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Virology Journal Mar 2008It has been demonstrated that the p53 pathway plays an important role in HIV-1 infection. Previous work from our lab has established a model demonstrating how p53 could...
It has been demonstrated that the p53 pathway plays an important role in HIV-1 infection. Previous work from our lab has established a model demonstrating how p53 could become inactivated in HIV-1 infected cells through binding to Tat. Subsequently, p53 was inactivated and lost its ability to transactivate its downstream target gene p21/waf1. P21/waf1 is a well-known cdk inhibitor (CKI) that can lead to cell cycle arrest upon DNA damage. Most recently, the p21/waf1 function was further investigated as a molecular barrier for HIV-1 infection of stem cells. Therefore, we reason that the restoration of the p53 and p21/waf1 pathways could be a possible theraputical arsenal for combating HIV-1 infection. In this current study, we show that a small chemical molecule, 9-aminoacridine (9AA) at low concentrations, could efficiently reactivate p53 pathway and thereby restoring the p21/waf1 function. Further, we show that the 9AA could significantly inhibit virus replication in activated PBMCs, likely through a mechanism of inhibiting the viral replication machinery. A mechanism study reveals that the phosphorylated p53ser15 may be dissociated from binding to HIV-1 Tat protein, thereby activating the p21/waf1 gene. Finally, we also show that the 9AA-activated p21/waf1 is recruited to HIV-1 preintegration complex, through a mechanism yet to be elucidated.
Topics: Aminacrine; Antiviral Agents; Cell Line; Cell Survival; Cyclin-Dependent Kinase Inhibitor p21; HIV-1; Humans; Leukocytes, Mononuclear; Phosphorylation; Reverse Transcription; Signal Transduction; T-Lymphocytes; Tumor Suppressor Protein p53; tat Gene Products, Human Immunodeficiency Virus
PubMed: 18348731
DOI: 10.1186/1743-422X-5-41 -
Journal of Radiation Research Sep 2007The endogenous tonB gene of Escherichia coli was used as a target for 9-aminoacridine-induced mutations that were identified in recA(-) and uvrA(-) cells. The...
The endogenous tonB gene of Escherichia coli was used as a target for 9-aminoacridine-induced mutations that were identified in recA(-) and uvrA(-) cells. The cytotoxicity of 9-aminoacridine was enhanced in the uvrA and recA strains compared to the wild-type strain, and the mutagenicity of 9-aminoacridine in the uvrA and recA strains was similar to that in the wild type. For all three strains, the most common mutations were minus frameshifts in repetitive G:C base-pairs followed by minus frameshifts in nonrepetitive G:C base-pairs. 9-aminoacridine-induced minus frameshifts in the wild-type strain were distributed with several hot and warm spots. These sites were also hot and warm spots for minus frameshifts in the recA and uvrA stains. Furthermore, they were hot and warm sites in a 9-aminoacridine-treated strain carrying the target tonB gene oriented in the opposite direction. 9-Aminoacridine is known to interact with DNA to form intercalations which are involved in minus frameshift mutagenesis. In this study, we therefore argue that 1) 9-aminoacridine can induce bulky DNA lesions which are excised by nucleotide excision repair and not involved in mutagenesis, 2) the presence or absence of a recA-dependent repair pathway does not influence the mutagenic effect of 9-aminoacridine, and 3) both leading strand and lagging strand replication equally produce minus frameshifts, therefore gene orientation is not an important determinant of the formation of hot and warm spots by 9-aminoacridine.
