ORCID Profile
0000-0002-3951-1866
Current Organisation
University of South Australia
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Publisher: American Society for Pharmacology & Experimental Therapeutics (ASPET)
Date: 02-11-2006
Abstract: Most drugs currently employed in the treatment of type 2 diabetes either target the sulfonylurea receptor stimulating insulin release (sulfonylureas, glinides), or target the peroxisome proliferator-activated receptor (PPARgamma) improving insulin resistance (thiazolidinediones). Our work shows that sulfonylureas and glinides additionally bind to PPARgamma and exhibit PPARgamma agonistic activity. This activity was predicted in silico by virtual screening and confirmed in vitro in a binding assay, a transactivation assay, and by measuring the expression of PPARgamma target genes. Among the measured compounds, gliquidone and glipizide (two sulfonylureas), as well as nateglinide (a glinide), exhibit PPARgamma agonistic activity at concentrations comparable with those reached under pharmacological treatment. The most active of these compounds, gliquidone, is shown to be as potent as pioglitazone at inducing PPARgamma target gene expression. This dual mode of action of sulfonylureas and glinides may open new perspectives for the molecular pharmacology of antidiabetic drugs, because it provides evidence that drugs can be designed that target both the sulfonylurea receptor and PPARgamma. Targeting both receptors could increase pancreatic insulin secretion and improve insulin resistance. Glinides, sulfonylureas, and other acidified sulfonamides may be promising leads in the development of new PPARgamma agonists. In addition, we provide a unified concept of the PPARgamma binding ability of seemingly disparate compound classes.
Publisher: Wiley
Date: 12-02-2014
Abstract: Phosphorylation of eIF4E by human mitogen-activated protein kinase (MAPK)-interacting kinases (Mnks) is crucial for human tumourigenesis and development. Targeting Mnks may provide a novel anticancer therapeutic strategy. However, the lack of selective Mnk inhibitors has so far h ered pharmacological target validation and clinical drug development. Herein, we report, for the first time, the discovery of a series of 5-(2-(phenylamino)pyrimidin-4-yl)thiazole-2(3H)-one derivatives as Mnk inhibitors. Several derivatives demonstrate very potent Mnk2 inhibitory activity. The most active and selective compounds were tested against a panel of cancer cell lines, and the results confirm the cell-type-specific effect of these Mnk inhibitors. Detailed cellular mechanistic studies reveal that Mnk inhibitors are capable of reducing the expression level of anti-apoptotic protein Mcl-1, and of promoting apoptosis in MV4-11 acute myeloid leukaemia cells.
Publisher: Oxford University Press (OUP)
Date: 10-1994
DOI: 10.1002/JLB.56.4.514
Abstract: It is well known that bacterial lipopolysaccharide (LPS) induces the synthesis of tumor necrosis factor α (TNF-α) and other inflammatory cytokines by primary monocytes and macrophages and that the Thl lymphokines, interleukin-2 (IL-2) and interferon-γ (IFN-γ), augment this response. We investigated the ability of IL-2 and IFN-γ to induce the production of TNF-α mRNA and protein independently of LPS and the modulation of this response by macrophage colony-stimulating factor (M-CSF) and IL-10. We found that IL-2 and IFN-γ were both able to induce the accumulation of TNF-α mRNA, albeit with slower kinetics than LPS, and that they acted synergistically. However, very little TNF bioactivity was secreted by lymphokine-stimulated macrophages unless LPS was also added. This finding underscores the importance of translational effects in the control of TNF production. M-CSF and IL-10 strongly inhibited TNF production at the level of both mRNA and bioactivity but had no effect on the production of IL-6. Bone marrow-derived or thiogycollate-elicited macrophages from the NZW mouse strain, which have been reported to be deficient in their ability to produce TNF, were at least as responsive to LPS or lymphokines as those taken from the C57B1/6 strain and were similarly affected by M-CSF and IL-10. Therefore, the genetic defect of NZW mice is not a primary deficiency in TNF production J. Leukoc. Biol. 56: 514–520 1994.
