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1.
Chemphyschem ; : e202400109, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38887191

RESUMO

The paper describes an investigation of phase decomposition of apatite lattice doped with rare earth ions (cerium, samarium, and holmium) at temperatures ranging from 25-1200 °C. The rare-earth ion-doped apatite minerals were synthesized using the sol-gel method. In situ high-temperature powder X-ray diffraction (XRD) was used to observe the phase changes and the lattice parameters were analyzed to ascertain the crystallographic transformations. The expansion coefficient of the compounds was determined, and it was found that the c-axis was the most expandable due to relatively weak chemical bonds along the c-crystallographic axis. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to examine the decomposition properties of the materials. Due to rare earth ion doping, the produced materials had slightly variable decomposition behaviour. The cerium and samarium ions were present in multiple oxidation states (Ce3+, Ce4+, Sm3+, Sm2+), whereas only Ho3+ ions were observed. Rare earth ion substitution affects tri-calcium phosphate proportion during decomposition by regulating concentrations of vacancies. X-ray photoelectron spectroscopy (XPS) analysis indicated that cerium and samarium ion-doped apatite yielded only 25 % tricalcium phosphate during decomposition. This finding advances our understanding of apatite structures, with implications for various high-temperature processes like calcination, sintering, hydrothermal processing, and plasma spraying.

2.
Gastroenterology ; 163(5): 1242-1251.e2, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35850198

RESUMO

BACKGROUND & AIMS: Early-onset colorectal cancer (EOCRC) is a distinct clinical and molecular entity with poor survival outcomes compared with late-onset CRC. Although the incidence of EOCRC is rising, current CRC screening strategies have several limitations in diagnostic performance for EOCRC. In view of this clinical challenge, novel and robust biomarkers for detection of EOCRC are necessary. The aim of this study was to develop a circulating micro RNA (miRNA) signature for the diagnosis of patients with EOCRC. METHODS: A systematic discovery approach by analyzing a large, publicly available, noncoding RNA expression profiling dataset (GSE115513) was used. A panel of miRNAs was identified, which was subsequently validated in blood samples from patients with EOCRC in 2 independent cohorts (n = 149) compared with controls (n = 110) and pre/postoperative plasma specimens (n = 22) using quantitative reverse-transcription polymerase chain reaction assays. RESULTS: In the discovery phase, 4 miRNAs were found to be expressed in blood samples. A combination signature of these 4 miRNAs (miR-193a-5p, miR-210, miR-513a-5p, and miR-628-3p) yielded an area under the curve of 0.92 (95% confidence interval, 0.85-0.96) for identification of EOCRC in the training cohort. The miRNA panel performance was then confirmed in an independent validation cohort (area under the curve, 0.88; 95% confidence interval, 0.82-0.93). Moreover, the miRNA panel robustly identified patients with early-stage EOCRC (P < .001). The decreased expression of miRNAs in postsurgery plasma specimens indicated their tumor specificity. CONCLUSIONS: Our novel miRNA signature for the diagnosis of EOCRC has the potential to identify patients with EOCRC with high accuracy for clinical application in the noninvasive diagnosis of EOCRC.


Assuntos
MicroRNA Circulante , Neoplasias Colorretais , MicroRNAs , Humanos , Biomarcadores Tumorais/genética , Curva ROC , MicroRNAs/genética , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/genética , Biópsia Líquida , Perfilação da Expressão Gênica
3.
Gastroenterology ; 163(5): 1252-1266.e2, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35850192

