSION: Our analysis demonstrates that the presence of more than one extra-nodal lesion and higher MTV in LBCL are associated with inferior outcome after CAR T-cell treatment. Based on an assessment tool including these two factors, patients can be assigned to one of three risk groups. Importantly, as shown by our study, metabolic tumor burden might facilitate CAR T-cell product selection and reflect the individual need for bridging therapy.


Asunto(s)
Inmunoterapia Adoptiva , Linfoma de Células B Grandes Difuso , Humanos , Inmunoterapia Adoptiva/efectos adversos , Inmunoterapia Adoptiva/métodos , Linfoma de Células B Grandes Difuso/diagnóstico por imagen , Linfoma de Células B Grandes Difuso/terapia , Pronóstico , Tomografía de Emisión de Positrones , Medición de Riesgo
6.
Eur J Haematol ; 112(6): 957-963, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38369814

RESUMEN

Although several promising approaches for the treatment of relapsed/refractory diffuse large B-cell lymphoma (rrDLBCL) have been approved recently, it remains unclear which patients will ultimately achieve long-term responses. Circulating tumor (ct)DNA sequencing has emerged as a valuable tool to assess minimal residual disease (MRD). Correlations between MRD and outcomes have been shown in previously untreated DLBCL, but data on the repeated assessment of MRD in the dynamic course of rrDLBCL is limited. Here, we present an approach leveraging cost- and time-sensitivity of digital droplet (dd)PCR to repeatedly assess MRD in rrDLBCL and present proof-of-principle for its ability to predict outcomes.


Asunto(s)
Linfoma de Células B Grandes Difuso , Neoplasia Residual , Reacción en Cadena de la Polimerasa , Humanos , Neoplasia Residual/diagnóstico , Linfoma de Células B Grandes Difuso/genética , Linfoma de Células B Grandes Difuso/diagnóstico , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Reacción en Cadena de la Polimerasa/métodos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Recurrencia , Pronóstico , ADN Tumoral Circulante/genética , Masculino , Femenino , Resistencia a Antineoplásicos/genética , Biomarcadores de Tumor , Persona de Mediana Edad , Resultado del Tratamiento
7.
Am J Hematol ; 99(2): 203-215, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38009469

RESUMEN

Although CMML since long has been separated from MDS, many studies continue to evaluate the outcomes of both diseases after hematopoietic cell transplantation (allo-HCT) together. Data evaluating outcomes of a large CMML cohort after allo-HCT compared to MDS are limited. We aim to compare outcomes of CMML to MDS patients who underwent allo-HCT between 2010 and 2018. Patients ≥18 years with CMML and MDS undergoing allo-HCT reported to the EBMT registry were analyzed. Progression to AML before allo-HCT was an exclusion criterion. Overall survival (OS), progression/relapse-free survival (PFS), relapse incidence (including progression) (REL), and non-relapse mortality (NRM) were evaluated in univariable and multivariable (MVA) Cox proportional hazard models including interaction terms between disease and confounders. In total, 10832 patients who underwent allo-HCT were included in the study, there were a total of 1466 CMML, and 9366 MDS. The median age at time of allo-HCT in CMML (median 60.5, IQR 54.3-65.2 years) was significantly higher than in the MDS cohort (median 58.8, IQR 50.2-64.5 years; p < .001). A significantly higher percentage of CMML patients were male (69.4%) compared to MDS (61.2%; p < .001). There were no clinically meaningful differences in the distribution of Karnofsky score, Sorror HCT-CI score at allo-HCT, and donor type, between the CMML and MDS patients. RIC platforms were utilized in 63.9% of CMML allo-HCT, and in 61.4% of MDS patients (p = .08). In univariable analyses, we found that OS, PFS, and REL were significantly worse in CMML when compared with MDS (all p < .0001), whereas no significant difference was observed in NRM (p = .77). In multivariable analyses, the HR comparing MDS versus CMML for OS was 0.81 (95% CI, 0.74-0.88, p < .001), PFS 0.76 (95% CI 0.70-0.82, p < .001), relapse 0.66 (95% CI 0.59-0.74, p < .001), and NRM 0.87 (95% CI 0.78-0.98, p = .02), respectively. The association between baseline variables and outcome was found to be similar in MDS and CMML (all interaction p > .05) except for a decreasing trend over time of the risk of relapse in CMML (HR allo-HCT per year later 0.94, 95% CI 0.90-0.98), whereas no such trend was observed in MDS (HR 1.00, 95% CI 0.98-1.02). The poor outcome observed for CMML could be related to variables not measured in this study or to factors inherent to the disease itself. This study demonstrates that outcomes of CMML patients after allo-HCT are significantly worse compared to MDS. The results of this study may contribute to future recommendations for allo-HCT in CMML patients.