Publisher: Wiley
Date: 12-1991
DOI: 10.1111/J.1432-1033.1991.TB16373.X
Abstract: To obtain information on the structural and functional role of highly conserved amino acid residues in the B870 alpha and beta light-harvesting polypeptides of Rhodobacter capsulatus, site-directed mutagenesis was performed. 18 mutants with single amino acid substitutions at nine different positions in the B870 antenna polypeptides were prepared in a B800-850-lacking strain. The characterization of the resulting phenotypes was based on a quantification of the core-complex elements (reaction center, light-harvesting polypeptides, bacteriochlorophyll a and carotenoid) and the core-complex spectral characteristics (absorption maximum, absorption coefficient and fluorescence intensity). These data generally showed that strong structural effects were caused by the amino acid substitutions. Thus, the three tryptophan exchanges at the position alpha 8 resulted in either the absence of a core complex (alpha Trp8----Leu), the absence of the core antenna (alpha Trp8----Ala) or a reduction in the carotenoid content (alpha Trp8----Tyr). Likewise, the mutants alpha Pro13Gly (i.e. alpha Pro13----Gly), beta Gly10Val and alpha Phe23Ala demonstrated an abnormal protein igment ratio in the core antenna, while a drastically reduced antenna size resulted from the amino acid exchange beta Arg45Asp. In contrast to the structural effects, the absorption maxima and the fluorescence intensities of the mutant antennae differed only slightly from the wild type. The strongest blue shift of the bacteriochlorophyll a (8-11 nm) was induced by substitutions of the Trp at position alpha 43 (alpha Trp43----Ala, Leu or Tyr). Contrary to the other spectral effects, the absorption coefficient of bacteriochlorophyll a was strongly influenced by the amino acid substitutions and varied by 1.6-times less (beta Arg45Asp) and 1.3-times greater (alpha Phe25Ala) than normal. The antenna-free mutant, alpha Trp8Ala, yielded a high rate of B800-850 revertants during phototrophic growth, indicating a direct energy transfer from the B800-850 antenna to the reaction center in these strains. Although conditions for growth were generally observed to influence phenotypic expression, the structural as well as spectral effects were demonstrated to differ to the greatest extent between chemotrophically grown and phototrophically grown cells.
Publisher: Future Science Ltd
Date: 03-2016
DOI: 10.4155/FMC.15.190
Abstract: The discovery of small molecules that selectively inhibit Mnks is considered of paramount importance towards deciphering the exact role of these proteins in carcinogenesis and to further validate them as anti-cancer drug targets. However, the dearth of structural information of Mnks is a major hurdle. This study unveils the 7H-pyrrolo[2,3-d]pyrimidine derivatives as potent inhibitors of Mnks. ATP and substrate competition assays showed that this scaffold interacts with the ATP binding site, but not with the substrate site. Screened against a panel of cancer cells, Mnk inhibitors were most potent against MV4-11 acute myeloid leukemia cells. The induction of apoptosis was shown to be mediated by downregulation of Mcl-1.
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.JCONREL.2019.07.001
Abstract: Stents are currently the primary choice for the treatment of both vascular and non-vascular occlusions and/or stenosis. Despite the proven history of clinical safety and efficacy, the benefit of traditional vascular or non-vascular stenting is often limited by in-stent restenosis, resulting in failure of existing stent or reintervention by use of another stent. Coronary drug-eluting stents (DESs) significantly reduce restenosis of vascular stents and have revolutionised the percutaneous coronary intervention (PCI) treatment in coronary stenting patients. Following the similar concept of coronary DESs, non-vascular DESs are being investigated to reduce non-vascular restenosis caused by tumour growth, enhance stenting functions, and increase their effectiveness in the treatment of obstructive gastrointestinal (GI) cancers. This article summarises and updates the outcomes of preclinical and clinical studies on non-vascular DESs for localised management of malignant GI obstructions with emphasis on fabrication techniques and regulatory requirements relevant to development and marketing approval.
Publisher: American Society for Pharmacology & Experimental Therapeutics (ASPET)
Date: 12-08-2015
Abstract: Elevated levels of phosphorylated eukaryotic initiation factor 4E (eIF4E) have been implicated in many tumor types, and mitogen activated protein kinase-interacting kinases (Mnks) are the only known kinases that phosphorylate eIF4E at Ser209. The phosphorylation of eIF4E is essential for oncogenic transformation but is of no significance to normal growth and development. Pharmacological inhibition of Mnks therefore provides a nontoxic and effective strategy for cancer therapy. However, a lack of specific Mnk inhibitors has confounded pharmacological target validation and clinical development. Herein, we report the identification of a novel series of Mnk inhibitors and their binding modes. A systematic workflow has been established to distinguish between type III and type I/II inhibitors. A selection of 66 compounds was tested for Mnk1 and Mnk2 inhibition, and 9 out of 20 active compounds showed type III interaction with an allosteric site of the proteins. Most of the type III inhibitors exhibited dual Mnk1 and Mnk2 activities and demonstrated potent antiproliferative properties against the MV4-11 acute myeloid leukemia cell line. Interestingly, ATP-/substrate-competitive inhibitors were found to be highly selective for Mnk2, with little or no activity for Mnk1. Our study suggests that Mnk1 and Mnk2 share a common structure of the allosteric inhibitory binding site but possess different structural features of the ATP catalytic domain. The findings will assist in the future design and development of Mnk targeted anticancer therapeutics.
