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1.
Nat Genet ; 51(12): 1714-1722, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31784732

RESUMO

Core regulatory transcription factors (CR TFs) orchestrate the placement of super-enhancers (SEs) to activate transcription of cell-identity specifying gene networks, and are critical in promoting cancer. Here, we define the core regulatory circuitry of rhabdomyosarcoma and identify critical CR TF dependencies. These CR TFs build SEs that have the highest levels of histone acetylation, yet paradoxically the same SEs also harbor the greatest amounts of histone deacetylases. We find that hyperacetylation selectively halts CR TF transcription. To investigate the architectural determinants of this phenotype, we used absolute quantification of architecture (AQuA) HiChIP, which revealed erosion of native SE contacts, and aberrant spreading of contacts that involved histone acetylation. Hyperacetylation removes RNA polymerase II (RNA Pol II) from core regulatory genetic elements, and eliminates RNA Pol II but not BRD4 phase condensates. This study identifies an SE-specific requirement for balancing histone modification states to maintain SE architecture and CR TF transcription.

2.
Nat Biotechnol ; 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31712774

RESUMO

Gene expression can be activated or suppressed using CRISPR--Cas9 systems. However, tools that enable dose-dependent activation of gene expression without the use of exogenous transcription regulatory proteins are lacking. Here we describe chemical epigenetic modifiers (CEMs) designed to activate the expression of target genes by recruiting components of the endogenous chromatin-activating machinery, eliminating the need for exogenous transcriptional activators. The system has two parts: catalytically inactive Cas9 (dCas9) in complex with FK506-binding protein (FKBP) and a CEM consisting of FK506 linked to a molecule that interacts with cellular epigenetic machinery. We show that CEMs upregulate gene expression at target endogenous loci up to 20-fold or more depending on the gene. We also demonstrate dose-dependent control of transcriptional activation, function across multiple diverse genes, reversibility of CEM activity and specificity of our best-in-class CEM across the genome.

3.
J Thorac Oncol ; 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31783178

RESUMO

INTRODUCTION: Children and young adults diagnosed with malignant mesothelioma may have unique genetic characteristics. In this study, we evaluated for the presence of the anaplastic lymphoma kinase (ALK) translocations in these patients. METHODS: In a prospective study of mesothelioma natural history (MNH) (ClinicalTrials.gov number NCT01950572) we assessed for the presence of the ALK translocation in patients less than 40 years old, irrespective of site of disease. The presence of this translocation was assessed via fluorescence in-situ hybridization (FISH). If positive, both immunohistochemistry (IHC) and RNA sequencing (RNASeq) were performed on the tumor specimen. RESULTS: Between September 2013 and December 2018, 373 patients were enrolled on the MNH study of which 32 patients were <40 years old at the time of their mesothelioma diagnosis. 25 patients had peritoneal, 5 pleural, 1 pericardial and 1 had bi-compartmental mesothelioma. Presence of an ALK translocation by FISH was seen in 2 of the 32 (6%) mesothelioma patients. Both patients, a 14 year old female and a 27 year old male, had peritoneal mesothelioma and neither had history of asbestos exposure, prior radiation or predisposing germline mutations. Neither had detectable ALK expression by IHC. RNAseq revealed the presence of an STRN fusion partner in the female patient but failed to identify any fusion protein in the male patient. CONCLUSIONS: Young patients with peritoneal mesothelioma should be evaluated for the presence of ALK translocations. Presence of this translocation should be assessed by FISH and these patients could potentially benefit from tyrosine kinase inhibitors targeting ALK.

