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1.
Ann Card Anaesth ; 27(3): 213-219, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38963355

RESUMEN

BACKGROUND: Neutrophil-lymphocyte ratio (NLR) is a valuable indicator for evaluating inflammatory response and red blood cell distribution width (RBDW), a routinely available biomarker of likely erythropoietic dysfunction, which may be associated with adverse outcomes after cardiac surgery. This study aimed to investigate the association between these two readily available haematological parameters, with the poor outcomes in paediatric patients undergoing cardiac surgery. METHODS: A comprehensive review of medical records for paediatric patients who underwent cardiac surgery at our tertiary care centre between April 2022 and June 2023 was carried out. RBDW and NLR values were collected from complete blood count reports obtained on admission to the ICU. Demographic data, surgical details, and postoperative complications were also recorded. A receiver operating characteristic (ROC) curve and multivariable logistic regression were applied to identify the prognosis performance of preoperative NLR and RBDW for poor outcomes. RESULTS: The study included 219 patients meeting the inclusion criteria of which a total of 90 (41%) children experienced at least one of the poor outcomes. Preoperative NLR (AUC=0.88, 95%CI 0.36-0.70, cut off- 4.2) and RBDW (AUC=0.88, 95%CI 0.39-0.73, cut off- 18.5%) showed prognostic significance in the perioperative period. CONCLUSION: This retrospective observational study highlights a significant association between elevated Red Blood Cell Distribution Width (RBDW) and Neutrophil Lymphocyte Ratio (NLR) values and poor outcomes in paediatric patients undergoing cardiac surgery. These readily available haematological parameters could serve as potential prognostic indicators for identifying patients at risk of poor outcomes.


Asunto(s)
Procedimientos Quirúrgicos Cardíacos , Índices de Eritrocitos , Linfocitos , Neutrófilos , Humanos , Estudios Retrospectivos , Masculino , Femenino , Niño , Preescolar , Lactante , Complicaciones Posoperatorias/sangre , Complicaciones Posoperatorias/epidemiología , Pronóstico , Adolescente
2.
Nutr Rev ; 82(4): 570-571, 2024 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-37354556

RESUMEN

This Letter to the Editor is a response to St-Jules and Fouque and their interpretation of postprandial hyperkalemia, especially regarding plant-based diets. Based on the reviewed literature review, potassium kinetic studies cited by the authors include only 1 study with a food-based intervention that actually showed reduced postprandial hyperkalemia with plant-based diets. The remainder of the studies used potassium salts or supplements that behave differently compared with whole plant foods. As such, we recommend avoiding restriction of whole plant foods in patients with chronic kidney disease when solely based on the theoretical risk of postprandial hyperkalemia.


Asunto(s)
Hiperpotasemia , Insuficiencia Renal Crónica , Humanos , Hiperpotasemia/prevención & control , Dieta a Base de Plantas , Cinética , Dieta , Potasio
3.
Cureus ; 15(9): e45275, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37846239

RESUMEN

INTRODUCTION: Periapical infection of primary molars affects the development of permanent teeth (premolars). Therefore, the present study was conducted to test the null hypothesis in children aged 4-10 years with chronic apical periodontitis (CAP) of the primary molars. MATERIALS AND METHODS: A retrospective, cross-sectional study was conducted on 185 panoramic radiographs of healthy children aged 4-10 years with CAP in the primary molars. A total of 256 infected primary molars (144 teeth in females, 112 teeth in males) were analyzed, radiographically, and compared with 245 healthy primary molars on the contralateral side. Permanent successors were evaluated for follicular damage, maturation, morphology, and deviation in the eruption path. Primary molars were evaluated for root resorption. Sixteen permanent teeth on the affected side and five teeth on the control side were excluded due to abnormal development. Student's t-test and the chi-square test were used to analyze the data. RESULTS: The null hypothesis is rejected. There were significant differences in the developmental status of permanent successors on the affected side, compared to the normal side at four to seven years (p<0.05). There were no significant sex differences in the abnormalities of permanent successors on the affected side (p>0.05). As the root resorption of the primary molars increased, the follicular damage observed in the permanent successors also increased (p<0.05), which suggests that, as the infection of primary molars increases, more damage is caused to underlying permanent successors (premolars). CONCLUSION: Apical periodontitis of the primary molars retards the development of permanent successors (premolars), affects their shape, causes follicular damage, and alters the eruption path.