RESUMO

BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDAC) incidence is rising worldwide, and most patients present with an unresectable disease at initial diagnosis. Measurement of carbohydrate antigen 19-9 (CA19-9) levels lacks adequate sensitivity and specificity for early detection; hence, there is an unmet need to develop alternate molecular diagnostic biomarkers for PDAC. Emerging evidence suggests that tumor-derived exosomal cargo, particularly micro RNAs (miRNAs), offer an attractive platform for the development of cancer-specific biomarkers. Herein, genomewide profiling in blood specimens was performed to develop an exosome-based transcriptomic signature for noninvasive and early detection of PDAC. METHODS: Small RNA sequencing was undertaken in a cohort of 44 patients with an early-stage PDAC and 57 nondisease controls. Using machine-learning algorithms, a panel of cell-free (cf) and exosomal (exo) miRNAs were prioritized that discriminated patients with PDAC from control subjects. Subsequently, the performance of the biomarkers was trained and validated in independent cohorts (n = 191) using quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays. RESULTS: The sequencing analysis initially identified a panel of 30 overexpressed miRNAs in PDAC. Subsequently using qRT-PCR assays, the panel was reduced to 13 markers (5 cf- and 8 exo-miRNAs), which successfully identified patients with all stages of PDAC (area under the curve [AUC] = 0.98 training cohort; AUC = 0.93 validation cohort); but more importantly, was equally robust for the identification of early-stage PDAC (stages I and II; AUC = 0.93). Furthermore, this transcriptomic signature successfully identified CA19-9 negative cases (<37 U/mL; AUC = 0.96), when analyzed in combination with CA19-9 levels, significantly improved the overall diagnostic accuracy (AUC = 0.99 vs AUC = 0.86 for CA19-9 alone). CONCLUSIONS: In this study, an exosome-based liquid biopsy signature for the noninvasive and robust detection of patients with PDAC was developed.


Assuntos
Adenocarcinoma , Carcinoma Ductal Pancreático , Exossomos , MicroRNAs , Neoplasias Pancreáticas , Humanos , Antígeno CA-19-9 , Exossomos/genética , Exossomos/patologia , Transcriptoma , Carcinoma Ductal Pancreático/diagnóstico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Biomarcadores Tumorais/genética , Estudos de Coortes , MicroRNAs/genética , Carboidratos , Neoplasias Pancreáticas
4.
Semin Cancer Biol ; 75: 153-168, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33049362

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, which is usually diagnosed at an advanced stage. The late disease diagnosis, the limited availability of effective therapeutic interventions and lack of robust diagnostic biomarkers, are some of the primary reasons for the dismal 5-year survival rates (∼8%) in patients with PDAC. The pancreatic cancer develops through accumulation of a series of genomic and epigenomic alterations which lead to the transformation of normal pancreatic epithelium into an invasive carcinoma - a process that can take up to 15-20 years to develop, from the occurrence of first initiating mutational event. These facts highlight a unique window of opportunity for the earlier detection of PDAC, which could allow timely disease interception and improvement in the overall survival outcomes in patients suffering from this fatal malignancy. Non-coding RNAs (ncRNAs) have been recognized to play a central role in PDAC pathogenesis and are emerging as attractive candidates for biomarker development in various cancers, including PDAC. More specifically, the ncRNAs play a pivotal role in PDAC biology as they affect tumor growth, migration, and invasion by regulating cellular processes including cell cycle, apoptosis, and epithelial-mesenchymal transition. In this review, we focus on three types of well-established ncRNAs - microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) - and discuss their potential as diagnostic, prognostic and predictive biomarkers in PDAC.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma Ductal Pancreático/patologia , Regulação Neoplásica da Expressão Gênica , Neoplasias Pancreáticas/patologia , RNA Longo não Codificante/genética , Animais , Biomarcadores Tumorais/genética , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Humanos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo
5.
Blood ; 136(14): 1657-1669, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32573700

RESUMO

Anaplastic large cell lymphoma (ALCL) is a T-cell malignancy predominantly driven by a hyperactive anaplastic lymphoma kinase (ALK) fusion protein. ALK inhibitors, such as crizotinib, provide alternatives to standard chemotherapy with reduced toxicity and side effects. Children with lymphomas driven by nucleophosmin 1 (NPM1)-ALK fusion proteins achieved an objective response rate to ALK inhibition therapy of 54% to 90% in clinical trials; however, a subset of patients progressed within the first 3 months of treatment. The mechanism for the development of ALK inhibitor resistance is unknown. Through genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) activation and knockout screens in ALCL cell lines, combined with RNA sequencing data derived from ALK inhibitor-relapsed patient tumors, we show that resistance to ALK inhibition by crizotinib in ALCL can be driven by aberrant upregulation of interleukin 10 receptor subunit alpha (IL10RA). Elevated IL10RA expression rewires the STAT3 signaling pathway, bypassing otherwise critical phosphorylation by NPM1-ALK. IL-10RA expression does not correlate with response to standard chemotherapy in pediatric patients, suggesting that a combination of crizotinib and chemotherapy could prevent ALK inhibitor resistance-specific relapse.


