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1.
Infect Agent Cancer ; 19(1): 21, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38693556

ABSTRACT

AIMS: This study compared the prevalences of metabolic syndrome and of cardiac or kidney comorbidities among patients with hepatocellular carcinoma (HCC) associated with metabolic dysfunction-related fatty liver disease (MAFLD), chronic infection with hepatitis B or C virus (HBV or HCV), or the combination of MAFLD and chronic HBV infection. METHODS: Medical records were retrospectively analyzed for patients with HCC who underwent hepatectomy between March 2013 and March 2023. Patients with HCC of different etiologies were compared in terms of their clinicodemographic characteristics and laboratory data before surgery. RESULTS: Of the 2422 patients, 1,822 (75.2%) were chronically infected with HBV without MAFLD and HCV, 415 (17.2%) had concurrent MAFLD and chronic HBV infection but no HCV infection, 121 (5.0%) had MAFLD without hepatitis virus infection, and 64 (2.6%) were chronically infected with HCV in the presence or absence of MAFLD and HBV infection. Compared to patients chronically infected with HBV without MAFLD and HCV, those with MAFLD but no hepatitis virus infection showed significantly lower prevalence of cirrhosis, ascites, portal hypertension, alpha-fetoprotein concentration ≥ 400 ng/mL, tumor size > 5 cm, multinodular tumors and microvascular invasion. Conversely, they showed significantly higher prevalence of metabolic syndrome, hypertension, type 2 diabetes, abdominal obesity, history of cardiovascular disease, T-wave alterations, hypertriglyceridemia and hyperuricemia, as well as higher risk of arteriosclerotic cardiovascular disease. Compared to patients with MAFLD but no hepatitis virus infection, those with concurrent MAFLD and chronic infection with HBV showed significantly higher prevalence of cirrhosis, ascites and portal hypertension, but significantly lower prevalence of hypertension and history of cardiovascular disease. Compared to patients with other etiologies, those chronically infected with HCV in the presence or absence of MAFLD and HBV infection, showed significantly higher prevalence of cirrhosis, portal hypertension, ascites, and esophagogastric varices. CONCLUSION: Patients with HCC associated with MAFLD tend to have a background of less severe liver disease than those with HCC of other etiologies, but they may be more likely to suffer metabolic syndrome or comorbidities affecting the heart or kidneys.

2.
Comput Struct Biotechnol J ; 24: 247-257, 2024 Dec.
Article in English | MEDLINE | ID: mdl-38617891

ABSTRACT

Objectives: Combination therapy of lenvatinib and immune checkpoint inhibitors (CLICI) has emerged as a promising approach for managing unresectable hepatocellular carcinoma (HCC). However, the response to such treatment is observed in only a subset of patients, underscoring the pressing need for reliable methods to identify potential responders. Materials & methods: This was a retrospective analysis involving 120 patients with unresectable HCC. They were divided into training (n = 72) and validation (n = 48) cohorts. We developed an interpretable deep learning model using multiphase computed tomography (CT) images to predict whether patients will respond or not to CLICI treatment, based on the Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1). We evaluated the models' performance and analyzed the impact of each CT phase. Critical regions influencing predictions were identified and visualized through heatmaps. Results: The multiphase model outperformed the best biphase and uniphase models, achieving an area under the curve (AUC) of 0.802 (95% CI = 0.780-0.824). The portal phase images were found to significantly enhance the model's predictive accuracy. Heatmaps identified six critical features influencing treatment response, offering valuable insights to clinicians. Additionally, we have made this model accessible via a web server at http://uhccnet.com/ for ease of use. Conclusions: The integration of multiphase CT images with deep learning-generated heatmaps for predicting treatment response provides a robust and practical tool for guiding CLICI therapy in patients with unresectable HCC.

