Publications by authors named "Sijin Wu"

27 Publications

  • Page 1 of 1

Listeria monocytogenes upregulates mitochondrial calcium signalling to inhibit LC3-associated phagocytosis as a survival strategy.

Nat Microbiol 2021 03 18;6(3):366-379. Epub 2021 Jan 18.

Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA.

Mitochondria are believed to have originated ~2.5 billion years ago. As well as energy generation in cells, mitochondria have a role in defence against bacterial pathogens. Despite profound changes in mitochondrial morphology and functions following bacterial challenge, whether intracellular bacteria can hijack mitochondria to promote their survival remains elusive. We report that Listeria monocytogenes-an intracellular bacterial pathogen-suppresses LC3-associated phagocytosis (LAP) by modulation of mitochondrial Ca (mtCa) signalling in order to survive inside cells. Invasion of macrophages by L. monocytogenes induced mtCa uptake through the mtCa uniporter (MCU), which in turn increased acetyl-coenzyme A (acetyl-CoA) production by pyruvate dehydrogenase. Acetylation of the LAP effector Rubicon with acetyl-CoA decreased LAP formation. Genetic ablation of MCU attenuated intracellular bacterial growth due to increased LAP formation. Our data show that modulation of mtCa signalling can increase bacterial survival inside cells, and highlight the importance of mitochondrial metabolism in host-microbial interactions.
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http://dx.doi.org/10.1038/s41564-020-00843-2DOI Listing
March 2021

ppGalNAc-T4-catalyzed O-Glycosylation of TGF-β type Ⅱ receptor regulates breast cancer cells metastasis potential.

J Biol Chem 2020 Dec 3;296:100119. Epub 2020 Dec 3.

School of Life Science & Pharmacy, Dalian University of Technology, Panjin, China. Electronic address:

GalNAc-type O-glycosylation, initially catalyzed by polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts), is one of the most abundant and complex posttranslational modifications of proteins. Emerging evidence has proven that aberrant ppGalNAc-Ts are involved in malignant tumor transformation. However, the exact molecular functions of ppGalNAc-Ts are still unclear. Here, the role of one isoform, ppGalNAc-T4, in breast cancer cell lines was investigated. The expression of ppGalNAc-T4 was found to be negatively associated with migration of breast cancer cells. Loss-of-function studies revealed that ppGalNAc-T4 attenuated the migration and invasion of breast cancer cells by inhibiting the epithelial-mesenchymal transition (EMT) process. Correspondingly, transforming growth factor beta (TGF-β) signaling, which is the upstream pathway of EMT, was impaired by ppGalNAc-T4 expression. ppGalNAc-T4 knockout decreased O-GalNAc modification of TGF-β type Ⅰ and Ⅱ receptor (TβR Ⅰ and Ⅱ) and led to the elevation of TGF-β receptor dimerization and activity. Importantly, a peptide from TβR Ⅱ was identified as a naked peptide substrate of ppGalNAc-T4 with a higher affinity than ppGalNAc-T2. Further, Ser31, corresponding to the extracellular domain of TβR Ⅱ, was identified as the O-GalNAcylation site upon in vitro glycosylation by ppGalNAc-T4. The O-GalNAc-deficient S31 A mutation enhanced TGF-β signaling activity and EMT in breast cancer cells. Together, these results identified a novel mechanism of ppGalNAc-T4-catalyzed TGF-β receptors O-GalNAcylation that suppresses breast cancer cell migration and invasion via the EMT process. Targeting ppGalNAc-T4 may be a potential therapeutic strategy for breast cancer treatment.
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http://dx.doi.org/10.1074/jbc.RA120.016345DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7948473PMC
December 2020

A computational study of effects on membrane recruitment of the polar linkers in Vitamin E derivatives.

Biochim Biophys Acta Gen Subj 2020 10 11;1864(10):129655. Epub 2020 Jun 11.

Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States. Electronic address:

Background: Previous studies found that Vitamin E (VE) could recruit protein kinase B (Akt1) to the membrane by targeting its unconventional lipid-binding site, which led to the dephosphorylation of Akt1 at Ser473, eventually deactivating the enzyme.

Methods: A series of VE-like compounds with varying types and lengths of the linker groups are designed to study the VE-driven membrane recruitment of Akt1 using a combined molecular docking and molecular dynamics (MD) simulation approach.

Results: We find that the linker groups with only one methylene linker and multiple hydrogen bond donors are optimal for achieving a balance between binding to the protein and partitioning into the membrane to form a stable protein-ligand-membrane ternary complex. These polar linkers are found to form stable hydrogen bonds with the lipid head groups during the MD simulations, which turns out critical for ensuring that the chromanol ring of the VE-like compounds resides above the membrane surface to fully engage in the protein.

Conclusions: Our results reveal the molecular determinants of the linker groups for VE derivatives' ability to anchor Akt1 to the membrane.

General Significance: These findings will facilitate the design of membrane interfacial compounds to recruit specific proteins to the membrane to modulate the protein function.
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http://dx.doi.org/10.1016/j.bbagen.2020.129655DOI Listing
October 2020

Reversible inhibitor of CRM1 sensitizes glioblastoma cells to radiation by blocking the NF-κB signaling pathway.

Cancer Cell Int 2020 30;20:97. Epub 2020 Mar 30.

Insititute of Nervous System Diseases, Affiliated Hospital of Xuzhou Medical University, Xuzhou Medical University, Xuzhou, Jiangsu China.

