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Genetic Analysis, Techniques and... Sep 1991
Review
Topics: Aphidicolin; Azacitidine; Blotting, Southern; Bromodeoxyuridine; Chromosome Fragile Sites; Chromosome Fragility; Folic Acid; Humans; Karyotyping; X Chromosome
PubMed: 1721827
DOI: 10.1016/1050-3862(91)90056-w -
Experimental Parasitology 2003The effect of aphidicolin, a specific inhibitor of the replicative DNA polymerases, on the excystation and metacystic development of Entamoeba invadens was examined. The...
The effect of aphidicolin, a specific inhibitor of the replicative DNA polymerases, on the excystation and metacystic development of Entamoeba invadens was examined. The protein profile of metacystic amoebae and their immunogenicity in the presence and absence of aphidicolin were also examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Excystation, which was assessed by counting the number of metacystic amoebae after the induction of excystation, was inhibited by aphidicolin in a concentration-dependent manner during incubation compared to the controls. Metacystic development, when determined by the number of nuclei in amoeba, was also inhibited by aphidicolin, because the percentage of 4-nucleate amoebae in cultures with aphidicolin during incubation was higher than that in cultures without the drug. The addition of aphidicolin to cultures at day 1 of incubation reduced the number of metacystic amoebae thereafter compared to cultures without the drug. The inhibitory effect of aphidicolin on excystation and metacystic development was reversed by removal of the drug. Pretreatment of cysts with aphidicolin before transfer to a growth medium containing the drug had no further effect on the excystation and metacystic development. Cellular proteins of metacystic amoebae with 4 nuclei, which were predominant even at day 3 in the cultures with aphidicolin, reacted strongly with rabbit anticyst serum absorbed with trophozoite proteins. In contrast, those of metacystic amoebae with 1 nucleus, which were predominant at day 3 in cultures without aphidicolin, no longer reacted with the absorbed anticyst serum, suggesting change in the expression of proteins during metacystic development.
Topics: Animals; Aphidicolin; Culture Media; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Entamoeba; Immunoblotting; Nucleic Acid Synthesis Inhibitors; Protozoan Proteins
PubMed: 12810048
DOI: 10.1016/s0014-4894(03)00073-0 -
Nucleic Acids Research Dec 2000Common fragile sites are chromosomal loci prone to breakage and rearrangement that can be induced by aphidicolin, an inhibitor of DNA polymerases. Within these loci,...
Common fragile sites are chromosomal loci prone to breakage and rearrangement that can be induced by aphidicolin, an inhibitor of DNA polymerases. Within these loci, sites of preferential DNA breaks were proposed to correlate with peaks of enhanced DNA flexibility, the function of which remains elusive. Here we show that mammalian DNA replication origins are enriched in peaks of enhanced flexibility. This finding suggests that the search for these features may help in the mapping of replication origins, and we present evidence supporting this hypothesis. The association of peaks of flexibility with replication origins also suggests that some origins may associate with minor levels of fragility. As shown here, an increased sensitivity to aphidicolin was found near two mammalian DNA replication origins.
Topics: Animals; Aphidicolin; Cell Line; Chromosome Breakage; Chromosome Fragile Sites; Chromosome Fragility; Chromosome Mapping; Cricetinae; DNA; DNA Replication; In Situ Hybridization, Fluorescence; Replication Origin; Replicon; Tetrahydrofolate Dehydrogenase
PubMed: 11095694
DOI: 10.1093/nar/28.23.4805 -
Genetics, Selection, Evolution : GSE 2002Fragile sites (FS) seem to play a role in genome instability and may be involved in karyotype evolution and chromosome aberrations. The majority of common fragile sites...
Fragile sites (FS) seem to play a role in genome instability and may be involved in karyotype evolution and chromosome aberrations. The majority of common fragile sites are induced by aphidicolin. Aphidicolin was used at two different concentrations (0.15 and 0.30 microM) to study the occurrence of FS in the cattle karyotype. In this paper, a map of aphidicolin induced break points and fragile sites in cattle chromosomes was constructed. The statistical analysis indicated that any band with three or more breaks was significantly damaged (P<0.05). According to this result, 30 of the 72 different break points observed were scored as fragile sites. The Pearson correlation test showed a positive association between chromosome length and the number of fragile sites (r=0.54). On the contrary, 21 FS were identified on negative R bands while 9 FS were located on positive R bands.
Topics: Animals; Aphidicolin; Cattle; Chromosome Banding; Chromosome Fragile Sites; Chromosome Fragility; Chromosome Mapping; Chromosomes; Enzyme Inhibitors
PubMed: 12486396
DOI: 10.1186/1297-9686-34-6-649 -
Oncology Reports 2003In order to assess the effect of the DNA polymerase inhibitor aphidicolin on resistance to cytosine arabinoside, blast cells from 15 children with ALL and 9 with AML...
In order to assess the effect of the DNA polymerase inhibitor aphidicolin on resistance to cytosine arabinoside, blast cells from 15 children with ALL and 9 with AML were exposed to a range of concentrations of ara-C +/- aphidicolin. Cell survival was measured using the MTT assay. Aphidicolin significantly increased sensitivity to ara-C in blast cells from both ALL (p=0.001) and AML (p<0.01). The median fold increase (sensitisation ratio) for ALL was 3.4 (range 1.2-13.6) compared to 12.4-fold (range 6.0-148) for AML blasts (p=0.005). There was a striking relationship between increasing ara-C resistance and increasing effect of aphidicolin in AML (p<0.001) but not ALL (p>0.05). These remarkable results suggest that aphidicolin should be considered for future clinical trials as a modulator of ara-C resistance, particularly in AML.
