| 26031918 |
Antileukemia activity of the novel peptidic CXCR4 antagonist LY2510924 as monotherapy and in combination with chemotherapy |
10.1182/blood-2015-02-628677. |
Blood |
Antileukemia activity of the novel peptidic CXCR4 antagonist LY2510924 as monotherapy and in combination with chemotherapy
Abstract
- Targeting the stromal cell-derived factor 1α (SDF-1α)/C-X-C chemokine receptor type 4 (CXCR4) axis has been shown to be a promising therapeutic approach to overcome chemoresistance in acute myeloid leukemia (AML). We investigated the antileukemia efficacy of a novel peptidic CXCR4 antagonist, LY2510924, in preclinical models of AML. LY2510924 rapidly and durably blocked surface CXCR4 and inhibited stromal cell-derived factor 1 (SDF-1)α-induced chemotaxis and prosurvival signals of AML cells at nanomolar concentrations more effectively than the small-molecule CXCR4 antagonist AMD3100. In vitro, LY2510924 chiefly inhibited the proliferation of AML cells with little induction of cell death and reduced protection against chemotherapy by stromal cells. In mice with established AML, LY2510924 caused initial mobilization of leukemic cells into the circulation followed by reduction in total tumor burden. LY2510924 had antileukemia effects as monotherapy as well as in combination with chemotherapy. Gene expression profiling of AML cells isolated from LY2510924-treated mice demonstrated changes consistent with loss of SDF-1α/CXCR4 signaling and suggested reduced proliferation and induction of differentiation, which was proved by showing the attenuation of multiple prosurvival pathways such as PI3K/AKT, MAPK, and β-catenin and myeloid differentiation in vivo. Effective disruption of the SDF-1α/CXCR4 axis by LY2510924 may translate into effective antileukemia therapy in future clinical applications.
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| 26036431 |
Vascular Targeting of a Gold Nanoparticle to Breast Cancer Metastasis |
10.1002/jps.24518. |
J Pharm Sci |
Vascular Targeting of a Gold Nanoparticle to Breast Cancer Metastasis
Abstract
- The vast majority of breast cancer deaths are due to metastatic disease. Although deep tissue targeting of nanoparticles is suitable for some primary tumors, vascular targeting may be a more attractive strategy for micrometastasis. This study combined a vascular targeting strategy with the enhanced targeting capabilities of a nanoparticle to evaluate the ability of a gold nanoparticle (AuNP) to specifically target the early spread of metastatic disease. As a ligand for the vascular targeting strategy, we utilized a peptide targeting alpha(v) beta(3) integrin, which is functionally linked to the development of micrometastases at a distal site. By employing a straightforward radiolabeling method to incorporate Technetium-99m into the AuNPs, we used the high sensitivity of radionuclide imaging to monitor the longitudinal accumulation of the nanoparticles in metastatic sites. Animal and histological studies showed that vascular targeting of the nanoparticle facilitated highly accurate targeting of micrometastasis in the 4T1 mouse model of breast cancer metastasis using radionuclide imaging and a low dose of the nanoparticle. Because of the efficient targeting scheme, 14% of the injected AuNP deposited at metastatic sites in the lungs within 60 min after injection, indicating that the vascular bed of metastasis is a viable target site for nanoparticles.
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| 26064310 |
Novel cyclotides from Hedyotis diffusa induce apoptosis and inhibit proliferation and migration of prostate cancer cells |
eCollection 2015. |
Int J Clin Exp Med |
Novel cyclotides from Hedyotis diffusa induce apoptosis and inhibit proliferation and migration of prostate cancer cells
Abstract
- Hedyotis diffusa is a well-known herb in traditional Chinese Medicine (TCM) which is used to treat various cancers including prostate cancer. Recently, lots of cyclotides possessing anti-cancer activities were found in Hedyotis family plants, suggesting that H.diffusa may also contain these bioactive ingredients. Cyclotides are heat-stable macrocyclic peptides from plants that display a wide range of biological activities. Currently, over 250 cyclotides have been discovered.
This study tried to isolate novel cyclotides from H.diffusa and further investigate their anti-cancer activities for the prostate cancer cells in vitro and in vivo.
The novel cyclotides from H.diffusa were isolated and purified by High-performance liquid chromatography (HPLC), amino acid sequences in their primary structure were confirmed using Edman degradation and gene cloning. Colorimetric cell viability assay (CCK8 assay), wound healing assay and human prostate cancer xenograft were used to analyze their anti-prostate cancer activity in vitro and in vivo.