Asunto(s)
Trasplante de Células Madre Hematopoyéticas , Humanos , Masculino , Persona de Mediana Edad , Anciano , Femenino , Trasplante Homólogo , Trasplante de Células Madre Hematopoyéticas/métodos , Modelos de Riesgos Proporcionales , Donantes de Tejidos , Recurrencia , Estudios Retrospectivos , Acondicionamiento Pretrasplante/métodos
8.
Haematologica ; 108(1): 34-41, 2023 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-35678031

RESUMEN

We retrospectively studied 125 patients with acute myeloid leukemia and trisomy 4 (median age at diagnosis, 58 years; range, 16-77 years) treated between 2000 and 2019 within a multicenter study. Trisomy 4 was the sole abnormality in 28 (22%) patients and additional abnormalities were present in 97 (78%) patients. Twenty-two (22%) and 15 (15%) of 101 tested patients harbored NPM1 and FLT3-ITD mutations. Two (3%) of 72 tested patients had double CEBPA mutations. Data on response to intensive anthracycline-based induction therapy were available for 119 patients. Complete remission was achieved in 67% (n=80) and the early death rate was 5% (n=6). Notably, patients with trisomy 4 as sole abnormality had a complete remission rate of 89%. Allogeneic hematopoietic cell transplantation was performed in 40 (34%) patients, of whom 19 were transplanted in first complete remission. The median follow-up of the intensively treated cohort was 5.76 years (95% confidence interval [95% CI]: 2.99-7.61 years). The 5-year overall survival and relapse-free survival rates were 30% (95% CI: 22-41%) and 27% (95% CI: 18-41%), respectively. An Andersen-Gill regression model on overall survival revealed that favorable-risk according to the European LeukemiaNet classification (hazard ratio [HR]=0.34; P=0.006) and trisomy 4 as sole abnormality (HR=0.41; P=0.01) were favorable factors, whereas age with a difference of 10 years (HR=1.15; P=0.11), female gender (HR=0.74; P=0.20) and allogeneic hematopoietic cell transplantation (HR=0.64; P=0.14) did not have an significant impact. In our cohort, patients with trisomy 4 as their sole abnormality had a high complete remission rate and favorable clinical outcome. Allogeneic hematopoietic cell transplantation did not seem to improve overall survival.


Asunto(s)
Trasplante de Células Madre Hematopoyéticas , Leucemia Mieloide Aguda , Femenino , Humanos , Persona de Mediana Edad , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/terapia , Mutación , Nucleofosmina , Pronóstico , Estudios Retrospectivos , Trisomía/genética , Masculino , Adolescente , Adulto Joven , Adulto , Anciano
9.
Cell ; 135(2): 343-54, 2008 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-18957207

RESUMEN

Signaling networks respond to diverse stimuli, but how the state of the signaling network is relayed to downstream cellular responses is unclear. We modeled how incremental activation of signaling molecules is transmitted to control apoptosis as a function of signal strength and dynamic range. A linear relationship between signal input and response output, with the dynamic range of signaling molecules uniformly distributed across activation states, most accurately predicted cellular responses. When nonlinearized signals with compressed dynamic range relay network activation to apoptosis, we observe catastrophic, stimulus-specific prediction failures. We develop a general computational technique, "model-breakpoint analysis," to analyze the mechanism of these failures, identifying new time- and stimulus-specific roles for Akt, ERK, and MK2 kinase activity in apoptosis, which were experimentally verified. Dynamic range is rarely measured in signal-transduction studies, but our experiments using model-breakpoint analysis suggest it may be a greater determinant of cell fate than measured signal strength.