Publisher: SAGE Publications
Date: 02-1995
DOI: 10.1177/096805199500200101
Abstract: The presence of functional lipopolysaccharide binding protein (LBP) was investigated in cerebrospinal fluid (CSF) s les of patients with neurological disorders. LBP was detected in CSF by RIA and by a bioassay that measures the ability of LBP to present LPS to human monocytes. Mean concentration of LBP was 1.72 μg/ml in normal CSF, i.e. 1/10 of the concentration measured in normal plasma. LBP concentration was found to be increased in CSF of patients with neurological disorders associated with increased protein levels in CSF, in patients with meningitis/encephalitis and with compressing tumors. LBP levels correlated with protein levels, but not with the clinical presentation. Even in normal CSF, LBP was present in concentrations sufficient to trigger maximal activation of monocytes upon LPS challenge, as measured by tumor necrosis factor induction of mRNA and protein synthesis. The role played by LBP in CSF remains to be determined. However, because it is present and functionally fully active, LBP could play a detrimental role in CSF in the presence of low concentrations of LPS during episodes of Gram-negative infections.
Publisher: American Chemical Society (ACS)
Date: 20-03-2019
Publisher: MDPI AG
Date: 21-04-2023
Abstract: Polymeric micelles are promising carriers for the delivery of poorly water-soluble drugs, providing enhanced drug solubility, blood circulation times, and bioavailability. Nevertheless, the storage and long-term stability of micelles in solution present challenges requiring the lyophilization and storage of formulations in the solid state, with reconstitution immediately prior to application. Therefore, it is important to understand the effects of lyophilization/reconstitution on micelles, particularly their drug-loaded counterparts. Herein, we investigated the use of β-cyclodextrin (β-CD) as a cryoprotectant for the lyophilization/reconstitution of a library of poly(ethylene glycol-b-ε-caprolactone) (PEG-b-PCL) copolymer micelles and their drug-loaded counterparts, as well as the effect of the physiochemical properties of different drugs (phloretin and gossypol). The critical aggregation concentration (CAC) of the copolymers decreased with increasing weight fraction of the PCL block (fPCL), plateauing at ~1 mg/L when the fPCL was .45. The blank (empty) and drug-loaded micelles were lyophilized/reconstituted in the absence and presence of β-CD (9% w/w) and analyzed via dynamic light scattering (DLS) and synchrotron small-angle X-ray scattering (SAXS) to assess for changes in aggregate size (hydrodynamic diameter, Dh) and morphology, respectively. Regardless of the PEG-b-PCL copolymer or the use of β-CD, the blank micelles displayed poor redispersibility ( % relative to the initial concentration), while the fraction that redispersed displayed similar Dh to the as-prepared micelles, increasing in Dh as the fPCL of the PEG-b-PCL copolymer increased. While most blank micelles displayed discrete morphologies, the addition of β-CD or lyophilization/reconstitution generally resulted in the formation of poorly defined aggregates. Similar results were also obtained for drug-loaded micelles, with the exception of several that retained their primary morphology following lyophilization/reconstitution, although no obvious trends were noted between the microstructure of the copolymers or the physicochemical properties of the drugs and their successful redispersion.
Publisher: MDPI AG
Date: 19-02-2021
Abstract: Synthetic polypeptides and polymer-peptide hybrid materials have been successfully implemented in an array of biomedical applications owing to their biocompatibility, biodegradability and ability to mimic natural proteins. In addition, these materials have the capacity to form complex supramolecular structures, facilitate specific biological interactions, and incorporate a erse selection of functional groups that can be used as the basis for further synthetic modification. Like conventional synthetic polymers, polypeptide-based materials can be designed to respond to external stimuli (e.g., light and temperature) or changes in the environmental conditions (e.g., redox reactions and pH). In particular, pH-responsive polypeptide-based systems represent an interesting avenue for the preparation of novel drug delivery systems that can exploit physiological or pathological pH variations within the body, such as those that arise in the extracellular tumour microenvironment, intracellularly within endosomes/lysosomes, or during tissue inflammation. Here, we review the significant progress made in advancing pH-responsive polypeptides and polymer-peptide hybrid materials during the last five years, with a particular emphasis on the manipulation of ionisable functional groups, pH-labile linkages, pH-sensitive changes to secondary structure, and supramolecular interactions.
Publisher: Frontiers Media SA
Date: 10-05-2021
Abstract: Cyclin-dependent kinases (CDKs) are proteins pivotal to a wide range of cellular functions, most importantly cell ision and transcription, and their dysregulations have been implicated as prominent drivers of tumorigenesis. Besides the well-established role of cell cycle CDKs in cancer, the involvement of transcriptional CDKs has been confirmed more recently. Most cancers overtly employ CDKs that serve as key regulators of transcription (e.g., CDK9) for a continuous production of short-lived gene products that maintain their survival. As such, dysregulation of the CDK9 pathway has been observed in various hematological and solid malignancies, making it a valuable anticancer target. This therapeutic potential has been utilized for the discovery of CDK9 inhibitors, some of which have entered human clinical trials. This review provides a comprehensive discussion on the structure and biology of CDK9, its role in solid and hematological cancers, and an updated review of the available inhibitors currently being investigated in preclinical and clinical settings.