Three novel cyclotides, termed as Diffusa cyclotide 1 to 3 (DC1-3) from the leaves and root of H.diffusa, were isolated firstly based on my knowledge. Using Edman degradation sequencing and gene cloning, we confirmed their amino acid sequence and obtained precursors of these peptides. By CCK8 assay, all present cyclotides showed potent cytotoxicity against all three prostate cancer cell lines, especially for DC3. In migration assay and wound healing assay, DC3 inhibited the cell migration and invasion Of LNCap cells. By model of prostate xenograft, DC3 could significantly inhibit development of the tumor in weight and size compared to the placebo.
The novel cyclotides extracted from H.Diffusa have anti-cancer effects, and they are potential bioactive ingredients in H.diffusa.
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| 26172377 |
Transforming conotoxins into cyclotides: Backbone cyclization of P-superfamily conotoxins |
10.1002/bip.22699. |
Biopolymers |
Transforming conotoxins into cyclotides: Backbone cyclization of P-superfamily conotoxins
Abstract
- Peptide backbone cyclization is a widely used approach to improve the activity and stability of small peptides but until recently it had not been applied to peptides with multiple disulfide bonds. Conotoxins are disulfide-rich conopeptides derived from the venoms of cone snails that have applications in drug design and development. However, because of their peptidic nature, they can suffer from poor bioavailability and poor stability in vivo. In this study two P-superfamily conotoxins, gm9a and bru9a, were backbone cyclized by joining the N- and C-termini with short peptide linkers using intramolecular native chemical ligation chemistry. The cyclized derivatives had conformations similar to the native peptides showing that backbone cyclization can be applied to three disulfide-bonded peptides with cystine knot motifs. Cyclic gm9a was more potent at high voltage-activated (HVA) calcium channels than its acyclic counterpart, highlighting the value of this approach in developing active and stable conotoxins containing cyclic cystine knot motifs.
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| 26174911 |
Identification, Characterization, and Three-Dimensional Structure of the Novel Circular Bacteriocin, Enterocin NKR-5-3B, from Enterococcus faecium |
10.1021/acs.biochem.5b00196. |
Biochemistry |
Identification, Characterization, and Three-Dimensional Structure of the Novel Circular Bacteriocin, Enterocin NKR-5-3B, from Enterococcus faecium
Abstract
- Enterocin NKR-5-3B, one of the multiple bacteriocins produced by Enterococcus faecium NKR-5-3, is a 64-amino acid novel circular bacteriocin that displays broad-spectrum antimicrobial activity. Here we report the identification, characterization, and three-dimensional nuclear magnetic resonance solution structure determination of enterocin NKR-5-3B. Enterocin NKR-5-3B is characterized by four helical segments that enclose a compact hydrophobic core, which together with its circular backbone impart high stability and structural integrity. We also report the corresponding structural gene, enkB, that encodes an 87-amino acid precursor peptide that undergoes a yet to be described enzymatic processing that involves adjacent cleavage and ligation of Leu(24) and Trp(87) to yield the mature (circular) enterocin NKR-5-3B.
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| 26184239 |
Identification of the Scopularide Biosynthetic Gene Cluster in Scopulariopsis brevicaulis |
10.3390/md13074331. |
Mar Drugs |
Identification of the Scopularide Biosynthetic Gene Cluster in Scopulariopsis brevicaulis
Abstract
- Scopularide A is a promising potent anticancer lipopeptide isolated from a marine derived Scopulariopsis brevicaulis strain. The compound consists of a reduced carbon chain (3-hydroxy-methyldecanoyl) attached to five amino acids (glycine, l-valine, d-leucine, l-alanine, and l-phenylalanine). Using the newly sequenced S. brevicaulis genome we were able to identify the putative biosynthetic gene cluster using genetic information from the structurally related emericellamide A from Aspergillus nidulans and W493-B from Fusarium pseudograminearum. The scopularide A gene cluster includes a nonribosomal peptide synthetase (NRPS1), a polyketide synthase (PKS2), a CoA ligase, an acyltransferase, and a transcription factor. Homologous recombination was low in S. brevicaulis so the local transcription factor was integrated randomly under a constitutive promoter, which led to a three to four-fold increase in scopularide A production. This indirectly verifies the identity of the proposed biosynthetic gene cluster.