4.
Cancers (Basel) ; 15(3)2023 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-36765888

RESUMEN

We previously reported that phenethyl isothiocyanate (PEITC), a dietary-related compound, can rescue mutant p53. A structure-activity relationships study showed that the synthetic analog 2,2-diphenylethyl isothiocyanate (DPEITC) is a more potent inducer of apoptosis than natural or synthetic ITCs. Here, we showed that DPEITC inhibited the growth of triple-negative breast cancer cells (MDA-MB-231, MDA-MB-468, and Hs578T) expressing "hotspot" p53 mutants, structural (p53R280K, p53R273H) or contact (p53V157F), at IC50 values significantly lower than PEITC. DPEITC inhibited the growth of HER2+ (p53R175H SK-BR-3, p53R175H AU565) and Luminal A (p53L194F T47D) breast cancer (BC) cells harboring a p53 structural mutant. DPEITC induced apoptosis, irrespective of BC subtypes, by rescuing p53 mutants. Accordingly, the rescued p53 mutants induced apoptosis by activating canonical WT p53 targets and delaying the cell cycle. DPEITC acted synergistically with doxorubicin and camptothecin to inhibit proliferation and induce apoptosis. Under these conditions, DPEITC delayed BC cells in the G1 phase, activated p53 canonical targets, and enhanced pS1981-ATM. DPEITC reduced the expression of MDR1 and ETS1. These findings are the first report of synergism between a synthetic ITC and a chemotherapy drug via mutant p53 rescue. Furthermore, our data demonstrate that ITCs suppress the expression of cellular proteins that play a role in chemoresistance.

5.
Indian J Med Microbiol ; 41: 97-100, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36470773

RESUMEN

PURPOSE: Hand, Foot and Mouth disease (HFMD) is a contagious pediatric viral disease caused due to enteroviruses (EV) of the family Picornaviridae. Cases of HFMD were reported from a tertiary care health centre, Udhampur, (Jammu and Kashmir), Northern India. The present study highlights the clinical and molecular virological aspects of HFMD cases. MATERIAL AND METHODS: Cases reported during August 2016-September 2017, and clinically diagnosed as HFMD of all age groups were included. Clinical, Biochemical and molecular virology aspects were compared. Clinical samples (n â€‹= â€‹50) such as vesicle swab, buccal and throat swabs were collected for enterovirus detection. EV-RNA was detected by 5'NCR based RT-PCR and genotyping by VP1 gene amplification and cycle sequencing. RESULTS: Of the cases of HFMD enrolled (n â€‹= â€‹50), highest (84%) were of children aged <5 years, presented either or both anathemas and exanthemas with prodromal symptoms (fever, irritability). Clinical presentations involved mainly oral ulcers on lips and tongue (48%). Oral erosions were either single or multiple in numbers. Exanthemas were seen on hand and palm, widely spread up to buttocks, legs, arms and trunk. Of these, six patients were found anemic. Complete blood count (CBC) indicated lymphocytosis and C-reactive protein (n â€‹= â€‹10) in children aged <5 years. EV-RNA was detected in 78% (39/50) of the clinical samples. VP1 gene based typing indicated the presence of CV-A16, CVA6 and EV-A71 types. CONCLUSIONS: The study highlights association of EVs in HFMD cases in the reported region. CV-A16, CV-A6 and EV-A71 types were reported for the first time from Udhampur (J&K), Northern India. No differences were observed in the clinical profile of EV strains detected. Circulation of the strains warrant and alarm outbreaks. More focused studies on HFMD and monitoring of viral strains is mandatory.