Asunto(s)
Citocinas/metabolismo , Modelos Biológicos , Transducción de Señal , Biología de Sistemas/métodos , Animales , Apoptosis , Humanos
10.
Hum Genet ; 140(12): 1679-1693, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34545459

RESUMEN

The highly conserved YrdC domain-containing protein (YRDC) interacts with the well-described KEOPS complex, regulating specific tRNA modifications to ensure accurate protein synthesis. Previous studies have linked the KEOPS complex to a role in promoting telomere maintenance and controlling genome integrity. Here, we report on a newborn with a severe neonatal progeroid phenotype including generalized loss of subcutaneous fat, microcephaly, growth retardation, wrinkled skin, renal failure, and premature death at the age of 12 days. By trio whole-exome sequencing, we identified a novel homozygous missense mutation, c.662T > C, in YRDC affecting an evolutionary highly conserved amino acid (p.Ile221Thr). Functional characterization of patient-derived dermal fibroblasts revealed that this mutation impairs YRDC function and consequently results in reduced t6A modifications of tRNAs. Furthermore, we established and performed a novel and highly sensitive 3-D Q-FISH analysis based on single-telomere detection to investigate the impact of YRDC on telomere maintenance. This analysis revealed significant telomere shortening in YRDC-mutant cells. Moreover, single-cell RNA sequencing analysis of YRDC-mutant fibroblasts revealed significant transcriptome-wide changes in gene expression, specifically enriched for genes associated with processes involved in DNA repair. We next examined the DNA damage response of patient's dermal fibroblasts and detected an increased susceptibility to genotoxic agents and a global DNA double-strand break repair defect. Thus, our data suggest that YRDC may affect the maintenance of genomic stability. Together, our findings indicate that biallelic variants in YRDC result in a developmental disorder with progeroid features and might be linked to increased genomic instability and telomere shortening.


Asunto(s)
Discapacidades del Desarrollo/genética , Proteínas de Unión al GTP/genética , Progeria/genética , Proteínas de Unión al ARN/genética , Alelos , Consanguinidad , Daño del ADN , Discapacidades del Desarrollo/patología , Genoma Humano , Inestabilidad Genómica , Homocigoto , Humanos , Recién Nacido , Masculino , Mutación , Linaje , Progeria/patología , ARN de Transferencia/genética , Análisis de Secuencia de ARN , Acortamiento del Telómero
11.
Curr Opin Hematol ; 25(4): 315-322, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29702521

RESUMEN

PURPOSE OF REVIEW: Recent lymphoma genome sequencing projects have shed light on the genomic landscape of indolent and aggressive lymphomas, as well as some of the molecular mechanisms underlying recurrent mutations and translocations in these entities. Here, we review these recent genomic discoveries, focusing on acquired DNA repair defects in lymphoma. In addition, we highlight recently identified actionable molecular vulnerabilities associated with recurrent mutations in chronic lymphocytic leukemia (CLL), which serves as a model entity. RECENT FINDINGS: The results of several large lymphoma genome sequencing projects have recently been reported, including CLL, T-PLL and DLBCL. We align these discoveries with proposed mechanisms of mutation acquisition in B-cell lymphomas. Moreover, novel autochthonous mouse models of CLL have recently been generated and we discuss how these models serve as preclinical tools to drive the development of novel targeted therapeutic interventions. Lastly, we highlight the results of early clinical data on novel compounds targeting defects in the DNA damage response of CLL with a particular focus on deleterious ATM mutations. SUMMARY: Defects in DNA repair pathways are selected events in cancer, including lymphomas. Specifically, ATM deficiency is associated with PARP1- and DNA-PKcs inhibitor sensitivity in vitro and in vivo.