Background: Activation of nuclear factor-kappa B (NF-κΒ) through DNA damage is one of the causes of tumor cell resistance to radiotherapy. Chromosome region 1 (CRM1) regulates tumor cell proliferation, drug resistance, and radiation resistance by regulating the nuclear-cytoplasmic translocation of important tumor suppressor proteins or proto-oncoproteins. A large number of studies have reported that inhibition of CRM1 suppresses the activation of NF-κΒ. Thus, we hypothesize that the reversible CRM1 inhibitor S109 may induce radiosensitivity in glioblastoma (GBM) by regulating the NF-κΒ signaling pathway.

Methods: This study utilized the cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), and colony formation assay to evaluate the effect of S109 combined with radiotherapy on the proliferation and survival of GBM cells. The therapeutic efficacy of S109 combined with radiotherapy was evaluated in vivo to explore the therapeutic mechanism of S109-induced GBM radiosensitization.

Results: We found that S109 combined with radiotherapy significantly inhibited GBM cell proliferation and colony formation. By regulating the levels of multiple cell cycle- and apoptosis-related proteins, the combination therapy induced G1 cell cycle arrest in GBM cells. In vivo studies showed that S109 combined with radiotherapy significantly inhibited the growth of intracranial GBM and prolonged survival. Importantly, we found that S109 combined with radiotherapy promoted the nuclear accumulation of IκΒα, and inhibited phosphorylation of p65 and the transcriptional activation of NF-κΒ.

Conclusion: Our findings provide a new therapeutic regimen for improving GBM radiosensitivity as well as a scientific basis for further clinical trials to evaluate this combination therapy.
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http://dx.doi.org/10.1186/s12935-020-01186-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7106748PMC
March 2020

Semi-synthetic cinnamodial analogues: Structural insights into the insecticidal and antifeedant activities of drimane sesquiterpenes against the mosquito Aedes aegypti.

PLoS Negl Trop Dis 2020 02 26;14(2):e0008073. Epub 2020 Feb 26.

Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America.

The Aedes aegypti mosquito serves as a major vector for viral diseases, such as dengue, chikungunya, and Zika, which are spreading across the globe and threatening public health. In addition to increased vector transmission, the prevalence of insecticide-resistant mosquitoes is also on the rise, thus solidifying the need for new, safe and effective insecticides to control mosquito populations. We recently discovered that cinnamodial, a unique drimane sesquiterpene dialdehyde of the Malagasy medicinal plant Cinnamosma fragrans, exhibited significant larval and adult toxicity to Ae. aegypti and was more efficacious than DEET-the gold standard for insect repellents-at repelling adult female Ae. aegypti from blood feeding. In this study several semi-synthetic analogues of cinnamodial were prepared to probe the structure-activity relationship (SAR) for larvicidal, adulticidal and antifeedant activity against Ae. aegypti. Initial efforts were focused on modification of the dialdehyde functionality to produce more stable active analogues and to understand the importance of the 1,4-dialdehyde and the α,ß-unsaturated carbonyl in the observed bioactivity of cinnamodial against mosquitoes. This study represents the first investigation into the SAR of cinnamodial as an insecticide and antifeedant against the medically important Ae. aegypti mosquito.
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http://dx.doi.org/10.1371/journal.pntd.0008073DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7062286PMC
February 2020

Na/K-ATPase-Targeted Cytotoxicity of (+)-Digoxin and Several Semisynthetic Derivatives.

J Nat Prod 2020 03 25;83(3):638-648. Epub 2020 Feb 25.

Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States.

(+)-Digoxin () is a well-known cardiac glycoside long used to treat congestive heart failure and found more recently to show anticancer activity. Several known cardenolides (-) and two new analogues, (+)-8(9)-β-anhydrodigoxigenin () and (+)-17--20,22-dihydro-21α-hydroxydigoxin (), were synthesized from and evaluated for their cytotoxicity toward a small panel of human cancer cell lines. A preliminary structure-activity relationship investigation conducted indicated that the C-12 and C-14 hydroxy groups and the C-17 unsaturated lactone unit are important for to mediate its cytotoxicity toward human cancer cells, but the C-3 glycosyl residue seems to be less critical for such an effect. Molecular docking profiles showed that the cytotoxic and the noncytotoxic derivative bind differentially to Na/K-ATPase. The HO-12β, HO-14β, and HO-3'aα hydroxy groups of (+)-digoxin () may form hydrogen bonds with the side-chains of Asp121 and Asn122, Thr797, and Arg880 of Na/K-ATPase, respectively, but the altered lactone unit of results in a rotation of its steroid core, which depotentiates the binding between this compound and Na/K-ATPase. Thus, was found to inhibit Na/K-ATPase, but did not. In addition, the cytotoxic did not affect glucose uptake in human cancer cells, indicating that this cardiac glycoside mediates its cytotoxicity by targeting Na/K-ATPase but not by interacting with glucose transporters.
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http://dx.doi.org/10.1021/acs.jnatprod.9b01060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7243443PMC
March 2020

Cytotoxic and non-cytotoxic cardiac glycosides isolated from the combined flowers, leaves, and twigs of Streblus asper.

Bioorg Med Chem 2020 02 7;28(4):115301. Epub 2020 Jan 7.

Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States. Electronic address:

A new non-cytotoxic [(+)-17β-hydroxystrebloside (1)] and two known cytotoxic [(+)-3'-de-O-methylkamaloside (2) and (+)-strebloside (3)] cardiac glycosides were isolated and identified from the combined flowers, leaves, and twigs of Streblus asper collected in Vietnam, with the absolute configuration of 1 established from analysis of its ECD and NMR spectroscopic data and confirmed by computational ECD calculations. A new 14,21-epoxycardanolide (3a) was synthesized from 3 that was treated with base. A preliminary structure-activity relationship study indicated that the C-14 hydroxy group and the C-17 lactone unit and the established conformation are important for the mediation of the cytotoxicity of 3. Molecular docking profiles showed that the cytotoxic 3 and its non-cytotoxic analogue 1 bind differentially to Na/K-ATPase. Compound 3 docks deeply in the Na/K-ATPase pocket with a sole pose, and its C-10 formyl and C-5, C-14, and C-4' hydroxy groups may form hydrogen bonds with the side-chains of Glu111, Glu117, Thr797, and Arg880 of Na/K-ATPase, respectively. However, 1 fits the cation binding sites with at least three different poses, which all depotentiate the binding between 1 and Na/K-ATPase. Thus, 3 was found to inhibit Na/K-ATPase, but 1 did not. In addition, the cytotoxic and Na/K-ATPase inhibitory 3 did not affect glucose uptake in human lung cancer cells, against which it showed potent activity, indicating that this cardiac glycoside mediates its cytotoxicity by targeting Na/K-ATPase but not by interacting with glucose transporters.
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http://dx.doi.org/10.1016/j.bmc.2019.115301DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7029422PMC
February 2020

Insecticidal and Antifeedant Activities of Malagasy Medicinal Plant ( sp.) Extracts and Drimane-Type Sesquiterpenes against Mosquitoes.

Insects 2019 Oct 25;10(11). Epub 2019 Oct 25.

Department of Entomology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691, USA.

The overuse of insecticides with limited modes of action has led to resistance in mosquito vectors. Thus, insecticides with novel modes of action are needed. Secondary metabolites in Madagascan plants of the genus (Canellaceae) are commonly used in traditional remedies and known to elicit antifeedant and toxic effects in insect pests. Here we test the hypothesis that extracts of sp. enriched in drimane sesquiterpenes are toxic and/or antifeedant to the yellow fever mosquito . We show that the bark and root extracts, which contain a higher abundance of drimane sesquiterpenes compared to leaves, were the most efficacious. Screening isolated compounds revealed cinnamodial to be the primary driver of adulticidal activity, whereas cinnamodial, polygodial, cinnafragrin A, and capsicodendrin contributed to the larvicidal activity. Moreover, an abundant lactone (cinnamosmolide) in the root extract synergized the larvicidal effects of cinnamodial. The antifeedant activity of the extracts was primarily contributed to cinnamodial, polygodial, and cinnamolide. Parallel experiments with warburganal isolated from (Canellaceae) revealed that aldehydes are critical for-and a hydroxyl modulates-insecticidal activity. Our results indicate that plant drimane sesquiterpenes provide valuable chemical platforms for developing insecticides and repellents to control mosquito vectors.
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http://dx.doi.org/10.3390/insects10110373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6920793PMC
October 2019

Stress-induced epinephrine enhances lactate dehydrogenase A and promotes breast cancer stem-like cells.

J Clin Invest 2019 03 28;129(3):1030-1046. Epub 2019 Jan 28.

CAS Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.

Chronic stress triggers activation of the sympathetic nervous system and drives malignancy. Using an immunodeficient murine system, we showed that chronic stress-induced epinephrine promoted breast cancer stem-like properties via lactate dehydrogenase A-dependent (LDHA-dependent) metabolic rewiring. Chronic stress-induced epinephrine activated LDHA to generate lactate, and the adjusted pH directed USP28-mediated deubiquitination and stabilization of MYC. The SLUG promoter was then activated by MYC, which promoted development of breast cancer stem-like traits. Using a drug screen that targeted LDHA, we found that a chronic stress-induced cancer stem-like phenotype could be reversed by vitamin C. These findings demonstrated the critical importance of psychological factors in promoting stem-like properties in breast cancer cells. Thus, the LDHA-lowering agent vitamin C can be a potential approach for combating stress-associated breast cancer.
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http://dx.doi.org/10.1172/JCI121685DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391112PMC
March 2019

Precise Detection of Wrist Pulse Using Digital Speckle Pattern Interferometry.

Evid Based Complement Alternat Med 2018 7;2018:4187349. Epub 2018 Jun 7.

Department of Mechanical Engineering, Oakland University, Rochester, MI 48309, USA.

Pulse diagnosis is one of the four diagnostic methods of traditional Chinese medicine. However it suffers from the lack of objective and efficient detection method. We propose a noncontact optical method to detect human wrist pulse, aiming at the precise determination of the temporal and spatial distributions of pulse. The method uses the spatial-carrier digital speckle pattern interferometry (DSPI) to measure the micro/nanoscale skin displacement dynamically. Significant improvements in DSPI measurement have been made to allow the DSPI to detect the comprehensive information of the arterial pulsation at locations of Cun, Guan, and Chi. The experimental results prove that the spatiotemporal distributions of pulse can be obtained by the proposed method. The obtained data can be further used to describe most of the pulse parameters such as rate, rhythm, depth, length, width, and contour.
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http://dx.doi.org/10.1155/2018/4187349DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6011166PMC
June 2018

Structural and enzymatic characterization of acetolactate decarboxylase from Bacillus subtilis.

