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31.
Nadia Mousavi Shahrzad Rahimi Hanane Emami Amir Hossein Kazemi Rana Mohammad Taghi Kashi Ronak Heidarian 《Reports of Biochemistry & Molecular Biology》2021,10(1):69
Background:Prostate cancer (PCa) is the second leading cause of cancer death in American population. In this manner, novel therapeutic approaches for identification of therapeutic targets for PCa has significant clinical implications. Quercetin is a potent cancer therapeutic agent and dietary antioxidant present in fruit and vegetables.Methods:To investigate the underlying mechanism by which the PCa was regulated, nanoparticles of quercetin were administrated to cells. For in vitro experiments, human PCa cell line LNCaP were involved. Cell viability assay and quantitative RT-PCR (qRT-PCR) for hedgehog signaling pathway genes were used to determine the key signaling pathway regulated for PCa progression.Results:The cell viability gradually decreased with increased concentration of quercetin nanoparticles. At 48 h, 40 mM concentration of quercetin treatment showed near 50% of viable cells. Quercetin nanoparticles upregulates Su(Fu) mRNA expressions and downregulates gli mRNA expressions in the LNCaP cells.Conclusion:The results showed that the hedgehog signaling targeted inhibition may have important implications of PCa therapeutics. Additionally, the outcomes provided new mechanistic basis for further examination of quercetin nanoparticles to discover potential treatment strategies and new targets for PCa inhibition.Key Words: Hedgehog, Prostate cancer, Proliferation, Quercetin nanoparticles, Signaling pathway 相似文献
32.
Human small heat shock protein 27 (Hsp27) undergoes concentration-dependent equilibrium dissociation from an ensemble of large oligomers to a dimer. This phenomenon plays a critical role in Hsp27 chaperone activity in vitro enabling high affinity binding to destabilized proteins. In vivo dissociation, which is regulated by phosphorylation, controls Hsp27 role in signaling pathways. In this study, we explore the sequence determinants of Hsp27 dissociation and define the structural basis underlying the increased affinity of Hsp27 dimers to client proteins. A systematic cysteine mutagenesis is carried out to identify residues in the N-terminal domain important for the equilibrium between Hsp27 oligomers and dimers. In addition, spin-labels were attached to the cysteine mutants to enable electron paramagnetic resonance (EPR) analysis of residue environment and solvent accessibility in the context of the large oligomers, upon dissociation to the dimer, and following complex formation with the model substrate T4 Lysozyme (T4L). The mutagenic analysis identifies residues that modulate the equilibrium dissociation in favor of the dimer. EPR analysis reveals that oligomer dissociation disrupts subunit contacts leading to the exposure of Hsp27 N-terminal domain to the aqueous solvent. Moreover, regions of this domain are highly dynamic with no evidence of a packed core. Interaction between T4L and sequences in this domain is inferred from transition of spin-labels to a buried environment in the substrate/Hsp27 complex. Together, the data provide the first structural analysis of sHSP dissociation and support a model of chaperone activity wherein unstructured and highly flexible regions in the N-terminal domain are critical for substrate binding. 相似文献
33.
Jian Shi Hanane A. Koteiche Ezelle T. McDonald Tara L. Fox Phoebe L. Stewart Hassane S. Mchaourab 《The Journal of biological chemistry》2013,288(7):4819-4830
Small heat shock proteins (sHSPs) are ubiquitous chaperones that bind and sequester non-native proteins preventing their aggregation. Despite extensive studies of sHSPs chaperone activity, the location of the bound substrate within the sHSP oligomer has not been determined. In this paper, we used cryoelectron microscopy (cryoEM) to visualize destabilized mutants of T4 lysozyme (T4L) bound to engineered variants of the small heat shock protein Hsp16.5. In contrast to wild type Hsp16.5, binding of T4L to these variants does not induce oligomer heterogeneity enabling cryoEM analysis of the complexes. CryoEM image reconstruction reveals the sequestration of T4L in the interior of the Hsp16.5 oligomer primarily interacting with the buried N-terminal domain but also tethered by contacts with the α-crystallin domain shell. Analysis of Hsp16.5-WT/T4L complexes uncovers oligomer expansion as a requirement for high affinity binding. In contrast, a low affinity mode of binding is found to involve T4L binding on the outer surface of the oligomer bridging the formation of large complexes of Hsp16.5. These mechanistic principles were validated by cryoEM analysis of an expanded variant of Hsp16.5 in complex with T4L and Hsp16.5-R107G, which is equivalent to a mutant of human αB-crystallin linked to cardiomyopathy. In both cases, high affinity binding is found to involve conformational changes in the N-terminal region consistent with a central role of this region in substrate recognition. 相似文献
34.