Assuntos
Antineoplásicos/farmacologia , Crizotinibe/farmacologia , Resistencia a Medicamentos Antineoplásicos/genética , Subunidade alfa de Receptor de Interleucina-10/genética , Linfoma Anaplásico de Células Grandes/genética , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/genética , Antineoplásicos/uso terapêutico , Sistemas CRISPR-Cas , Linhagem Celular , Crizotinibe/uso terapêutico , Relação Dose-Resposta a Droga , Edição de Genes , Expressão Gênica , Humanos , Imuno-Histoquímica , Subunidade alfa de Receptor de Interleucina-10/metabolismo , Linfoma Anaplásico de Células Grandes/tratamento farmacológico , Linfoma Anaplásico de Células Grandes/metabolismo , Linfoma Anaplásico de Células Grandes/patologia , Modelos Biológicos , Nucleofosmina , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Tirosina Quinases/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos
7.
Biochemistry ; 55(38): 5434-41, 2016 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-27571378

RESUMO

Palbociclib is a cyclin-dependent kinase (CDK) 4/CDK6 inhibitor approved for breast cancer that is estrogen receptor (ER)-positive and human epidermal growth factor receptor 2 (HER2)-negative. We profiled palbociclib in cells either sensitive or resistant to the drug using an ATP/ADP probe-based chemoproteomics platform. Palbociclib only engaged CDK4 or CDK6 in sensitive cells. In resistant cells, no inhibition of CDK4 or CDK6 was observed, although the off-target profiles were similar in both cell types. Prolonged incubation of sensitive cells with the compound (24 h) resulted in the downregulation of additional kinases, including kinases critical for cell cycle progression. This downregulation is consistent with cell cycle arrest caused by palbociclib treatment. Both the direct and indirect targets were also observed in a human tumor xenograft study using the COLO-205 cell line in which phosphorylation of the retinoblastoma protein was tracked as the pharmacodyanamic marker. Together, these results suggest that this probe-based approach could be an important strategy toward predicting patient responsiveness to palbociclib.


Assuntos
Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Neoplasias/patologia , Piperazinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteômica , Piridinas/farmacologia , Animais , Linhagem Celular Tumoral , Humanos , Camundongos , Neoplasias/enzimologia , Ensaios Antitumorais Modelo de Xenoenxerto
8.
J Anaesthesiol Clin Pharmacol ; 32(1): 89-93, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27006549

RESUMO

BACKGROUND AND AIMS: Pain of propofol injection has been recalled by many patients as the most painful part of the induction of anesthesia. Tramadol and butorphanol are commonly used analgesics for perioperative analgesia in anesthesia practice. However, their potential to relieve propofol injection pain still needs to be explored. MATERIAL AND METHODS: A randomized, double-blind, placebo-controlled study was conducted on 90 American Society of Anesthesiologists I and II adult patients undergoing elective surgery under general anesthesia with propofol as an induction agent. Consecutive sampling technique with random assignment was used to allocate three groups of 30 patients each. Group I patients received an injection of normal saline 3 ml intravenously (placebo) while Group II and Group III patients received injection of tramadol 50 mg and butorphanol 1 mg intravenously, respectively. Before induction of anesthesia patients were asked about the intensity of pain on propofol injection by using visual analog scale (VAS) before the loss of consciousness. Descriptive statistics and analysis of variance with Chi-square test were used to analyze the data. The value of P < 0.05 was considered as a significant and P < 0.0001 as highly significant. RESULTS: The incidence of pain in Group I was observed in 80% of the patients, while it was observed in 23.33% and 20% of patients in Group II and III, respectively. Mean VAS scores were 2.27 ± 1.51, 1.14 ± 1.74, and 1.03 ± 1.72 in Group I, II, and Group III patients, respectively. The incidence of pruritus was 10% and 6.7% and erythema in 13.2% and 6.7% in Group II and III, respectively. CONCLUSION: Pretreatment with both butorphanol and tramadol significantly reduced pain on propofol injection; however, they exhibited comparable efficacy among each other. Thus, either of these two drugs can be considered for pretreatment to reduce propofol injection pain.