Appl Microbiol Biotechnol 2018 Aug 23;102(15):6479-6491. Epub 2018 May 23.

School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, 116024, People's Republic of China.

Acetoin is an important physiological metabolite excreted by microbes. Its functions include avoiding acidification, participating in regulation of the NAD/NADH ratio, and storing carbon. Acetolactate decarboxylase is a well-characterized anabolic enzyme involved with 3-hydroxy butanone (acetoin). It catalyzes conversion of the (R)- and (S)-enantiomers of acetolactate to generate the single product, (R)-acetoin. In addition to the X-ray crystal structure of acetolactate decarboxylase from Bacillus brevis, although the enzyme is widely present in microorganisms, very few atomic structures of acetolactate decarboxylase are reported. In this paper, we solved and reported a 1.5 Å resolution crystal structure of acetolactate decarboxylase from Bacillus subtilis. Dimeric assembly is observed in the solved structure, which is consistent with the elution profile conducted by molecular filtration. A zinc ion is coordinated by highly conserved histidines (191, 193, and 204) and conserved glutamates (62 and 251). We performed kinetic studies on acetolactate decarboxylase from Bacillus subtilis using circular dichroism, allowing the conversion of acetolactate to chiral acetoin for real-time tracking, yielding a K value of 21 mM and a k value of 2.2 s. Using the two enantiomers of acetolactate as substrates, we further investigated the substrate preference of acetolactate decarboxylase from Bacillus subtilis by means of molecular docking and dynamic simulation in silico. The binding free energy of (S)-acetolactate was found to be ~ 30 kcal/mol greater than that of (R)-acetolactate, indicating a more stable binding for (S)-acetolactate.
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http://dx.doi.org/10.1007/s00253-018-9049-7DOI Listing
August 2018

Spatial phase-shift dual-beam speckle interferometry.

Appl Opt 2018 Jan;57(3):414-419

The spatial phase-shift technique has been successfully applied to an out-of-plane speckle interferometry system. Its application to a pure in-plane sensitive system has not been reported yet. This paper presents a novel optical configuration that enables the application of the spatial phase-shift technique to pure in-plane sensitive dual-beam speckle interferometry. The new spatial phase-shift dual-beam speckle interferometry (SPS-DBSP) uses a dual-beam in-plane electronic speckle pattern interferometry configuration with individual aperture shears, avoiding the interference in the object plane by the use of a low-coherence source, and different optical paths. The measured object is illuminated by two incoherent beams that are generated by a delay line, which is larger than the coherence length of the laser. The two beams reflected from the object surface interfere with each other at the CCD plane because of different optical paths. A spatial phase shift is introduced by the angle between the two apertures when they are mapped to the same optical axis. The phase of the in-plane deformation can directly be extracted from the speckle patterns by the Fourier transform method. The capability of SPS-DBSI is demonstrated by theoretical discussion as well as experiments.
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http://dx.doi.org/10.1364/AO.57.000414DOI Listing
January 2018

Traditional Herbal Medicine-Derived Sulforaphene LFS-01 Reverses Colitis in Mice by Selectively Altering the Gut Microbiota and Promoting Intestinal Gamma-Delta T Cells.

Front Pharmacol 2017 9;8:959. Epub 2018 Jan 9.

Center for Molecular Medicine, School of Life Sciences and Biotechnology, Dalian University of Technology, Dalian, China.

Sulforaphene (LFS-01) is a natural compound derived from traditional herbal medicine. Here, we show that oral administration of LFS-01 is able to dramatically alter the skewed gut microbiota and reverse colitis in model mice associated with an increase of intestinal γδT cells. Through 16S rDNA sequencing, we showed that LFS-01 can selectively suppress enteric pathogens such as and whereas the protective strains including and were significantly expanded after LFS-01 treatment. Interestingly, we demonstrated that LFS-01 administration can significantly promote the IL-17+γδT cells in model mice in response to the expanded . We verified that the intracellular components of can stimulate the growth of IL-17+γδT cells upon preincubation. The increased IL-17A after LFS-01 treatment in turn recovers the disrupted occludin subcellular location and protects the epithelial barrier in the colon of model mice. Remarkably, LFS-01 does not show apparent toxicity to animals and we demonstrated that LFS-01 also exerts strong protective effects in TNBS-induced colitis rats. Therefore, LFS-01 holds great promise for the treatment of inflammatory bowel disease (IBD) and warrants translation for use in clinical trials. Our work provided a new avenue for the treatment of IBD based on the strategy of harnessing intestinal symbiosis.
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http://dx.doi.org/10.3389/fphar.2017.00959DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5767259PMC
January 2018

Recurrent ECSIT mutation encoding V140A triggers hyperinflammation and promotes hemophagocytic syndrome in extranodal NK/T cell lymphoma.

Nat Med 2018 02 1;24(2):154-164. Epub 2018 Jan 1.

Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.