Publisher: Wiley
Date: 29-08-1994
DOI: 10.1016/0014-5793(94)00817-5
Abstract: The recent demonstration of the anti-oxidant properties of the Bcl-2 gene product suggested that expression of Bcl-2 may interfere with the nuclear migration of the NF-kappa B transcription factor, which is thought to depend on the presence of reactive oxygen intermediates. In mouse L cells, overexpression of Bcl-2 interfered with the activation of NF-kappa B by H2O2. However, Bcl-2 had no effect on the activation of NF-kappa B by TNF, even though it protected cells from TNF-induced apoptosis. The effects of exogenous pyrrolidine dithiocarbamate were very similar to those of Bcl-2 overexpression. We conclude that the protective effects of anti-oxidants against induced apoptotic cell death are unrelated to their ability to interfere with NF-kappa B activation.
Publisher: MDPI AG
Date: 02-09-2019
DOI: 10.3390/PHARMACEUTICS11090454
Abstract: The use of many anticancer drugs is problematic due to severe adverse effects. While the recent clinical launch of several kinase inhibitors led to tremendous progress, these targeted agents tend to be of non-specific nature within the kinase target class. Moreover, target mediated adverse effects limit the exploitation of some very promising kinase targets, including mitotic kinases. A future strategy will be the development of nanocarrier-based systems for the active delivery of kinase inhibitors using cancer specific surface receptors. The G-protein-coupled-receptors (GPCRs) represent the largest cell surface receptor family and some members are known to be frequently overexpressed in various cancer types. In the presented study, we used ovarian cancer tissues as an ex le to systematically identify concurrently overexpressed GPCRs and kinases. The rationale of this approach will guide the future design of nanoparticles, which will dock to GPCRs on cancer cells via specific ligands and deliver anticancer compounds after receptor mediated internalization. In addition to this, the approach is expected to be most effective by matching the inhibitor profiles of the delivered kinase inhibitors to the observed kinase gene expression profiles. We validated the suggested strategy in a meta-analysis, revealing overexpression of selected GPCRs and kinases in in idual s les of a large ovarian cancer data set. The presented data demonstrate a large untapped potential for personalized cancer therapy using high-end targeted nanopharmaceuticals with kinase inhibitors.
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.EJMECH.2017.08.006
Abstract: The discovery of novel anti-AML therapeutic agents is urgently needed, but the complex heterogeneity of the disease has so far h ered the development of a curative treatment. FLT3 inhibitors have shown therapeutic potential in clinical trials but a monotherapy regimen has been associated with resistance mediated by the activation of parallel signalling circuitry, including MAPK and mTOR. Therefore, inhibiting a nexus of the two signalling pathways along with inhibition of FLT3 might be advantageous. Herein, we propose that a dual inhibition of FLT3 and Mnk would provide a better clinical option for AML patients compared to targeting FLT3 alone. Thus, a series of N-phenyl-4-(thiazol-5-yl)pyrimidin-2-amines and 4-(indol-3-yl)-N-phenylpyrimidin-2-amines were prepared. Potent Mnk2 inhibitors, FLT3 inhibitors, and dual inhibitors of Mnk2 and FLT3 were identified and their anti-proliferative activities assessed against MV4-11 AML cell lines. Dual inhibition of FLT3 and Mnk2 caused the increased apoptotic cell death of MV4-11 cells compared to inhibition of FLT3 or Mnk2 alone.
Publisher: Bentham Science Publishers Ltd.
Date: 26-08-2019
DOI: 10.2174/1573406415666181219111511
Abstract: Aberrant expression of eukaryotic translation initiation factor 4E (eIF4E) is common in many types of cancer including acute myeloid leukaemia (AML). Phosphorylation of eIF4E by MAPK-interacting kinases (Mnks) is essential for the eIF4E-mediated oncogenic activity. As such, the pharmacological inhibition of Mnks can be an effective strategy for the treatment of cancer. A series of N-phenyl-4-(1H-pyrrol-3-yl)pyrimidin-2-amine derivatives was designed and synthesised. The Mnk inhibitory activity of these derivatives as well as their anti-proliferative activity against MV4-11 AML cells was determined. These compounds were identified as potent Mnk2 inhibitors. Most of them demonstrated potent anti-proliferative activity against MV4-11 AML cells. The cellular mechanistic studies of the representative inhibitors revealed that they reduced the level of phosphorylated eIF4E and induced apoptosis by down-regulating the anti-apoptotic protein myeloid cell leukaemia 1 (Mcl-1) and by cleaving poly(ADP-ribose)polymerase (PARP). The lead compound 7k possessed desirable pharmacokinetic properties and oral bioavailability. This work proposes that exploration of the structural ersity in the context of Nphenyl- 4-(1H-pyrrol-3-yl)pyrimidin-2-amine would offer potent and selective Mnk inhibitors.