10.
Bioorg Med Chem Lett ; 24(1): 337-43, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-24279990

RESUMO

A co-crystal structure of amide-containing compound (4) in complex with the nicotinamide phosphoribosyltransferase (Nampt) protein and molecular modeling were utilized to design and discover a potent novel cyanoguanidine-containing inhibitor bearing a sulfone moiety (5, Nampt Biochemical IC50=2.5nM, A2780 cell proliferation IC50=9.7nM). Further SAR exploration identified several additional cyanoguanidine-containing compounds with high potency and good microsomal stability. Among these, compound 15 was selected for in vivo profiling and demonstrated good oral exposure in mice. It also exhibited excellent in vivo antitumor efficacy when dosed orally in an A2780 ovarian tumor xenograft model. The co-crystal structure of this compound in complex with the NAMPT protein was also determined.


Assuntos
Antineoplásicos/farmacologia , Citocinas/antagonistas & inibidores , Descoberta de Drogas , Inibidores Enzimáticos/farmacologia , Guanidinas/farmacologia , Neoplasias Experimentais/tratamento farmacológico , Nicotinamida Fosforribosiltransferase/antagonistas & inibidores , Neoplasias Ovarianas/tratamento farmacológico , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Citocinas/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/química , Feminino , Guanidinas/administração & dosagem , Guanidinas/química , Humanos , Camundongos , Modelos Moleculares , Estrutura Molecular , Nicotinamida Fosforribosiltransferase/metabolismo , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de Xenoenxerto
11.
J Oral Maxillofac Pathol ; 28(2): 268-274, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39157825

RESUMO

Background: There are still certain gaps in the research that need to be filled despite the fact that numerous studies have looked into the transformation of odontogenic cysts into neoplastic lesions. To identify pertinent research that had been published and to synthesise the available data and provide an overview of the current body of knowledge, this review also sought to do so. Materials and Methods: Adopting the Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a search strategy was implemented across several online databases to search for relevant articles as per the defined selection criterion. Results: After the search strategy was complete, 31 studies were chosen. Men tended to have more cancer than women. Swelling and discomfort were the primary pathology-related complaints. Although two cases were not detailed, radiologically, well-defined and poorly defined borders were reported in 18 and 11 participants, respectively. Squamous cell carcinoma with good differentiation (n = 12) was the most common cancer kind. More than 74% of patients were still living 6 months to 10 years following follow-up, four (12.90%) experienced recurrences and/or metastases and two (6.45%) experienced a disease-related mortality between 2 months and a year. Conclusion: Prompt surgical follow-ups and cautious excision of odontogenic cysts are essential to avoiding neoplastic change and recurrence. Future research is required to look at possible reasons why odontogenic cysts can convert neoplastically.

12.
J Clin Med ; 13(7)2024 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-38610881

RESUMO

The heightened awareness of ethnic dermatology aligns with the growing prevalence of skin of color communities globally, where hyperpigmentation disorders pose a common dermatological challenge. Effectively addressing dermal pigmentation is challenging due to its resistance to conventional therapies and its association with impaired quality of life. This underscores the need for effective treatments and a thorough grasp of laser advancements. A relevant literature search spanning the last 7 years across the PubMed database reveals core studies, challenges, and the evolution of laser technologies tailored for various forms of congenital and acquired dermal hyperpigmentation in skin of color. This comprehensive review explores the mechanisms, applications, and recommendations for pigmentary laser technologies, highlighting the key role of Q-switched lasers in their established millisecond/ nanosecond forms and emerging picosecond lasers, fractional non-ablative and ablative lasers, Intense Pulsed Light, etc. The summary of evidence includes studies on dermal melanocytosis (nevus of Ota and Hori's nevus), tattoos, acquired dermal macular hyperpigmentation, etc., and also entities with mixed epidermal-dermal components, such as melasma and post-inflammatory hyperpigmentation. The review offers valuable insights for clinicians to make informed decisions based on diagnosis, skin type, and the latest technologies to optimize results and minimize complications, especially in darker Fitzpatrick skin types. In their five-year study with 122 Indian patients, the authors applied specific laser combinations for diverse dermal melanoses, including tattoos, dermal/mixed melasma, acquired dermal macular hyperpigmentation, and dermal nevi. Substantial pigmentation reduction, subjectively assessed by both physicians and patients, was observed across all groups. A one-way ANOVA indicated a significant difference in mean improvement scores across various pigmentary conditions (F = 3.39, p = 0.02), with melasma patients exhibiting a significantly higher improvement score than tattoos (p = 0.03). The results affirmed the safety and efficacy of sequential laser therapy for dermal pigmentation in skin of color, advocating for flexibility in approach while maintaining the rationale behind the laser sequences. Despite advancements, challenges persist, and gaps in the current literature are identified. In conclusion, this summary highlights the ongoing pursuit of optimal protocols in dermatological laser treatments for dermal melanoses, offering valuable insights for future research and clinical practice.