Mushrush DJ Koteiche HA Sammons MA Link AJ McHaourab HS Lacy DB 《The Journal of biological chemistry》2011,286(30):27011-27018
Botulinum neurotoxin (BoNT) belongs to a large class of toxic proteins that act by enzymatically modifying cytosolic substrates within eukaryotic cells. The process by which a catalytic moiety is transferred across a membrane to enter the cytosol is not understood for any such toxin. BoNT is known to form pH-dependent pores important for the translocation of the catalytic domain into the cytosol. As a first step toward understanding this process, we investigated the mechanism by which the translocation domain of BoNT associates with a model liposome membrane. We report conditions that allow pH-dependent proteoliposome formation and identify a sequence at the translocation domain C terminus that is protected from proteolytic degradation in the context of the proteoliposome. Fluorescence quenching experiments suggest that residues within this sequence move to a hydrophobic environment upon association with liposomes. EPR analyses of spin-labeled mutants reveal major conformational changes in a distinct region of the structure upon association and indicate the formation of an oligomeric membrane-associated intermediate. Together, these data support a model of how BoNT orients with membranes in response to low pH. 相似文献
35.
Marco Alifano Audrey Mansuet-Lupo Filippo Lococo Nicolas Roche Antonio Bobbio Emelyne Canny Olivier Schussler Hervé Dermine Jean-Fran?ois Régnard Barbara Burroni Jérémy Goc Jér?me Biton Hanane Ouakrim Isabelle Cremer Marie-Caroline Dieu-Nosjean Diane Damotte 《PloS one》2014,9(9)
Background
Hypothesizing that nutritional status, systemic inflammation and tumoral immune microenvironment play a role as determinants of lung cancer evolution, the purpose of this study was to assess their respective impact on long-term survival in resected non-small cell lung cancers (NSCLC).Methods and Findings
Clinical, pathological and laboratory data of 303 patients surgically treated for NSCLC were retrospectively analyzed. C-reactive protein (CRP) and prealbumin levels were recorded, and tumoral infiltration by CD8+ lymphocytes and mature dendritic cells was assessed. We observed that factors related to nutritional status, systemic inflammation and tumoral immune microenvironment were correlated; significant correlations were also found between these factors and other relevant clinical-pathological parameters. With respect to outcome, at univariate analysis we found statistically significant associations between survival and the following variables: Karnofsky index, American Society of Anesthesiologists (ASA) class, CRP levels, prealbumin concentrations, extent of resection, pathologic stage, pT and pN parameters, presence of vascular emboli, and tumoral infiltration by either CD8+ lymphocytes or mature dendritic cells and, among adenocarcinoma type, tumor grade (all p<0.05). In multivariate analysis, prealbumin levels (Relative Risk (RR): 0.34 [0.16–0.73], p = 0.0056), CD8+ cell count in tumor tissue (RR = 0.37 [0.16–0.83], p = 0.0162), and disease stage (RR 1.73 [1.03–2.89]; 2.99[1.07–8.37], p = 0.0374- stage I vs II vs III-IV) were independent prognostic markers. When taken together, parameters related to systemic inflammation, nutrition and tumoral immune microenvironment allowed robust prognostic discrimination; indeed patients with undetectable CRP, high (>285 mg/L) prealbumin levels and high (>96/mm2) CD8+ cell count had a 5-year survival rate of 80% [60.9–91.1] as compared to 18% [7.9–35.6] in patients with an opposite pattern of values. When stages I-II were considered alone, the prognostic significance of these factors was even more pronounced.Conclusions
Our data show that nutrition, systemic inflammation and tumoral immune contexture are prognostic determinants that, taken together, may predict outcome. 相似文献36.