Asunto(s)
Infecciones por Enterovirus , Enterovirus , Enfermedad de Boca, Mano y Pie , Niño , Humanos , Lactante , Enterovirus/genética , Tipificación Molecular , Antígenos Virales/genética , India/epidemiología , ARN , China/epidemiología
6.
Sci Adv ; 8(40): eabq6657, 2022 10 07.
Artículo en Inglés | MEDLINE | ID: mdl-36197974

RESUMEN

DnaA, the initiator of Escherichia coli chromosomal replication, has in its adenosine triphosphatase (ATPase) domain residues required for adenosine 5'-triphosphate (ATP) binding and membrane attachment. Here, we show that D118Q substitution in the DnaA linker domain, a domain known to be without major regulatory functions, influences ATP binding of DnaA and replication initiation in vivo. Although initiation defective by itself, overexpression of DnaA(D118Q) caused overinitiation of replication in dnaA46ts cells and prevented cell growth. The growth defect was rescued by overexpressing the initiation inhibitor, SeqA, indicating that the growth inhibition resulted from overinitiation. Small deletions within the linker showed another unexpected phenotype: cellular growth without requiring normal levels of anionic membrane lipids, a property found in DnaA mutated in its ATPase domain. The deleted proteins were defective in association with anionic membrane vesicles. These results show that changes in the linker domain can alter DnaA functions similarly to the previously shown changes in the ATPase domain.


Asunto(s)
Proteínas de Unión al ADN , Escherichia coli , Adenosina/metabolismo , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , Adenosina Trifosfato/metabolismo , Proteínas Bacterianas/metabolismo , Replicación del ADN , Proteínas de Unión al ADN/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Lípidos de la Membrana/metabolismo , Origen de Réplica
8.
Med J Armed Forces India ; 78(2): 232-234, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35463539

RESUMEN

Parasitic infections of the intestine are a major health problem, which is found more prevalent in developing countries such as India. They are one of the important causes of morbidity and mortality among people all over the world. Acute amoebic appendicitis is a rare entity. We came across a case of acute appendicitis in a young pregnant woman, which revealed colonies of Entamoeba histolytica trophozoites in the mucosal epithelium and submucosal layer of the appendix with marked evidence of acute appendicitis. This report highlights acute appendicitis of amoebic origin and emphasises the importance of thorough examination of the appendix at various levels during histopathology and about the combined treatment of appendicectomy combined with antimicrobials as the treatment of choice. Appendicectomy removes the focus of infection, and antimicrobials reduce the incidence of septic complications.

9.
J Med Chem ; 64(10): 6621-6633, 2021 05 27.
Artículo en Inglés | MEDLINE | ID: mdl-33961435

RESUMEN

Mutant p53 rescue by small molecules is a promising therapeutic strategy. In this structure-activity relationship study, we examined a series of adamantyl isothiocyanates (Ad-ITCs) to discover novel agents as therapeutics by targeting mutant p53. We demonstrated that the alkyl chain connecting adamantane and ITC is a crucial determinant for Ad-ITC inhibitory potency. Ad-ITC 6 with the longest chain between ITC and adamantane displayed the maximum growth inhibition in p53R280K, p53R273H, or p53R306Stop mutant cells. Ad-ITC 6 acted in a mutant p53-dependent manner. It rescued p53R280K and p53R273H mutants, thereby resulting in upregulating canonical wild-type (WT) p53 targets and phosphorylating ATM. Ad-ISeC 14 with selenium showed a significantly enhanced inhibitory potency, without affecting its ability to rescue mutant p53. Ad-ITCs selectively depleted mutant p53, but not the WT, and this activity correlates with their inhibitory potencies. These data suggest that Ad-ITCs may serve as novel promising leads for the p53-targeted drug development.