Hemophagocytic syndrome (HPS) is a fatal hyperinflammatory disease with a poorly understood mechanism that occurs most frequently in extranodal natural killer/T cell lymphoma (ENKTL). Through exome sequencing of ENKTL tumor-normal samples, we have identified a hotspot mutation (c.419T>C) in the evolutionarily conserved signaling intermediate in Toll pathway (ECSIT) gene, encoding a V140A variant of ECSIT. ECSIT-V140A activated NF-κB more potently than the wild-type protein owing to its increased affinity for the S100A8 and S100A9 heterodimer, which promotes NADPH oxidase activity. ECSIT-T419C knock-in mice showed higher peritoneal NADPH oxidase activity than mice with wild-type ECSIT in response to LPS. ECSIT-T419C-transfected ENKTL cell lines produced tumor necrosis factor (TNF)-α and interferon (IFN)-γ, which induced macrophage activation and massive cytokine secretion in cell culture and mouse xenografts. In individuals with ENKTL, ECSIT-V140A was associated with activation of NF-κB, higher HPS incidence, and poor prognosis. The immunosuppressive drug thalidomide prevented NF-κB from binding to the promoters of its target genes (including TNF and IFNG), and combination treatment with thalidomide and dexamethasone extended survival of mice engrafted with ECSIT-T419C-transfected ENKTL cells. We added thalidomide to the conventional dexamethasone-containing therapy regimen for two patients with HPS who expressed ECSIT-V140A, and we observed reversal of their HPS and disease-free survival for longer than 3 years. These findings provide mechanistic insights and a potential therapeutic strategy for ENKTL-associated HPS.
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http://dx.doi.org/10.1038/nm.4456DOI Listing
February 2018

Traditional herbal medicine-derived sulforaphene promotes mitophagic cell death in lymphoma cells through CRM1-mediated p62/SQSTM1 accumulation and AMPK activation.

Chem Biol Interact 2018 Feb 13;281:11-23. Epub 2017 Dec 13.

Center for Molecular Medicine (CMM), School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116023, China. Electronic address:

Sulforaphene (LFS-01) is the major chemical constituent of Raphanus sativus, a medicinal herb used for over a thousand years in traditional Chinese medicine. Here we identified that LFS-01 can selectively eradicate lymphoma cells while sparing normal lymphocytes by triggering concomitant mitophagy and apoptosis. We demonstrated that LFS-01 can retain Nrf2 in the nucleus by covalently modulating CRM1 and consequently upregulate p62/SQSTM1, an essential structural component of the autophagosomes during mitophagic process. We found that LFS-01 treatment also stimulated AMPK and thereby inhibited the mTOR pathway. On the contrary, we revealed that AMPK inhibition can severely impair the LFS-01-mediated mitophagy. Transcriptomic studies confirmed that 15 autophagy-associated genes such as p62/SQSTM1, VCP and BCL2 were differentially expressed after LFS-01 treatment. Furthermore, protein interactome network analysis revealed that the events of apoptosis and the assembly of autophagy vacuole were significant upon LFS-01 exposure. Lastly, we found that LFS-01 exhibited strong efficacy in xenograft mouse model yet with the lack of apparent toxicity to animals. We concluded that LFS-01 triggered mitophagic cell death via CRM1-mediated p62 overexpression and AMPK activation. Our findings provide new insights into the mechanism of action for LFS-01 and highlight its potential applications in treating major human diseases.
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http://dx.doi.org/10.1016/j.cbi.2017.12.017DOI Listing
February 2018

Discovery of a Low Toxicity O-GlcNAc Transferase (OGT) Inhibitor by Structure-based Virtual Screening of Natural Products.

Sci Rep 2017 09 26;7(1):12334. Epub 2017 Sep 26.

School of Life Science & Medicine, Dalian University of Technology, Panjin, China.

O-GlcNAc transferase (OGT) plays an important role in regulating numerous cellular processes through reversible post-translational modification of nuclear and cytoplasmic proteins. However, the function of O-GlcNAcylation is still not well understood. Cell permeable OGT inhibitors are needed to manipulate O-GlcNAcylation levels and clarify the regulatory mechanism of this modification. Here, we report a specific natural-product OGT inhibitor (L01), which was identified from a structure-based virtual screening analysis. L01 inhibited O-GlcNAcylation both in vitro and in cells without significantly altering cell surface glycans. Molecular dynamics and site-directed mutagenesis indicated a new binding mechanism in which L01 could interact with Asn557 near the UDP binding pocket of OGT. This residue may contribute to the specificity of L01. Furthermore, as a specific OGT inhibitor, L01 produced low toxicity in cellular and zebrafish models. The identification of L01 validates structure-based virtual screening approaches for the discovery of OGT inhibitors. L01 can also serve as a chemical tool to further characterize O-GlcNAcylation functions or a new molecular core for structure-activity relationship studies to optimize the biochemical potencies.
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http://dx.doi.org/10.1038/s41598-017-12522-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5615061PMC
September 2017

Cancer Stem Cells Therapeutic Target Database: The First Comprehensive Database for Therapeutic Targets of Cancer Stem Cells.

Stem Cells Transl Med 2017 02 11;6(2):331-334. Epub 2016 Oct 11.

Center for Molecular Medicine, School of Life Science and Biotechnology, Dalian University of Technology, Dalian, People's Republic of China.