Asunto(s)
Transformación Celular Neoplásica , Daño del ADN , Linfoma de Células B , Mutación , Animales , Proteínas de la Ataxia Telangiectasia Mutada/genética , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/metabolismo , Transformación Celular Neoplásica/patología , Proteína Quinasa Activada por ADN/genética , Proteína Quinasa Activada por ADN/metabolismo , Humanos , Leucemia Linfocítica Crónica de Células B/genética , Leucemia Linfocítica Crónica de Células B/metabolismo , Leucemia Linfocítica Crónica de Células B/patología , Linfoma de Células B/genética , Linfoma de Células B/metabolismo , Linfoma de Células B/patología , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Poli(ADP-Ribosa) Polimerasa-1/genética , Poli(ADP-Ribosa) Polimerasa-1/metabolismo
12.
Cancer Immunol Immunother ; 67(11): 1797-1807, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30203262

RESUMEN

Oncogenic MYD88 mutations, most notably the Leu 265 Pro (L265P) mutation, were recently identified as potential driver mutations in various B-cell non-Hodgkin Lymphomas (NHLs). The L265P mutation is now thought to be common to virtually all NHLs and occurs in between 4 and 90% of cases, depending on the entity. Since it is tumor-specific, the mutation, and the pathways it regulates, might serve as advantageous therapeutic targets for both conventional chemotherapeutic intervention, as well as immunotherapeutic strategies. Here, we review recent progress on elucidating the molecular and cellular processes affected by the L265P mutation of MYD88, describe a new in vivo model for MyD88 L265P-mediated oncogenesis, and summarize how these findings could be exploited therapeutically by specific targeting of signaling pathways. In addition, we summarize current and explore future possibilities for conceivable immunotherapeutic approaches, such as L265P-derived peptide vaccination, adoptive transfer of L265P-restricted T cells, and use of T-cell receptor-engineered T cells. With clinical trials regarding their efficacy rapidly expanding to NHLs, we also discuss potential combinations of immune checkpoint inhibitors with the described targeted chemotherapies of L265P signaling networks, and/or with the above immunological approaches as potential ways of targeting MYD88-mutated lymphomas in the future.


Asunto(s)
Antineoplásicos/uso terapéutico , Linfoma/tratamiento farmacológico , Linfoma/genética , Terapia Molecular Dirigida , Mutación , Factor 88 de Diferenciación Mieloide/genética , Humanos
13.
Blood ; 127(22): 2732-41, 2016 06 02.
Artículo en Inglés | MEDLINE | ID: mdl-27048211

RESUMEN

The adaptor protein MYD88 is critical for relaying activation of Toll-like receptor signaling to NF-κB activation. MYD88 mutations, particularly the p.L265P mutation, have been described in numerous distinct B-cell malignancies, including diffuse large B-cell lymphoma (DLBCL). Twenty-nine percent of activated B-cell-type DLBCL (ABC-DLBCL), which is characterized by constitutive activation of the NF-κB pathway, carry the p.L265P mutation. In addition, ABC-DLBCL frequently displays focal copy number gains affecting BCL2 Here, we generated a novel mouse model in which Cre-mediated recombination, specifically in B cells, leads to the conditional expression of Myd88(p.L252P) (the orthologous position of the human MYD88(p.L265P) mutation) from the endogenous locus. These mice develop a lymphoproliferative disease and occasional transformation into clonal lymphomas. The clonal disease displays the morphologic and immunophenotypical characteristics of ABC-DLBCL. Lymphomagenesis can be accelerated by crossing in a further novel allele, which mediates conditional overexpression of BCL2 Cross-validation experiments in human DLBCL samples revealed that both MYD88 and CD79B mutations are substantially enriched in ABC-DLBCL compared with germinal center B-cell DLBCL. Furthermore, analyses of human DLBCL genome sequencing data confirmed that BCL2 amplifications frequently co-occurred with MYD88 mutations, further validating our approach. Finally, in silico experiments revealed that MYD88-mutant ABC-DLBCL cells in particular display an actionable addiction to BCL2. Altogether, we generated a novel autochthonous mouse model of ABC-DLBCL that could be used as a preclinical platform for the development and validation of novel therapeutic approaches for the treatment of ABC-DLBCL.