4.
J Med Chem ; 62(21): 9931-9946, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31638797

RESUMO

RORγt is an important nuclear receptor that regulates the production of several pro-inflammatory cytokines such as IL-17 and IL-22. As a result, RORγt has been identified as a potential target for the treatment of various immunological disorders such as psoriasis, psoriatic arthritis, and inflammatory bowel diseases. Structure and computer-assisted drug design led to the identification of a novel series of tricyclic RORγt inverse agonists with significantly improved in vitro activity in the reporter (Gal4) and human whole blood assays compared to our previous chemotype. Through careful structure activity relationship, several potent and selective RORγt inverse agonists have been identified. Pharmacokinetic studies allowed the identification of the lead molecule 32 with a low peak-to-trough ratio. This molecule showed excellent activity in an IL-2/IL-23-induced mouse pharmacodynamic study and demonstrated biologic-like efficacy in an IL-23-induced preclinical model of psoriasis.

5.
Biomed Res Int ; 2019: 3264846, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31341895

RESUMO

In this study, GC-MS analysis has shown that whole plant butanol fraction of rheum ribes (WBFRR) comprises of 21 compounds which exhibited anticancer (MCF-7) activity having IC50 value of 36.01± 0.26. MTT assay (MCF-7), Oxidative Burst assay using chemiluminescence technique, and B-Hatching techniques were the methods used for anticancer MCF-7, anti-inflammatory, and Brine Shrimp Lethality Assay (BSLA). GC-MS was used for structural elucidation. Whole plant methanol extract of rheum ribes (WMERR), whole plant n-hexane fraction of rheum ribes (WHFRR), and whole plant aqueous fraction of rheum ribes (WAFRR) were inactive against anticancer (MCF-7) cell line. Whole plant methanol extract of rheum ribes (WMERR), whole plant aqueous fraction of rheum ribes (WAFRR) and whole plant butanol fraction of rheum ribes (WBFRR) showed anti-inflammatory activity on ROS having IC50 value of 23.2±1.9, 24.2±2.7 and 12.0±0.6. Whole plant butanol fraction of rheum ribes (WBFRR) showed Brine Shrimp Lethality with LD50 693.302 while whole plant methanol extract of rheum ribes (WMERR) and whole plant aqueous fraction of rheum ribes (WAFRR) showed high lethality at highest concentration. This study revealed that whole plant butanol fraction of rheum ribes (WBFRR) exhibited significant anticancer (MCF-7) activity. In the near future, the constituent of whole plant butanol fraction of rheum ribes (WBFRR) can be the alternative drug against MCF-7 cell line with least toxicity and side effects.

6.
Bioorg Med Chem Lett ; 29(16): 2265-2269, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31257087

RESUMO

An X-ray crystal structure of one of our previously discovered RORγt inverse agonists bound to the RORγt ligand binding domain revealed that the cyclohexane carboxylic acid group of compound 2 plays a significant role in RORγt binding, forming four hydrogen bonding and ionic interactions with RORγt. SAR studies centered around the cyclohexane carboxylic acid group led to identification of several structurally diverse and more potent compounds, including new carboxylic acid analogues 7 and 20, and cyclic sulfone analogues 34 and 37. Notably, compounds 7 and 20 were found to maintain the desirable pharmacokinetic profile of 2.

7.
J Med Chem ; 62(20): 8973-8995, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31318208

RESUMO

Small molecule JAK inhibitors have emerged as a major therapeutic advancement in treating autoimmune diseases. The discovery of isoform selective JAK inhibitors that traditionally target the catalytically active site of this kinase family has been a formidable challenge. Our strategy to achieve high selectivity for TYK2 relies on targeting the TYK2 pseudokinase (JH2) domain. Herein we report the late stage optimization efforts including a structure-guided design and water displacement strategy that led to the discovery of BMS-986165 (11) as a high affinity JH2 ligand and potent allosteric inhibitor of TYK2. In addition to unprecedented JAK isoform and kinome selectivity, 11 shows excellent pharmacokinetic properties with minimal profiling liabilities and is efficacious in several murine models of autoimmune disease. On the basis of these findings, 11 appears differentiated from all other reported JAK inhibitors and has been advanced as the first pseudokinase-directed therapeutic in clinical development as an oral treatment for autoimmune diseases.