Publisher: Impact Journals, LLC
Date: 18-05-2018
Publisher: Elsevier BV
Date: 2001
Publisher: Future Science Ltd
Date: 10-2017
Abstract: Selective abrogation of cyclin-dependent kinases (CDK) activity is a highly promising strategy in cancer treatment. The atypical CDK, CDK5 has long been known for its role in neurodegenerative diseases, and is becoming an attractive drug target for cancer therapy. Myriads of recent studies have uncovered that aberrant expression of CDK5 contributes to the oncogenic initiation and progression of multiple solid and hematological malignancies. CDK5 is also implicated in the regulation of cancer stem cell biology. In this review, we present the current state of knowledge of CDK5 as a druggable target for cancer treatment. We also provide a detailed outlook of designing selective and potent inhibitors of this enzyme.
Publisher: American Society for Pharmacology & Experimental Therapeutics (ASPET)
Date: 04-06-2015
Abstract: The Ras/Raf/MAPK and PI3K/Akt/mTOR pathways are key signaling cascades involved in the regulation of cell proliferation and survival, and have been implicated in the pathogenesis of several types of cancers, including acute myeloid leukemia (AML). The oncogenic activity of eIF4E driven by the Mnk kinases is a convergent determinant of the two cascades, suggesting that targeting the Mnk/eIF4E axis may provide therapeutic opportunity for the treatment of cancer. Herein, a potent and selective Mnk2 inhibitor (MNKI-85) and a dual-specific Mnk1 and Mnk2 inhibitor (MNKI-19), both derived from a thienopyrimidinyl chemotype, were selected to explore their antileukemic properties. MNKI-19 and MNKI-85 are effective in inhibiting the growth of AML cells that possess an M5 subtype with FLT3-internal tandem duplication mutation. Further mechanistic studies show that the downstream effects with respect to the selective Mnk1/2 kinase inhibition in AML cells causes G1 cell cycle arrest followed by induction of apoptosis. MNKI-19 and MNKI-85 demonstrate similar Mnk2 kinase activity and cellular antiproliferative activity but exhibit different time-dependent effects on cell cycle progression and apoptosis. Collectively, this study shows that pharmacologic inhibition of both Mnk1 and Mnk2 can result in a more pronounced cellular response than targeting Mnk2 alone. However, MNKI-85, a first-in-class inhibitor of Mnk2, can be used as a powerful pharmacologic tool in studying the Mnk2/eIF4E-mediated tumorigenic mechanism. In conclusion, this study provides a better understanding of the mechanism underlying the inhibition of AML cell growth by Mnk inhibitors and suggests their potential utility as a therapeutic agent for AML.
Publisher: Informa UK Limited
Date: 04-2021
DOI: 10.2147/DDDT.S299401
Publisher: Informa UK Limited
Date: 2018
DOI: 10.2147/IJN.S152485
Publisher: Bentham Science Publishers Ltd.
Date: 12-2004
Abstract: A cell-based assay using homogeneous time-resolved fluorescence has been developed for high throughput screening of putative beta-amyloid (Abeta)production inhibitors. In this assay, total Abeta is detected by simply adding two commercially available antibody complexes. The first was a biotinylated monoclonal antibody (4G8), specifically recognizing an epitope comprising the residues 17-24 of the Abetapeptide, complexed with europium cryptate-streptavidin conjugate. The second was a polyclonal antibody (BioS-N), raised against the N-terminus of the Abeta peptide, complexed with an allophycocyanin-anti rabbit antibody conjugate. Binding of the two complexes to the Abeta peptide brought europium cryptate (fluorescence donor) and allophycocyanin (fluorescence acceptor) into close proximity, consequently a fluorescent resonance energy transfer signal was produced upon excitation at 337 nm. The resulting fluorescence signal (665 nm) was then detected using a Discovery or a ViewLux reader. Detection of Abeta by the proposed method is possible at concentrations of approximately 1 nM. The method was employed for the detection of Abeta secreted from a stable transfected human neuroglioma cell line (H4) overexpressing a mutated form of the human amyloid precursor protein (APP695NL) and developed for robotic automation. At optimized conditions, signal-to-background ratios exceeding 5 and Z' factors around 0.7 were achieved in a 384-well format. High throughput screening of 56,913 potential Abeta production inhibitors led to identification of new non-cytotoxic and cell permeable compounds with potencies in the submicromolar range.
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.EJMECH.2015.03.032
Abstract: Phosphorylation of the eukaryotic initiation factor 4E (eIF4E) by mitogen-activated protein kinase (MAPK)-interacting kinases (Mnks) is essential for oncogenesis but unnecessary for normal development. Thus, pharmacological inhibition of Mnks may offer an effective and non-toxic anti-cancer therapeutic strategy. Herein, we report the discovery of 4-(dihydropyridinon-3-yl)amino-5-methylthieno[2,3-d]pyrimidine derivatives as potent Mnk inhibitors. Docking study of 7a in Mnk2 suggests that the compound is stabilised in the ATP binding site through multiple hydrogen bonds and hydrophobic interaction. Cellular mechanistic studies on MV-4-11 cells with leads 7a, 8e and 8f reveal that they are able to down-regulate the phosphorylated eIF4E, Mcl-1 and cyclin D1, and induce apoptosis.