Hanane Hamdali Mohamed Hafidi Marie Joëlle Virolle Yedir Ouhdouch 《World journal of microbiology & biotechnology》2008,24(11):2565-2575
In order to select Actinobacteria that could improve plant growth and thus agricultural yield, we assessed different plant
growth promoting (PGP) abilities of eight rock phosphate (RP)-solubilizing Actinomycete isolates originating from Moroccan
phosphate mines. Six of these strains were able to grow on root exudates of the wheat plant as sole nutrient sources and were
efficiently releasing soluble phosphate from RP. These strains also inhibited the growth of potentially phytopathogenic fungi,
bacteria (Gram +/−) or yeasts. Five of these strains produced indoleacetic acid and four showed endophytic properties. When
these strains were grown, in the presence of the wheat plant, in a synthetic minimum medium (SMM) containing insoluble RP
as unique phosphate source or in soil experiment, the most active RP-solubilizing strains had the highest stimulatory effect
on the production of plant biomass. The most efficient strain Streptomyces griseus-related strain (BH7), stimulated aerial growth of the plant more than 70% in test tubes and more than 30% in RP soil compared to the non-inoculated
control treatment. This study demonstrated that our selected Actinomycete strains could be used for the development of novel,
non-polluting; farming practices by entering in the formulation of novel biofertilizer and biocontrol products constituted
by spores and/or mycelium of the ad hoc Actinobacteria in association with pulverized RP. 相似文献
37.
Mechanisms of radio-induced apoptosis 总被引:4,自引:0,他引:4
Baatout S Derradji H Petitfour O von Suchodoletz H Mergeay M 《Canadian journal of physiology and pharmacology》2002,80(7):629-637
A general overview of the activation mechanisms of programmed cell death or apoptosis following an irradiation is given in this review. First, are summarized the main induction pathways of radiation-induced apoptosis by which extracellular (tumor necrosis factor (TNF), Fas ligand, TNF-related apoptosis-inducing ligand (TRAIL)) and intracellular (mitochondria and caspases) signals are integrated. A second part is then devoted to the importance of p53 and of its regulators (ATR, ATM, DNA-PKcs) in the process of radiation-induced apoptosis. Thereafter, signal transduction pathways and more specially the role of some protein kinases (MEKK, SAPK/JNK, p38-MAPK) is treated. At last, a chapter concerns the clinical interest of radiation-induced apoptosis and the implication of apoptosis in the treatment of certain diseases. 相似文献
38.
Site-directed spin labeling (SDSL) was used to explore the structural framework responsible for the obligatory drug-proton exchange in the Escherichia coli multidrug transporter, EmrE. For this purpose, a nitroxide scan was carried out along a stretch of 26 residues that include transmembrane segment 1 (TMS1). This segment has been implicated in the catalytic mechanism of EmrE due to the presence of the highly conserved glutamate 14, a residue absolutely required for ligand binding. Sequence-specific variation in the accessibilities of the introduced nitroxides to molecular oxygen reveals a transmembrane helical conformation along TMS1. One face of the helix is in contact with the hydrocarbon interior of the detergent micelle while the other face appears to be solvated by an aqueous environment, resulting in significant exposure of the nitroxides along this face to NiEDDA. TMS1 from two different subunits are in close proximity near a 2-fold axis of symmetry as revealed by the analysis of spin-spin interactions at sites 14 and 18. The limited extent of spin-spin interactions is consistent with a scissor-like packing of the two TMS1. This results in a V-shaped chamber which is in contact with the aqueous phase near the N-terminus. The spatial organization of TMS1, particularly the close proximity of E14, is consistent with a proposed mechanistic model of EmrE [Yerushalmi, H., and Schuldiner, S. (2000) Biochemistry 39, 14711-14719] where substrate extrusion is coupled to proton influx through electrostatic interactions and shifts of the glutamate 14 pK(a) during the cycle. 相似文献
39.
Gheziel Chahira Russo Pasquale Arena Mattia Pia Spano Giuseppe Ouzari Hadda-Imene Kheroua Omar Saidi Djamel Fiocco Daniela Kaddouri Hanane Capozzi Vittorio 《Probiotics and antimicrobial proteins》2019,11(1):113-123
Probiotics and Antimicrobial Proteins - Lactobacilli naturally present in the neonatal gut are believed to be beneficial for the human hosts and are investigated as potential probiotics. In this... 相似文献