8.
Nat Commun ; 10(1): 3004, 2019 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-31285436

RESUMO

Identity determining transcription factors (TFs), or core regulatory (CR) TFs, are governed by cell-type specific super enhancers (SEs). Drugs to selectively inhibit CR circuitry are of high interest for cancer treatment. In alveolar rhabdomyosarcoma, PAX3-FOXO1 activates SEs to induce the expression of other CR TFs, providing a model system for studying cancer cell addiction to CR transcription. Using chemical genetics, the systematic screening of chemical matter for a biological outcome, here we report on a screen for epigenetic chemical probes able to distinguish between SE-driven transcription and constitutive transcription. We find that chemical probes along the acetylation-axis, and not the methylation-axis, selectively disrupt CR transcription. Additionally, we find that histone deacetylases (HDACs) are essential for CR TF transcription. We further dissect the contribution of HDAC isoforms using selective inhibitors, including the newly developed selective HDAC3 inhibitor LW3. We show HDAC1/2/3 are the co-essential isoforms that when co-inhibited halt CR transcription, making CR TF sites hyper-accessible and disrupting chromatin looping.


Assuntos
Elementos Facilitadores Genéticos/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Rabdomiossarcoma/genética , Acetilação/efeitos dos fármacos , Linhagem Celular Tumoral , Cromatina/efeitos dos fármacos , Cromatina/metabolismo , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Ensaios de Triagem em Larga Escala , Inibidores de Histona Desacetilases/química , Histona Desacetilases/química , Humanos , Simulação de Dinâmica Molecular , Sondas Moleculares/química , Sondas Moleculares/farmacologia , Proteínas de Fusão Oncogênica/genética , Fatores de Transcrição Box Pareados/genética , Cultura Primária de Células , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Rabdomiossarcoma/patologia , Análise de Sequência de RNA , Transcrição Genética/efeitos dos fármacos
9.
Pediatr Blood Cancer ; 66(10): e27869, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31222885

RESUMO

Overall survival rates for pediatric patients with high-risk or relapsed rhabdomyosarcoma (RMS) have not improved significantly since the 1980s. Recent studies have identified a number of targetable vulnerabilities in RMS, but these discoveries have infrequently translated into clinical trials. We propose streamlining the process by which agents are selected for clinical evaluation in RMS. We believe that strong consideration should be given to the development of combination therapies that add biologically targeted agents to conventional cytotoxic drugs. One example of this type of combination is the addition of the WEE1 inhibitor AZD1775 to the conventional cytotoxic chemotherapeutics, vincristine and irinotecan.

10.
J Thorac Oncol ; 14(8): 1447-1457, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31063862

RESUMO

PURPOSE: Despite high tumor mutationburden, immune checkpoint blockade has limited efficacy in SCLC. We hypothesized that poly (ADP-ribose) polymerase inhibition could render SCLC more susceptible to immune checkpoint blockade. METHODS: A single-arm, phase II trial (NCT02484404) enrolled patients with relapsed SCLC who received durvalumab, 1500 mg every 4 weeks, and olaparib, 300 mg twice a day. The primary outcome was objective response rate. Correlative studies included mandatory collection of pretreatment and during-treatment biopsy specimens, which were assessed to define SCLC immunephenotypes: desert (CD8-positive T-cell prevalence low), excluded (CD8-positive T cells in stroma immediately adjacent/within tumor), and inflamed (CD8-positive T cells in direct contact with tumor). RESULTS: A total of 20 patients were enrolled. Their median age was 64 years, and most patients (60%) had platinum-resistant/refractory disease. Of 19 evaluable patients, two were observed to have partial or complete responses (10.5%), including a patient with EGFR-transformed SCLC. Clinical benefit was observed in four patients (21.1% [95% confidence interval: 6.1%-45.6%]) with confirmed responses or prolonged stable disease (≥8 months). The most common treatment-related adverse events were anemia (80%), lymphopenia (60%), and leukopenia (50%). Nine of 14 tumors (64%) exhibited an excluded phenotype; 21% and 14% of tumors exhibited the inflamed and desert phenotypes, respectively. Tumor responses were observed in all instances in which pretreatment tumors showed an inflamed phenotype. Of the five tumors without an inflamed phenotype at baseline, no during-treatment increase in T-cell infiltration or programmed death ligand 1 expression on tumor-infiltrating immune cells was observed. CONCLUSIONS: The study combination did not meet the preset bar for efficacy. Pretreatment and during-treatment biopsy specimens suggested that tumor immune phenotypes may be relevant for SCLC responses to immune checkpoint blockade combinations. The predictive value of preexisting CD8-positive T-cell infiltrates observed in this study needs to be confirmed in larger cohorts.