Publisher: Impact Journals, LLC
Date: 23-07-2016
Publisher: Wiley
Date: 04-07-1995
Abstract: Local administration of high-dose r-TNF alpha with IFN gamma in the limbs of melanoma patients has proved to be a very promising treatment. To understand the role played by the effect of TNF on melanoma cells in tumor destruction, we have investigated the expression of TNF-receptors in melanoma cells using monoclonal antibodies specific for the type-A (75-kDa) and the type-B (55-kDa) TNF receptors. Flow cytometric analysis of cultured melanoma cells indicated the presence of both types of receptor. Quantificative differences in the relative levels of receptors were observed for different cells lines, although the type-B receptor was generally more strongly expressed. Similar results were obtained by immunohistochemistry on cryosections from tumor s les. Positive staining of variable intensity was observed for the type-B TNF-receptor in a high percentage of tumor cells. The type-A TNF-receptor was also detected, but with a weaker staining. The total TNF-binding activity of cultured melanoma cells, as measured by binding of 125I-labeled TNF alpha, was up-regulated between 2- and 4-fold by incubation of cells with activators of protein kinase A or IFN gamma. Treatment of cultured melanoma cells with dbc-AMP resulted in a selective induction of type-A TNF-receptors, without affecting the type-B receptor level. In contrast, IFN gamma was able to induce either type of receptor in a cell-line-dependent fashion. Addition of TNF alpha to melanoma cells induced the activation of the nuclear transcription factor kappa B, as measured in an electrophoretic mobility shift assay, thus indicating the biological significance of the TNF-receptors on these cells.
Publisher: Elsevier BV
Date: 03-2008
Abstract: Fluorometric imaging plate reader (FLIPR) membrane potential dyes (FMP-Red-Dye and FMP-Blue-Dye) were evaluated for the detection of compounds acting either as positive allosteric modulators or agonists on the GABA(A) receptor (GABA(A)R). A stable HEK293 cell line with constitutive expression of the rat GABA(A)R alpha1, beta2, and gamma2 genes was used to establish a functional high-throughput screening (HTS) assay based on measurement of the membrane potential change in living cells. The assay was validated with the FLIPR technology for identification of agonists and positive allosteric modulators using GABA and diazepam as model compounds. The FMP-Red-Dye showed better performance than the FMP-Blue-Dye, and the effects induced by GABA and diazepam were comparable to electrophysiology data. Subsequently, the assay was also validated with an ultra-HTS approach known as microarrayed compound screening (microARCS). The LOPAC library was used in a test screen for an initial assessment of the technology. Finally, the FLIPR and microARCS technologies were tested with a larger screening c aign. A focused library of 3520 putative positive modulators was tested with the FLIPR assay, and a erse subset of 84,480 compounds was selected for screening with the microARCS technology. All hits were subjected to verification using the FLIPR technology, and confirmed hits were subsequently evaluated by EC50 determination. Finally, selected hits were further confirmed with electrophysiology testing.
Publisher: CRC Press
Date: 16-09-2012
DOI: 10.1201/B11341-20
Publisher: Elsevier BV
Date: 12-2020
Publisher: American Chemical Society (ACS)
Date: 16-02-2017
Abstract: Aberrant activity of cyclin-dependent kinase (CDK) 8 is implicated in various cancers. While CDK8-targeting anticancer drugs are highly sought-after, no CDK8 inhibitor has yet reached clinical trials. Herein a large library of drug-like molecules was computationally screened using two complementary cascades to identify potential CDK8 inhibitors. Thirty-three hits were identified to inhibit CDK8 and seven of them were active against colorectal cancer cell lines. Finally, the primary target was confirmed using three promising hits.
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.EJMECH.2015.09.008
Abstract: Deregulation of protein synthesis is a common event in cancer. As MAPK-interacting kinases (Mnks) play critical roles in regulation of protein synthesis, they have emerged as novel anti-cancer targets. Mnks phosphorylate eukaryotic initiation factor 4E (eIF4E) and promote eIF4E-mediated oncogenic activity. Given that the kinase activity of Mnks is essential for oncogenesis but is dispensable for normal development, the discovery of potent and selective pharmacological Mnk inhibitors provides pharmacological target validation and offers a new strategy for cancer treatment. Herein, comprehensive in silico screening approaches were deployed, and three thieno[2,3-d]pyrimidine and pyrazolo[3,4-d]pyrimidine derivatives were identified as hit compounds. Further chemical modification of thieno[2,3-d]pyrimidine derivative 3 has given rise to a series of highly potent Mnk2 inhibitors that could be potential leads for the treatment of acute myeloid leukemia.