Asunto(s)
Adamantano/análogos & derivados , Anticarcinógenos/química , Isotiocianatos/química , Proteína p53 Supresora de Tumor/metabolismo , Adamantano/química , Adamantano/metabolismo , Adamantano/farmacología , Anticarcinógenos/metabolismo , Anticarcinógenos/farmacología , Apoptosis/efectos de los fármacos , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Puntos de Control del Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Humanos , Isotiocianatos/metabolismo , Isotiocianatos/farmacología , Mutación , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Relación Estructura-Actividad , Proteína p53 Supresora de Tumor/antagonistas & inhibidores , Proteína p53 Supresora de Tumor/genética
10.
J Obstet Gynaecol India ; 71(1): 78-81, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33814803

RESUMEN

Multiple myeloma is a B-cell neoplastic disorder and represents 1% of all cancers and 13% of hematological malignancies. It is predominantly a disease of elderly, and less than 3% of all cases are below the age of 40 years. We present the case of a 29-year-old lady with multiple myeloma who had spontaneous conception during maintenance therapy and subsequently a successful pregnancy outcome. She gave birth to a healthy female infant through normal vaginal delivery and subsequently could remain off therapy for 5 years. Since the patient had a history of abortions and stillbirth, it was a precious pregnancy and we could successfully salvage both the mother and the baby. Young female patients of myeloma who are in remission can be encouraged to start a family during their reproductive years with the support of a comprehensive care team of hematologists/oncologists and obstetricians.

11.
J Pharm Bioallied Sci ; 13(Suppl 2): S1375-S1380, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35017992

RESUMEN

BACKGROUND AND AIM: The patient who is wearing a denture after missing teeth faces traumatic ulceration very frequently. This ulceration creates difficulties in denture wearing. Hence, this study aimed to evaluate the most common locations of traumatic injuries in form of ulcerations, their frequency, and also the duration and number of adjustment visits required to achieve patient comfort following placement of complete removable dentures. MATERIALS AND METHODS: Eighty edentulous patients were selected from a private clinic. Complete removable dentures were fabricated for all patients. All patients were evaluated for their complaints after denture insertion. Patients were followed up till the problem persisted. Descriptive analysis was done. Chi-squared test was used to differentiate the associations between lesions, postinsertion visits, and gender. RESULTS: About 85.62% of patients need denture adjustment because of mucosal injuries during their first visit following. Approximately four appointments are needed for maxillary and six appointments needed for mandibular denture. Male and female have no difference in the number of mucosal injuries in the anatomical area evaluated in the maxilla and mandible using Fisher's exact test (P > 0.05). Mandibular dentures need more appointments than maxillary dentures after post insertion (P < 0.001). CONCLUSION: The vestibule was the most common site for mucosal injuries which can be corrected by proper extension of denture flanges during border molding. Pressure indicator ink (arti spot) and paste is used to correct the overextended denture flanges.