Asunto(s)
Linfocitos B/metabolismo , Transformación Celular Neoplásica/metabolismo , Linfoma de Células B Grandes Difuso/metabolismo , Mutación Missense , Factor 88 de Diferenciación Mieloide/biosíntesis , Neoplasias Experimentales/metabolismo , Animales , Linfocitos B/patología , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/patología , Humanos , Linfoma de Células B Grandes Difuso/genética , Linfoma de Células B Grandes Difuso/patología , Ratones , Ratones Transgénicos , Factor 88 de Diferenciación Mieloide/genética , Neoplasias Experimentales/genética , Neoplasias Experimentales/patología , Proteínas Proto-Oncogénicas c-bcl-2/biosíntesis , Proteínas Proto-Oncogénicas c-bcl-2/genética
14.
Mol Cell ; 40(1): 34-49, 2010 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-20932473

RESUMEN

Following genotoxic stress, cells activate a complex kinase-based signaling network to arrest the cell cycle and initiate DNA repair. p53-defective tumor cells rewire their checkpoint response and become dependent on the p38/MK2 pathway for survival after DNA damage, despite a functional ATR-Chk1 pathway. We used functional genetics to dissect the contributions of Chk1 and MK2 to checkpoint control. We show that nuclear Chk1 activity is essential to establish a G(2)/M checkpoint, while cytoplasmic MK2 activity is critical for prolonged checkpoint maintenance through a process of posttranscriptional mRNA stabilization. Following DNA damage, the p38/MK2 complex relocalizes from nucleus to cytoplasm where MK2 phosphorylates hnRNPA0, to stabilize Gadd45α mRNA, while p38 phosphorylates and releases the translational inhibitor TIAR. In addition, MK2 phosphorylates PARN, blocking Gadd45α mRNA degradation. Gadd45α functions within a positive feedback loop, sustaining the MK2-dependent cytoplasmic sequestration of Cdc25B/C to block mitotic entry in the presence of unrepaired DNA damage. Our findings demonstrate a critical role for the MK2 pathway in the posttranscriptional regulation of gene expression as part of the DNA damage response in cancer cells.


Asunto(s)
Proteínas de Ciclo Celular/genética , Ciclo Celular , Citoplasma/enzimología , Daño del ADN , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Nucleares/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Procesamiento Postranscripcional del ARN , Estabilidad del ARN , ARN Mensajero/metabolismo , Regiones no Traducidas 3' , Transporte Activo de Núcleo Celular , Antibióticos Antineoplásicos/farmacología , Ciclo Celular/efectos de los fármacos , Ciclo Celular/genética , Ciclo Celular/efectos de la radiación , Núcleo Celular/enzimología , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Reparación del ADN , Doxorrubicina/farmacología , Exorribonucleasas/metabolismo , Retroalimentación Fisiológica , Células HeLa , Neoplasias de Cabeza y Cuello/enzimología , Neoplasias de Cabeza y Cuello/genética , Ribonucleoproteínas Nucleares Heterogéneas/metabolismo , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Mitosis , Fosforilación , Proteínas Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Interferencia de ARN , Procesamiento Postranscripcional del ARN/efectos de los fármacos , Procesamiento Postranscripcional del ARN/efectos de la radiación , Estabilidad del ARN/efectos de los fármacos , Estabilidad del ARN/efectos de la radiación , Proteínas de Unión al ARN/metabolismo , Transducción de Señal , Factores de Tiempo , Transfección , Rayos Ultravioleta , Fosfatasas cdc25/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
15.
Trends Genet ; 30(8): 326-39, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25017190

RESUMEN

Defects in DNA repair pathways enable cancer cells to accumulate genomic alterations that contribute to their aggressive phenotype. However, tumors rely on residual DNA repair capacities to survive the damage induced by genotoxic stress. This dichotomy might explain why only isolated DNA repair pathways are inactivated in cancer cells. Accordingly, synergism has been observed between DNA-damaging drugs and targeted inhibitors of DNA repair. DNA repair pathways are generally thought of as mutually exclusive mechanistic units handling different types of lesions in distinct cell cycle phases. Recent preclinical studies, however, provide strong evidence that multifunctional DNA repair hubs, which are involved in multiple conventional DNA repair pathways, are frequently altered in cancer. We therefore propose that targeted anticancer therapies should not only exploit synthetic lethal interactions between two single genes but also consider alterations in DNA repair hubs. Such a network-based approach considerably increases the opportunities for targeting DNA repair-defective tumors.


