33 research outputs found
Characterization of the G-quadruplexes in the duplex nuclease hypersensitive element of the PDGF-A promoter and modulation of PDGF-A promoter activity by TMPyP4
The proximal 5ā²-flanking region of the human platelet-derived growth factor A (PDGF-A) promoter contains one nuclease hypersensitive element (NHE) that is critical for PDGF-A gene transcription. On the basis of circular dichroism (CD) and electrophoretic mobility shift assay (EMSA), we have shown that the guanine-rich (G-rich) strand of the DNA in this region can form stable intramolecular parallel G-quadruplexes under physiological conditions. A Taq polymerase stop assay has shown that the G-rich strand of the NHE can form two major G-quadruplex structures, which are in dynamic equilibrium and differentially stabilized by three G-quadruplex-interactive drugs. One major parallel G-quadruplex structure of the G-rich strand DNA of NHE was identified by CD and dimethyl sulfate (DMS) footprinting. Surprisingly, CD spectroscopy shows a stable parallel G-quadruplex structure formed within the duplex DNA of the NHE at temperatures up to 100Ā°C. This structure has been characterized by DMS footprinting in the double-stranded DNA of the NHE. In transfection experiments, 10 Ī¼M TMPyP4 reduced the activity of the basal promoter of PDGF-A ā¼40%, relative to the control. On the basis of these results, we have established that ligand-mediated stabilization of G-quadruplex structures within the PDGF-A NHE can silence PDGF-A expression
Azole compounds designed by molecular modelling show antifungal activity as predicted
372-381Rational approaches involving drug discovery
technologies such as computational and combinatorial chemistry and high throughput
screening have been useful tools to design and discover new drugs more efficiently.
The interplay among structure-activity relationships, computer modelling, chemical
synthesis and pharmacological testing can lead to better
products for a particular therapeutic purpose.
The work presented in this paper reports an example of successful application of
computer-aided drug design method to find new azole antifungal agents. The designed
compounds have been synthesized in the laboratory and tested for anti fungal activity
against Candida albicans ATCC 24433 in vitro. Two compounds exhibit
good activity in vitro, which can be optimized for better activity
Simultaneous Drug Targeting of the Promoter <i>MYC</i> GāQuadruplex and <i>BCL2</i> iāMotif in Diffuse Large BāCell Lymphoma Delays Tumor Growth
Secondary DNA structures
are uniquely poised as therapeutic targets
due to their molecular switch function in turning gene expression
on or off and scaffold-like properties for protein and small molecule
interaction. Strategies to alter gene transcription through these
structures thus far involve targeting single DNA conformations. Here
we investigate the feasibility of simultaneously targeting different
secondary DNA structures to modulate two key oncogenes, cellular-myelocytomatosis
(<i>MYC</i>) and B-cell lymphoma gene-2 (<i>BCL2</i>), in diffuse large B-cell lymphoma (DLBCL). Cotreatment with previously
identified ellipticine and pregnanol derivatives that recognize the <i>MYC</i> G-quadruplex and <i>BCL2</i> i-motif promoter
DNA structures lowered mRNA levels and subsequently enhanced sensitivity
to a standard chemotherapy drug, cyclophosphamide, in DLBCL cell lines.
In vivo repression of <i>MYC</i> and <i>BCL2</i> in combination with cyclophosphamide also significantly slowed tumor
growth in DLBCL xenograft mice. Our findings demonstrate concurrent
targeting of different DNA secondary structures offers an effective,
precise, medicine-based approach to directly impede transcription
and overcome aberrant pathways in aggressive malignancies
Specific G-quadruplex ligands regulate the alternative splicing of Bcl-x
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Discovery of a novel class of AKT pleckstrin homology domain inhibitors
AKT, a phospholipid-binding serine/threonine kinase, is a key component of the phosphoinositide 3-kinase cell survival signaling pathway that is aberrantly activated in many human cancers. Many attempts have been made to inhibit AKT; however, selectivity remains to be achieved. We have developed a novel strategy to inhibit AKT by targeting the pleckstrin homology (PH) domain. Using in silico library screening and interactive molecular docking, we have identified a novel class of non-lipid-based compounds that bind selectively to the PH domain of AKT, with in silico calculated KD values ranging from 0.8 to 3.0 Ī¼mol/L. In order to determine the selectivity of these compounds for AKT, we used surface plasmon resonance to measure the binding characteristics of the compounds to the PH domains of AKT1, insulin receptor substrate-1, and 3-phosphoinositide-dependent protein kinase 1. There was excellent correlation between predicted in silico and measured in vitro KDs for binding to the PH domain of AKT, which were in the range 0.4 to 3.6 Ī¼mol/L. Some of the compounds exhibited PH domain-binding selectivity for AKT compared with insulin receptor substrate-1 and 3-phosphoinositide-dependent protein kinase 1. The compounds also inhibited AKT in cells, induced apoptosis, and inhibited cancer cell proliferation. In vivo, the lead compound failed to achieve the blood concentrations required to inhibit AKT in cells, most likely due to rapid metabolism and elimination, and did not show antitumor activity. These results show that these compounds are the first small molecules selectively targeting the PH domain of AKT. Copyright Ā© 2008 American Association for Cancer Research
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Dyrk1 inhibition improves Alzheimer's disease-like pathology
There is an urgent need for the development of new therapeutic strategies for Alzheimer's disease (AD). The dual-specificity tyrosine phosphorylation-regulated kinase-1A (Dyrk1a) is a protein kinase that phosphorylates the amyloid precursor protein (APP) and tau and thus represents a link between two key proteins involved in AD pathogenesis. Furthermore, Dyrk1a is upregulated in postmortem human brains, and high levels of Dyrk1a are associated with mental retardation. Here, we sought to determine the effects of Dyrk1 inhibition on AD-like pathology developed by 3xTg-AD mice, a widely used animal model of AD. We dosed 10-month-old 3xTg-AD and nontransgenic (NonTg) mice with a Dyrk1 inhibitor (Dyrk1-inh) or vehicle for eight weeks. During the last three weeks of treatment, we tested the mice in a battery of behavioral tests. The brains were then analyzed for the pathological markers of AD. We found that chronic Dyrk1 inhibition reversed cognitive deficits in 3xTg-AD mice. These effects were associated with a reduction in amyloid-beta (Ab) and tau pathology. Mechanistically, Dyrk1 inhibition reduced APP and insoluble tau phosphorylation. The reduction in APP phosphorylation increased its turnover and decreased Ab levels. These results suggest that targeting Dyrk1 could represent a new viable therapeutic approach for AD.Arizona Alzheimer's Consortium; National Institutes of Health [R01 AG037637]Open access journal.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]