Publisher: Society for Neuroscience
Date: 27-10-2004
DOI: 10.1523/JNEUROSCI.3306-04.2004
Abstract: Serine proteases are considered to be involved in plasticity-related events in the nervous system, but their in vivo targets and the importance of their control by endogenous inhibitors are still not clarified. Here, we demonstrate the crucial role of a potent serine protease inhibitor, protease nexin-1 (PN-1), in the regulation of activity-dependent brain proteolytic activity and the functioning of sensory pathways. Neuronal activity regulates the expression of PN-1, which in turn controls brain proteolytic activity. In PN-1 -/- mice, absence of PN-1 leads to increased brain proteolytic activity, which is correlated with an activity-dependent decrease in the NR1 subunit of the NMDA receptor. Correspondingly, reduced NMDA receptor signaling is detected in their barrel cortex. This is coupled to decreased sensory evoked potentials in the barrel cortex and impaired whisker-dependent sensory motor function. Thus, a tight control of serine protease activity is critical for the in vivo function of the NMDA receptors and the proper function of sensory pathways.
Publisher: Bioscientifica
Date: 12-2016
DOI: 10.1530/ERC-16-0299
Abstract: Cyclin-dependent kinase 9 (CDK9) is a key transcriptional regulator and a lucrative target for cancer treatment. Targeting CDK9 can effectively confine the hyperactivity of androgen receptor and the constitutive expression of anti-apoptotic proteins both being main causes of prostate cancer (PCa) development and progression. In castrate-resistant PCa, traditional therapies that only target androgen receptor (AR) have become obsolete due to reprograming in AR activity to make the cells independent of androgen. CDK9 inhibitors may provide a new and better therapeutic opportunity over traditional treatment options by targeting both androgen receptor activity and anti-apoptotic proteins, improving the chances of positive outcomes, especially in patients with the advanced disease. This review focuses on biological functions of CDK9, its involvement with AR and the potential for therapeutic opportunities in PCa treatment.
Publisher: MDPI AG
Date: 22-02-2022
Abstract: Mutations in FMS-like tyrosine kinase 3 (FLT3) occur in approximately one-third of AML patients and are associated with a particularly poor prognosis. The most common mutation, FLT3-ITD, is a self-activating internal tandem duplication (ITD) in the FLT3 juxtamembrane domain. Many FLT3 inhibitors have shown encouraging results in clinical trials, but the rapid emergence of resistance has severely limited sustainable efficacy. Co-targeting of CDK9 and FLT3 is a promising two-pronged strategy to overcome resistance as the former plays a role in the transcription of cancer cell-survival genes. Most prominently, MCL-1 is known to be associated with AML tumorigenesis and drug resistance and can be down-regulated by CDK9 inhibition. We have developed CDDD11-8 as a potent CDK9 inhibitor co-targeting FLT3-ITD with Ki values of 8 and 13 nM, respectively. The kinome selectivity has been confirmed when the compound was tested in a panel of 369 human kinases. CDDD11-8 displayed antiproliferative activity against leukemia cell lines, and particularly potent effects were observed against MV4-11 and MOLM-13 cells, which are known to harbor the FLT3-ITD mutation and mixed lineage leukemia (MLL) fusion proteins. The mode of action was consistent with inhibition of CDK9 and FLT3-ITD. Most importantly, CDDD11-8 caused a robust tumor growth inhibition by oral administration in animal xenografts. At 125 mg/kg, CDDD11-8 induced tumor regression, and this was translated to an improved survival of animals. The study demonstrates the potential of CDDD11-8 towards the future development of a novel AML treatment.
Publisher: MDPI AG
Date: 10-05-2022
Abstract: The five-year survival rate for women with ovarian cancer is very poor despite radical cytoreductive surgery and chemotherapy. Although most patients initially respond to platinum-based chemotherapy, the majority experience recurrence and ultimately develop chemoresistance, resulting in fatal outcomes. The current administration of cytotoxic compounds is h ered by dose-limiting severe adverse effects. There is an unmet clinical need for targeted drug delivery systems that transport chemotherapeutics selectively to tumor cells while minimizing off-target toxicity. G protein-coupled receptors (GPCRs) are the largest family of membrane receptors, and many are overexpressed in solid tumors, including ovarian cancer. This review summarizes the progress in engineered nanoparticle research for drug delivery for ovarian cancer and discusses the potential use of GPCRs as molecular entry points to deliver anti-cancer compounds into ovarian cancer cells. A newly emerging treatment paradigm could be the personalized design of nanomedicines on a case-by-case basis.