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| 26195308 |
CycloBranch: De Novo Sequencing of Nonribosomal Peptides from Accurate Product Ion Mass Spectra |
10.1007/s13361-015-1211-1. |
J Am Soc Mass Spectrom |
CycloBranch: De Novo Sequencing of Nonribosomal Peptides from Accurate Product Ion Mass Spectra
Abstract
- Nonribosomal peptides have a wide range of biological and medical applications. Their identification by tandem mass spectrometry remains a challenging task. A new open-source de novo peptide identification engine CycloBranch was developed and successfully applied in identification or detailed characterization of 11 linear, cyclic, branched, and branch-cyclic peptides. CycloBranch is based on annotated building block databases the size of which is defined by the user according to ribosomal or nonribosomal peptide origin. The current number of involved nonisobaric and isobaric building blocks is 287 and 521, respectively. Contrary to all other peptide sequencing tools utilizing either peptide libraries or peptide fragment libraries, CycloBranch represents a true de novo sequencing engine developed for accurate mass spectrometric data. It is a stand-alone and cross-platform application with a graphical and user-friendly interface; it supports mzML, mzXML, mgf, txt, and baf file formats and can be run in parallel on multiple threads. It can be downloaded for free from http://ms.biomed.cas.cz/cyclobranch/ , where the User's manual and video tutorials can be found.
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| 26206286 |
Antimicrobial activity of human α-defensin 5 and its linear analogs: N-terminal fatty acylation results in enhanced antimicrobial activity of the linear analogs |
10.1016/j.peptides.2015.07.009. |
Peptides |
Antimicrobial activity of human α-defensin 5 and its linear analogs: N-terminal fatty acylation results in enhanced antimicrobial activity of the linear analogs
Abstract
- Human α-defensin 5 (HD5) exhibits broad spectrum antimicrobial activity and plays an important role in mucosal immunity of the small intestine. Although there have been several studies, the structural requirements for activity and mechanism of bacterial killing is yet to be established unequivocally. In this study, we have investigated the antimicrobial activity of HD5 and linear analogs. Cysteine deletions attenuated the antibacterial activity considerably. Candidacidal activity was affected to a lesser extent. Fatty acid conjugated linear analogs showed antimicrobial activity comparable activity to HD5. Effective surface charge neutralization of bacteria was observed for HD5 as compared to the non-fatty acylated linear analogs. Our results show that HD5 and non-fatty acylated linear analogs enter the bacterial cytoplasm without causing damage to the bacterial inner membrane. Although fatty acylated peptides exhibited antimicrobial activity comparable to HD5, their mechanism of action involved permeabilization of the Escherichia coli inner membrane. HD5 and analogs had the ability to bind plasmid DNA. HD5 had greater binding affinity to plasmid DNA as compared to the analogs. The three dimensional structure of HD5 favors greater interaction with the bacterial cell surface and also with DNA. Antibacterial activity of HD5 involves entry into bacterial cytoplasm and binding to DNA which would result in shut down of the bacterial metabolism leading to cell death. We show how a moderately active linear peptide derived from the α-defensin HD5 can be engineered to enhance antimicrobial activity almost comparable to the native peptide.
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| 26213786 |
Callyaerins from the Marine Sponge Callyspongia aerizusa: Cyclic Peptides with Antitubercular Activity |
10.1021/acs.jnatprod.5b00266. |
J Nat Prod |
Callyaerins from the Marine Sponge Callyspongia aerizusa: Cyclic Peptides with Antitubercular Activity
Abstract
- Chemical investigation of the Indonesian sponge Callyspongia aerizusa afforded five new cyclic peptides, callyaerins I-M (1-5), along with the known callyaerins A-G (6-12). The structures of the new compounds were unambiguously elucidated on the basis of one- and two-dimensional NMR spectroscopy and mass spectrometry. In addition, the structures of callyaerins D (9), F (11), and G (12), previously available in only small amounts, have been reinvestigated and revised. All compounds were tested in vitro against Mycobacterium tuberculosis, as well as against THP-1 (human acute monocytic leukemia) and MRC-5 (human fetal lung fibroblast) cell lines, in order to assess their general cytotoxicity. Callyaerins A (6) and B (7) showed potent anti-TB activity with MIC₉₀ values of 2 and 5 μM, respectively. Callyaerin C (8) was found to be less active, with an MIC₉₀ value of 40 μM. Callyaerin A (6), which showed the strongest anti-TB activity, was not cytotoxic to THP-1 or MRC-5 cells (IC₅₀ > 10 μM), which highlights the potential of these compounds as promising anti-TB agents.
