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1.
iScience ; 27(2): 108880, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38333710

RESUMO

Local cryoablation can engender systemic immune activation/anticancer responses in tumors otherwise resistant to immune checkpoint blockade (ICB). We evaluated the safety/tolerability of preoperative cryoablation plus ipilimumab and nivolumab in 5 early-stage/resectable breast cancers. The primary endpoint was met when all 5 patients underwent standard-of-care primary breast surgery undelayedly. Three patients developed transient hyperthyroidism; one developed grade 4 liver toxicity (resolved with supportive management). We compared this strategy with cryoablation and/or ipilimumab. Dual ICB plus cryoablation induced higher expression of T cell activation markers and serum Th1 cytokines and reduced immunosuppressive serum CD4+PD-1hi T cells, improving effector-to-suppressor T cell ratio. After dual ICB and before cryoablation, T cell receptor sequencing of 4 patients showed increased T cell clonality. In this small subset of patients, we provide preliminary evidence that preoperative cryoablation plus ipilimumab and nivolumab is feasible, inducing systemic adaptive immune activation potentially more robust than cryoablation with/without ipilimumab.

2.
Pharmacogenomics ; 25(1): 29-40, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38189154

RESUMO

Aim: Successful treatment with tacrolimus to prevent graft versus host disease (GVHD) and minimize tacrolimus-related toxicities among allogeneic hematopoietic cell transplantation (alloHCT) recipients is contingent upon quickly achieving and maintaining concentrations within a narrow therapeutic range. The primary objective was to investigate associations between CYP3A4, CYP3A5 or ABCB1 genotype and the proportion of patients that attained an initial tacrolimus goal concentration following initiation of intravenous (iv.) and conversion to oral administration. Materials & methods: We retrospectively evaluated 86 patients who underwent HLA-matched (8/8) related donor alloHCT and were prescribed a tacrolimus-based regimen for GVHD prophylaxis. Results & conclusion: The findings of the present study suggests that CYP3A5 genotype may impact attainment of initial therapeutic tacrolimus concentrations with oral administration in alloHCT recipients.


Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Humanos , Tacrolimo , Citocromo P-450 CYP3A/genética , Citocromo P-450 CYP3A/metabolismo , Imunossupressores , Estudos Retrospectivos , Doença Enxerto-Hospedeiro/tratamento farmacológico , Doença Enxerto-Hospedeiro/genética , Doença Enxerto-Hospedeiro/prevenção & controle , Resultado do Tratamento , Genótipo , Transplante de Células-Tronco Hematopoéticas/métodos , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética
3.
Cancers (Basel) ; 15(5)2023 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-36900251

RESUMO

We examined the safety and immunogenicity of sequential administration of a tetravalent, non-HLA (human leukocyte antigen) restricted, heteroclitic Wilms' Tumor 1 (WT1) peptide vaccine (galinpepimut-S) with anti-PD-1 (programmed cell death protein 1) nivolumab. This open-label, non-randomized phase I study enrolled patients with WT1-expressing ovarian cancer in second or third remission from June 2016 to July 2017. Therapy included six (every two weeks) subcutaneous inoculations of galinpepimut-S vaccine adjuvanted with Montanide, low-dose subcutaneous sargramostim at the injection site, with intravenous nivolumab over 12 weeks, and up to six additional doses until disease progression or toxicity. One-year progression-free survival (PFS) was correlated to T-cell responses and WT1-specific immunoglobulin (Ig)G levels. Eleven patients were enrolled; seven experienced a grade 1 adverse event, and one experienced a grade ≥3 adverse event considered a dose-limiting toxicity. Ten (91%) of eleven patients had T-cell responses to WT1 peptides. Seven (88%) of eight evaluable patients had IgG against WT1 antigen and full-length protein. In evaluable patients who received >2 treatments of galinpepimut-S and nivolumab, the 1-year PFS rate was 70%. Coadministration of galinpepimut-S and nivolumab demonstrated a tolerable toxicity profile and induced immune responses, as indicated by immunophenotyping and WT1-specific IgG production. Exploratory analysis for efficacy yielded a promising 1-year PFS rate.