13.
AJP Rep ; 14(3): e202-e204, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-39211811

RESUMO

We present a case of a vein of Galen aneurysmal malformation (VGAM), a rare congenital arteriovenous malformation, in one fetus of a monochorionic-diamniotic twin pregnancy. The diagnosis was made with color Doppler ultrasonography at 28 weeks and the affected fetus was found to have worsening cardiomegaly on subsequent fetal echocardiograms. She was emergently delivered at 32 weeks for abnormal fetal heart rate tracing of the affected twin. Magnetic resonance imaging of the brain findings after delivery demonstrated severe neurological injury; therefore, postnatal embolization was not performed. The neonate died on day of life 9. The cotwin survived without neurological complications. This is the first case in the literature of a VGAM diagnosed prenatally in a monochorionic-diamniotic twin pregnancy and demonstrates the challenge of delivery timing with prenatal diagnosis in a twin pregnancy.

14.
NPJ Precis Oncol ; 8(1): 29, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38448512

RESUMO

ALK and ROS1 fusions are effectively targeted by tyrosine kinase inhibitors (TKIs), however patients inevitably relapse after an initial response, often due to kinase domain mutations. We investigated circulating DNA from TKI-relapsed NSCLC patients by deep-sequencing. New EML4::ALK substitutions, L1198R, C1237Y and L1196P, were identified in the plasma of NSCLC ALK patients and characterized in a Ba/F3 cell model. Variants C1237Y and L1196P demonstrated pan-inhibitor resistance across 5 clinical and 2 investigational TKIs.

15.
Cancer Res Commun ; 4(9): 2427-2443, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39028932

RESUMO

An in-depth multiomic molecular characterization of PARP inhibitors revealed a distinct poly-pharmacology of niraparib (Zejula) mediated by its interaction with lanosterol synthase (LSS), which is not observed with other PARP inhibitors. Niraparib, in a similar way to the LSS inhibitor Ro-48-8071, induced activation of the 24,25-epoxysterol shunt pathway, which is a regulatory signaling branch of the cholesterol biosynthesis pathway. Interestingly, the combination of an LSS inhibitor with a PARP inhibitor that does not bind to LSS, such as olaparib, had an additive effect on killing cancer cells to levels comparable with niraparib as a single agent. In addition, the combination of PARP inhibitors and statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, an enzyme catalyzing the rate-limiting step in the mevalonate pathway, had a synergistic effect on tumor cell killing in cell lines and patient-derived ovarian tumor organoids. These observations suggest that concomitant inhibition of the cholesterol biosynthesis pathway and PARP activity might result in stronger efficacy of these inhibitors against tumor types highly dependent on cholesterol metabolism. SIGNIFICANCE: The presented data indicate, to our knowledge, for the first time, the potential benefit of concomitant modulation of cholesterol biosynthesis pathway and PARP inhibition and highlight the need for further investigation to assess its translational relevance.