Topics: Aminacrine; Dose-Response Relationship, Drug; Dose-Response Relationship, Radiation; Escherichia coli; Frameshift Mutation; Radiation Tolerance; Rec A Recombinases; Ultraviolet Rays
PubMed: 17611351
DOI: 10.1269/jrr.07036 -
In Vivo (Athens, Greece) 2006A proton pump-deleted mutant E. coli, AG100 A, had greater sensitivity to ampicillin, tetracycline and erythromycin than the wild-type parent E. coli AG100 containing... (Comparative Study)
Comparative Study
A proton pump-deleted mutant E. coli, AG100 A, had greater sensitivity to ampicillin, tetracycline and erythromycin than the wild-type parent E. coli AG100 containing the proton pump. This antibiotic sensitivity was further increased by resistance modifiers such as the Ca2+ channel blocker (+/-) verapamil (VP) and the calmodulin antagonist promethazine (PMZ). Whereas the newly-synthesized trifluoromethyl-ketone (TF) enhanced the activity of these antibiotics against the wild-type strain, it did not enhance the activity of ampicillin against the proton pump-deleted mutant. These results suggested that TF14 had an inhibitory effect on the proton pump. Elimination of plasmids from another strain of E. coli, K12, was promoted by PMZ and 9-amino-acridine (9-AA), but not by TF14 alone. However, combinations of TF14 with either PMZ or 9-AA enhanced the plasmid elimination capacity of the latter compounds. The combination of TF14, PMZ and VP proved that the Ca2+ channel blocker was not effective by itself These results collectively suggest that TF14 inhibited the proton pump of E. coli and that it was this pump which, when inhibited by TF14, allowed more PMZ to reach its plasmid elimination target.
Topics: Aminacrine; Ampicillin; Anti-Bacterial Agents; Drug Resistance, Multiple; Drug Synergism; Erythromycin; Escherichia coli; Microbial Sensitivity Tests; Plasmids; Promethazine; Proton Pump Inhibitors; Tetracycline; Verapamil
PubMed: 16724672
DOI: No ID Found -
FEBS Letters Apr 2006Leaves and chloroplasts from Arabidopsis plants with increased amounts of PsbS protein showed the same percentage increase in nonphotochemical quenching in comparison to...
Leaves and chloroplasts from Arabidopsis plants with increased amounts of PsbS protein showed the same percentage increase in nonphotochemical quenching in comparison to the wild type both in the presence and absence of zeaxanthin. The absorption change at 525-535 nm was also more pronounced in both cases. It is suggested that PsbS alone can cause the quenching, supporting the model in which zeaxanthin acts as an allosteric activator and is not the primary cause of the process. It is proposed that PsbS acts as a trigger of the conformational change that leads to the establishment of nonphotochemical quenching.
Topics: Aminacrine; Arabidopsis Proteins; Chloroplasts; Chromatography, High Pressure Liquid; Fluorescence; Gene Expression; Kinetics; Light-Harvesting Protein Complexes; Photochemistry; Photosynthetic Reaction Center Complex Proteins; Photosystem II Protein Complex; Plant Leaves; Time Factors; Xanthophylls; Zeaxanthins
PubMed: 16545380
DOI: 10.1016/j.febslet.2006.03.005 -
Proceedings of the National Academy of... Nov 2005Renal cell carcinomas (RCC) commonly retain wild-type but functionally inactive p53, which is repressed by an unknown dominant mechanism. To help reveal this mechanism,... (Comparative Study)
Comparative Study
Renal cell carcinomas (RCC) commonly retain wild-type but functionally inactive p53, which is repressed by an unknown dominant mechanism. To help reveal this mechanism, we screened a diverse chemical library for small molecules capable of restoring p53-dependent transactivation in RCC cells carrying a p53-responsive reporter. Among the compounds isolated were derivatives of 9-aminoacridine (9AA), including the antimalaria drug quinacrine, which strongly induced p53 function in RCC and other types of cancer cells. Induction of p53 by these compounds does not involve genotoxic stress and is mediated by suppression of NF-kappaB activity. In contrast to agents that target IkappaB kinase 2, 9AA and quinacrine can effectively suppress both basal and inducible activities of NF-kappaB, representing inhibitors of a previously undescribed type that convert NF-kappaB from a transactivator into a transrepressor, leading to accumulation of inactive nuclear complexes with unphosphorylated Ser-536 in the p65/RelA subunit. p53 function in RCC can be restored by ectopic expression of a superrepressor of IkappaB as effectively as by 9AA-derived compounds. These findings suggest that the complete or partial repression of p53 observed in many tumors can be the result of constitutive activation of NF-kappaB. The results demonstrate, in principle, the possibility to kill cancer cells selectively through simultaneous inhibition of NF-kappaB and activation of p53 by a single small molecule and suggest anticancer applications for the well known antimalaria drug quinacrine.