11.
Spectrochim Acta A Mol Biomol Spectrosc ; 219: 313-318, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31054495

RESUMO

The interactions between cetyltrimethylammonium bromide (CTAB) and hen egg white lysozymes (HEWL) was carried out to investigate protein-surfactant interaction mechanisms while both exist in the overall same charged state. The interactions between CTAB and the HEWL were examined with circular dichroism (CD), dynamic light scattering (DLS), fluorescence spectroscopy, and computational docking at a pH9.0 at room temperature. The far-UV CD and fluorescence results revealed that CTAB at concentrations from 0.15 to 10.0mM influenced the secondary as well as the tertiary structure of HEWL. The secondary structure of the HEWL was retained, while the tertiary structure of the HEWL was disrupted in the CTAB-treated samples at pH9.0. The hydrodynamic radii of the HEWL were also expanded in the presence of CTAB. Molecular docking studies showed that CTAB formed one electrostatic and four hydrophobic interactions, as well as one carbon hydrogen bond with HEWL. The data obtained from spectroscopic and computational studies demonstrated that the positively charged head and 18­carbon alkyl chain of the CTAB interacted through weak electrostatic and strong hydrophobic interactions.


Assuntos
Cetrimônio/metabolismo , Muramidase/metabolismo , Tensoativos/metabolismo , Animais , Galinhas , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas/efeitos dos fármacos , Simulação de Acoplamento Molecular , Muramidase/química , Ligação Proteica , Conformação Proteica/efeitos dos fármacos , Desdobramento de Proteína/efeitos dos fármacos , Eletricidade Estática
12.
Nanotechnology ; 30(38): 385204, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31048572

RESUMO

In bulk heterojunction organic solar cells (OSCs), nanomorphology of the photoactive layer plays a crucial role in determining photocurrent and fill factor (FF) of OSCs, and therefore it is essential to control the nanomorphology of the photoactive layer to fabricate devices with high power conversion efficiency (PCE). We demonstrate the combined effects of a ZnO nanorippled electron transport layer (ETL) and solvent additive (1,8-diiodooctane (DIO)) on the nanomorphology and performance of a model OSC in an inverted geometry. The photoactive layer in the model OSC is composed of Poly [4,8-bis (5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl] (PTB7-Th):phenyl-C71-butyric acid methyl ester (PC71BM) blend. It is observed that the use of ZnO nanoripples as an ETL and DIO as a solvent additive facilitates the formation of near ideal nanomorphology of bi-continuous interpenetrating network of donor and acceptor. This is confirmed by morphological studies using atomic force microscopy, scanning electron microscopy and transmission electron microscopy. Photo-electrochemical impedance spectroscopy measurements confirm that obtained nanomorphology of bicontinuous interpenetrating network is contributing to the improved device performance. The device with 3 vol% DIO, with underneath ZnO nanoripples exhibited improved current density (J sc), FF, open circuit voltage (V oc) and PCE of 15.57 mA cm-2, 64.50%, 0.81V and 8.20%, respectively.

