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1.
Annu Rev Biochem ; 79: 233-69, 2010.
Article in English | MEDLINE | ID: mdl-20334529

ABSTRACT

Specific interactions between proteins and DNA are fundamental to many biological processes. In this review, we provide a revised view of protein-DNA interactions that emphasizes the importance of the three-dimensional structures of both macromolecules. We divide protein-DNA interactions into two categories: those when the protein recognizes the unique chemical signatures of the DNA bases (base readout) and those when the protein recognizes a sequence-dependent DNA shape (shape readout). We further divide base readout into those interactions that occur in the major groove from those that occur in the minor groove. Analogously, the readout of the DNA shape is subdivided into global shape recognition (for example, when the DNA helix exhibits an overall bend) and local shape recognition (for example, when a base pair step is kinked or a region of the minor groove is narrow). Based on the >1500 structures of protein-DNA complexes now available in the Protein Data Bank, we argue that individual DNA-binding proteins combine multiple readout mechanisms to achieve DNA-binding specificity. Specificity that distinguishes between families frequently involves base readout in the major groove, whereas shape readout is often exploited for higher resolution specificity, to distinguish between members within the same DNA-binding protein family.


Subject(s)
DNA-Binding Proteins/chemistry , DNA-Binding Proteins/metabolism , DNA/chemistry , DNA/metabolism , Base Sequence , Crystallography, X-Ray , Cyclic AMP Receptor Protein/chemistry , Cyclic AMP Receptor Protein/metabolism , Nucleic Acid Conformation , Repressor Proteins/chemistry , Repressor Proteins/metabolism , Viral Regulatory and Accessory Proteins/chemistry , Viral Regulatory and Accessory Proteins/metabolism
2.
BMC Cancer ; 24(1): 776, 2024 Jun 27.
Article in English | MEDLINE | ID: mdl-38937664

ABSTRACT

BACKGROUND: Primary cervical cancer screening and treating precancerous lesions are effective ways to prevent cervical cancer. However, the coverage rates of human papillomavirus (HPV) vaccines and routine screening are low in most developing countries and even some developed countries. This study aimed to explore the benefit of an artificial intelligence-assisted cytology (AI) system in a screening program for a cervical cancer high-risk population in China. METHODS: A total of 1231 liquid-based cytology (LBC) slides from women who underwent colposcopy at the Chinese PLA General Hospital from 2018 to 2020 were collected. All women had received a histological diagnosis based on the results of colposcopy and biopsy. The sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), false-positive rate (FPR), false-negative rate (FNR), overall accuracy (OA), positive likelihood ratio (PLR), negative likelihood ratio (NLR) and Youden index (YI) of the AI, LBC, HPV, LBC + HPV, AI + LBC, AI + HPV and HPV Seq LBC screening strategies at low-grade squamous intraepithelial lesion (LSIL) and high-grade squamous intraepithelial lesion (HSIL) thresholds were calculated to assess their effectiveness. Receiver operating characteristic (ROC) curve analysis was conducted to assess the diagnostic values of the different screening strategies. RESULTS: The Se and Sp of the primary AI-alone strategy at the LSIL and HSIL thresholds were superior to those of the LBC + HPV cotesting strategy. Among the screening strategies, the YIs of the AI strategy at the LSIL + threshold and HSIL + threshold were the highest. At the HSIL + threshold, the AI strategy achieved the best result, with an AUC value of 0.621 (95% CI, 0.587-0.654), whereas HPV testing achieved the worst result, with an AUC value of 0.521 (95% CI, 0.484-0.559). Similarly, at the LSIL + threshold, the LBC-based strategy achieved the best result, with an AUC of 0.637 (95% CI, 0.606-0.668), whereas HPV testing achieved the worst result, with an AUC of 0.524 (95% CI, 0.491-0.557). Moreover, the AUCs of the AI and LBC strategies at this threshold were similar (0.631 and 0.637, respectively). CONCLUSIONS: These results confirmed that AI-only screening was the most authoritative method for diagnosing HSILs and LSILs, improving the accuracy of colposcopy diagnosis, and was more beneficial for patients than traditional LBC + HPV cotesting.


Subject(s)
Artificial Intelligence , Early Detection of Cancer , Papillomavirus Infections , Uterine Cervical Neoplasms , Humans , Female , Uterine Cervical Neoplasms/diagnosis , Uterine Cervical Neoplasms/virology , Uterine Cervical Neoplasms/pathology , Adult , Early Detection of Cancer/methods , Middle Aged , Papillomavirus Infections/diagnosis , Papillomavirus Infections/virology , Colposcopy , China/epidemiology , Sensitivity and Specificity , Uterine Cervical Dysplasia/diagnosis , Uterine Cervical Dysplasia/virology , Uterine Cervical Dysplasia/pathology , Uterine Cervical Dysplasia/epidemiology , Young Adult , ROC Curve , Cytodiagnosis/methods
3.
Ann Hematol ; 103(7): 2445-2454, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38605231