Cancer stem cells (CSCs) are a subpopulation of tumor cells that have strong self-renewal capabilities and may contribute to the failure of conventional cancer therapies. Hence, therapeutics homing in on CSCs represent a novel and promising approach that may eradicate malignant tumors. However, the lack of information on validated targets of CSCs has greatly hindered the development of CSC-directed therapeutics. Herein, we describe the Cancer Stem Cells Therapeutic Target Database (CSCTT), the first online database to provide a rich bioinformatics resource for the display, search, and analysis of structure, function, and related annotation for therapeutic targets of cancer stem cells. CSCTT contains 135 proteins that are potential targets of CSCs, with validated experimental evidence manually curated from existing literatures. Proteins are carefully annotated with a detailed description of protein families, biological process, related diseases, and experimental evidences. In addition, CSCTT has compiled 213 documented therapeutic methods for cancer stem cells, including 118 small molecules and 20 biotherapy methods. The CSCTT may serve as a useful platform for the development of CSC-directed therapeutics against various malignant tumors. The CSCTT database is freely available to the public at http://www.csctt.org/. Stem Cells Translational Medicine 2017;6:331-334.
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http://dx.doi.org/10.5966/sctm.2015-0289DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5442812PMC
February 2017

Caffeic acid phenethyl ester (CAPE) revisited: Covalent modulation of XPO1/CRM1 activities and implication for its mechanism of action.

Chem Biol Drug Des 2017 05 8;89(5):655-662. Epub 2017 Mar 8.

Center for Molecular Medicine, School of Life Science and Biotechnology, Dalian University of Technology, Dalian, China.

Caffeic acid phenethyl ester (CAPE) is the bioactive constituent of propolis from honeybee hives and is well known for its anti-inflammatory, anticarcinogenic, antioxidant, and immunomodulatory properties. Herein, we revisited the cellular mechanism underlying the diverse biological effects of CAPE. We demonstrated that XPO1/CRM1, a major nuclear export receptor, is a cellular target of CAPE. Through nuclear export functional assay, we observed a clear shift of XPO1 cargo proteins from a cytoplasmic localization to nucleus when treated with CAPE. In particular, we showed that CAPE could specifically target the non-catalytic and conserved Cys of XPO1 through the means of mass spectrometric analysis. In addition, we demonstrated that the mutation of Cys residue in XPO1 could rescue the nuclear export defects caused by CAPE. Furthermore, we performed position-restraint molecular dynamics simulation to show that the Michael acceptor moiety of CAPE is the warhead to enable covalent binding with Cys residue of XPO1. The covalent modulation of nuclear export by CAPE may explain its diverse biological effects. Our findings may have general implications for further investigation of CAPE and its structural analogs.
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http://dx.doi.org/10.1111/cbdd.12905DOI Listing
May 2017

Cysteinome: The first comprehensive database for proteins with targetable cysteine and their covalent inhibitors.

Biochem Biophys Res Commun 2016 09 20;478(3):1268-73. Epub 2016 Aug 20.

Center for Molecular Medicine, School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116023, PR China. Electronic address:

The covalent modification of intrinsically nucleophilic cysteine in proteins is crucial for diverse biochemical events. Bioinformatics approaches may prove useful in the design and discovery of covalent molecules targeting the cysteine in proteins to tune their functions and activities. Herein, we describe the Cysteinome, the first online database that provides a rich resource for the display, search and analysis of structure, function and related annotation for proteins with targetable cysteine as well as their covalent modulators. To this end, Cysteinome compiles 462 proteins with targetable cysteine from 122 different species along with 1217 covalent modulators curated from existing literatures. Proteins are annotated with a detailed description of protein families, biological process and related diseases. In addition, covalent modulators are carefully annotated with chemical name, chemical structure, binding affinity, physicochemical properties, molecule type and related diseases etc. The Cysteinome database may serve as a useful platform for the identification of crucial proteins with targetable cysteine in certain cellular context. Furthermore, it may help biologists and chemists for the design and discovery of covalent chemical probes or inhibitors homing at functional cysteine of critical protein targets implicated in various physiological or disease process. The Cysteinome database is freely available to public at http://www.cysteinome.org/.
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http://dx.doi.org/10.1016/j.bbrc.2016.08.109DOI Listing
September 2016

TmcN is involved in ATP regulation of tautomycetin biosynthesis in Streptomyces griseochromogenes.

Biochem Biophys Res Commun 2016 09 18;478(1):221-226. Epub 2016 Jul 18.

Research Center for Molecular Medicine, Dalian University of Technology, Dalian, Liaoning 116023, China. Electronic address:

The regulatory mechanism of tautomycetin (TMC) biosynthesis remains largely unknown, although it has been of great interest to the pharmaceutical industry. Our previous study showed that intracellular adenosine triphosphate (inATP) level is negatively correlated with secondary metabolite biosynthesis in various Streptomyces spp. In this study, by exogenous treatment of ATP, we also found a negative correlation between TMC biosynthesis and inATP level in Streptomyces griseochromogenes (S. griseochromogenes). However, the underlying mechanism remains unclear. TmcN, a pathway-specific transcriptional regulator of TMC biosynthetic genes, was previously revealed as a large ATP-binding LuxR (LAL) family protein. The predicted amino acid sequence of TmcN shows highly conserved Walker A and B binding motifs, which suggest an ATPase function of TmcN. We therefore hypothesized that the ATPase domain of TmcN may play a role in sensing endogenous pool of ATP, and is thus involved in the ATP regulation of TMC biosynthesis. To test the hypothesis, we first explored the key residue that affects the ATPase activity of TmcN by amino acid sequence alignment and structural simulation. After that, we disrupted tmcN gene in S. griseochromogenes, and the tmcN or site-direct-mutated tmcN were re-introduced to get the complementary and ATPase domain disrupted strains. The transcription level of tmcN, TMC yield, and inATP, as well as the effect of ATP on TMC production of different mutants were evaluated. Deletion of tmcN or site-direct mutation of ATPase domain of TmcN in S. griseochromogenes significantly reduced the TMC production, and it was not affected by exogenous ATP treatment. In addition, a relatively high level of inATP was detected in tmcN deletion and site-direct mutation strains. Our results here suggested that TmcN, especially its ATPase domain, is involved in consuming of endogenous ATP pool and thus plays pivotal role in connecting the primary and secondary metabolite in S. griseochromogenes.
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http://dx.doi.org/10.1016/j.bbrc.2016.07.064DOI Listing
September 2016

Spatiotemporal three-dimensional phase unwrapping in digital speckle pattern interferometry.