13.
Proc Natl Acad Sci U S A ; 116(18): 9008-9013, 2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-30975761

RESUMO

Survival from malignant mesothelioma, particularly pleural mesothelioma, is very poor. For patients with breast, ovarian, or prostate cancers, overall survival is associated with increased sensitivity to platinum chemotherapy due to loss-of-function mutations in DNA repair genes. The goal of this project was to evaluate, in patients with malignant mesothelioma, the relationship between inherited loss-of-function mutations in DNA repair and other tumor suppressor genes and overall survival following platinum chemotherapy. Patients with histologically confirmed malignant mesothelioma were evaluated for inherited mutations in tumor suppressor genes. Survival was evaluated with respect to genotype and site of mesothelioma. Among 385 patients treated with platinum chemotherapy, median overall survival was significantly longer for patients with loss-of-function mutations in any of the targeted genes compared with patients with no such mutation (P = 0.0006). The effect of genotype was highly significant for patients with pleural mesothelioma (median survival 7.9 y versus 2.4 y, P = 0.0012), but not for patients with peritoneal mesothelioma (median survival 8.2 y versus 5.4 y, P = 0.47). Effect of patient genotype on overall survival, measured at 3 y, remained independently significant after adjusting for gender and age at diagnosis, two other known prognostic factors. Patients with pleural mesothelioma with inherited mutations in DNA repair and other tumor suppressor genes appear to particularly benefit from platinum chemotherapy compared with patients without inherited mutations. These patients may also benefit from other DNA repair targeted therapies such as poly-ADP ribose polymerase (PARP) inhibitors.

14.
Cell Rep ; 26(10): 2651-2666.e6, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30840888

RESUMO

Intratumor mutational heterogeneity has been documented in primary non-small-cell lung cancer. Here, we elucidate mechanisms of tumor evolution and heterogeneity in metastatic thoracic tumors (lung adenocarcinoma and thymic carcinoma) using whole-exome and transcriptome sequencing, SNP array for copy-number alterations (CNAs), and mass-spectrometry-based quantitative proteomics of metastases obtained by rapid autopsy. APOBEC mutagenesis, promoted by increased expression of APOBEC3 region transcripts and associated with a high-risk APOBEC3 germline variant, correlated with mutational tumor heterogeneity. TP53 mutation status was associated with APOBEC hypermutator status. Interferon pathways were enriched in tumors with high APOBEC mutagenesis and IFN-γ-induced expression of APOBEC3B in lung adenocarcinoma cells, suggesting that the immune microenvironment may promote mutational heterogeneity. CNAs occurring late in tumor evolution correlated with downstream transcriptomic and proteomic heterogeneity, although global proteomic heterogeneity was significantly greater than transcriptomic and CNA heterogeneity. These results illustrate key mechanisms underlying multi-dimensional heterogeneity in metastatic thoracic tumors.

15.
Sci Total Environ ; 669: 333-341, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30878939

RESUMO

Removal of cadmium (Cd2+), a highly toxic heavy metal, from aqueous solutions was investigated using nano zerovalent iron (Fe0). Cadmium was efficiently removed by Fe0, although reactivity and reusability of Fe0 was significantly promoted by coupling with bismuth (Bi). At a reaction time of 20 min, 85% and 96% Cd2+ was removed by Fe0 and Bi/Fe0, respectively, at first cycle using [Cd2+]0 = 10 mg/L and [Fe0]0 = [Bi/Fe0]0 = 1.0 g/L. However, Cd2+ removal efficiency was reduced to 12% and 80% at sixth cycle by Fe0 and Bi/Fe0, respectively. The X-Ray diffraction and energy dispersive X-Ray spectroscopy analysis proved successful formation of Fe0 by the chemical reduction method and also confirmed coupling of Bi with Fe0 to form bimetallic Bi/Fe0. The oxidation of Fe0 and Bi/Fe0 yielded electron that played significant role in the conversion of toxic Cd2+ into non-toxic Cd0. The reactivity of electron with Cd2+ was calculated to be 4.3 × 109 M-1 s-1. The pH of solution showed pronounced effects on the reactivity of both Fe0 and Bi/Fe0. Removal of Cd2+ by both Fe0 and Bi/Fe0 followed pseudo-first-order kinetic model. The conversion of Cd2+ into non-toxic Cd0 proved Fe0 and Bi/Fe0 to be highly efficient and rewarding in detoxification of Cd2+ and other toxic metals in aqueous environments.