3.
Hepatol Int ; 18(1): 73-90, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38159218

ABSTRACT

PURPOSE: Cytokeratin 19-positive cancer stem cells (CK19 + CSCs) and their tumor-associated macrophages (TAMs) have not been fully explored yet in the hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). EXPERIMENTAL DESIGN: Single-cell RNA sequencing was performed on the viable cells obtained from 11 treatment-naïve HBV-associated HCC patients, including 8 CK19 + patients, to elucidate their transcriptomic landscape, CK19 + CSC heterogeneity, and immune microenvironment. Two in-house primary HCC cohorts (96 cases-related HBV and 89 cases with recurrence), TCGA external cohort, and in vitro and in vivo experiments were used to validate the results. RESULTS: A total of 64,581 single cells derived from the human HCC and adjacent normal tissues were sequenced, and 11 cell types were identified. The result showed that CK19 + CSCs were phenotypically and transcriptionally heterogeneous, co-expressed multiple hepatics CSC markers, and were positively correlated with worse prognosis. Moreover, the SPP1 + TAMs (TAM_SPP1) with strong M2-like features and worse prognosis were specifically enriched in the CK19 + HCC and promoted tumor invasion and metastasis by activating angiogenesis. Importantly, matrix metalloproteinase 9 (MMP9) derived from TAM_SPP1, as the hub gene of CK19 + HCC, was activated by the VEGFA signal. CONCLUSIONS: This study revealed the heterogeneity and stemness characteristics of CK19 + CSCs and specific immunosuppressive TAM_SPP1 in CK19 + HCC. The VEGFA signal can activate TAM_SPP1-derived MMP9 to promote the invasion and metastasis of CK19 + HCC tumors. This might provide novel insights into the clinical treatment of HCC patients.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Humans , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , Hepatitis B virus/genetics , Matrix Metalloproteinase 9/genetics , Keratin-19/genetics , Keratin-19/metabolism , Tumor-Associated Macrophages/metabolism , Tumor-Associated Macrophages/pathology , Neoplastic Stem Cells , Sequence Analysis, RNA , Tumor Microenvironment , Osteopontin/genetics , Osteopontin/metabolism
4.
bioRxiv ; 2023 Mar 20.
Article in English | MEDLINE | ID: mdl-36993586

ABSTRACT

Metastasis to the cerebrospinal fluid (CSF)-filled leptomeninges, or leptomeningeal metastasis (LM), represents a fatal complication of cancer. Proteomic and transcriptomic analyses of human CSF reveal a substantial inflammatory infiltrate in LM. We find the solute and immune composition of CSF in the setting of LM changes dramatically, with notable enrichment in IFN-γ signaling. To investigate the mechanistic relationships between immune cell signaling and cancer cells within the leptomeninges, we developed syngeneic lung, breast, and melanoma LM mouse models. Here we show that transgenic host mice, lacking IFN-γ or its receptor, fail to control LM growth. Overexpression of Ifng through a targeted AAV system controls cancer cell growth independent of adaptive immunity. Instead, leptomeningeal IFN-γ actively recruits and activates peripheral myeloid cells, generating a diverse spectrum of dendritic cell subsets. These migratory, CCR7+ dendritic cells orchestrate the influx, proliferation, and cytotoxic action of natural killer cells to control cancer cell growth in the leptomeninges. This work uncovers leptomeningeal-specific IFN-γ signaling and suggests a novel immune-therapeutic approach against tumors within this space.

5.
Expert Rev Gastroenterol Hepatol ; 17(5): 499-507, 2023 May.
Article in English | MEDLINE | ID: mdl-36975382

ABSTRACT

OBJECTIVES: To analyze prognostic value of total tumor volume (TTV) and tumor burden score (TBS) in surgically treated patients with hepatocellular carcinoma and concurrent fatty liver disease and hepatitis B virus (FLD-HCC). METHODS: FLD-HCC patients who treated with hepatectomy from 2010 to 2018 were analyzed. Prognostic performance of TTV and TBS was determined by ROC analysis. Patients were stratified into low and high tumor burden by optimal cutoff value of 113.4 cm3 for TTV or 6.3 points for TBS. Survival rates were compared between subgroups and independent risk factors were identified by Cox regression. Correlation between TTV and TBS was evaluated. RESULTS: This study enrolled 342 FLD-HCC patients. Survival was significantly higher among patients with low tumor burden than among those with high tumor burden (p < 0.001). High TTV and TBS were independent risk factors for poor survival of FLD-HCC (HR: 3.27 (2.17-4.93) and 3.48 (2.31-5.26), respectively, all p < 0.001). ROC analyses revealed that TTV and TBS had comparable discriminative ability in stratifying overall and recurrence-free survival of FLD-HCC. Correlation analysis revealed a strong correlation between TTV and TBS. CONCLUSIONS: Both TTV and TBS have comparable prognostic value and high TTV/TBS predicts poor survival of patients with FLD-HCC.


Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Non-alcoholic Fatty Liver Disease , Humans , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , Hepatitis B virus , Tumor Burden , Survival Rate , Retrospective Studies , Prognosis , Non-alcoholic Fatty Liver Disease/complications , Non-alcoholic Fatty Liver Disease/diagnosis , Non-alcoholic Fatty Liver Disease/surgery , Hepatectomy
6.
PLoS Negl Trop Dis ; 17(1): e0011012, 2023 01.
Article in English | MEDLINE | ID: mdl-36638133

ABSTRACT

BACKGROUND: This study aimed to determine the impact of co-infection of Clonorchis sinensis (CS) and hepatitis B virus (HBV) on the prognosis of patients with hepatocellular carcinoma (HCC) following hepatectomy. METHODS: The clinicopathological information of 946 patients with HCC following hepatectomy was retrospectively analyzed. The patients were divided into four groups depending on whether they had CS infection and/or HBV infection: double-negative group (infected with neither CS nor HBV), simple CS group (infected with only CS), simple HBV group (infected with only HBV), and double-positive group (co-infected with CS and HBV). Kaplan-Meier curves were used to evaluate the overall survival (OS) and recurrence-free survival (RFS), while log-rank tests were used to compare survival rates. Further, Cox regression was used to perform both univariate and multivariate survival analyses to identify variables linked to the prognosis of HCC. RESULTS: The median overall survival (OS) and recurrence-free survival (RFS) in the double-positive, simple CS, simple HBV, and double-negative groups were 27 months and 9 months, 20 months and 7 months, 44 months and 12 months, and 42 months and 17 months, respectively. The double-positive group's 1-year, 3-year, and 5-year OS and RFS rates were 79.2% and 46.9%, 62.6% and 28.4%, 47.8%, and 12.2%, respectively. The simple CS group's 1-year, 3-year, and 5-year OS and RFS rates were 86.3% and 41.5%, 56.5% and 27.7%, 50.2%, and 18.5%, respectively. The simple HBV group's 1-year, 3-year, and 5-year OS and RFS rates were 89.8% and 56.0%, 72.5% and 30.5%, 63.8%, and 19.9%, respectively. The double-negative group's 1-year, 3-year, and 5-year OS and RFS rates were 91.5% and 62.3%, 76.1% and 32.9%, 64.0%, and 22.4%, respectively. Further, according to a Cox multivariate analysis, tumor size (> 5cm), Edmonson grade (III-IV), BCLC-C stage, and tumor satellite focus were independent risk factors for RFS and OS in patients with HCC. CONCLUSION: Patients with HCC and Clonorchis sinensis infection experience a poor prognosis after hepatectomy, regardless of whether they are co-infected with HBV.


Subject(s)
Carcinoma, Hepatocellular , Clonorchis sinensis , Hepatitis B , Liver Neoplasms , Humans , Animals , Carcinoma, Hepatocellular/surgery , Carcinoma, Hepatocellular/pathology , Hepatitis B virus , Liver Neoplasms/complications , Liver Neoplasms/surgery , Retrospective Studies , Hepatectomy , Disease-Free Survival , Prognosis , Hepatitis B/complications
7.
Neurotherapeutics ; 19(6): 1782-1798, 2022 10.
Article in English | MEDLINE | ID: mdl-35790709