Opt Lett 2016 Mar;41(5):1050-3

We propose a hybrid spatiotemporal three-dimensional phase unwrapping algorithm for use in digital speckle pattern interferometry (DSPI). The feature of the proposed algorithm is the integration of one-dimensional temporal and two-dimensional spatial phase unwrapping algorithms. By demodulating the phase on a single reference point or multiple reference points using temporal phase unwrapping and on each separated phase map region using spatial phase unwrapping, the DSPI with the spatiotemporal three-dimensional phase unwrapping algorithm can realize the measurement of dynamic absolute displacements and the determination of abrupt phase changes which are usually caused by object discontinuities. We demonstrate that the presented algorithm can overcome the drawbacks of the traditional spatial and temporal phase unwrapping algorithms.
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http://dx.doi.org/10.1364/OL.41.001050DOI Listing
March 2016

Assessing the potential of four cathelicidins for the management of mouse candidiasis and Candida albicans biofilms.

Biochimie 2016 Feb 2;121:268-77. Epub 2015 Dec 2.

College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China. Electronic address:

As the most common fungal pathogen of humans, severe drug resistance has emerged in the clinically isolated Candida albicans, which lead to the urgency to develop novel antifungal agents. Here, four our previously characterized cathelicidins (cathelicidin-BF, Pc-CATH1, Cc-CATH2, Cc-CATH3) were selected and their antifungal activities against C. albicans were evaluated in vitro and in vivo using amphotericin B and LL-37 as control. Results showed that all four cathelicidins could eradicate standard and clinically isolated C. albicans strains with most MIC values ranging from 1 to 16 μg/ml, in less than 0.5 h revealed by time-kill kinetic assay. Four peptides only exhibited slight hemolytic activity with most HC50 > 200 μg/ml, and retained potent anti-C. albicans activity at salt concentrations below and beyond physiological level. In animal experiment, 50 mg/kg administration of the four cathelicidins could significantly reduce the fungal counts in a murine oral candidiasis model induced by clinically isolated C. albicans. The antibiofilm activity of cathelicidin-BF, the most potent among the five peptides was evaluated, and result showed that cathelicidin-BF strongly inhibited C. albicans biofilm formation at 20 μg/ml. Furthermore, cathelicidin-BF also exhibited potent anti-C. albicans activity in established biofilms as measured by metabolic and fluorescent viability assays. Structure-function analyses suggest that they mainly adopt an α-helical conformations, which enable them to act as a membrane-active molecule. Altogether, the four cathelicidins display great potential for antifungal agent development against candidiasis.
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http://dx.doi.org/10.1016/j.biochi.2015.11.028DOI Listing
February 2016

Identification and Characterization of the First Cathelicidin from Sea Snakes with Potent Antimicrobial and Anti-inflammatory Activity and Special Mechanism.

J Biol Chem 2015 Jul 26;290(27):16633-52. Epub 2015 May 26.

From the Department of Pharmaceutical Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, China,

Cathelicidins are a family of gene-encoded peptide effectors of innate immunity found exclusively in vertebrates. They play pivotal roles in host immune defense against microbial invasions. Dozens of cathelicidins have been identified from several vertebrate species. However, no cathelicidin from marine reptiles has been characterized previously. Here we report the identification and characterization of a novel cathelicidin (Hc-CATH) from the sea snake Hydrophis cyanocinctus. Hc-CATH is composed of 30 amino acids, and the sequence is KFFKRLLKSVRRAVKKFRKKPRLIGLSTLL. Circular dichroism spectroscopy and structure modeling analysis indicated that Hc-CATH mainly assumes an amphipathic α-helical conformation in bacterial membrane-mimetic solutions. It possesses potent broad-spectrum and rapid antimicrobial activity. Meanwhile, it is highly stable and shows low cytotoxicity toward mammalian cells. The microbial killing activity of Hc-CATH is executed through the disruption of cell membrane and lysis of bacterial cells. In addition, Hc-CATH exhibited potent anti-inflammatory activity by inhibiting the LPS-induced production of nitric oxide (NO) and pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6. Hc-CATH directly binds with LPS to neutralize its toxicity, and it also binds to Toll-like receptor 4 (TLR4/MD2 complex), which therefore inhibits the binding of LPS to TLR4/MD2 complex and the subsequent activation of LPS-induced inflammatory response pathways. Taken together, our study demonstrates that Hc-CATH, the first cathelicidin from sea snake discovered to have both antimicrobial and anti-inflammatory activity, is a potent candidate for the development of peptide antibiotics.
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http://dx.doi.org/10.1074/jbc.M115.642645DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4505416PMC
July 2015

Cyclin-dependent kinase 5 decreases in gastric cancer and its nuclear accumulation suppresses gastric tumorigenesis.