Assuntos
Colesterol , Sinergismo Farmacológico , Inibidores de Poli(ADP-Ribose) Polimerases , Humanos , Colesterol/biossíntese , Colesterol/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Linhagem Celular Tumoral , Feminino , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia
16.
Cancer Discov ; 14(8): 1457-1475, 2024 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-38587317

RESUMO

Microsatellite-unstable (MSI) cancers require WRN helicase to resolve replication stress due to expanded DNA (TA)n dinucleotide repeats. WRN is a promising synthetic lethal target for MSI tumors, and WRN inhibitors are in development. In this study, we used CRISPR-Cas9 base editing to map WRN residues critical for MSI cells, validating the helicase domain as the primary drug target. Fragment-based screening led to the development of potent and highly selective WRN helicase covalent inhibitors. These compounds selectively suppressed MSI model growth in vitro and in vivo by mimicking WRN loss, inducing DNA double-strand breaks at expanded TA repeats and DNA damage. Assessment of biomarkers in preclinical models linked TA-repeat expansions and mismatch repair alterations to compound activity. Efficacy was confirmed in immunotherapy-resistant organoids and patient-derived xenograft models. The discovery of potent, selective covalent WRN inhibitors provides proof of concept for synthetic lethal targeting of WRN in MSI cancer and tools to dissect WRN biology. Significance: We report the discovery and characterization of potent, selective WRN helicase inhibitors for MSI cancer treatment, with biomarker analysis and evaluation of efficacy in vivo and in immunotherapy-refractory preclinical models. These findings pave the way to translate WRN inhibition into MSI cancer therapies and provide tools to investigate WRN biology. See related commentary by Wainberg, p. 1369.


Assuntos
Helicase da Síndrome de Werner , Humanos , Helicase da Síndrome de Werner/genética , Camundongos , Animais , Instabilidade de Microssatélites , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/patologia , Linhagem Celular Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico
17.
J Neurophysiol ; 109(3): 867-72, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23136348

RESUMO

Addition of newly generated neurons into mature neural circuits in the adult CNS responds to changes in neurotransmitter levels and is tightly coupled to the activity of specific brain regions. This postnatal neurogenesis contributes to plasticity of the olfactory bulb and hippocampus and is thought to play a role in learning and memory, context and odor discrimination, as well as perceptual learning. While acetylcholine plays an important role in odor discrimination and perceptual learning, its role in adult neurogenesis in the olfactory bulb has not been elucidated. In this study, I have examined the functional expression of nAChRs in progenitor cells of the rostral migratory stream (RMS) in the adult olfactory bulb of mice. I show that most of these cells in the RMS exhibit large nAChR-mediated calcium transients upon application of acetylcholine (ACh). Unlike in the hippocampus, the predominant functional nAChRs on progenitor cells are of α3ß4 subtype. Interestingly, functional receptor expression is lost once progenitor cells mature, and are incorporated into the granule cell layer. Instead, nAChRs are now expressed on some presynaptic terminals and modulate glutamate release onto granule cells. My results imply that ACh is a part of the permissive niche and likely plays a role in development of progenitor cells.


Assuntos
Células-Tronco Adultas/metabolismo , Células-Tronco Neurais/metabolismo , Bulbo Olfatório/metabolismo , Subunidades Proteicas/metabolismo , Receptores Nicotínicos/metabolismo , Acetilcolina/metabolismo , Animais , Cálcio/metabolismo , Sinalização do Cálcio , Camundongos , Camundongos Endogâmicos C57BL , Bulbo Olfatório/citologia , Terminações Pré-Sinápticas/metabolismo , Subunidades Proteicas/química , Receptores Nicotínicos/química
18.
Langmuir ; 29(36): 11431-9, 2013 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-23947652

RESUMO

The catalytic activity of porous platinum nanostructures, viz. platinum nanonets (PtNNs) and platinum nanoballs (PtNBs), synthesized by radiolysis were studied using two model reactions (i) electron transfer reaction between hexacyanoferrate (III) and sodium thiosulfate and (ii) the reduction of p-nitrophenol by sodium borohydride to p-aminophenol. The kinetic investigations were carried out for the platinum nanostructure-catalyzed reactions at different temperatures. The pseudofirst-order rate constant for the electron transfer reaction between hexacyanoferrate (III) and sodium thiosulfate catalyzed by PtNNs and PtNBs at 293 K are (9.1 ± 0.7) × 10(-3) min(-1) and (16.9 ± 0.6) × 10(-3) min(-1), respectively. For the PtNN- and PtNB-catalyzed reduction of p-nitrophenol to p-aminophenol by sodium borohydride, the pseudofirst-order rate constant was (8.4 ± 0.3) × 10(-2) min(-1) and (12.6 ± 2.5) × 10(-2) min(-1), respectively. The accessible surface area of the PtNNs and PtNBs determined before the reaction are 99 and 110 m(2)/g, respectively. These nanostructures exhibit significantly higher catalytic activity, consistent with the largest accessible surface area reported so far for the solid platinum nanoparticles. The equilibrium of the reactants on the surface of the platinum nanostructures played an important role in the induction time (t0) observed in the reaction. A possible role of structural modifications of PtNBs catalyzed the reaction leading to change in the accessible surface area of PtNBs is being explored to explain the nonlinear behavior in the kinetic curve. The activation energy of the PtNN- and PtNB-catalyzed reduction of p-nitrophenol are 26 and 6.4 kJ/mol, respectively. These observations open up new challenges in the field of material science to design and synthesize platinum nanostructures which could withstand such reaction conditions.