16.
Biochimie ; 160: 61-75, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30797879

RESUMO

Nanoparticles (NPs) are one of the leading and promising technologies for gene and drug delivery. However, despite continuous advancements in the delivery of NPs, endosomal escape remains a major issue and a matter of grave concern for developing an efficient and targeted delivery system for therapeutic applications. Most of NPs generally follow endocytic pathway for internalization into the cells. Following the internalization process, NPs must escape into the cell cytoplasm for evading degradation by hydrolytic enzymes present in the lysosomes. Various types of lipids have been used in the past viz. fusogenic lipid dioleoylphosphatidylethanolamine (DOPE), pH-sensitive lipids, cationic lipid and multiple charges containing lipid to escape from endosomes. Recently, several novel polymers, pH-sensitive peptides, proteins and many others endosomolytic agents have been identified and developed for incorporating into gene and drug delivery system to facilitate endosomal escape. In this review, endosomal escape mechanisms of different types of NPs have been discussed in detail and compared with endosomal escape mechanisms of viruses and other synthetic gene delivery systems to escape from endosomes. Also, the designing of endosomolytic agents to facilitate endosomal escape based on different approaches and strategies is explored. Moreover, this review article highlights the recent advancements in the development of NPs equipped with endosomolytic agents including its future directions and applications in the field of nanomedicine.


Assuntos
Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Desenho de Drogas , Endossomos/metabolismo , Nanopartículas/química , Polímeros/química , Polinucleotídeos/administração & dosagem , Endossomos/efeitos dos fármacos , Humanos
17.
J Assoc Nurses AIDS Care ; 30(3): 344-351, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30768434

RESUMO

Stigma has negatively influenced the lives of people living with HIV since the beginning of the epidemic. It affects every facet of their lives and can cause mental health problems, loss of human rights, and barriers to care. Studies in developing countries have shown a high prevalence of HIV stigma among health care workers. Few studies have been conducted in the United States. We used a validated instrument to survey 330 health care workers in Washington, DC, a high HIV prevalence area. The goal was to obtain data to assess the severity of the problem. We found that stigmatizing beliefs and attitudes were prevalent as reflected in responses from 66% of the participants. Of clinicians surveyed, 31% reported using double gloves. Participants with stigma training had lower stigma levels, whereas older individuals and support staff were more stigmatizing. Negative attitudes affect access to care and have major public health implications.

18.
Neuro Oncol ; 2019 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-30722027

RESUMO

Background: Neurofibromatosis type 1 (NF1) is a tumor-predisposition disorder caused by germline mutations in NF1. NF1 patients have an 8-16% lifetime risk of developing a malignant peripheral nerve sheath tumor (MPNST), a highly-aggressive soft-tissue sarcoma, often arising from pre-existing benign plexiform neurofibromas (PN) and atypical neurofibromas (ANF). ANF are distinct from both PN and MPNST, representing an intermediate step in malignant transformation. Methods: In the first comprehensive genomic analysis of ANF originating from multiple patients, we performed tumor/normal whole-exome sequencing (WES) of 16 ANFs. In addition, we conducted WES of three MPNSTs, copy-number meta-analysis of 26 ANFs and 28 MPNSTs, and whole transcriptome sequencing analysis of five ANFs and five MPNSTs. Results: We identified a low number of mutations (median 1, range 0-5) in the exomes of ANFs (only NF1 somatic mutations were recurrent), and frequent deletions of CDKN2A/B (69%) and SMARCA2 (42%). We determined that polycomb repressor complex 2 (PRC2) genes EED or SUZ12 were frequently mutated, deleted or downregulated in MPNSTs but not in ANFs. Our pilot gene expression study revealed upregulated NRAS, MDM2, CCND1/2/3 and CDK4/6 in ANFs and MPNSTs, and overexpression of EZH2 in MPNSTs only. Conclusions: The PN-ANF transition is primarily driven by the deletion of CDKN2A/B. Further progression from ANF to MPNST likely involves broad chromosomal rearrangements and frequent inactivation of the PRC2 genes, loss of the DNA repair genes, and copy-number increase of signal transduction, cell cycle and pluripotency self-renewal genes.