ABSTRACT

BACKGROUND: Real-world data on outcomes of upfront allogeneic hematopoietic stem cell transplantation (allo-HCT) for adult T-cell acute lymphoblastic leukemia/lymphoma (T-ALL) patients in first complete remission (CR1) is still lacking. METHODS: A single center retrospective study was conducted from 94 consecutive patients received their first allo-HCT between 2010 and 2021, which include 76 patients received upfront allo-HCT and 18 patients received allo-HCT in non-upfront settings. RESULTS: There were no significant differences in most variables. In the upfront allo-HCT group, 52 (68%) patients achieved CR1 with one cycle of induction regimen. 24 (32%) patients achieved CR1 with more than one cycle. In the non-upfront group, there were 14 patients with active disease and 4 patients in second CR before transplant. The majority of patients received antithymocyte globulin-based graft-versus-host disease prophylaxis. Median follow-up time was 51 months for both groups. 5-year overall survival (OS) was 54% in the upfront allo-HCT group. While, in the non-upfront group, 5-year OS were 19% (P = 0.013). 5-year progression free survival in the upfront group was higher than that in the non-upfront group (50% versus 20%, P = 0.02). 5-year cumulative incidence relapse rate was significantly higher in non-upfront group (64% vs. 32%, P = 0.006). While, there was no difference in the 5-year non-relapse mortality (NRM) rate (19% versus 16%, P = 0.56). The most common cause of death was disease progression. In multivariable analysis, non-upfront allo-HCT (hazard ratios (HR) 2.14, P = 0.03) and HCT-CI (≥ 2) (HR 6.07, P = 0.002) were identified to be associated with worse OS. Non-upfront allo-HCT and HCT-CI (≥ 2) were also found to be independent risk factors for higher relapse rate. While, haploidentical-HCT was found to be associated with increased NRM. CONCLUSIONS: Our study indicated that allo-HCT remains an important curative treatment for adult patients with T-ALL, especially when it was performed in the upfront setting.


Subject(s)
Hematopoietic Stem Cell Transplantation , Remission Induction , Humans , Adult , Male , Female , Retrospective Studies , Middle Aged , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/therapy , Precursor T-Cell Lymphoblastic Leukemia-Lymphoma/mortality , Young Adult , Transplantation, Homologous , Survival Rate , Aged , Graft vs Host Disease/etiology , Graft vs Host Disease/prevention & control , Adolescent , Allografts , Leukemia-Lymphoma, Adult T-Cell/therapy , Leukemia-Lymphoma, Adult T-Cell/mortality , Follow-Up Studies , Disease-Free Survival
4.
Ann Hematol ; 103(11): 4707-4719, 2024 Nov.
Article in English | MEDLINE | ID: mdl-39243311

ABSTRACT

The prognosis of patients with high-risk acute myeloid leukemia (AML) is dismal even after allogeneic stem cell transplantation (allo-HSCT), with relapse remaining the leading cause of treatment failure. Here, we investigated whether ruxolitinib and decitabine plus modified busulfan-cyclophosphamide (mBu/Cy) conditioning could reduce relapse in high-risk AML after allo-HSCT. This prospective, single-arm, phase II trial enrolled 37 patients who received allo-HSCT between September 2020 and March 2022 at the First Medical Center of Chinese People's Liberation Army (PLA) General Hospital. Eligible patients (10-62 years) had relapsed/refractory, positive measurable residual disease (MRD) prior to conditioning or adverse genetic abnormalities. Ruxolitinib (35 mg twice daily, days - 15 to - 10) and decitabine (20 mg/m2/day, days - 15 to - 10) were administered followed by mBu/Cy conditioning. All patients achieved engraftment. The cumulative incidences (CIs) of acute graft-versus-host disease (GVHD) grades II-IV and III-IV were 35.0% and 10.5%, respectively. The 1-year cumulative incidence of chronic GVHD was 8.1%. The 1-year CI of relapse was 29.7% among all patients, 0% in patients who achieved the first complete remission (CR1) prior to conditioning, and 0% in those with MRD-negative prior to conditioning. The 1-year non-relapse mortality was 5.4%. The 1-year probabilities of overall survival, disease-free survival, and GVHD-free relapse-free survival were 70.3%, 62.2%, and 54.1%, respectively. In conclusion, the novel conditioning showed primary efficacy in terms of a reduction in relapse in high-risk patients with AML after allo-HSCT, especially in those who achieved CR1 and MRD-negative prior to conditioning. Also, the new conditioning regimen may help reduce the incidence of chronic GVHD. ClinicalTrials.gov identifier: NCT04582604.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols , Busulfan , Cyclophosphamide , Decitabine , Hematopoietic Stem Cell Transplantation , Leukemia, Myeloid, Acute , Nitriles , Pyrazoles , Pyrimidines , Transplantation Conditioning , Humans , Decitabine/administration & dosage , Decitabine/therapeutic use , Adult , Leukemia, Myeloid, Acute/therapy , Leukemia, Myeloid, Acute/mortality , Male , Female , Middle Aged , Transplantation Conditioning/methods , Prospective Studies , Busulfan/administration & dosage , Cyclophosphamide/administration & dosage , Cyclophosphamide/therapeutic use , Adolescent , Pyrimidines/administration & dosage , Pyrimidines/therapeutic use , Pyrazoles/administration & dosage , Pyrazoles/therapeutic use , Young Adult , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Nitriles/administration & dosage , Child , Graft vs Host Disease/prevention & control , Graft vs Host Disease/etiology , Recurrence
5.
Am J Hematol ; 98(11): 1732-1741, 2023 11.
Article in English | MEDLINE | ID: mdl-37706580