4.
Nat Commun ; 14(1): 1726, 2023 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-36977662

RESUMO

Mis-sense mutations affecting TP53 promote carcinogenesis both by inactivating tumor suppression, and by conferring pro-carcinogenic activities. We report here that p53 DNA-binding domain (DBD) and transactivation domain (TAD) mis-sense mutants unexpectedly activate pro-carcinogenic epidermal growth factor receptor (EGFR) signaling via distinct, previously unrecognized molecular mechanisms. DBD- and TAD-specific TP53 mutants exhibited different cellular localization and induced distinct gene expression profiles. In multiple tissues, EGFR is stabilized by TAD and DBD mutants in the cytosolic and nuclear compartments respectively. TAD mutants promote EGFR-mediated signaling by enhancing EGFR interaction with AKT via DDX31 in the cytosol. Conversely, DBD mutants maintain EGFR activity in the nucleus, by blocking EGFR interaction with the phosphatase SHP1, triggering c-Myc and Cyclin D1 upregulation. Our findings suggest that p53 mutants carrying gain-of-function, mis-sense mutations affecting two different domains form new protein complexes that promote carcinogenesis by enhancing EGFR signaling via distinctive mechanisms, exposing clinically relevant therapeutic vulnerabilities.


Assuntos
Receptores ErbB , Proteína Supressora de Tumor p53 , Proteína Supressora de Tumor p53/metabolismo , Receptores ErbB/genética , Receptores ErbB/metabolismo , Transdução de Sinais , Ativação Transcricional , Fosforilação
5.
J Pers Med ; 13(2)2023 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-36836519

RESUMO

Diazepam is a benzodiazepine widely prescribed for the management of patients with severe alcohol withdrawal syndrome to prevent agitation, withdrawal seizures, and delirium tremens. Despite standard dosing of diazepam, a subset of patients experience refractory withdrawal syndromes or adverse drug reactions, such as impaired motor coordination, dizziness, and slurred speech. The CYP2C19 and CYP3A4 enzymes play a key role in the biotransformation of diazepam. Given the highly polymorphic nature of the CYP2C19 gene, we reviewed the clinical impact of variants in the CYP2C19 gene on both the pharmacokinetics of diazepam and treatment outcomes related to the management of alcohol withdrawal syndrome.

6.
J Am Coll Clin Pharm ; 5(2): 239-250, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35784584

RESUMO

Ineffective pain control is the most commonly cited reason for misuse of prescription opioids and is influenced by genetics. In particular, the gene encoding the CYP2D6 enzyme, which metabolizes some of the most commonly prescribed opioids (e.g., tramadol, hydrocodone) to their more potent forms, is highly polymorphic and can lead to reduced concentrations of the active metabolites and decreased opioid effectiveness. Consideration of the CYP2D6 genotype may allow for predicting opioid response and identifying patients who are likely to respond well to lower potency opioids as well as those who may derive greater pain relief from non-opioid analgesics versus certain opioids. There is emerging evidence that a CYP2D6-guided approach to pain management improves pain control and reduces opioid consumption and thus may be a promising means for combating opioid misuse. Clinical practice guidelines are available for select opioids and other analgesics to support medication and dose selection based on pharmacogenetic data. This article describes the evidence supporting genotype-guided pain management as a means of improving pain control and reducing opioid misuse and clinical recommendations for genotype-guided analgesic prescribing. In addition, a "how to" guide using patient case examples is provided to demystify the process for implementing pharmacogenetics-guided pain management in order to optimize analgesia and minimize adverse effects. Optimizing pain management through genotype-guided approaches may ultimately provide safer and more effective therapy for pain control while decreasing the risk for opioid misuse.

7.
Am J Health Syst Pharm ; 79(19): 1634-1644, 2022 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-35876085

RESUMO

PURPOSE: This article explores approaches to pharmacogenomic counseling for patients who have undergone multigene panel testing by describing the collective experience of 5 institutions. SUMMARY: Multigene panel pharmacogenomic testing has the potential to unlock a myriad of information about a patient's past, present, and future drug response. The multifaceted nature of drug response coupled with the complexity of genetic results necessitates some form of patient education through pharmacogenomic counseling. Published literature regarding disclosure of pharmacogenomic test results is limited. This article compares the counseling practices of pharmacists from 5 different institutions with pharmacogenomics clinics whose experience represents perspectives ranging from academia to community clinical environments. Overarching counseling themes discussed during result disclosure center around (1) pharmacogenomic results, (2) gene-drug interactions, (3) gene-drug-drug interactions, (4) drug changes (5) future, familial, or disease-risk implications, (6) updates in the interpretation and application of pharmacogenomic results, (7) gauging patient comprehension, and (8) sharing results and supplemental information. CONCLUSION: Dedicating time to counseling patients on the results of a multigene pharmacogenomic panel is important given the lifelong applications of a test that is generally performed only once. The content and methods of disclosing test results shared by the experiences of pharmacists at 5 different institutions serve as guide to be further refined as research addresses effective communication strategies that enhance patient comprehension of pharmacogenomic results.