ABSTRACT

Leptomeningeal metastases arise from cancer cell entry into the subarachnoid space, inflicting significant neurologic morbidity and mortality across a wide range of malignancies. The modern era of cancer therapeutics has seen an explosion of molecular-targeting agents and immune-mediated strategies for patients with breast, lung, and melanoma malignancies, with meaningful extracranial disease control and improvement in patient survival. However, the clinical efficacy of these agents in those with leptomeningeal metastases remains understudied, due to the relative rarity of this patient population, the investigational challenges associated with studying this dynamic disease state, and brisk disease pace. Nevertheless, retrospective studies, post hoc analyses, and small prospective trials in the last two decades provide a glimmer of hope for patients with leptomeningeal metastases, suggesting that several cancer-directed strategies are not only active in the intrathecal space but also improve survival against historical odds. The continued development of clinical trials devoted to patients with leptomeningeal metastases is critical to establish robust efficacy outcomes in this patient population, define drug pharmacokinetics in the intrathecal space, and uncover new avenues for treatment in the face of leptomeningeal therapeutic resistance.


Subject(s)
Meningeal Neoplasms , Humans , Meningeal Neoplasms/drug therapy , Meningeal Neoplasms/pathology , Retrospective Studies , Prospective Studies , Treatment Outcome
8.
Curr Oncol Rep ; 24(3): 343-350, 2022 03.
Article in English | MEDLINE | ID: mdl-35138599

ABSTRACT

PURPOSE OF REVIEW: The goal of this paper is to provide a review on the current emerging management strategies as described in the literature pertaining to breast cancer and central nervous system metastases. As systemic oncology treatments evolve, so are new approaches to the management of central nervous system metastases from breast cancer. RECENT FINDINGS: In this review, we describe how novel treatment strategies have evolved from standard chemotherapy to more targeted approaches, innovative drug delivery methodologies, immunotherapeutics, and radiotherapeutic approaches. We describe innovative treatment strategies on the horizon for breast cancer and central nervous metastases. Future therapeutics may be better able to penetrate through the blood-brain-barrier bypassing limitations from standard therapies. These pioneering strategies will hopefully improve patients' quality of life as well as survival.


Subject(s)
Brain Neoplasms , Breast Neoplasms , Central Nervous System Neoplasms , Neoplasms, Second Primary , Brain Neoplasms/drug therapy , Breast Neoplasms/drug therapy , Central Nervous System/pathology , Central Nervous System Neoplasms/therapy , Female , Humans , Quality of Life
9.
J Gastroenterol Hepatol ; 37(5): 782-794, 2022 May.
Article in English | MEDLINE | ID: mdl-35080052

ABSTRACT

BACKGROUND AND AIM: Previous smaller meta-analyses comparing the incidence of hepatocellular carcinoma (HCC) in chronic hepatitis B (CHB) patients treated with tenofovir disoproxil fumarate (TDF) versus entecavir (ETV) provided controversial results. This updated meta-analysis aimed to reliably identify any difference in the HCC incidence between TDF-treated or ETV-treated CHB patients in general or in specific subgroups. METHODS: PubMed, EMBASE, Web of Science, and Cochrane Library were systematically searched for relevant studies with hazard ratios (HRs) for HCC between TDF-treated and ETV-treated CHB patients. Retrieved dates ranged from January 2009 to October 2021. HRs with or without adjustment were pooled with random-effects model. RESULTS: Twenty-four comparative studies involving 37 771 CHB patients treated with TDF and 72 094 treated with ETV were included. TDF was associated with lower risk of HCC compared with ETV, with pooled unadjusted HR of 0.76 (95% confidence interval [CI]: 0.67-0.86) (24 studies) and adjusted HR of 0.81 (95% CI: 0.72-0.91) (21 studies). In propensity score matching cohorts, the TDF superiority was confirmed for unadjusted HR 0.83 (95% CI: 0.71-0.97) (14 studies) and was close to significance for adjusted HR (0.78, 95% CI: 0.58-1.04) (8 studies). Subgroup analyses showed that TDF was associated with lower HCC risk than ETV treatment in CHB patients who were from Asia (adjusted HR: 0.76, 95% CI: 0.66-0.87; 15 studies) or nucleos(t)ide naïve (adjusted HR:0.74, 95% CI: 0.65-0.84; 18 studies). CONCLUSION: Current evidence from a sizable population suggests that TDF is associated with significantly lower HCC risk compared with ETV treatment in patients who are from Asia and/or nucleos(t)ide naïve.