19.
Bioorg Med Chem Lett ; 23(20): 5488-97, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24021463

RESUMO

Potent, 1H-pyrazolo[3,4-b]pyridine-containing inhibitors of the human nicotinamide phosphoribosyltransferase (NAMPT) enzyme were identified using structure-based design techniques. Many of these compounds exhibited nanomolar antiproliferation activities against human tumor lines in in vitro cell culture experiments, and a representative example (compound 26) demonstrated encouraging in vivo efficacy in a mouse xenograft tumor model derived from the A2780 cell line. This molecule also exhibited reduced rat retinal exposures relative to a previously studied imidazo-pyridine-containing NAMPT inhibitor. Somewhat surprisingly, compound 26 was only weakly active in vitro against mouse and monkey tumor cell lines even though it was a potent inhibitor of NAMPT enzymes derived from these species. The compound also exhibited only minimal effects on in vivo NAD levels in mice, and these changes were considerably less profound than those produced by an imidazo-pyridine-containing NAMPT inhibitor. The crystal structures of compound 26 and the corresponding PRPP-derived ribose adduct in complex with NAMPT were also obtained.


Assuntos
Amidas/química , Ácidos Carboxílicos/química , Citocinas/antagonistas & inibidores , Inibidores Enzimáticos/química , Niacinamida/análogos & derivados , Nicotinamida Fosforribosiltransferase/antagonistas & inibidores , Pirazóis/química , Piridinas/química , Sulfonas/química , Amidas/síntese química , Amidas/farmacocinética , Animais , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Citocinas/metabolismo , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacocinética , Feminino , Meia-Vida , Haplorrinos , Humanos , Camundongos , Camundongos Nus , NAD/metabolismo , Niacinamida/sangue , Niacinamida/química , Niacinamida/farmacocinética , Nicotinamida Fosforribosiltransferase/metabolismo , Estrutura Terciária de Proteína , Pirazóis/sangue , Pirazóis/farmacocinética , Ratos , Retina/efeitos dos fármacos , Retina/metabolismo , Relação Estrutura-Atividade , Sulfonas/sangue , Sulfonas/farmacocinética , Transplante Heterólogo
20.
Bioorg Med Chem Lett ; 23(12): 3531-8, 2013 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-23668988

RESUMO

Potent, reversible inhibition of the cytochrome P450 CYP2C9 isoform was observed in a series of urea-containing nicotinamide phosphoribosyltransferase (NAMPT) inhibitors. This unwanted property was successfully removed from the described inhibitors through a combination of structure-based design and medicinal chemistry activities. An optimized compound which did not inhibit CYP2C9 exhibited potent anti-NAMPT activity (17; BC NAMPT IC50=3 nM; A2780 antiproliferative IC50=70 nM), good mouse PK properties, and was efficacious in an A2780 mouse xenograft model. The crystal structure of this compound in complex with the NAMPT protein is also described.


Assuntos
Hidrocarboneto de Aril Hidroxilases/antagonistas & inibidores , Nicotinamida Fosforribosiltransferase/antagonistas & inibidores , Ureia/análogos & derivados , Ureia/farmacologia , Animais , Hidrocarboneto de Aril Hidroxilases/química , Hidrocarboneto de Aril Hidroxilases/metabolismo , Citocromo P-450 CYP2C9 , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Nicotinamida Fosforribosiltransferase/química , Nicotinamida Fosforribosiltransferase/metabolismo , Ureia/síntese química
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