ABSTRACT

Anti-thymocyte globulin (ATG) is widely used in allogeneic hematopoietic stem cell transplantation to prevent severe graft-versus-host disease (GVHD) and graft failure. However, overexposure to ATG may increase cytomegalovirus (CMV), Epstein-Barr virus (EBV) reactivation, non-relapse mortality, and disease recurrence. To investigate the optimal dosing of ATG, we established a targeted dosing strategy based on ATG concentration monitoring for haploidentical peripheral blood stem cell transplantation (haplo-PBSCT). The aim of this phase 2 trial is to evaluate the safety and efficacy of the ATG-targeted dosing strategy in adult unmanipulated haplo-PBSCT. ATG was administered for 4 days (-5 days to -2 days) during conditioning. The ATG doses on -3 days and -2 days were adjusted by our dosing strategy to achieve the optimal ATG exposure. The primary endpoint was CMV reactivation on +180 days. Between December 2020 and January 2022, 66 haplo-PBSCT patients were enrolled and 63 of them were evaluable with a median follow-up of 632 days. The cumulative incidence of CMV reactivation was 36.7% and that of EBV was 58.7%. The 1-year disease-free survival was 82.5%, overall survival was 92.1%, and CD4+ T-cell reconstruction on +100 days was 76.8%. The most common severe regimen-associated toxicities (> grade 3) were infections (51.5%) and gastrointestinal toxicity (25.5%). A total of 102 haplo-PBSCT patients who received the conventional fixed ATG dose (cumulative 10 mg/kg) comprised historical control. The outcomes in historical control were inferior to those of phase 2 trial cohort (CMV reactivation: 70.8%, p < .001; EBV reactivation: 76.0%, p = .024; CD4 + T-cell reconstruction: 54.1%, p = .040). In conclusion, ATG-targeted dosing strategy reduced CMV/EBV reactivation and improved survival without increasing GVHD after haplo-PBSCT. These advantages may be associated with accelerated immune reconstitution.


Subject(s)
Cytomegalovirus Infections , Epstein-Barr Virus Infections , Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Peripheral Blood Stem Cell Transplantation , Humans , Adult , Antilymphocyte Serum , Herpesvirus 4, Human , Graft vs Host Disease/etiology , Graft vs Host Disease/prevention & control , Graft vs Host Disease/epidemiology , Cytomegalovirus , Transplantation Conditioning , Retrospective Studies , Cytomegalovirus Infections/prevention & control
6.
World J Surg Oncol ; 21(1): 197, 2023 Jul 04.
Article in English | MEDLINE | ID: mdl-37403056

ABSTRACT

BACKGROUND: This study compared the survival outcomes of abdominal radical hysterectomy (ARH) (N = 32), laparoscopic radical hysterectomy (LRH) (N = 61), robot-assisted radical hysterectomy (RRH) (N = 100) and vaginal radical hysterectomy (VRH) (N = 45) approaches for early-stage cervical cancer to identify the surgical approach that provides the best survival. METHODS: Disease-free survival (DFS) and overall survival (OS) were calculated using the Kaplan-Meier method, and survival curves were compared using the log-rank test. RESULTS: The volume of intraoperative blood loss was greater in the ARH group than in the LRH group, the RRH group or the VRH group [(712.50 ± 407.59) vs. (224.43 ± 191.89), (109.80 ± 92.98) and (216.67 ± 176.78) ml, respectively; P < 0.001]. Total 5-year OS was significantly different among the four groups (ARH, 96.88%; LRH, 82.45%; RRH, 94.18%; VRH, 91.49%; P = 0.015). However, no significant difference in 5-year DFS was observed among the four groups (ARH, 96.88%; LRH, 81.99%; RRH, 91.38%; VRH, 87.27%; P = 0.061). CONCLUSION: This retrospective study demonstrated that ARH and RRH achieved higher 5-year OS rates than LRH for early-stage cervical cancer.


Subject(s)
Laparoscopy , Robotics , Uterine Cervical Neoplasms , Female , Humans , Retrospective Studies , Robotics/methods , Uterine Cervical Neoplasms/pathology , Neoplasm Staging , Hysterectomy/methods , Laparoscopy/methods
7.
Hematol Oncol ; 40(4): 743-751, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35385135