Subject(s)
Carcinoma, Hepatocellular , Hepatitis B, Chronic , Liver Neoplasms , Antiviral Agents/therapeutic use , Carcinoma, Hepatocellular/epidemiology , Carcinoma, Hepatocellular/etiology , Carcinoma, Hepatocellular/prevention & control , Guanine/analogs & derivatives , Hepatitis B, Chronic/complications , Hepatitis B, Chronic/drug therapy , Humans , Liver Neoplasms/epidemiology , Liver Neoplasms/etiology , Liver Neoplasms/prevention & control , Retrospective Studies , Tenofovir/therapeutic use , Treatment Outcome
10.
J Neuroimmunol ; 361: 577727, 2021 12 15.
Article in English | MEDLINE | ID: mdl-34688068

ABSTRACT

Meninges, or the membranous coverings of the brain and spinal cord, play host to dozens of morbid pathologies. In this study we provide a method to isolate the leptomeningeal cell layer, identify leptomeninges in histologic slides, and maintain leptomeningeal fibroblasts in in vitro culture. Using an array of transcriptomic, histological, and cytometric analyses, we identified ICAM1 and SLC38A2 as two novel markers of leptomeningeal cells in vivo and in vitro. Our results confirm the fibroblastoid nature of leptomeningeal cells and their ability to form a sheet-like layer that covers the brain and spine parenchyma. These findings will enable researchers in central nervous system barriers to describe leptomeningeal cell functions in health and disease.


Subject(s)
Fibroblasts/cytology , Meninges/cytology , Adult , Aged , Amino Acid Transport System A/analysis , Amino Acid Transport System A/biosynthesis , Amino Acid Transport System A/genetics , Animals , Base Sequence , Biomarkers , Cell Separation , Cells, Cultured , Child, Preschool , Female , Fibroblasts/metabolism , Humans , Intercellular Adhesion Molecule-1/analysis , Intercellular Adhesion Molecule-1/biosynthesis , Intercellular Adhesion Molecule-1/genetics , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Microdissection , Middle Aged , Primary Cell Culture , Staining and Labeling/methods , Transcriptome
11.
Acta Pharmacol Sin ; 41(9): 1167-1177, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32737471

ABSTRACT

Human infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) and there is no cure currently. The 3CL protease (3CLpro) is a highly conserved protease which is indispensable for CoVs replication, and is a promising target for development of broad-spectrum antiviral drugs. In this study we investigated the anti-SARS-CoV-2 potential of Shuanghuanglian preparation, a Chinese traditional patent medicine with a long history for treating respiratory tract infection in China. We showed that either the oral liquid of Shuanghuanglian, the lyophilized powder of Shuanghuanglian for injection or their bioactive components dose-dependently inhibited SARS-CoV-2 3CLpro as well as the replication of SARS-CoV-2 in Vero E6 cells. Baicalin and baicalein, two ingredients of Shuanghuanglian, were characterized as the first noncovalent, nonpeptidomimetic inhibitors of SARS-CoV-2 3CLpro and exhibited potent antiviral activities in a cell-based system. Remarkably, the binding mode of baicalein with SARS-CoV-2 3CLpro determined by X-ray protein crystallography was distinctly different from those of known 3CLpro inhibitors. Baicalein was productively ensconced in the core of the substrate-binding pocket by interacting with two catalytic residues, the crucial S1/S2 subsites and the oxyanion loop, acting as a "shield" in front of the catalytic dyad to effectively prevent substrate access to the catalytic dyad within the active site. Overall, this study provides an example for exploring the in vitro potency of Chinese traditional patent medicines and effectively identifying bioactive ingredients toward a specific target, and gains evidence supporting the in vivo studies of Shuanghuanglian oral liquid as well as two natural products for COVID-19 treatment.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections , Drugs, Chinese Herbal , Flavanones , Flavonoids , Pandemics , Pneumonia, Viral , Virus Replication/drug effects , Administration, Oral , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Betacoronavirus/physiology , COVID-19 , Chlorocebus aethiops , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/pharmacology , Enzyme Assays , Flavanones/chemistry , Flavanones/pharmacokinetics , Flavonoids/chemistry , Flavonoids/pharmacokinetics , Humans , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , SARS-CoV-2 , Vero Cells , Virus Replication/physiology
13.
Opt Lett ; 43(11): 2656-2659, 2018 Jun 01.
Article in English | MEDLINE | ID: mdl-29856389