19.
Artigo em Inglês | MEDLINE | ID: mdl-30763917

RESUMO

ß-lactoglobulin (BLG) is a well characterized milk protein and a model for folding and aggregation studies. Rutin is a quercetin based-flavanoid and a famous dietary supplement. It is a potential protector from coronary heart disease, cancers, and inflammatory bowel disease. In this study, amyloid fibrillation is reported in BLG at pH 2.0 and temperature 358 K. It is inhibited to some extent by rutin with a rate of 99.3 h-1 M-1. Amyloid fibrillation started taking place after 10 h of incubation and completed near 40 h at a rate of 16.6 × 10-3 h-1, with a plateau during 40-108 h. Disruption of tertiary structure of BLG and increased solvent accessibility of hydrophobic core seem to trigger intermolecular assembly. Increase in 7% ß-sheet structure at the cost of 10% α-helical structures and the electron micrograph of BLG fibrils at 108 h further support the formation of amyloid. Although it could not block amyloidosis completely, and even the time required to reach plateau remains the same, a decrease of growth rate from 16.6 × 10-3 to 13.5 × 10-3 h-1 was observed in the presence of 30.0 µM rutin. Rutin seems to block solvent accessibility of the hydrophobic core of BLG. A decrease in the fibril population was observed in electron micrographs, with the increase in rutin concentration. All evidences indicate reversal of fibrillation in BLG in the presence of rutin.


Assuntos
Amiloide/química , Lactoglobulinas/química , Quercetina/química , Rutina/química , Animais , Bovinos , Concentração de Íons de Hidrogênio , Domínios Proteicos , Estrutura Secundária de Proteína
20.
Int J Biol Macromol ; 127: 297-305, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30654033

RESUMO

Allura red (AR) is an artificial azo dye mostly used in food industries and has potential health risks. We examined the role of AR in amyloidogenesis using hen egg white lysozyme (HEWL) at pH 7.0. The amyloidogenic induction properties of AR in HEWL were identified by circular dichroism (CD), turbidity, intrinsic fluorescence, light scattering, transmission electron microscopy (TEM), and molecular dynamic simulation studies. Turbidity and light scattering measurements showed that HEWL becomes aggregated in the presence of 0.03-15.0 mM of AR at pH 7.0 but not at very low AR concentrations (0.01-0.28 mM). However, AR-induced aggregation is a kinetically rapid process, with no observable lag phase and saturation within 6 s. The kinetics results suggested that the HEWL aggregation induced by AR is very rapid. The CD results demonstrated that the total ß-sheet content of HEWL was increased in the AR treated samples. The TEM results are established that AR-induced aggregates had amyloid-like structures. Molecular dynamics simulations analysis showed that the bound AR-HEWL structures were highly favored compared to unbound structures. The mechanism of AR-induced amyloid fibril formation may involve electrostatic, hydrogen bonding, and hydrophobic interactions.


Assuntos
Amiloide/química , Compostos Azo/química , Muramidase/química , Agregados Proteicos , Animais , Galinhas , Concentração de Íons de Hidrogênio , Domínios Proteicos , Estrutura Quaternária de Proteína
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