Assuntos
Farmacogenética , Testes Farmacogenômicos , Interações Medicamentosas , Humanos , Farmacêuticos
8.
JMIR Pediatr Parent ; 5(2): e28238, 2022 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-35666565

RESUMO

BACKGROUND: Increasingly, mobile apps are being used to promote oral care. Many of them are aimed at children. OBJECTIVE: This study aimed to systematically search and evaluate apps that promote oral care and hygiene for children. METHODS: A broad search strategy (13 keywords) was developed to identify apps from Apple's App Store and the Google Play Store in April 2019. After reviewing the apps' titles and summaries, potentially relevant apps were downloaded for viewing. The quality of the apps that met the inclusion criteria was assessed by the Health on the Net Foundation Code of Conduct (HONcode) criteria for medical and health websites and the Scientific Basis of Oral Self-care (SBOSC). RESULTS: More than 3000 Apps were identified and 54 relevant apps informed the review. The quality of the apps according to the HONcode criteria was generally low. The mean HONcode score was 1.8/8.0. One-quarter of the apps had a HONcode score of 0 (14/54, 26%). The SBOSC score of the apps was evaluated based on a 6-point scale. The mean SBOSC score was 1.5/6.0; 19% (10/54) of the apps had a score of 0. There was a significant and positive correlation between HONcode and SBOSC scores (r=0.37; P<.01). More recently uploaded apps had significantly higher HONcode scores (P<.05). CONCLUSIONS: There are many apps aiming to promote oral self-care among children. The quality and scientific basis of these apps are low. Newer apps are of higher quality in terms of scientific basis. There is a need to ensure high-quality and evidence-based apps are available. The effectiveness of apps in terms of oral care and clinical outcomes among children needs to be evaluated.

9.
Proc Natl Acad Sci U S A ; 119(10): e2113233119, 2022 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-35235448

RESUMO

SignificanceOur work focuses on the critical longstanding question of the nontranscriptional role of p53 in tumor suppression. We demonstrate here that poly(ADP-ribose) polymerase (PARP)-dependent modification of p53 enables rapid recruitment of p53 to damage sites, where it in turn directs early repair pathway selection. Specifically, p53-mediated recruitment of 53BP1 at early time points promotes nonhomologous end joining over the more error-prone microhomology end-joining. Similarly, p53 directs nucleotide excision repair by mediating DDB1 recruitment. This property of p53 also correlates with tumor suppression in vivo. Our study provides mechanistic insight into how certain transcriptionally deficient p53 mutants may retain tumor-suppressive functions through regulating the DNA damage response.


Assuntos
Dano ao DNA , Reparo do DNA por Junção de Extremidades , Proteína Supressora de Tumor p53/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Proteínas de Ligação a DNA , Humanos , Mutação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Domínios Proteicos , Proteína Supressora de Tumor p53/genética , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética
10.
Per Med ; 19(1): 15-23, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34881640

RESUMO

Aim: Characterize current perceptions, practices, preferences and barriers to integrating pharmacogenomics into patient care at an institution with an established pharmacogenomics clinic. Materials & methods: A 16-item anonymous survey was sent to healthcare professionals practicing at Tampa General Hospital and the University of South Florida Health. Results: Survey participants consisted of nine advanced practice providers, 41 pharmacists and 64 physicians. Majority of survey participants did not feel confident in their ability to interpret and apply pharmacogenomic results. In the past 12 months, 27% of physicians reported ordering a pharmacogenomic test. The greatest reported barrier to integrating pharmacogenomics was the absence of established guidelines or protocols. Conclusion: Most clinicians believed pharmacogenomics would be useful in their clinical practice but do not feel prepared to interpret pharmacogenomic results.


Lay abstract Pharmacogenomics is a field of personalized medicine where genetic information may be used to guide treatment decisions. Many advanced practice providers, pharmacists, and physicians are not as familiar with interpreting pharmacogenomic results to make medication changes. This survey was designed and administered to clinicians at Tampa General Hospital and the University of South Florida Health to characterize perceptions, practices, preferences and barriers to integrating pharmacogenomics into patient care. Survey results revealed that most clinicians believed pharmacogenomics would be useful in their clinical practice but do not feel prepared to interpret pharmacogenomic results.