ABSTRACT

A comparative stability analysis of Ince-Gaussian and Hermite-Gaussian modes in elliptical core few-mode fibers is provided to inform the design of spatial division multiplexing systems. The correlation method is used to construct crosstalk matrices that characterize the spatial modes of the fiber. Up to six low-order modes are shown to exhibit about -20 dB crosstalk. The crosstalk performance of each mode set is found to be similar. However, a direct comparison between modes of equal Gouy phase shift, a parameter that ensures identical beam quality, and phase at the detector, demonstrates better relative power transmission for Ince-Gaussian beams. This result is consistent with the natural modes supported by a 100 m elliptical core fiber for which a mode ellipticity of ϵ=2 was found to be optimal. The relative power difference is expected to be magnified over longer fiber lengths in favor of Ince-Gaussian modes.

14.
Sci Rep ; 7(1): 6196, 2017 07 21.
Article in English | MEDLINE | ID: mdl-28733604

ABSTRACT

TDP-43 is a nuclear factor that functions in promoting pre-mRNA splicing. Deletion of the N-terminal domain (NTD) and nuclear localization signal (NLS) (i.e., TDP-35) results in mislocalization to cytoplasm and formation of inclusions. However, how the NTD functions in TDP-43 activity and proteinopathy remains largely unknown. Here, we studied the structure and function of the NTD in inclusion formation and pre-mRNA splicing of TDP-43 by using biochemical and biophysical approaches. We found that TDP-43 NTD forms a homodimer in solution in a concentration-dependent manner, and formation of intermolecular disulfide results in further tetramerization. Based on the NMR structure of TDP-43 NTD, the dimerization interface centered on Leu71 and Val72 around the ß7-strand was defined by mutagenesis and size-exclusion chromatography. Cell experiments revealed that the N-terminal dimerization plays roles in protecting TDP-43 against formation of cytoplasmic inclusions and enhancing pre-mRNA splicing activity of TDP-43 in nucleus. This study may provide mechanistic insights into the physiological function of TDP-43 and its related proteinopathies.


Subject(s)
DNA-Binding Proteins/chemistry , DNA-Binding Proteins/genetics , RNA Splicing , Chromatography, Gel , Cytoplasm/metabolism , Disulfides/metabolism , HEK293 Cells , Humans , Models, Molecular , Mutation , Protein Multimerization , Protein Structure, Secondary
15.
Nucleic Acids Res ; 45(21): 12551-12564, 2017 12 01.
Article in English | MEDLINE | ID: mdl-30053256

ABSTRACT

RecJ nucleases specifically degrade single-stranded (ss) DNA in the 5' to 3' direction. Archaeal RecJ is different from bacterial RecJ in sequence, domain organization, and substrate specificity. The RecJ from archaea Pyrococcus furiosus (PfuRecJ) also hydrolyzes RNA strands in the 3' to 5' direction. Like eukaryotic Cdc45 protein, archaeal RecJ forms a complex with MCM helicase and GINS. Here, we report the crystal structures of PfuRecJ and the complex of PfuRecJ and two CMPs. PfuRecJ bind one or two divalent metal ions in its crystal structure. A channel consisting of several positively charged residues is identified in the complex structure, and might be responsible for binding substrate ssDNA and/or releasing single nucleotide products. The deletion of the complex interaction domain (CID) increases the values of kcat/Km of 5' exonuclease activity on ssDNA and 3' exonuclease activity on ssRNA by 5- and 4-fold, respectively, indicating that the CID functions as a regulator of enzymatic activity. The DHH domain of PfuRecJ interacts with the C-terminal beta-sheet domain of the GINS51 subunit in the tetrameric GINS complex. The relationship of archaeal and bacterial RecJs, as well as eukaryotic Cdc45, is discussed based on biochemical and structural results.