ABSTRACT

Acute graft-versus-host disease (aGVHD) causes significant morbidity and mortality. While most studies focus on classic or late aGVHD, some patients with previous aGVHD achieve complete remission and later develop another episode of aGVHD. Data on recurrence of aGVHD (RaGVHD) are lacking. This study aimed to identify the incidence, risk factors, and impacts of RaGVHD after T-cell-replete haploidentical hematopoietic cell transplantation (haplo-HCT) without posttransplantation cyclophosphamide. We evaluated patients with RaGVHD after haplo-HCT between 2017 and 2019 and compared their outcomes to those of patients with no aGVHD and those of patients with one episode of de novo aGVHD. Of 199 patients included in the analysis, 45 experienced 50 cases of RaGVHD with a 1-year cumulative incidence of 19.0% (95% CI: 14.5-24.6). Grade III-IV aGVHD was more common in RaGVHD than in previous aGVHD (22.2% vs. 4.4%, p = 0.01). Female donor to male recipient was strongly associated with RaGVHD (HR: 2.5, p = 0.009). The most common death in patients with RaGVHD was GVHD-related, which was different from controls who mostly died from relapse (p = 0.008). RaGVHD was an independent risk factor for chronic GVHD (HR: 2.6, p = 0.006) and nonrelapse mortality (HR: 2.4, p = 0.019) and a significant predictor of lower GVHD relapse-free survival (HR: 1.9, p = 0.020) and cGVHD relapse-free survival (HR: 2.1, p = 0.007). In conclusion, clinical manifestations and negative impacts of RaGVHD needs to be recognized independently.


Subject(s)
Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Cyclophosphamide , Female , Hematopoietic Stem Cell Transplantation/adverse effects , Humans , Male , Neoplasm Recurrence, Local/etiology , Recurrence , Retrospective Studies , T-Lymphocytes , Transplantation Conditioning/adverse effects
8.
Ann Hematol ; 101(3): 621-630, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34816294

ABSTRACT

We started a single-arm, phase II, open-label, prospective clinical trial using steroids-ruxolitinib as the first-line therapy for intermediate- to high-risk aGVHD (NCT04397367). Here, we report the association of a biomarker panel (sST2, REG3α, sTNFR1, IL-6 and IL-8) with responses to GVHD therapy. The novel first-line therapy for 39 patients with newly diagnosed aGVHD consisted of 1 mg/kg methylprednisolone and 5 mg/day ruxolitinib. The serum concentrations of the biomarkers were prospectively detected at planned time points. Of the 39 patients, the complete response rate at day 28 was 82.05%. In patients who achieved CR, the concentrations of REG3α (P14 = 0.01; P28 = 0.10) and sTNFR1 (P14 = 0.42; P28 = 0.04) declined at day 14 and day 28 compared with the pre-enrolment levels. In refractory patients, the levels of REG3α at day 14 were higher than those pre-enrolment (P = 0.04). REG3α (P = 0.02) was elevated in the refractory patients compared with the patients achieving CR at day 14 after enrolment, while there was no significant difference in the levels of sST2, sTNFR1 or IL-6. Elevated REG3α levels may predict refractory aGVHD after novel first-line therapy with steroids-ruxolitinib.


Subject(s)
Graft vs Host Disease/blood , Nitriles/therapeutic use , Pancreatitis-Associated Proteins/blood , Pyrazoles/therapeutic use , Pyrimidines/therapeutic use , Steroids/therapeutic use , Adolescent , Adult , Biomarkers/blood , Female , Graft vs Host Disease/diagnosis , Graft vs Host Disease/prevention & control , Humans , Male , Middle Aged , Prognosis , Prospective Studies , Young Adult
9.
J Am Chem Soc ; 141(43): 17125-17132, 2019 10 30.
Article in English | MEDLINE | ID: mdl-31557439

ABSTRACT

Protein conformational switches or allosteric proteins play a key role in the regulation of many essential biological pathways. Nonetheless, the implementation of protein conformational switches in protein design applications has proven challenging, with only a few known examples that are not derivatives of naturally occurring allosteric systems. We have discovered that the domain-swapped (DS) dimer of hCRBPII undergoes a large and robust conformational change upon retinal binding, making it a potentially powerful template for the design of protein conformational switches. Atomic resolution structures of the apo- and holo-forms illuminate a simple, mechanical movement involving sterically driven torsion angle flipping of two residues that drive the motion. We further demonstrate that the conformational "readout" can be altered by addition of cross-domain disulfide bonds, also visualized at atomic resolution. Finally, as a proof of principle, we have created an allosteric metal binding site in the DS dimer, where ligand binding results in a reversible 5-fold loss of metal binding affinity. The high resolution structure of the metal-bound variant illustrates a well-formed metal binding site at the interface of the two domains of the DS dimer and confirms the design strategy for allosteric regulation.


Subject(s)
Protein Engineering/methods , Retinol-Binding Proteins, Cellular/chemistry , Retinol-Binding Proteins, Cellular/metabolism , Allosteric Regulation , Binding Sites , Circular Dichroism , Crystallography, X-Ray , Disulfides/chemistry , Ligands , Metals/metabolism , Models, Molecular , Mutation , Protein Domains , Protein Multimerization , Retinol-Binding Proteins, Cellular/genetics , Threonine/genetics , Tyrosine/genetics , Zinc/metabolism
10.
Nature ; 496(7445): 317-22, 2013 Apr 18.
Article in English | MEDLINE | ID: mdl-23598339

ABSTRACT

TrkH belongs to a superfamily of K(+) transport proteins required for growth of bacteria in low external K(+) concentrations. The crystal structure of TrkH from Vibrio parahaemolyticus showed that TrkH resembles a K(+) channel and may have a gating mechanism substantially different from K(+) channels. TrkH assembles with TrkA, a cytosolic protein comprising two RCK (regulate the conductance of K(+)) domains, which are found in certain K(+) channels and control their gating. However, fundamental questions on whether TrkH is an ion channel and how it is regulated by TrkA remain unresolved. Here we show single-channel activity of TrkH that is upregulated by ATP via TrkA. We report two structures of the tetrameric TrkA ring, one in complex with TrkH and one in isolation, in which the ring assumes two markedly different conformations. These results suggest a mechanism for how ATP increases TrkH activity by inducing conformational changes in TrkA.