Topics: Aminacrine; Carcinoma, Renal Cell; Cell Line, Tumor; Colorimetry; Gene Expression Regulation, Neoplastic; Humans; NF-kappa B; Quinacrine; Structure-Activity Relationship; Tumor Suppressor Protein p53; beta-Galactosidase
PubMed: 16287968
DOI: 10.1073/pnas.0508888102 -
Bioorganic & Medicinal Chemistry Jan 2006A parallel synthetic strategy to the 9-aminoacridine scaffold of the classical anti-malarial drug quinacrine (2) is presented. The method features a new route to...
A parallel synthetic strategy to the 9-aminoacridine scaffold of the classical anti-malarial drug quinacrine (2) is presented. The method features a new route to 9-chloroacridines that utilizes triflates of salicylic acid derivatives, which are commercially available in a variety of substitution patterns. The route allows ready variation of the two diversity elements present in this class of molecules: the tricyclic aromatic heterocyclic core, and the disubstituted diamine sidechain. In this study, a library of 175 compounds was designed, although only 93 of the final products had purities acceptable for screening. Impurity was generally due to incomplete removal of 9-acridones (18), a degradation product of the 9-chloroacridine synthetic intermediates. The library was screened against two strains of Plasmodium falciparum, including a model of the drug-resistant parasite, and six novel compounds were found to have IC(50) values in the low nanomolar range.
Topics: Aminacrine; Animals; Antimalarials; Cells, Cultured; Chloroquine; Drug Resistance; Erythrocytes; Humans; Plasmodium falciparum
PubMed: 16216519
DOI: 10.1016/j.bmc.2005.08.017 -
Nucleic Acids Research 2004A series of peptide nucleic acid (PNA) oligomers targeting the mdm2 oncogene mRNA has been tested for the ability to inhibit the growth of JAR cells. The effect of these...
A series of peptide nucleic acid (PNA) oligomers targeting the mdm2 oncogene mRNA has been tested for the ability to inhibit the growth of JAR cells. The effect of these PNAs on the cells was also reflected in reduced levels of the MDM2 protein and increased levels of the p53 tumor suppressor protein, which is negatively regulated by MDM2. Initially, PNA oligomers were delivered as DNA complexes with lipofectamine, but it was discovered that PNA conjugated to the DNA intercalator 9-aminoacridine (Acr) (Acr-PNA) could be effectively delivered to JAR cells (as well as to HeLa pLuc705 cells) even in the absence of a DNA carrier. Using such lipofectamine-delivered Acr-PNA conjugates, one PNA targeting a cryptic AUG initiation site was identified that at a concentration of 2 microM caused a reduction of MDM2 levels to approximately 20% (but no reduction in mdm2 mRNA levels) and a 3-fold increase in p53 levels, whereas a 2-base mismatch control had no such effects. Furthermore, transcriptional activation by p53 was also increased (6-fold), and cell viability was reduced to 80%. Finally, this PNA acted cooperatively with camptothecin treatment both with regard to p53 activity induction as well as cell viability. Using this novel cell delivery system, we have identified a target on the mdm2 mRNA that appears sensitive to antisense inhibition by PNA and therefore could be used as a lead for further development of mdm2-targeted antisense (PNA and other) gene therapeutic anticancer drugs.
Topics: Aminacrine; Antineoplastic Agents; Base Sequence; Camptothecin; Cell Line; Cell Line, Tumor; Cell Survival; DNA Damage; DNA, Antisense; Down-Regulation; HeLa Cells; Humans; Molecular Sequence Data; Nuclear Proteins; Peptide Nucleic Acids; Protein Transport; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-mdm2; RNA, Messenger; Transfection; Tumor Suppressor Protein p53
PubMed: 15371552
DOI: 10.1093/nar/gkh820 -
Biochimica Et Biophysica Acta Apr 2003This work reports the production of a liposomal formulation, having a lipidic membrane with known chemical composition and a low proton permeability, as confirmed by...
This work reports the production of a liposomal formulation, having a lipidic membrane with known chemical composition and a low proton permeability, as confirmed by physicochemical characterization of the maintenance of a transmembranic pH gradient. These liposomes consist of DSPC, DSPE-PEG, DSPG and cholesterol, with low internal pH. To verify the low proton permeability of these liposomal bilayers, a study of proton migration according to the fluorescence quenching of 9-aminoacridine (9AA), as well as CPT-11 encapsulation, were used to monitor the acidification of the intravesicular space. Both experiments showed that this liposomal formulation is able to maintain a transmembranic proton gradient.