Publisher: Elsevier BV
Date: 06-2022
DOI: 10.1016/J.PHRS.2022.106249
Abstract: Cyclin-dependent kinase 3 (CDK3) is a major player driving retinoblastoma (Rb) phosphorylation during the G
Publisher: MDPI AG
Date: 24-12-2020
DOI: 10.3390/PHARMACEUTICS13010017
Abstract: Self-expanding metal stents (SEMSs) are currently the gold standard for the localised management of malignant gastrointestinal (GI) stenosis and/or obstructions. Despite encouraging clinical success, in-stent restenosis caused by tumour growth is a significant challenge. Incorporating chemotherapeutic drugs into GI stents is an emerging strategy to provide localised and sustained release of drugs to intestinal malignant tissues to prevent tumour growth. Therefore, the aim of this work was to develop and evaluate a local GI stent-based delivery system that provides a controlled release of 5-fluorouracil (5FU) over a course of several weeks to months, for the treatment of colorectal cancer and cancer-related stenosis/obstructions. The 5FU-loaded GI stents were fabricated via sequential dip-coating of commercial GI stents with a drug-loaded polyurethane (PU) basecoat and a drug-free poly(ethylene-co-vinyl acetate) (PEVA) topcoat. For comparison, two types of commercial stents were investigated, including bare and silicone (Si) membrane-covered stents. The physicochemical properties of the 5FU-loaded stents were evaluated using photoacoustic Fourier-transform infrared (PA-FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and thermal analysis. In vitro release studies in biological medium revealed that the 5FU-loaded stents provided a sustained release of drug over the period studied (18 d), and cell viability, cell cycle distribution and apoptosis assays showed that the released 5FU had comparable anticancer activity against human colon cancer cells (HCT-116) to pure 5FU. This study demonstrates that dip-coating is a facile and reliable approach for fabricating drug-eluting stents (DESs) that are promising candidates for the treatment of GI obstructions and/or restenosis.
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.IJPHARM.2016.09.039
Abstract: In recent years G protein-coupled receptors (GPCRs) have emerged as crucial tumorigenic factors that drive aberrant cancer growth, metastasis and angiogenesis. Consequently, a number of GPCRs are strongly expressed in cancer derived cell lines and tissue s les. Therefore a rational anti-cancer strategy is the design of nano-medicines that specifically target GPCRs to bind and internalise cytotoxic drugs into cancer cells. Herein, we report the genetic engineering of a self-assembling nanoparticle based on elastin-like polypeptide (ELP), which has been fused with gastrin releasing peptide (GRP). These nanoparticles increased intracellular calcium concentrations when added to GRP receptor positive PC-3 prostate cancer cells, demonstrating specific receptor activation. Moreover, GRP-displaying fluorescent labelled nanoparticles showed specific cell-surface interaction with PC-3 prostate cancer cells and increased endocytic uptake. These nanoparticles therefore provide a targeted molecular carrier system for evaluating the delivery of cytotoxic drugs into cancer cells.
Publisher: Elsevier BV
Date: 07-2002
Publisher: Elsevier BV
Date: 09-2019
DOI: 10.1016/J.BMCL.2019.07.043
Abstract: Post-translational modulation of eIF4E through phosphorylation by Mnks is highly integral to the pathogenesis of different cancers. Therefore, inhibition of Mnks offers a strategy for cancer treatment. Herein, a series of 2'H-spiro[cyclohexane-1,3'-imidazo[1,5-a]pyridine]-1',5'-dione derivatives is presented as Mnk inhibitors. Some of them showed sub-micromolar to low nanomolar inhibitory activities against Mnk1/2 with a high level of selectivity for both kinases over CDKs. Biochemical assays revealed that compounds 4c and 4t are non-ATP-competitive inhibitors of Mnks. Lead compound 4t demonstrated a high selectivity for Mnk1/2 over a selection of 51 kinases, and displayed anti-proliferative activities against a panel of cancer cell lines. However, this compound in combination with our in-house CDK4/6 inhibitor 83 did not show a synergistic effect in A2780 ovarian cancer cells, suggesting that caution be exercised in the selection of an agent to be combined with an Mnk inhibitor.
Publisher: American Chemical Society (ACS)
Date: 16-02-2017
DOI: 10.1021/ACS.JMEDCHEM.6B01670
Abstract: Cyclin D dependent kinases (CDK4 and CDK6) regulate entry into S phase of the cell cycle and are validated targets for anticancer drug discovery. Herein we detail the discovery of a novel series of 4-thiazol-N-(pyridin-2-yl)pyrimidin-2-amine derivatives as highly potent and selective inhibitors of CDK4 and CDK6. Medicinal chemistry optimization resulted in 83, an orally bioavailable inhibitor molecule with remarkable selectivity. Repeated oral administration of 83 caused marked inhibition of tumor growth in MV4-11 acute myeloid leukemia mouse xenografts without having a negative effect on body weight and showing any sign of clinical toxicity. The data merit 83 as a clinical development candidate.
No related grants have been discovered for Hugo Albrecht.