Subject(s)
Bacterial Proteins/chemistry , Exodeoxyribonucleases/chemistry , Pyrococcus furiosus/enzymology , Amino Acid Motifs , Amino Acid Sequence , Bacterial Proteins/physiology , Cations , Cell Cycle Proteins , Conserved Sequence , Crystallography, X-Ray , DNA Repair , DNA Replication , DNA, Bacterial/metabolism , DNA, Single-Stranded/metabolism , DNA-Binding Proteins/metabolism , Evolution, Molecular , Exodeoxyribonucleases/physiology , Models, Molecular , Multiprotein Complexes/metabolism , Phosphodiesterase I/metabolism , Protein Binding , Protein Conformation , Protein Domains , Sequence Alignment , Sequence Homology, Amino Acid
16.
Acta Crystallogr D Biol Crystallogr ; 68(Pt 1): 13-25, 2012 Jan.
Article in English | MEDLINE | ID: mdl-22194329

ABSTRACT

ß-Secretase (ß-site amyloid precursor protein-cleaving enzyme 1; BACE1) is a transmembrane aspartic protease that cleaves the ß-amyloid precursor protein en route to generation of the amyloid ß-peptide (Aß) that is believed to be responsible for the Alzheimer's disease amyloid cascade. It is thus a prime target for the development of inhibitors which may serve as drugs in the treatment and/or prevention of Alzheimer's disease. In the following determination of the crystal structures of both apo and complexed BACE1, structural analysis of all crystal structures of BACE1 deposited in the PDB and molecular dynamics (MD) simulations of monomeric and `dimeric' BACE1 were used to study conformational changes in the active-site region of the enzyme. It was observed that a flap able to cover the active site is the most flexible region, adopting multiple conformational states in the various crystal structures. Both the presence or absence of an inhibitor within the active site and the crystal packing are shown to influence the flap's conformation. An open conformation of the flap is mostly observed in the apo structures, while direct hydrogen-bonding interaction between main-chain atoms of the flap and the inhibitor is a prerequisite for the flap to adopt a closed conformation in the crystal structures of complexes. Thus, a systematic study of the conformational flexibility of the enzyme may not only contribute to structure-based drug design of BACE1 inhibitors and of other targets with flexible conformations, but may also help to better understand the mechanistic events associated with the binding of substrates and inhibitors to the enzyme.


Subject(s)
Amyloid Precursor Protein Secretases/chemistry , Aspartic Acid Endopeptidases/chemistry , Catalytic Domain , Crystallography, X-Ray , Humans , Hydrogen Bonding , Ligands , Models, Molecular , Molecular Dynamics Simulation , Protein Structure, Quaternary
17.
J Med Chem ; 54(10): 3575-80, 2011 May 26.
Article in English | MEDLINE | ID: mdl-21473635

ABSTRACT

Selective estrogen receptor modulators, such as 17ß-estradiol derivatives bound to metal complexes, have been synthesized as targeted probes for the diagnosis and treatment of breast cancer. Here, we report the detailed 3D structure of estrogen receptor α ligand-binding domain (ERα-LBD) bound with a novel estradiol-derived metal complex, estradiol-pyridine tetra acetate europium(III), at 2.6 Å resolution. This structure provides important information pertinent to the design of novel functional ERα targeted probes for clinical applications.


Subject(s)
Chelating Agents/chemistry , Estradiol/chemistry , Estrogen Receptor alpha/antagonists & inhibitors , Metals/chemistry , Selective Estrogen Receptor Modulators/pharmacology , Chemistry, Pharmaceutical/methods , Crystallography, X-Ray/methods , Dimerization , Europium/chemistry , Humans , Ligands , Models, Chemical , Molecular Conformation , Protein Binding , Protein Structure, Tertiary , Selective Estrogen Receptor Modulators/chemistry
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