Assuntos
Farmacêuticos , Farmacogenética , Atenção à Saúde , Pessoal de Saúde , Humanos , Testes Farmacogenômicos
11.
Cells ; 10(4)2021 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-33917037

RESUMO

Immunosuppression in cancer has emerged as a major hurdle to immunotherapy efforts. Immunosuppression can arise from oncogene-induced signaling within the tumor as well as from tumor-associated immune cells. Understanding various mechanisms by which the tumor can undermine and evade therapy is critical in improving current cancer immunotherapies. While mouse models have allowed for the characterization of key immune cell types and their role in tumor development, extrapolating these mechanisms to patients has been challenging. There is need for better models to unravel the effects of genetic alterations inherent in tumor cells and immune cells isolated from tumors on tumor growth and to investigate the feasibility of immunotherapy. Three-dimensional (3D) organoid model systems have developed rapidly over the past few years and allow for incorporation of components of the tumor microenvironment such as immune cells and the stroma. This bears great promise for derivation of patient-specific models in a dish for understanding and determining the impact on personalized immunotherapy. In this review, we will highlight the significance of current experimental models employed in the study of tumor immunosuppression and evaluate current tumor organoid-immune cell co-culture systems and their potential impact in shedding light on cancer immunosuppression.


Assuntos
Terapia de Imunossupressão , Neoplasias/imunologia , Neoplasias/patologia , Especificidade de Órgãos , Microambiente Tumoral/imunologia , Animais , Modelos Animais de Doenças , Humanos , Modelos Biológicos
12.
Pharmacogenomics ; 22(3): 165-176, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33461326

RESUMO

The accessibility of pharmacogenomic (PGx) testing has grown substantially over the last decade and with it has arisen a demand for patients to be counseled on the use of these tests. While guidelines exist for the use of PGx results; objective determinants for who should receive PGx testing remain incomplete. PGx clinical services have been created to meet these screening and education needs and significant variability exists between these programs. This article describes the practices of four PGx clinics during pretest counseling sessions. A description of the major tenets of the benefits, limitations and risks of testing are compiled. Additional tools are provided to serve as a foundation for those wishing to begin or expand their own counseling service.


Assuntos
Tomada de Decisão Clínica/métodos , Aconselhamento Genético/métodos , Educação de Pacientes como Assunto/métodos , Testes Farmacogenômicos/métodos , Medicina de Precisão/métodos , Aconselhamento Genético/normas , Humanos , Educação de Pacientes como Assunto/normas , Testes Farmacogenômicos/normas , Medicina de Precisão/normas
13.
Int J Mol Sci ; 21(1)2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31861395

RESUMO

It has been four decades since the discovery of p53, the designated 'Guardian of the Genome'. P53 is primarily known as a master transcription factor and critical tumor suppressor, with countless studies detailing the mechanisms by which it regulates a host of gene targets and their consequent signaling pathways. However, transcription-independent functions of p53 also strongly define its tumor-suppressive capabilities and recent findings shed light on the molecular mechanisms hinted at by earlier efforts. This review highlights the transcription-independent mechanisms by which p53 influences the cellular response to genomic instability (in the form of replication stress, centrosome homeostasis, and transposition) and cell death. We also pinpoint areas for further investigation in order to better understand the context dependency of p53 transcription-independent functions and how these are perturbed when TP53 is mutated in human cancer.


Assuntos
Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose/genética , Centrossomo/metabolismo , Dano ao DNA , Reparo do DNA por Junção de Extremidades , Reparo do DNA , Replicação do DNA , Regulação da Expressão Gênica , Recombinação Homóloga , Humanos , Transdução de Sinais , Estresse Fisiológico , Fatores de Transcrição/metabolismo , Transcrição Gênica , Proteína Supressora de Tumor p53/genética
14.
Pharmacogenomics ; 20(2): 69-73, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30520338

RESUMO

Clonazepam undergoes nitroreduction to 7-amino-clonazepam via CYP3A4/5, followed by acetylation to 7-acetamido-clonazepam via NAT2 enzyme. While no pharmacological activity is attributed to the metabolites of clonazepam, 7-amino-clonazepam has some affinity for the benzodiazepine receptor as a partial agonist for the gamma aminobutyric acid-A receptor and can compete with clonazepam. Interindividual variability in the incidence of adverse events in patients may, in part, be attributable to differences in clonazepam metabolism. Here, we report on a case of a 70-year-old Caucasian female with insomnia and difficulty weaning off long-term use of clonazepam suggesting that a slow acetylator phenotype contributing to patient's presentation. This hypothesis was confirmed by NAT2 gene sequencing. NAT2 genotyping may play a role in guiding clonazepam therapy.