12.
J Exp Clin Cancer Res ; 38(1): 307, 2019 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-31307507

RESUMEN

BACKGROUND: We reported previously that phenethyl isothiocyanate (PEITC), a dietary compound, can reactivate p53R175H mutant in vitro and in SK-BR-3 (p53R175H) breast xenograft model resulting in tumor inhibition. Because of the diversity of human cancers with p53 mutations, these findings raise important questions whether this mechanism operates in different cancer types with same or different p53 mutations. In this study, we investigated whether PEITC recuses mutant p53 in prostate cancer cells harboring different types of p53 mutants, structural and contact, in vitro and in vivo. METHODS: Cell proliferation, cell apoptosis and cell cycle arrest assays were performed to examine the effects of PEITC on prostate cancer cell lines with p53 mutation(s), wild-type p53, p53 null or normal prostate cells in vitro. Western blot analysis was used to monitor the expression levels of p53 protein, activation of ATM and upregulation of canonical p53 targets. Immunoprecipitation, subcellular protein fraction and qRT-PCR was performed to determine change in conformation and restoration of transactivation functions/ inhibition of gain-of-function (GOF) activities to p53 mutant(s). Mice xenograft models were established to evaluate the antitumor efficacy of PEITC and PEITC-induced reactivation of p53 mutant(s) in vivo. Immunohistochemistry of xenograft tumor tissues was performed to determine effects of PEITC on expression of Ki67 and mutant p53 in vivo. RESULTS: We demonstrated that PEITC inhibits the growth of prostate cancer cells with different "hotspot" p53 mutations (structural and contact), however, preferentially towards structural mutants. PEITC inhibits proliferation and induces apoptosis by rescuing mutant p53 in p53R248W contact (VCaP) and p53R175H structural (LAPC-4) mutant cells with differential potency. We further showed that PEITC inhibits the growth of DU145 cells that co-express p53P223L (structural) and p53V274F (contact) mutants by targeting p53P223L mutant selectively, but not p53V274F. The mutant p53 restored by PEITC induces apoptosis in DU145 cells by activating canonical p53 targets, delaying cells in G1 phase and phosphorylating ATM. Importantly, PEITC reactivated p53R175H and p53P223L/V274F mutants in LAPC-4 and DU145 prostate xenograft models, respectively, resulting in significant tumor inhibition. CONCLUSION: Our studies provide the first evidence that PEITC's anti-cancer activity is cancer cell type-independent, but p53 mutant-type dependent.


Asunto(s)
Anticarcinógenos/administración & dosificación , Isotiocianatos/administración & dosificación , Neoplasias de la Próstata/tratamiento farmacológico , Proteína p53 Supresora de Tumor/genética , Animales , Anticarcinógenos/farmacología , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Ciclo Celular/efectos de los fármacos , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Humanos , Isotiocianatos/farmacología , Masculino , Ratones , Mutación , Fosforilación , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Ensayos Antitumor por Modelo de Xenoinjerto
13.
Am J Trop Med Hyg ; 101(1): 62-64, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-31094314

RESUMEN

We report an unusual case of paragonimiasis in a Nepali patient presenting with massive pericardial effusion and pericardial tamponade. The patient reported neither the consumption of crabs or crayfish nor the consumption of wild animal meat, which are the usual sources of infection. It is suspected that the source of infection was instead the ingestion of raw live slugs as part of a traditional medicine treatment.


Asunto(s)
Antihelmínticos/uso terapéutico , Taponamiento Cardíaco/etiología , Paragonimiasis/complicaciones , Paragonimiasis/diagnóstico , Praziquantel/uso terapéutico , Animales , Femenino , Gastrópodos/parasitología , Humanos , Medicina Tradicional , Persona de Mediana Edad , Paragonimiasis/tratamiento farmacológico
14.
Hepatology ; 67(1): 159-170, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28718980

RESUMEN

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide, mainly because of its poor prognosis. A valid mechanism-based prognostic biomarker is urgently needed. γ-hydroxy-1,N2 -propanodeoxyguanosine (γ-OHPdG) is an endogenously formed mutagenic DNA adduct derived from lipid peroxidation. We examined the relationship of γ-OHPdG with hepatocarcinogenesis in two animal models and its potential role as a prognostic biomarker for recurrence in HCC patients. Bioassays were conducted in xeroderma pigmentosum group A knockout mice and diethylnitrosamine-injected mice, both prone to HCC development. γ-OHPdG levels in the livers of these animals were determined. The effects of antioxidant treatments on γ-OHPdG and hepatocarcinogenesis were examined. Using two independent sets of HCC specimens from patients, we examined the relationship between γ-OHPdG and survival or recurrence-free survival. γ-OHPdG levels in liver DNA showed an age-dependent increase and consistently correlated with HCC development in all three animal models. Theaphenon E treatment significantly decreased γ-OHPdG levels in the liver DNA of xeroderma pigmentosum group A knockout mice and remarkably reduced HCC incidence in these mice to 14% from 100% in the controls. It also effectively inhibited HCC development in the diethylnitrosamine-injected mice. Using clinical samples from two groups of patients, our study revealed that higher levels of γ-OHPdG are strongly associated with low survival (P < 0.0001) and low recurrence-free survival (P = 0.007). CONCLUSION: These results support γ-OHPdG as a mechanism-based, biologically relevant biomarker for predicting the risk of HCC and its recurrence. (Hepatology 2018;67:159-170).