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| 26235946 |
Antimicrobial activity of doubly-stapled alanine/lysine-based peptides |
10.1016/j.bmcl.2015.06.053. |
Bioorg Med Chem Lett |
Antimicrobial activity of doubly-stapled alanine/lysine-based peptides
Abstract
- In this study, we examined the potential of Verdine's double-stapling system for the de novo design of amphipathic helical antimicrobial peptides. We designed, synthesized, and tested a prototypical doubly-stapled helix of an alanine/lysine based model sequence, which showed reasonable antimicrobial activities and highly increased proteolytic stability. We then show that its hemolytic activity as well as antimicrobial activities can be further manipulated through the systematic modifications. Overall, the preliminary results obtained from this study imply that the doubly-stapled helices of short peptides can serve as a highly promising scaffold for the rational design of potent, selective, and metabolically stable antimicrobial peptides that can combat against the growing problems of antibiotic-resistance.
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| 26242382 |
Pharmacokinetics and Safety of Single Intravenous Doses of JNJ-54452840, an Anti-β1-Adrenergic Receptor Antibody Cyclopeptide, in Healthy Male Japanese and Caucasian Participants |
10.1007/s40262-015-0309-8. |
Clin Pharmacokinet |
Pharmacokinetics and Safety of Single Intravenous Doses of JNJ-54452840, an Anti-β1-Adrenergic Receptor Antibody Cyclopeptide, in Healthy Male Japanese and Caucasian Participants
Abstract
- To evaluate the pharmacokinetics and safety of single intravenous doses of JNJ-54452840 infused over 1 minute in healthy male Japanese and Caucasian participants. JNJ-54452840 is a novel peptide for the treatment of chronic heart failure, with a proposed mechanism of action of binding interference and decreased production of anti-β1-adrenergic receptor (anti-β1-AR) antibodies, which stimulate the cardiac β1-AR.
In this randomized, single-centre, double-blind, placebo-controlled, four-way crossover study, 32 male Japanese and Caucasian participants (16 in each group) received single intravenous doses of JNJ-54452840 20, 80 and 240 mg, and placebo, each separated by a ≥7-day washout period. Pharmacokinetics and safety were assessed predose and at specified timepoints for 24 h. Anti-β1-AR antibodies were monitored.
The mean JNJ-54452840 maximum observed plasma concentration (C max) and area under the concentration-time curve from time zero to infinity with extrapolation of the terminal phase (AUCinf) values increased linearly with dose, with rapid elimination in both groups. Dose proportionality criteria were not met between the 20 and 240 mg doses for both study cohorts. The median time to reach C max (T max) ranged from 1 to 5 minutes. The mean total systemic clearance after intravenous administration (CL), volume of distribution at steady state (V ss), mean residence time (MRT) and terminal half-life (T ½) values were similar for both groups. The mean T ½ values ranged from 5.9 to 26.1 min in a dose-dependent manner. The overall prevalence of antibodies was 9.4 % at baseline; antibodies not present at baseline developed in five Caucasians (15.6 %) but not in Japanese participants. One participant in each group experienced a serious thromboembolic event (pulmonary embolism, ischaemic stroke).
JNJ-54452840 demonstrated similar pharmacokinetics in both groups. JNJ-54452840 was possibly immunogenic, and two participants reported thromboembolic serious adverse events. The relationship between these events and antibody formation is not known.
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| 26246035 |
Exogenous plant hormones and cyclotide expression in Viola uliginosa (Violaceae) |
10.1016/j.phytochem.2015.07.016. |
Phytochemistry |
Exogenous plant hormones and cyclotide expression in Viola uliginosa (Violaceae)
Abstract
- Plants from Violaceae produce cyclotides, peptides characterized by a circular peptide backbone and a cystine knot. This signature motif gives stability that can harness a wide spectrum of biological activities, with implications in plant defense and with applications in medicine and biotechnology. In the current work, cyclotide expressing in vitro cultures were established from Viola uliginosa. These cultures are useful models for studying biosynthesis of cyclotides and can also be used in their production. The cyclotide expression pattern is shown to be dependent on exogenous plant growth regulators, both on peptide and gene expression levels. The highest yields of cyclotides were obtained on media containing only a cytokinin and were correlated with storage material accumulation. Exposure to auxins decreased cyclotide production and caused shifting of the biosynthesis pattern to root specific cyclotides. The response to stimuli in terms of cyclotide expression pattern appears to be developmental, and related to polar auxin transportation and the auxin/cytokinin ratio regulating tissue differentiation. By the use of whole transcriptome shotgun sequencing (WTSS) and peptidomics, 20 cyclotide sequences from V. uliginosa (including 12 new) and 12 complete precursor proteins could be identified. The most abundant cyclotides were cycloviolacin O3 (CyO3), CyO8 and CyO13. A suspension culture was obtained that grew exponentially with a doubling time of approximately 3 days. After ten days of growth, the culture provided a yield of more than 4 mg CyO13 per gram dry mass.