Assuntos
Arilamina N-Acetiltransferase/genética , Clonazepam/efeitos adversos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/genética , Síndrome de Abstinência a Substâncias/genética , Acetilação/efeitos dos fármacos , Idoso , Clonazepam/administração & dosagem , Citocromo P-450 CYP3A/genética , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/patologia , Feminino , Genótipo , Humanos , Polimorfismo Genético , Medicina de Precisão , Síndrome de Abstinência a Substâncias/patologia
15.
J Clin Pharm Ther ; 44(2): 174-179, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30578565

RESUMO

WHAT IS KNOWN AND OBJECTIVE: Pharmacogenomics holds promise in smoking cessation because of its potential to shed light on the complexity of drug metabolism and improve treatments using therapeutic agents. The cytochrome P450 2B6 gene (CYP2B6) encodes CYP2B6 enzyme that has been found to mediate the hydroxylation of bupropion, a smoking cessation aid. CYP2B6 exhibits a range of polymorphic variants that alter the pharmacokinetics and pharmacodynamics of bupropion. Genetic variations in CYP2B6 may influence the risk of adverse effects or efficacy of treatment with bupropion. The objective of this review was to investigate the influence of pharmacogenomics on smoking cessation therapy. METHODS: A thorough literature search was conducted on PubMed, SCOPUS and EMBASE using keywords related to bupropion, smoking cessation, pharmacogenomics and CYP2B6. Research and review articles, case reports and clinical and preclinical studies pertinent to the research topic were identified, evaluated and summarized. Cited articles within the above-mentioned sources also provided pertinent information. RESULTS: There is strong literature evidence to prove that CYP2B6 polymorphisms affect pharmacokinetic and pharmacodynamic properties of bupropion, thus affecting the therapeutic outcome of smoking cessation therapy. WHAT IS NEW AND CONCLUSIONS: Complete understanding of pharmacogenetic variation of bupropion pharmacokinetics and pharmacodynamics will be beneficial for designing safer and more personalized smoking cessation therapy with improved outcomes.


Assuntos
Bupropiona/administração & dosagem , Citocromo P-450 CYP2B6/genética , Abandono do Hábito de Fumar/métodos , Bupropiona/efeitos adversos , Bupropiona/farmacocinética , Variação Genética , Humanos , Farmacogenética , Agentes de Cessação do Hábito de Fumar/administração & dosagem , Agentes de Cessação do Hábito de Fumar/efeitos adversos , Agentes de Cessação do Hábito de Fumar/farmacocinética
16.
Clin Cancer Res ; 25(3): 937-945, 2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30563938

RESUMO

PURPOSE: Mutations in the RAS/RAF/MEK/ERK signaling pathway are commonly found in biliary tract cancer (BTC). Binimetinib, a selective inhibitor of MEK1/2, has single-agent activity. Preclinical data support binimetinib combination with chemotherapy, when given in an interrupted dosing schedule.Patients and Methods: A phase I/II trial evaluated binimetinib in combination with gemcitabine and cisplatin in patients with untreated advanced BTC. The primary endpoints were to determine the MTD (phase I), and PFS 6 and RR (phase II). Tumor tissue for targeted gene sequencing and blood samples for peripheral blood pERK expression were evaluated. Patients received oral binimetinib twice daily with gemcitabine and cisplatin on day 8 and 15 of a 21-day cycle. Binimetinib was held for 2 days prior to and on day of each chemotherapy treatment. RESULTS: Twelve patients enrolled in the phase I showed the MTD of binimetinib at 45 mg orally twice daily with gemcitabine 800 and cisplatin 20 mg/m2. Twenty-nine patients were treated in the phase II. Six patients treated at MTD in phase I were evaluable as part of phase II. PFS 6 months was 54% and RR was 36%. Median overall survival was 13.3 months (95% CI, 9.8-16.5). MSK-IMPACT 410-gene panel showed aberrations in the RAS-RAF-MEK-ERK pathway and mutations in PIK3CA, AKT2, PIK3CG, BRAF, and MAP3K1 in responding patients. CONCLUSIONS: Binimetinib with gemcitabine and cisplatin did not show an improvement in PFS 6 and RR. Molecular profiling may help select patients who may benefit from this triplet therapy, which is not planned at this time.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Sistema Biliar/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Benzimidazóis/administração & dosagem , Cisplatino/administração & dosagem , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Esquema de Medicação , Feminino , Humanos , Estimativa de Kaplan-Meier , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/genética , Masculino , Pessoa de Meia-Idade , Mutação , Proteínas Proto-Oncogênicas B-raf/genética , Gencitabina
17.
CRISPR J ; 1: 258-260, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-31021215
18.
EMBO Rep ; 18(11): 1991-2003, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29021206