Asunto(s)
Antineoplásicos/uso terapéutico , Enzimas Reparadoras del ADN/antagonistas & inhibidores , Reparación del ADN/efectos de los fármacos , Neoplasias/genética , Neoplasias/terapia , Medicina de Precisión , Transducción de Señal/efectos de los fármacos , Enzimas Reparadoras del ADN/genética , Diseño de Fármacos , Humanos
16.
Genes Dev ; 23(16): 1895-909, 2009 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-19608766

RESUMEN

While the contribution of specific tumor suppressor networks to cancer development has been the subject of considerable recent study, it remains unclear how alterations in these networks are integrated to influence the response of tumors to anti-cancer treatments. Here, we show that mechanisms commonly used by tumors to bypass early neoplastic checkpoints ultimately determine chemotherapeutic response and generate tumor-specific vulnerabilities that can be exploited with targeted therapies. Specifically, evaluation of the combined status of ATM and p53, two commonly mutated tumor suppressor genes, can help to predict the clinical response to genotoxic chemotherapies. We show that in p53-deficient settings, suppression of ATM dramatically sensitizes tumors to DNA-damaging chemotherapy, whereas, conversely, in the presence of functional p53, suppression of ATM or its downstream target Chk2 actually protects tumors from being killed by genotoxic agents. Furthermore, ATM-deficient cancer cells display strong nononcogene addiction to DNA-PKcs for survival after DNA damage, such that suppression of DNA-PKcs in vivo resensitizes inherently chemoresistant ATM-deficient tumors to genotoxic chemotherapy. Thus, the specific set of alterations induced during tumor development plays a dominant role in determining both the tumor response to conventional chemotherapy and specific susceptibilities to targeted therapies in a given malignancy.


Asunto(s)
Antineoplásicos/uso terapéutico , Proteínas de Ciclo Celular/metabolismo , Proteínas de Unión al ADN/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/fisiopatología , Proteínas Serina-Treonina Quinasas/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Antineoplásicos/farmacología , Apoptosis/efectos de los fármacos , Proteínas de la Ataxia Telangiectasia Mutada , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/fisiopatología , Línea Celular Tumoral , Quinasa de Punto de Control 2 , Proteínas de Unión al ADN/deficiencia , Resistencia a Antineoplásicos , Femenino , Humanos , Ratones , Ratones Desnudos , Células 3T3 NIH , Proteínas Serina-Treonina Quinasas/deficiencia , Transducción de Señal , Análisis de Supervivencia , Proteínas Supresoras de Tumor/deficiencia
17.
EMBO J ; 31(20): 3961-75, 2012 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-22909821

RESUMEN

Following genotoxic stress, cells activate a complex signalling network to arrest the cell cycle and initiate DNA repair or apoptosis. The tumour suppressor p53 lies at the heart of this DNA damage response. However, it remains incompletely understood, which signalling molecules dictate the choice between these different cellular outcomes. Here, we identify the transcriptional regulator apoptosis-antagonizing transcription factor (AATF)/Che-1 as a critical regulator of the cellular outcome of the p53 response. Upon genotoxic stress, AATF is phosphorylated by the checkpoint kinase MK2. Phosphorylation results in the release of AATF from cytoplasmic MRLC3 and subsequent nuclear translocation where AATF binds to the PUMA, BAX and BAK promoter regions to repress p53-driven expression of these pro-apoptotic genes. In xenograft experiments, mice exhibit a dramatically enhanced response of AATF-depleted tumours following genotoxic chemotherapy with adriamycin. The exogenous expression of a phospho-mimicking AATF point mutant results in marked adriamycin resistance in vivo. Nuclear AATF enrichment appears to be selected for in p53-proficient endometrial cancers. Furthermore, focal copy number gains at the AATF locus in neuroblastoma, which is known to be almost exclusively p53-proficient, correlate with an adverse prognosis and reduced overall survival. These data identify the p38/MK2/AATF signalling module as a critical repressor of p53-driven apoptosis and commend this pathway as a target for DNA damage-sensitizing therapeutic regimens.