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| 26264857 |
Design of substrate-based BCR-ABL kinase inhibitors using the cyclotide scaffold |
10.1038/srep12974. |
Sci Rep |
Design of substrate-based BCR-ABL kinase inhibitors using the cyclotide scaffold
Abstract
- The constitutively active tyrosine kinase BCR-ABL is the underlying cause of chronic myeloid leukemia (CML). Current CML treatments rely on the long-term use of tyrosine kinase inhibitors (TKIs), which target the ATP binding site of BCR-ABL. Over the course of treatment, 20-30% of CML patients develop TKI resistance, which is commonly attributed to point mutations in the drug-binding region. We design a new class of peptide inhibitors that target the substrate-binding site of BCR-ABL by grafting sequences derived from abltide, the optimal substrate of Abl kinase, onto a cell-penetrating cyclotide MCoTI-II. Three grafted cyclotides show significant Abl kinase inhibition in vitro in the low micromolar range using a novel kinase inhibition assay. Our work also demonstrates that a reengineered MCoTI-II with abltide sequences grafted in both loop 1 and 6 inhibits the activity of [T315I]Abl in vitro, a mutant Abl kinase harboring the "gatekeeper" mutation which is notorious for being multidrug resistant. Results from serum stability and cell internalization studies confirm that the MCoTI-II scaffold provides enzymatic stability and cell-penetrating properties to the lead molecules. Taken together, our study highlights that reengineered cyclotides incorporating abltide-derived sequences are promising substrate-competitive inhibitors for Abl kinase and the T315I mutant.
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| 26322745 |
Lysine-rich Cyclotides: A New Subclass of Circular Knotted Proteins from Violaceae |
10.1021/acschembio.5b00454. |
ACS Chem Biol |
Lysine-rich Cyclotides: A New Subclass of Circular Knotted Proteins from Violaceae
Abstract
- Cyclotides are macrocyclic proteins produced by plants for host defense. Although they occur sparsely in other plant families, cyclotides have been detected in every Violaceae plant species so far screened. Many of the Violaceae species examined until now have been from closely related geographical regions or habitats. To test the hypothesis that cyclotides are ubiquitous in this family, two geographically isolated (and critically endangered) species of Australasian Violaceae, namely Melicytus chathamicus and M. latifolius, were examined. Surprisingly, we discovered a suite of cyclotides possessing novel sequence features, including a lysine-rich nature, distinguishing them from "conventional" cyclotides and suggesting that they might have different physiological activities in plants to those reported to date. The newly discovered cyclotides were found to bind to lipid membranes and were cytotoxic against cancer cell lines but had low toxicity against red blood cells, which is advantageous for potential therapeutic applications. This suite of novel Lys-rich cyclotides emphasizes the broad diversity of cyclotides in Violaceae species.
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| 26322961 |
Comparative Venomics Reveals the Complex Prey Capture Strategy of the Piscivorous Cone Snail Conus catus |
10.1021/acs.jproteome.5b00630. |
J Proteome Res |
Comparative Venomics Reveals the Complex Prey Capture Strategy of the Piscivorous Cone Snail Conus catus
Abstract
- Venomous marine cone snails produce a unique and remarkably diverse range of venom peptides (conotoxins and conopeptides) that have proven to be invaluable as pharmacological probes and leads to new therapies. Conus catus is a hook-and-line fish hunter from clade I, with ∼20 conotoxins identified, including the analgesic ω-conotoxin CVID (AM336). The current study unravels the venom composition of C. catus with tandem mass spectrometry and 454 sequencing data. From the venom gland transcriptome, 104 precursors were recovered from 11 superfamilies, with superfamily A (especially κA-) conotoxins dominating (77%) their venom. Proteomic analysis confirmed that κA-conotoxins dominated the predation-evoked milked venom of each of six C. catus analyzed and revealed remarkable intraspecific variation in both the intensity and type of conotoxins. High-throughput FLIPR assays revealed that the predation-evoked venom contained a range of conotoxins targeting the nAChR, Cav, and Nav ion channels, consistent with α- and ω-conotoxins being used for predation by C. catus. However, the κA-conotoxins did not act at these targets but induced potent and rapid immobilization followed by bursts of activity and finally paralysis when injected intramuscularly in zebrafish. Our venomics approach revealed the complexity of the envenomation strategy used by C. catus, which contains a mix of both excitatory and inhibitory venom peptides.
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