Asunto(s)
Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/prevención & control , Aductos de ADN/metabolismo , Dietilnitrosamina/farmacología , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/prevención & control , Animales , Biomarcadores de Tumor/metabolismo , Carcinogénesis/patología , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/mortalidad , Modelos Animales de Enfermedad , Femenino , Humanos , Estimación de Kaplan-Meier , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas Experimentales/tratamiento farmacológico , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Distribución Aleatoria , Valores de Referencia , Tasa de Supervivencia
15.
16.
J Clin Diagn Res ; 10(4): ZE01-3, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27190968

RESUMEN

Orthodontics like any other specialty has much to offer law enforcement in the detection and solution of crime or in civil proceedings. Forensic odontology often requires an interdisciplinary approach towards dentistry for the purpose of proper diagnosis of cases. In cases where the forensic odontologist has to establish a person's identity, an orthodontist can be of great help at times. Teeth, with their anatomic/physiologic variations and therapy such as orthodontic treatment, restorations and prosthesis may record information that remains throughout life and beyond. The teeth may also be used as weapons for defense or offense and as such may leave information about the identity of the biter at the time of crime. Forensic odontology also plays an important role in the recognition of crime and abuse among people of all ages. Orthodontists like all other dental professionals can play a major role by maintaining proper dental records and thus providing important or vital information or clues to the legal authorities in order to help them in their search.

17.
Methods ; 108: 130-41, 2016 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-27064001

RESUMEN

The growing number of DNA helicases implicated in hereditary disorders and cancer indicates that this particular class of enzymes plays key roles in genomic stability and cellular homeostasis. Indeed, a large body of work has provided molecular and cellular evidence that helicases act upon a variety of nucleic acid substrates and interact with numerous proteins to enact their functions in replication, DNA repair, recombination, and transcription. Understanding how helicases operate in unique and overlapping pathways is a great challenge to researchers. In this review, we describe a series of experimental approaches and methodologies to identify and characterize DNA helicase inhibitors which collectively provide an alternative and useful strategy to explore their biological significance in cell-based systems. These procedures were used in the discovery of biologically active compounds that inhibited the DNA unwinding function catalyzed by the human WRN helicase-nuclease defective in the premature aging disorder Werner syndrome. We describe in vitro and in vivo experimental approaches to characterize helicase inhibitors with WRN as the model, anticipating that these approaches may be extrapolated to other DNA helicases, particularly those implicated in DNA repair and/or the replication stress response.


Asunto(s)
Bioensayo/métodos , ADN Helicasas/antagonistas & inhibidores , Replicación del ADN/genética , Inhibidores Enzimáticos/aislamiento & purificación , ADN Helicasas/química , Reparación del ADN/genética , Inhibidores Enzimáticos/química , Humanos , Especificidad por Sustrato
18.
RSC Adv ; 4(8): 3920-3923, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-28725420

RESUMEN

Here we report the identification of protein targets of chemopreventive phenethyl isothiocyanate (PEITC) via "click" chemistry in the A549 human lung cancer cell line, using a novel alkyne-tagged PEITC which was also found to show potent in vitro anticancer activity.