Asunto(s)
Proteínas Reguladoras de la Apoptosis/fisiología , Apoptosis/fisiología , Daño del ADN/fisiología , Proteínas Represoras/fisiología , Proteína p53 Supresora de Tumor/fisiología , Transporte Activo de Núcleo Celular , Secuencia de Aminoácidos , Animales , Proteínas Reguladoras de la Apoptosis/genética , Puntos de Control del Ciclo Celular , Daño del ADN/genética , Doxorrubicina/farmacología , Resistencia a Antineoplásicos/genética , Neoplasias Endometriales/genética , Femenino , Amplificación de Genes , Dosificación de Gen , Células HEK293 , Humanos , Ratones , Datos de Secuencia Molecular , Complejos Multiproteicos , Cadenas Ligeras de Miosina/metabolismo , Neuroblastoma/genética , Neuroblastoma/mortalidad , Presión Osmótica , Fosforilación , Pronóstico , Procesamiento Proteico-Postraduccional , Proteínas Represoras/genética
18.
Trends Genet ; 28(3): 128-36, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22265392

RESUMEN

Genome instability contributes to cancer development and accelerates age-related pathologies as evidenced by a variety of congenital cancer susceptibility and progeroid syndromes that are caused by defects in genome maintenance mechanisms. DNA damage response (DDR) pathways that are mediated through the tumor suppressor p53 play an important role in the cell-intrinsic responses to genome instability, including a transient cell cycle arrest, senescence and apoptosis. Both senescence and apoptosis are powerful tumor-suppressive pathways preventing the uncontrolled proliferation of transformed cells. However, both pathways can potentially deplete stem and progenitor cell pools, thus promoting tissue degeneration and organ failure, which are both hallmarks of aging. p53 signaling is also involved in mediating non-cell-autonomous interactions with the innate immune system and in the systemic adjustments during the aging process. The network of p53 target genes thus functions as an important regulator of cancer prevention and aging.


Asunto(s)
Envejecimiento , Daño del ADN , Neoplasias/genética , Proteína p53 Supresora de Tumor/metabolismo , Animales , Susceptibilidad a Enfermedades , Humanos , Neoplasias/inmunología , Neoplasias/metabolismo , Transducción de Señal , Proteína p53 Supresora de Tumor/inmunología
19.
Cancer Cell ; 11(2): 175-89, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17292828

RESUMEN

In response to DNA damage, eukaryotic cells activate ATM-Chk2 and/or ATR-Chk1 to arrest the cell cycle and initiate DNA repair. We show that, in the absence of p53, cells depend on a third cell-cycle checkpoint pathway involving p38MAPK/MK2 for cell-cycle arrest and survival after DNA damage. MK2 depletion in p53-deficient cells, but not in p53 wild-type cells, caused abrogation of the Cdc25A-mediated S phase checkpoint after cisplatin exposure and loss of the Cdc25B-mediated G2/M checkpoint following doxorubicin treatment, resulting in mitotic catastrophe and pronounced regression of murine tumors in vivo. We show that the Chk1 inhibitor UCN-01 also potently inhibits MK2, suggesting that its clinical efficacy results from the simultaneous disruption of two critical checkpoint pathways in p53-defective cells.


Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Proteínas de Unión al ADN/metabolismo , Proteínas Quinasas/fisiología , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal , Proteína p53 Supresora de Tumor/fisiología , Proteínas Supresoras de Tumor/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Animales , Antibióticos Antineoplásicos/farmacología , Antineoplásicos/farmacología , Proteínas de la Ataxia Telangiectasia Mutada , Neoplasias Óseas/metabolismo , Neoplasias Óseas/patología , División Celular/efectos de los fármacos , División Celular/efectos de la radiación , Supervivencia Celular , Células Cultivadas , Cisplatino/farmacología , Daño del ADN/efectos de los fármacos , Daño del ADN/efectos de la radiación , Reparación del ADN/efectos de los fármacos , Reparación del ADN/efectos de la radiación , Doxorrubicina/farmacología , Fase G2/efectos de los fármacos , Fase G2/efectos de la radiación , Humanos , Péptidos y Proteínas de Señalización Intracelular , Ratones , Ratones Noqueados , Ratones Desnudos , Mitosis/efectos de los fármacos , Mitosis/efectos de la radiación , Neoplasias Experimentales/metabolismo , Neoplasias Experimentales/patología , Osteosarcoma/metabolismo , Osteosarcoma/patología , Fosforilación/efectos de los fármacos , Fosforilación/efectos de la radiación , Proteína Quinasa C/antagonistas & inhibidores , Proteínas Quinasas/genética , Fase S/efectos de los fármacos , Fase S/efectos de la radiación , Estaurosporina/análogos & derivados , Estaurosporina/farmacología , Rayos Ultravioleta , Fosfatasas cdc25/metabolismo
20.
Hum Mol Genet ; 21(26): 5528-38, 2012 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-23026745

RESUMEN

Nephronophthisis (NPH) is a genetically heterogenous kidney disease and represents the most common genetic cause for end-stage renal disease in children. It is caused by the mutation of genes encoding for the nephrocystin proteins (NPHPs) which localize to primary cilia or centrosomes, classifying this disease as a 'ciliopathy'. Recently, it has been shown that NPHP4 acts as a potent negative regulator of mammalian Hippo signalling by interacting with the Lats protein kinase and controlling the phosphorylation of the oncogenic transcriptional activator TAZ. Here, we demonstrate that NPHP9, another NPH family member, also controls TAZ activity by a distinct mechanism. NPHP9, which is also called NEK8, directly interacted with TAZ and induced nuclear translocation of the TAZ/NPHP9 protein complex. Binding of NPHP9 to TAZ was enhanced in a TAZ mutant that lost its ability to bind 14-3-3, suggesting that 14-3-3 and NPHP9 may compete for TAZ binding, with 14-3-3 favouring cytoplasmic retention and NPHP9 mediating nuclear delivery. Consistently, co-expression of NPHP4, which inhibits TAZ phosphorylation at the 14-3-3 binding site through the inhibition of Lats kinase activity, induced efficient nuclear delivery of the TAZ/NPHP9 protein pair. Consistent with a role for TAZ in controlling proliferation and tumorigenesis, the downregulation of NPHP9 inhibited the TAZ-dependent proliferation of hippo-responsive normal epithelial and also breast cancer cells. As NPHP9 has been shown to be upregulated in breast cancer, these data do not only support a critical role for TAZ/hippo signalling in the pathogenesis of NPH but may also imply a possible role for NPHP9 in TAZ-mediated tumorigenesis.


Asunto(s)
Cilios/patología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Enfermedades Renales Quísticas/genética , Proteínas Quinasas/metabolismo , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Núcleo Celular/metabolismo , Proliferación Celular , Centrosoma/metabolismo , Cilios/metabolismo , Regulación hacia Abajo , Técnica del Anticuerpo Fluorescente , Regulación de la Expresión Génica , Células HEK293 , Humanos , Inmunoprecipitación , Péptidos y Proteínas de Señalización Intracelular/genética , Enfermedades Renales Quísticas/patología , Luciferasas/metabolismo , Mutación , Quinasas Relacionadas con NIMA , Fosforilación , Plásmidos , Proteínas Quinasas/genética , Proteínas/genética , Proteínas/metabolismo , Transducción de Señal , Transactivadores , Factores de Transcripción , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ
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