RESUMO

Single-stranded DNA (ssDNA) regions form as an intermediate in many DNA-associated transactions. Multiple cellular proteins interact with ssDNA via the oligonucleotide/oligosaccharide-binding (OB) fold domain. The heterotrimeric, multi-OB fold domain-containing Replication Protein A (RPA) complex has an essential genome maintenance role, protecting ssDNA regions from nucleolytic degradation and providing a recruitment platform for proteins involved in responses to replication stress and DNA damage. Here, we identify the uncharacterized protein RADX (CXorf57) as an ssDNA-binding factor in human cells. RADX binds ssDNA via an N-terminal OB fold cluster, which mediates its recruitment to sites of replication stress. Deregulation of RADX expression and ssDNA binding leads to enhanced replication fork stalling and degradation, and we provide evidence that a balanced interplay between RADX and RPA ssDNA-binding activities is critical for avoiding these defects. Our findings establish RADX as an important component of cellular pathways that promote DNA replication integrity under basal and stressful conditions by means of multiple ssDNA-binding proteins.


Assuntos
Reparo do DNA , Replicação do DNA , DNA de Cadeia Simples/genética , Proteínas de Ligação a DNA/genética , Proteína de Replicação A/genética , Sítios de Ligação , Linhagem Celular Tumoral , Dano ao DNA , DNA de Cadeia Simples/metabolismo , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Células HCT116 , Humanos , Modelos Moleculares , Osteoblastos/citologia , Osteoblastos/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Proteína de Replicação A/química , Proteína de Replicação A/metabolismo
19.
Nat Cell Biol ; 18(11): 1196-1207, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27723717

RESUMO

Activation of the ATR kinase following perturbations to DNA replication relies on a complex mechanism involving ATR recruitment to RPA-coated single-stranded DNA via its binding partner ATRIP and stimulation of ATR kinase activity by TopBP1. Here, we discovered an independent ATR activation pathway in vertebrates, mediated by the uncharacterized protein ETAA1 (Ewing's tumour-associated antigen 1). Human ETAA1 accumulates at DNA damage sites via dual RPA-binding motifs and promotes replication fork progression and integrity, ATR signalling and cell survival after genotoxic insults. Mechanistically, this requires a conserved domain in ETAA1 that potently and directly stimulates ATR kinase activity independently of TopBP1. Simultaneous loss of ETAA1 and TopBP1 gives rise to synthetic lethality characterized by massive genome instability and abrogation of ATR-dependent signalling. Our findings demonstrate that parallel TopBP1- and ETAA1-mediated pathways underlie ATR activation and that their combined action is essential for coping with replication stress.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Dano ao DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Antígenos de Superfície/metabolismo , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Proteínas de Transporte/metabolismo , Proteínas de Ciclo Celular/metabolismo , Replicação do DNA/genética , DNA de Cadeia Simples/genética , Proteínas de Ligação a DNA/genética , Células HeLa , Humanos , Proteínas Nucleares/metabolismo , Fosforilação
20.
Cell Rep ; 15(4): 724-734, 2016 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-27149840

RESUMO

Regulation of DNA replication and cell division is essential for tissue growth and maintenance of genomic integrity and is particularly important in tissues that undergo continuous regeneration such as mammary glands. We have previously shown that disruption of the KRAB-domain zinc finger protein Roma/Zfp157 results in hyperproliferation of mammary epithelial cells (MECs) during pregnancy. Here, we delineate the mechanism by which Roma engenders this phenotype. Ablation of Roma in MECs leads to unscheduled proliferation, replication stress, DNA damage, and genomic instability. Furthermore, mouse embryonic fibroblasts (MEFs) depleted for Roma exhibit downregulation of p21Cip1 and geminin and have accelerated replication fork velocities, which is accompanied by a high rate of mitotic errors and polyploidy. In contrast, overexpression of Roma in MECs halts cell-cycle progression, whereas siRNA-mediated p21Cip1 knockdown ameliorates, in part, this phenotype. Thus, Roma is an essential regulator of the cell cycle and is required to maintain genomic stability.

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