Topics: Aminacrine; Camptothecin; Fluorescent Dyes; Hydrogen-Ion Concentration; Irinotecan; Liposomes; Membrane Lipids; Permeability; Protons; Spectrometry, Fluorescence
PubMed: 12659939
DOI: 10.1016/s0005-2736(03)00035-x -
Journal of Applied Physiology... May 2003The purpose of the present investigation was to establish a method for estimating intracellular Ca(2+) concentrations ([Ca(2+)](i)) in isolated rat epitrochlearis...
The purpose of the present investigation was to establish a method for estimating intracellular Ca(2+) concentrations ([Ca(2+)](i)) in isolated rat epitrochlearis muscles. Epitrochlearis muscles excised from 4-wk-old male Sprague-Dawley rats were loaded with a fluorescent Ca(2+) indicator, fura 2-AM, for 60-90 min at 35 degrees C in oxygenated Krebs-Henseleit buffer. After fura 2 loading and subsequent 20-min incubation, the intensities of 500-nm fluorescence, induced by 340- and 380-nm excitation lights (F(total)340 and F(total)380), were measured. The fluorescences specific to fura-2 (F(fura 2)340 and F(fura 2)380) were calculated by subtracting the non-fura 2-specific component from F(total)340 and F(total)380, respectively. The ratio of F(fura 2)340 to F(fura 2)380 was calculated as R, and the change in the ratio from the baseline value (DeltaR) was used as an index of the change in [Ca(2+)](i). In resting muscle, DeltaR was stable for 60 min. Incubation for 20 min with caffeine (3-10 mM) significantly increased DeltaR in a concentration-dependent manner. Incubation with hypoxic Krebs-Henseleit buffer for 10-60 min significantly elevated DeltaR, depending on the duration of the incubation. Incubation with 50 microM N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide for 20 min significantly elevated DeltaR (P < 0.05). No significant increases in DeltaR were observed during incubation for 20 min with 2 mM 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside or with 2 mU/ml insulin. These results demonstrated that, by using the fura 2-AM fluorescence method, the changes in [Ca(2+)](i) can be monitored in the rat epitrochlearis muscle and suggest that the method can be utilized to observe quantitative information regarding [Ca(2+)](i) that may be involved in contraction- and hypoxia-stimulated glucose transport activity in skeletal muscle.
Topics: Aminacrine; Animals; Biological Transport; Caffeine; Calcium; Dantrolene; Fura-2; Glucose; Hypoxia; Ionomycin; Ionophores; Male; Muscle Contraction; Muscle, Skeletal; Phosphodiesterase Inhibitors; Rats; Rats, Sprague-Dawley; Stimulation, Chemical; Sulfonamides
PubMed: 12547839
DOI: 10.1152/japplphysiol.00780.2002 -
Cytometry. Part a : the Journal of the... Jan 2003Successful automated chromosome analysis requires the development of new techniques to increase and standardize chromosome length and improve banding patterns. (Comparative Study)
Comparative Study
BACKGROUND
Successful automated chromosome analysis requires the development of new techniques to increase and standardize chromosome length and improve banding patterns.
METHODS
Human and plant cells were pretreated with the DNA intercalator 9-aminoacridine (9-AMA), and chromosomes were stained with GTG and aceto-orcein banding techniques and investigated by an image analysis system.
RESULTS
The human optimal chromosome spreads with the 850 G-band resolution level, suitable for image analysis, were obtained by 9-AMA pretreatment for 1 h at a final concentration of 0.5-1 microg/ml, as compared with 600-700 bands after ethidium bromide treatment and about 400 bands without pretreatment. The best results for plant chromosomes were obtained after pretreatment with 1-2 microg/ml of 9-AMA for 12-24 h. The chromosomes elongated approximately 1.5-fold, and the resolution of chromosome banding patterns increased, reaching approximately 140 bands per haploid set in the case of camomile.
CONCLUSIONS
9-AMA is an efficient reagent for the standardization and increasing the resolution of chromosome banding patterns in human and plant chromosomes. It is extremely important for chromosome investigation in small plants.
Topics: Aminacrine; Cells, Cultured; Chromosome Banding; Chromosomes; DNA, Plant; Ethidium; Humans; Image Processing, Computer-Assisted; Lymphocytes; Reproducibility of Results
PubMed: 12500305
DOI: 10.1002/cyto.a.10002