Subject(s)
Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Ion Channel Gating , Adenosine Diphosphate/metabolism , Adenosine Triphosphate/metabolism , Crystallography, X-Ray , Electric Conductivity , Ion Transport , Models, Molecular , Protein Folding , Protein Structure, Quaternary , Protein Structure, Tertiary , Vibrio parahaemolyticus
11.
Nature ; 473(7345): 50-4, 2011 May 05.
Article in English | MEDLINE | ID: mdl-21471968

ABSTRACT

Saccharides have a central role in the nutrition of all living organisms. Whereas several saccharide uptake systems are shared between the different phylogenetic kingdoms, the phosphoenolpyruvate-dependent phosphotransferase system exists almost exclusively in bacteria. This multi-component system includes an integral membrane protein EIIC that transports saccharides and assists in their phosphorylation. Here we present the crystal structure of an EIIC from Bacillus cereus that transports diacetylchitobiose. The EIIC is a homodimer, with an expansive interface formed between the amino-terminal halves of the two protomers. The carboxy-terminal half of each protomer has a large binding pocket that contains a diacetylchitobiose, which is occluded from both sides of the membrane with its site of phosphorylation near the conserved His250 and Glu334 residues. The structure shows the architecture of this important class of transporters, identifies the determinants of substrate binding and phosphorylation, and provides a framework for understanding the mechanism of sugar translocation.


Subject(s)
Bacillus cereus/enzymology , Membrane Transport Proteins/chemistry , Models, Molecular , Binding Sites , Carbohydrate Metabolism , Crystallization , Phosphorylation , Protein Structure, Quaternary , Protein Structure, Tertiary
12.
Nature ; 471(7338): 336-40, 2011 Mar 17.
Article in English | MEDLINE | ID: mdl-21317882

ABSTRACT

The TrkH/TrkG/KtrB proteins mediate K(+) uptake in bacteria and probably evolved from simple K(+) channels by multiple gene duplications or fusions. Here we present the crystal structure of a TrkH from Vibrio parahaemolyticus. TrkH is a homodimer, and each protomer contains an ion permeation pathway. A selectivity filter, similar in architecture to those of K(+) channels but significantly shorter, is lined by backbone and side-chain oxygen atoms. Functional studies showed that TrkH is selective for permeation of K(+) and Rb(+) over smaller ions such as Na(+) or Li(+). Immediately intracellular to the selectivity filter are an intramembrane loop and an arginine residue, both highly conserved, which constrict the permeation pathway. Substituting the arginine with an alanine significantly increases the rate of K(+) flux. These results reveal the molecular basis of K(+) selectivity and suggest a novel gating mechanism for this large and important family of membrane transport proteins.


Subject(s)
Potassium Channels/chemistry , Potassium Channels/metabolism , Vibrio parahaemolyticus/chemistry , ATP-Binding Cassette Transporters/chemistry , Amino Acid Sequence , Crystallography, X-Ray , Escherichia coli Proteins/chemistry , Ion Channel Gating , Ion Transport , Models, Molecular , Molecular Sequence Data , Potassium/metabolism , Structure-Activity Relationship , Substrate Specificity
13.
Proc Natl Acad Sci U S A ; 111(40): E4175-84, 2014 Oct 07.
Article in English | MEDLINE | ID: mdl-25253890

ABSTRACT

Type I cadherin cell-adhesion proteins are similar in sequence and structure and yet are different enough to mediate highly specific cell-cell recognition phenomena. It has previously been shown that small differences in the homophilic and heterophilic binding affinities of different type I family members can account for the differential cell-sorting behavior. Here we use a combination of X-ray crystallography, analytical ultracentrifugation, surface plasmon resonance and double electron-electron resonance (DEER) electron paramagnetic resonance spectroscopy to identify the molecular determinants of type I cadherin dimerization affinities. Small changes in sequence are found to produce subtle structural and dynamical changes that impact relative affinities, in part via electrostatic and hydrophobic interactions, and in part through entropic effects because of increased conformational heterogeneity in the bound states as revealed by DEER distance mapping in the dimers. These findings highlight the remarkable ability of evolution to exploit a wide range of molecular properties to produce closely related members of the same protein family that have affinity differences finely tuned to mediate their biological roles.