Clin Cancer Res 2015 Mar 21;21(6):1419-28. Epub 2015 Jan 21.

Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian China. Cancer Research Center, Xiamen University, Xiamen, Fujian, China.

Purpose: As a cyclin-independent atypical CDK, the role of CDK5 in regulating cell proliferation in gastric cancer remains unknown.

Experimental Design: Expression of CDK5 in gastric tumor and paired adjacent noncancerous tissues from 437 patients was measured by Western blotting, immunohistochemistry, and real-time PCR. The subcellular translocation of CDK5 was monitored during gastric cancer cell proliferation. The role of nuclear CDK5 in gastric cancer tumorigenic proliferation and ex vivo xenografts was explored. Furthermore, by screening for compounds in the PubChem database that disrupt CDK5 association with its nuclear export facilitator, we identified a small molecular (NS-0011) that inhibits gastric cancer cell growth.

Results: CDK5 level was significantly decreased in the majority of gastric tumor tissues, and the reduction of CDK5 correlated with the severity of gastric cancer based on tumor and lymph node metastasis and patient 5-year fatality rate. Nuclear localization of CDK5 was found to be significantly decreased in tumor tissues and gastric cancer cell lines, whereas exogenously expression of nucleus-targeted CDK5 inhibited the proliferation and xenograft implantation of gastric cancer cells. Treatment with the small molecule NS-0011, which increases CDK5 accumulation in the nucleus, suppressed both cancer cell proliferation and xenograft tumorigenesis.

Conclusions: Our results suggest that low CDK5 expression is associated with poor overall survival in patients with gastric cancer, and nuclear accumulation of CDK5 inhibits the proliferation and tumorigenicity of human gastric cancer cells.
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http://dx.doi.org/10.1158/1078-0432.CCR-14-1950DOI Listing
March 2015

Structural bioinformatics-based identification of EGFR inhibitor gefitinib as a putative lead compound for BACE.

Chem Biol Drug Des 2014 Jan;83(1):81-8

β-secretase (BACE-1) is a potential target for the treatment of Alzheimer's disease (AD). Despite its potential, only few compounds targeting BACE have entered the clinical trials. Herein, we describe the identification of Gefitinib as a potential lead compound for BACE through an integrated approach of structural bioinformatics analysis, experimental assessment and computational analysis. In particular, we performed ELISA and western analysis to assess the effect of Gefitinib using N2a human APP695 cells. In addition, we investigated the binding mechanism of Gefitinib with BACE through molecular docking coupled with molecular dynamics simulations. The computational analyses revealed that hydrophobic contact is a major contributing factor to the binding of Gefitinib with BACE. The results obtained in the study have rendered Gefitinib as a putative lead compound for BACE. Further optimization studies are warranted to improve its potency and pharmacological properties against BACE for potential AD treatment.
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http://dx.doi.org/10.1111/cbdd.12200DOI Listing
January 2014

CRM1 is a cellular target of curcumin: new insights for the myriad of biological effects of an ancient spice.

Traffic 2013 Oct 31;14(10):1042-52. Epub 2013 Jul 31.

School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, P.R. China.

Curcumin is the major constituent of turmeric plant, an ancient spice widely used in Indian cuisine and traditional herbal medicine. Recently, the potential medical use of curcumin as anti-cancer and anti-inflammatory agent has set off an upsurge in research into the mechanism for its broad biological effects. We showed that CRM1, an important nuclear exportin, is a cellular target of curcumin by serious experimental and theoretical investigation. Using a nuclear export functional assay, we observed a clear and rapid shift of cargo proteins from a cytoplasmic localization to the nucleus when treated with curcumin or its structural analogue dibenzylideneacetone (DBA). We demonstrated that curcumin could specifically target the conserved Cys(528) of CRM1 through mass spectrometric analysis and in vivo experiments. Furthermore, computational modeling has revealed that curcumin could be correctly docked into the hydrophobic pocket of CRM1 judged from shape complementarity and putative molecular interactions. The Michael acceptor moiety on curcumin is within the appropriate distance to enable Michael reaction with Cys residue of CRM1. More importantly, we showed that nuclear retention of FOXO1 could be observed in the presence of Leptomycin B (LMB) or curcumin whereas in cells expressing the CRM1-Cys(528) mutant, only a cytoplasmic localization was observed. The inhibition of nuclear traffic by curcumin may account for its myriad of biological effects, particularly for its therapeutic properties in cancer and inflammatory diseases. Our findings may have important implications for further clinical investigation of curcumin.
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http://dx.doi.org/10.1111/tra.12090DOI Listing
October 2013

Enlarging the angle of view in Michelson-interferometer-based shearography by embedding a 4f system.

Appl Opt 2011 Jul;50(21):3789-94

School of Science, Beijing Jiaotong University, Beijing 100044, China.

Digital shearography based on Michelson interferometers suffers from the disadvantage of a small angle of view due to the structure. We demonstrate a novel digital shearography system with a large angle of view. In the optical arrangement, the imaging lens is in front of the Michelson interferometer rather than behind it as in traditional digital shearography. Thus, the angle of view is no longer limited by the Michelson interferometer. The images transmitting between the separate lens and camera are accomplished by a 4f system in the new style of shearography. The influences of the 4f system on shearography are also discussed.
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http://dx.doi.org/10.1364/AO.50.003789DOI Listing
July 2011