ABSTRACT
PURPOSE: The p38 mitogen-activated protein kinase (MAPKs) play a crucial role in the production of pro-inflammatory cytokines and over-expression of it increase cytokines which promote cancer. Among four isoforms, p38α has been well studied in head and neck squamous cell carcinoma (HNSCC) and other cancers as a therapeutic target. p38δ has recently emerged as a potential disease-specific drug target. Elevated serum p38α level in HNSCC was reported earlier from our lab. This study aims to estimate the levels of p38 MAPK-isoforms in the serum of HNSCC and design peptide inhibitor targeting the same. MATERIALS AND METHODS: Levels of p38 MAPK isoforms in the serum of HNSCC and healthy controls were quantified by surface plasmon resonance technology. The peptide inhibitor for p38 MAPK was designed by molecular modeling using Grid-based Ligand Docking with Energetics tools and compared with known specific inhibitors. RESULTS: We have observed highly elevated levels of all four isoforms of p38 MAPK in serum of HNSCC patients compared to the control group. Further, serum p38α, p38β, and p38δ levels were down regulated after therapy in follow-up patients, while p38γ showed no response to the therapy. Present study screened designed peptide WFYH as a specific inhibitor against p38δ. The specific inhibitor of p38δ was found to have no effect on p38α due to great structural difference at ATP binding pocket. CONCLUSION: In this study, first time estimated the levels of p38 MAPK isoforms in the serum of HNSCC. It can be concluded that p38 MAPK isoforms can be a diagnostic and prognostic marker for HNSCC and p38δ as a therapeutic target.
Subject(s)
Humans , Adenosine Triphosphate , Carcinoma, Squamous Cell , Cytokines , Epithelial Cells , Follow-Up Studies , Head , Models, Molecular , Neck , p38 Mitogen-Activated Protein Kinases , Protein Isoforms , Protein Kinases , Surface Plasmon ResonanceABSTRACT
Objective: To design and synthesize APC/Asef peptide inhibitors and investigate the structure-activity relationship between peptides inhibitors and APC protein for exploring better inhibitors. Methods: Based on the best-class inhibitor we had found before-MAI-400, eleven peptide inhibitors were designed, which included the changes of N-terminal capping group, the first amino acid Ala, the fifth amino acid Leu and the last amino acid Glu. According to the results of fluorescence polarization activity detection system and molecular docking, the structure-activity relationship of peptide inhibitors was investigated. Results: Among the eleven peptides, MPI-11 had the highest affinity, whose half maximal inhibitory concentration (IC50) was 0.973 1 mmol/L. The capping group of peptide N-terminal with tert-butoxycarbonyl group reduced the activity slightly. The substitution of the Ala caused different results, changing into Trp, His and Thr definitely reduced the activity but the substitution by Tyr or Phe did not influence the activity too much. And introducing benzene ring into the side chain of Leu had few effects on activity improving. The substitution of side chain carboxyl for amide at the C-terminal glutamate had little effect on the activity. Conclusion: Among the eleven peptides, the capping group of peptide N-terminal cannot be substituted into small groups and Ala cannot be substituted into other amino acids.
ABSTRACT
Objective: To design and synthesize APC/Asef peptide inhibitors, and investigate the relationship between the structures and affinity of peptides. Methods: Based on crystal structure of the APC-MAI-150 complex, on the one hand, 3-phenylpropane, Glu-Glu (GG) and β-Ala-Ala (β-AA) were used to replace carbobenzoxy (CBZ) at the N terminal of MAI-150 to bind -NH2; on the other hand, -CN, -NO2, -NH2, and -F were replaced the parahydroxyl on the sixth tyrosine (Tyr) side chain benzene at the N terminal of MAI-150. And seven peptides were synthesized. Fluorescence polarization was applied to test peptide affinity, and molecular design laboratory-3 (MDL-3), MDL-4 and MDL-5 were docked into APC protein based on the results of activity. The structure-activity relationship of the three peptides was studied by combining the binding patterns of computer docked peptide and APC protein. Results: Among the seven peptides, the N terminal 3-phenylpropane linked -NH2 of peptide MDL-5 had the highest affinity, which IC50 was 2.35 μmol/L. Compared with MDL-5, the affinity of MDL-6 and MDL-7 were significantly reduced. The para-hydroxyl on the sixth Tyr side chain benzene at the N terminal replaced with -NH2 (MDL-3) and -F (MDL-4), which the affinity were higher than -CN (MDL-1) and -NO2 (MDL-2). However, the affinity of newly synthesized peptides was lower than MAI-150. Conclusion: Transforming peptide N terminal linked -NH2 and the para-hydroxyl group on the sixth Tyr side chain benzene doesn't help to improve the affinity of peptides.