Subject(s)
Cadherins/chemistry , Protein Multimerization , Protein Structure, Secondary , Protein Structure, Tertiary , Amino Acid Sequence , Animals , Binding, Competitive , Cadherins/genetics , Cadherins/metabolism , Crystallography, X-Ray , Electron Spin Resonance Spectroscopy , HEK293 Cells , Humans , Hydrophobic and Hydrophilic Interactions , Kinetics , Mice , Models, Molecular , Molecular Sequence Data , Mutation , Protein Binding , Sequence Homology, Amino Acid , Static Electricity , Xenopus , Xenopus Proteins/chemistry , Xenopus Proteins/genetics , Xenopus Proteins/metabolism
14.
Int J Mol Sci ; 18(9)2017 Aug 30.
Article in English | MEDLINE | ID: mdl-28867761

ABSTRACT

The downregulation of tight junction protein CLDN6 promotes breast cancer cell migration and invasion; however, the exact mechanism underlying CLDN6 downregulation remains unclear. CLDN6 silence is associated with DNA methyltransferase 1 (DNMT1) mediated DNA methylation, and DNMT1 is regulated by the transforming growth factor beta (TGFß)/SMAD pathway. Therefore, we hypothesized that TGFß/SMAD pathway, specifically SMAD2, may play a critical role for CLDN6 downregulation through DNA methyltransferase 1 (DNMT1) mediated DNA methylation. To test this hypothesis, we blocked the SMAD2 pathway with SB431542 in two human breast cancer cell lines (MCF-7 and SKBR-3). Our results showed that treatment with SB431542 led to a decrease of DNMT1 expression and the binding activity for CLDN6 promoter. The methylation level of CLDN6 promoter was decreased, and simultaneously CLDN6 protein expression increased. Upregulation of CLDN6 inhibited epithelial to mesenchymal transition (EMT) and reduced the migration and invasion ability of both MCF-7 and SKBR-3 cells. Furthermore, knocked down of CLDN6 abolished SB431542 effects on suppression of EMT associated gene expression and inhibition of migration and invasion. Thus, we demonstrated that the downregulation of CLDN6 is regulated through promoter methylation by DNMT1, which depends on the SMAD2 pathway, and that CLDN6 is a key regulator in the SMAD2/DNMT1/CLDN6 pathway to inhibit EMT, migration and invasion of breast cancer cells.


Subject(s)
Breast Neoplasms/genetics , Claudins/genetics , Smad2 Protein/genetics , Breast Neoplasms/pathology , Cell Movement/genetics , Cell Proliferation/genetics , Claudins/antagonists & inhibitors , DNA (Cytosine-5-)-Methyltransferase 1/genetics , DNA Methylation/genetics , Epithelial-Mesenchymal Transition/genetics , Female , Gene Expression Regulation, Neoplastic/genetics , Gene Knockdown Techniques , Humans , MCF-7 Cells , Neoplasm Invasiveness/genetics , Neoplasm Invasiveness/pathology , Signal Transduction/genetics
15.
Proc Natl Acad Sci U S A ; 109(3): E127-34, 2012 Jan 17.
Article in English | MEDLINE | ID: mdl-22171007

ABSTRACT

Vertebrate classical cadherins mediate selective calcium-dependent cell adhesion by mechanisms now understood at the atomic level. However, structures and adhesion mechanisms of cadherins from invertebrates, which are highly divergent yet function in similar roles, remain unknown. Here we present crystal structures of three- and four-tandem extracellular cadherin (EC) domain segments from Drosophila N-cadherin (DN-cadherin), each including the predicted N-terminal EC1 domain (denoted EC1') of the mature protein. While the linker regions for the EC1'-EC2' and EC3'-EC4' pairs display binding of three Ca(2+) ions similar to that of vertebrate cadherins, domains EC2' and EC3' are joined in a "kinked" orientation by a previously uncharacterized Ca(2+)-free linker. Biophysical analysis demonstrates that a construct containing the predicted N-terminal nine EC domains of DN-cadherin forms homodimers with affinity similar to vertebrate classical cadherins, whereas deleting the ninth EC domain ablates dimerization. These results suggest that, unlike their vertebrate counterparts, invertebrate cadherins may utilize multiple EC domains to form intercellular adhesive bonds. Sequence analysis reveals that similar Ca(2+)-free linkers are widely distributed in the ectodomains of both vertebrate and invertebrate cadherins.


Subject(s)
Cadherins/chemistry , Calcium/metabolism , Drosophila Proteins/chemistry , Drosophila melanogaster/metabolism , Adhesiveness , Amino Acid Sequence , Animals , Cadherins/metabolism , Crystallography, X-Ray , Drosophila Proteins/metabolism , Kinetics , Models, Molecular , Molecular Sequence Data , Protein Binding , Protein Multimerization , Protein Structure, Tertiary , Sequence Alignment , Sequence Analysis, Protein
16.
Mol Cell Biochem ; 388(1-2): 113-21, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24293287