19.
Cell Cycle ; 12(20): 3329-35, 2013 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-24036544

RESUMEN

Our recently published work suggests that DNA helicases such as the Werner syndrome helicase (WRN) represent a novel class of proteins to target for anticancer therapy. Specifically, pharmacological inhibition of WRN helicase activity in human cells defective in the Fanconi anemia (FA) pathway of interstrand cross-link (ICL) repair are sensitized to the DNA cross-linking agent and chemotherapy drug mitomycin C (MMC) by the WRN helicase inhibitor NSC 617145. (1) The mechanistic basis for the synergistic interaction between NSC 617145 and MMC is discussed in this paper and extrapolated to potential implications for genetic or chemically induced synthetic lethality provoked by cellular exposure to the WRN helicase inhibitor under the context of relevant DNA repair deficiencies associated with cancers or induced by small-molecule inhibitors. Experimental data are presented showing that small-molecule inhibition of WRN helicase elevates sensitivity to MMC-induced stress in human cells that are deficient in both FANCD2 and DNA protein kinase catalytic subunit (DNA-PKcs). These findings suggest a model in which drug-mediated inhibition of WRN helicase activity exacerbates the deleterious effects of MMC-induced DNA damage when both the FA and NHEJ pathways are defective. We conclude with a perspective for the FA pathway and synthetic lethality and implications for DNA repair helicase inhibitors that can be developed for anticancer strategies.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Anemia de Fanconi/enzimología , Neoplasias/enzimología , RecQ Helicasas/antagonistas & inhibidores , Línea Celular , Reparación del ADN por Unión de Extremidades/efectos de los fármacos , Anemia de Fanconi/patología , Humanos , Maleimidas/farmacología , Mitomicina/farmacología , Modelos Biológicos , Neoplasias/patología , RecQ Helicasas/metabolismo , Transducción de Señal/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacos
20.
Cancer Res ; 73(17): 5497-507, 2013 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-23867477

RESUMEN

Werner syndrome is genetically linked to mutations in WRN that encodes a DNA helicase-nuclease believed to operate at stalled replication forks. Using a newly identified small-molecule inhibitor of WRN helicase (NSC 617145), we investigated the role of WRN in the interstrand cross-link (ICL) response in cells derived from patients with Fanconi anemia, a hereditary disorder characterized by bone marrow failure and cancer. In FA-D2(-/-) cells, NSC 617145 acted synergistically with very low concentrations of mitomycin C to inhibit proliferation in a WRN-dependent manner and induce double-strand breaks (DSB) and chromosomal abnormalities. Under these conditions, ataxia-telangiectasia mutated activation and accumulation of DNA-dependent protein kinase, catalytic subunit pS2056 foci suggested an increased number of DSBs processed by nonhomologous end-joining (NHEJ). Rad51 foci were also elevated in FA-D2(-/-) cells exposed to NSC 617145 and mitomycin C, suggesting that WRN helicase inhibition interferes with later steps of homologous recombination at ICL-induced DSBs. Thus, when the Fanconi anemia pathway is defective, WRN helicase inhibition perturbs the normal ICL response, leading to NHEJ activation. Potential implication for treatment of Fanconi anemia-deficient tumors by their sensitization to DNA cross-linking agents is discussed.


Asunto(s)
Roturas del ADN de Doble Cadena/efectos de los fármacos , Reparación del ADN/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Exodesoxirribonucleasas/antagonistas & inhibidores , Anemia de Fanconi/tratamiento farmacológico , Maleimidas/farmacología , RecQ Helicasas/antagonistas & inhibidores , Alquilantes/farmacología , Apoptosis/efectos de los fármacos , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Western Blotting , Proliferación Celular/efectos de los fármacos , Cromatina/genética , Inestabilidad Cromosómica , Replicación del ADN/efectos de los fármacos , Proteína Quinasa Activada por ADN/metabolismo , Sinergismo Farmacológico , Quimioterapia Combinada , Exodesoxirribonucleasas/genética , Exodesoxirribonucleasas/metabolismo , Anemia de Fanconi/genética , Anemia de Fanconi/patología , Células HCT116 , Células HeLa , Humanos , Mitomicina/farmacología , Proteínas Nucleares/metabolismo , ARN Interferente Pequeño/genética , Recombinasa Rad51/metabolismo , RecQ Helicasas/genética , RecQ Helicasas/metabolismo , Helicasa del Síndrome de Werner
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