ABSTRACT
BACKGROUND: Glycogen synthase kinase 3beta (GSK3beta) is a ubiquitous serine/threonine kinase that is regulated by serine phosphorylation at 9. Recent studies have reported the beneficial effects of a number of the pharmacological GSK3beta inhibitors in rodent models of septic shock. Since most of the GSK3beta inhibitors are targeted at the ATP-binding site, which is highly conserved among diverse protein kinases, the development of novel non-ATP competitive GSK3beta inhibitors is needed. METHODS: Based on the unique phosphorylation motif of GSK3beta, we designed and generated a novel class of GSK3beta inhibitor (GSK3i) peptides. In addition, we investigated the effects of a GSK3i peptide on lipopolysaccharide (LPS)-stimulated cytokine production and septic shock. Mice were intraperitoneally injected with GSK3i peptide and monitored over a 7-day period for survival. RESULTS: We first demonstrate its effects on LPS-stimulated pro-inflammatory cytokine production including interleukin (IL)-6 and IL-12p40. LPS-induced IL-6 and IL-12p40 production in macrophages was suppressed when macrophages were treated with the GSKi peptide. Administration of the GSK3i peptide potently suppressed LPS-mediated endotoxin shock. CONCLUSION: Collectively, we present a rational strategy for the development of a therapeutic GSK3i peptide. This peptide may serve as a novel template for the design of non-ATP competitive GSK3 inhibitors.
Subject(s)
Animals , Mice , Cytokines , Glycogen Synthase Kinase 3 , Glycogen Synthase Kinases , Interleukin-12 Subunit p40 , Interleukin-6 , Interleukins , Macrophages , Peptides , Phosphorylation , Phosphotransferases , Protein Kinases , Rodentia , Serine , Shock , Shock, SepticABSTRACT
To obtain the recombinant tumor necrosis factor-α converting enzyme (TACE) ectodomain and use it as a selective molecule for the screening of TACE peptide inhibitors, the cDNA coding catalytic domain (T800) and full-length ectodomain (T1300) of TACE were amplified by RTPCR, and the expression plasmids were constructed by inserting T800 and T1300 into plasmid pET28a and pET-28c respectively. The recombinant T800 and T1300 were induced by IPTG, and SDSPAGE and Western blotting analysis results revealed that T800 and T1300 were highly expressed in the form of inclusion body. After Ni2+-NTA resin affinity chromatography, the recombinant proteins were used in the screening of TACE-binding peptides from phage display peptide library respectively. After 4 rounds of biopanning, the positive phage clones were analyzed by ELISA, competitive inhibition assay and DNA sequencing. A common amino acid sequence (TRWLVYFSRPYLVAT) was found and synthesized. The synthetic peptide could inhibit the TNF-α release from LPS-stimulated human peripheral blood mononuclear cells (PBMC) up to 60.3 %. FACS analysis revealed that the peptide mediated the accumulation of TNF-α on the cell surface. These results demonstrate that the TACE-binding peptide is an effective antagonist of TACE.
ABSTRACT
Objective:To study the effects of TNF? converting enzyme(TACE)inhibitors on TNF? secretion and develop an approach to interfere inflammation processes.Methods:(1)Stimulate the HL-60 cell lines in vitro with LPS for different time to establish the cellular model of inflammation and simultaneously induce in vivo inflammatoin animal model by LPS.(2)Check the cytotoxic effects of TNF? secretion using MTT colorimetric method for cell proliferaton.(3)Detect the level of expression of TACE carrying out RT-PCR,FCM techniques and immuno-histochemical dying technique.Results:(1)PDQ had the inhibitive effect on TNF?mRNA expression induced by LPS stimulation( P