ABSTRACT

To research the effects of silencing transcription factor SNAI1 on the in vitro biological phenotypes of breast cancer cell line MCF-7, based on the gene sequence of SNAI1, we linked shRNA with the green fluorescent protein-expressing eukaryotic expression vector pGCsilencer™ U6/Neo/GFP, and transfected it into MCF-7 cells. The SNAI1 gene-silencing effect was authenticated by RT-PCR and immunofluorescence. We then examined the effect of gene silencing on the expression of epithelial and mesenchymal markers and on their biological phenotypes of the target cells. Finally, we explained that SNAI1 was bound to E-cadherin in MCF-7 cells by ChIP. Silencing SNAI1 upregulated the expression of epithelial markers claudin-4, claudin-7, and E-cadherin, while expression of the mesenchymal marker matrix metalloproteinase-2 was downregulated. The capacity for proliferation, migration, and invasion was diminished. SNAI1 binds to the E-cadherin gene promoter and inhibits its transcription. We can conclude that silencing gene SNAI1 inhibits expression of properties that are associated with the malignant phenotype of MCF-7 cells and reverses the epithelial-mesenchymal transition process by regulating relevant target gene E-cadherin.


Subject(s)
Breast Neoplasms/genetics , Cadherins/genetics , Epithelial-Mesenchymal Transition/genetics , Neoplasm Invasiveness/genetics , Transcription Factors/genetics , 3T3 Cells , Animals , Biomarkers, Tumor/genetics , Breast Neoplasms/classification , Cadherins/biosynthesis , Cadherins/metabolism , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation , Claudin-4/biosynthesis , Claudins/biosynthesis , Female , Green Fluorescent Proteins/genetics , Humans , MCF-7 Cells , Matrix Metalloproteinase 2/biosynthesis , Mice , Phenotype , Promoter Regions, Genetic , RNA Interference , RNA, Small Interfering , Snail Family Transcription Factors
17.
PeerJ ; 12: e18157, 2024.
Article in English | MEDLINE | ID: mdl-39372720

ABSTRACT

Background: The incidence and mortality of cervical cancer remain high in female malignant tumors worldwide. There is still a lack of diagnostic and prognostic markers for cervical carcinoma. This study aimed to screen differentially expressed genes (DEGs) between normal and cervical cancer tissues to identify candidate genes for further research. Methods: Uterine cervical specimens were resected from our clinical patients after radical hysterectomy. Three patients' transcriptomic datasets were built by the next generation sequencing (NGS) results. DEGs were selected through the edgeR and DESeq2 packages in the R environment. Functional enrichment analysis, including GO/DisGeNET/KEGG/Reactome enrichment analysis, was performed. Normal and cervical cancer tissue data from the public databases TCGA and GTEx were collected to compare the expression levels of 10 selected DEGs in tumor and normal tissues. ROC curve and survival analysis were performed to compare the diagnostic and prognostic values of each gene. The expression levels of candidate genes were verified in 15 paired clinical specimens via quantitative real-time polymerase chain reaction. Results: There were 875 up-regulated and 1,482 down-regulated genes in cervical cancer samples compared with the paired adjacent normal cervical tissues according to the NGS analysis. The top 10 DEGs included APOD, MASP1, ACKR1, C1QTNF7, SFRP4, HSPB6, GSTM5, IGFBP6, F10 and DCN. GO, DisGeNET and Reactome analyses revealed that the DEGs were related to extracellular matrix and angiogenesis which might influence tumorigenesis. KEGG enrichment showed that PI3K-Akt signaling pathway might be involved in cervical cancer tumorigenesis and progression. The expression levels of selected genes were decreased in tumors in both the public database and our experimental clinical specimens. All the candidate genes showed excellent diagnostic value, and the AUC values exceeded 0.90. Additionally, APOD, ACKR1 and SFRP4 expression levels could help predict the prognosis of patients with cervical cancer. Conclusions: In this study, we selected the top 10 DEGs which were down-regulated in cervical cancer tissues. All of them had dramatically diagnostic value. APOD, ACKR1 and SFRP4 were associated with the survivals of cervical cancer. C1QTNF7, HSPB6, GSTM5, IGFBP6 and F10 were first reported to be candidate genes of cervical carcinoma.


Subject(s)
Carcinogenesis , Gene Expression Regulation, Neoplastic , High-Throughput Nucleotide Sequencing , Uterine Cervical Neoplasms , Humans , Female , Uterine Cervical Neoplasms/genetics , Uterine Cervical Neoplasms/pathology , Gene Expression Regulation, Neoplastic/genetics , Carcinogenesis/genetics , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Gene Expression Profiling/methods , Prognosis , Middle Aged , Transcriptome/genetics
18.
Antibiotics (Basel) ; 13(10)2024 Oct 15.
Article in English | MEDLINE | ID: mdl-39452239

ABSTRACT

The worrying issue of antibiotic resistance in pathogenic bacteria is aggravated by the scarcity of novel therapeutic agents. Antibiotic adjuvants offer a promising solution due to their cost-effectiveness and high efficacy in addressing this issue, such as the ß-lactamase inhibitor sulbactam (a ß-lactam adjuvant) and the dihydrofolate reductase inhibitor trimethoprim (a sulfonamide adjuvant). This study aimed to discover potential adjuvants for tetracyclines from a list of previously approved drugs to restore susceptibility to Escherichia coli carrying the tetA gene. We have screened guanethidine, a compound from the Chinese pharmacopoeia, which effectively potentiates the activity of tetracyclines by reversing resistance in tetA-positive Escherichia coli, enhancing its antibacterial potency, and retarding the development of resistance. Guanethidine functions via the inhibition of the TetA efflux pump, thereby increasing the intracellular concentration of tetracyclines. Our findings suggest that guanethidine holds promise as an antibiotic adjuvant.

19.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 32(3): 896-905, 2024 Jun.
Article in Zh | MEDLINE | ID: mdl-38926986

ABSTRACT

OBJECTIVE: To investigate the effect of CD8+ CD28- T cells on acute graft-versus-host disease(aGVHD) after haploidentical hematopoietic stem cell transplantation(haplo-HSCT). METHODS: The relationship between absolute count of CD8+ CD28- T cells and aGVHD in 60 patients with malignant hematological diseases was retrospectively analyzed after haplo-HSCT, and the differences in the incidence rate of chronic graft-versus host disease(cGVHD), infection and prognosis between different CD8+ CD28- T absolute cells count groups were compared. RESULTS: aGVHD occurred in 40 of 60 patients after haplo-HSCT, with an incidence rate of 66.67%. The median occurrence time of aGVHD was 32.5(20-100) days. At 30 days after the transplantation, the absolute count of CD8+ CD28- T cells of aGVHD group was significantly lower than that of non-aGVHD group (P =0.03). Thus the absolute count of CD8+ CD28- T cells at 30 days after transplantation can be used to predict the occurrence of aGVHD to some extent. At 30 days after transplantation, the incidence rate of aGVHD in the low cell count group (CD8+ CD28- T cells absolute count < 0.06/µl) was significantly higher than that in the high cell count group (CD8+ CD28- T cells absolute count ≥0.06/µl,P =0.011). Multivariate Cox regression analysis further confirmed that the absolute count of CD8+ CD28-T cells at 30 days after transplantation was an independent risk factor for aGVHD, and the risk of aGVHD in the low cell count group was 2.222 times higher than that in the high cell count group (P =0.015). The incidence of cGVHD, fungal infection, EBV infection and CMV infection were not significantly different between the two groups with different CD8+ CD28- T cells absolute count. The overall survival, non-recurrent mortality and relapse rates were not significantly different between different CD8+ CD28- T cells absolute count groups. CONCLUSION: Patients with delayed CD8+ CD28- T cells reconstitution after haplo-HSCT are more likely to develop aGVHD, and the absolute count of CD8+ CD28- T cells can be used to predict the incidence of aGVHD to some extent. The absolute count of CD8+ CD28- T cells after haplo-HSCT was not associated with cGVHD, fungal infection, EBV infection, and CMV infection, and was also not significantly associated with the prognosis after transplantation.


Subject(s)
CD28 Antigens , CD8-Positive T-Lymphocytes , Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Humans , Hematopoietic Stem Cell Transplantation/adverse effects , Retrospective Studies , Prognosis , Transplantation, Haploidentical , Acute Disease , Male , Female , Adult
20.
Ann Transplant ; 29: e943688, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38952007

ABSTRACT

BACKGROUND The relationship between clonal hematopoiesis (CH)-associated gene mutations and allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been extensively studied since next-generation sequencing (NGS) technology became widely available. However, research has mainly focused on the relationship between donor CH mutations and transplant prognosis, and research into the relationship between CH mutations in the recipient and acute graft-versus-host disease (aGVHD) is lacking. MATERIAL AND METHODS We analyzed NGS results and their correlation with aGVHD and prognosis in 196 AML patients undergoing allo-HSCT. RESULTS A total of 93 (47.4%) patients had CH mutations. The most frequently mutated genes were DNMT3A (28 of 196; 14.3%), TET2 (22 of 196; 11.2%), IDH1 (15 of 196; 7.7%), IDH2 (14 of 196; 7.1%), and ASXL1 (13 of 196; 6.6%). The incidence of aGVHD was higher in patients older than 45 years old with DTA mutations (DNMT3A, TET2 or ASXL1). DNMT3A mutation but not with TET2 or ASXL1 mutation was an independent risk factor for aGVHD in patients receiving allo-HSCT older than 45 years old. With a median follow-up of 42.7 months, CH mutations were not associated with overall survival and leukemia-free survival. CONCLUSIONS DNMT3A mutation, but not TET2 or ASXL1 mutation, was associated with higher incidence of aGVHD.


Subject(s)
Clonal Hematopoiesis , Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Leukemia, Myeloid, Acute , Mutation , Humans , Hematopoietic Stem Cell Transplantation/adverse effects , Male , Female , Graft vs Host Disease/genetics , Graft vs Host Disease/etiology , Middle Aged , Adult , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/therapy , Clonal Hematopoiesis/genetics , Young Adult , Adolescent , DNA Methyltransferase 3A , Dioxygenases , DNA (Cytosine-5-)-Methyltransferases/genetics , Aged , Prognosis , Transplantation, Homologous , High-Throughput Nucleotide Sequencing , DNA-Binding Proteins , Repressor Proteins
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