Topics: Aphidicolin; Cell Survival; Child; Child, Preschool; Clinical Trials as Topic; Cytarabine; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Drug Synergism; Enzyme Inhibitors; Female; Humans; Infant; Leukemia, Myeloid, Acute; Male; Nucleic Acid Synthesis Inhibitors; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Time Factors
PubMed: 14534738
DOI: 10.3892/or.10.6.2027 -
Journal of Medicinal Chemistry Nov 1993A variety of isosteres of the DNA polymerase inhibitor aphidicolin were synthesized as potential antiherpes agents. Modeling studies indicated that the bicyclooctane C,...
A variety of isosteres of the DNA polymerase inhibitor aphidicolin were synthesized as potential antiherpes agents. Modeling studies indicated that the bicyclooctane C, D rings of aphidicolin could be replaced by an aromatic moiety while maintaining the spatial arrangement of the hydroxyl group equivalent to the essential C18 hydroxyl group of aphidicolin. Of the racemic isosteres synthesized only 13, the compound with the greatest structural similarity to aphidicolin, showed any significant antiviral activity in primary assays. An enantioselective synthesis of the compound was carried out and the 4aS isomer 36 was shown to account for the observed antiviral activity noted against herpes simplex virus 1 and human cytomegalovirus.
Topics: Antiviral Agents; Aphidicolin; Binding Sites; Crystallography, X-Ray; Cytomegalovirus; Deoxycytosine Nucleotides; Herpesvirus 1, Human; Herpesvirus 2, Human; Models, Molecular; Molecular Structure; Nucleic Acid Synthesis Inhibitors; Phenanthrenes; Stereoisomerism; Structure-Activity Relationship
PubMed: 8246219
DOI: 10.1021/jm00075a003 -
International Journal of Oncology Apr 2010Since the first description of human fragile sites (FS) more than 40 years ago, a variety of substances were reported to induce chromosomal breaks at non-random,...
Since the first description of human fragile sites (FS) more than 40 years ago, a variety of substances were reported to induce chromosomal breaks at non-random, breakage-prone regions. According to information available from human genome browsers aphidicolin, an inhibitor of DNA replication induces 77 of 88 known common FS. However, in the literature additional FS are reported, which are also, at least in part, inducible by aphidicolin. To the best of our knowledge, here we present the first and largest ever done systematic, whole genome-directed and comprehensive screening for aphidicolin-inducible breakage-prone regions. The study was performed on stimulated peripheral blood lymphocytes of 3 unrelated healthy individuals. Twenty-five thousand metaphase spreads were analyzed and overall 22,537 FS located in 230 different loci were recorded. Sixty-one of those FS were never observed before and 52 were already previously reported but not included in genome browsers and yet verified. Interestingly, aphidicolin was able to induce all types of rare and common FS, suggesting that these breakage-prone regions are less dependent on the inducing chemicals than originally supposed. Overall, we provide the first comprehensive genome wide map for FS and studied possible correlations of chromosome length and GTG-banding level with FS-frequency. To handle FS better in future, an extension of the already existing alphabetical nomenclature for FS on single chromosomes is suggested.
Topics: Aphidicolin; Cells, Cultured; Chromosome Fragile Sites; Chromosome Fragility; Chromosomes, Human; Cytogenetic Analysis; Female; Genomics; Humans; Lymphocytes; Metaphase; Terminology as Topic
PubMed: 20198338
DOI: 10.3892/ijo_00000572 -
Mutation Research. Genetic Toxicology... Jun 2016The comet assay in combination with the polymerase inhibitor aphidicolin (APC) has been used to measure DNA excision repair activity, DNA repair kinetics and individual...
The comet assay in combination with the polymerase inhibitor aphidicolin (APC) has been used to measure DNA excision repair activity, DNA repair kinetics and individual DNA repair capacity. Since APC can enhance genotoxic effects of mutagens measured by the comet assay, this approach has been proposed for increasing the sensitivity of the comet assay in human biomonitoring. The APC-modified comet assay has mainly been performed with human blood and it was shown that it not only enhances the detection of DNA damage repaired by nucleotide excision repair (NER) but also damage typically repaired by base excision repair (BER). Recently, we reported that in contrast to blood leukocytes, A549 cells (a human lung adenocarcinoma cell line) seem to be insensitive towards the repair-inhibiting action of APC. To further elucidate the general usefulness of the APC-modified comet assay for studying repair in cultured mammalian cells, we comparatively investigated further cell lines (HeLa, TK6, V79). DNA damage was induced by BPDE (benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide) and MMS (methyl methanesulfonate) in the absence and presence of APC (3 or 15μM). APC was either added for 2h together with the mutagen or cells were pre-incubated for 30min with APC before the mutagen was added. The results indicate that the cell lines tested differ fundamentally with regard to their sensitivity and specificity towards the repair-inhibiting effect of APC. The actual cause for these differences is still unclear but potential molecular explanations are discussed. Irrespective of the underlying mechanism(s), our study revealed practical limitations of the use of the APC-modified comet assay.
Topics: Aphidicolin; Cell Line; Comet Assay; DNA; DNA Damage; DNA Polymerase II; DNA Polymerase III; Humans; Mutagens
PubMed: 27265376
DOI: 10.1016/j.mrgentox.2016.05.001 -
British Journal of Cancer Mar 2001Treatment failure in AML is often attributed to P-glycoprotein-associated multidrug resistance. However, the importance of increased DNA repair in resistant cells is...
Treatment failure in AML is often attributed to P-glycoprotein-associated multidrug resistance. However, the importance of increased DNA repair in resistant cells is becoming more apparent. In order to investigate the ability of the DNA repair inhibitor aphidicolin to modulate drug resistance, we continually exposed blasts cells, isolated from 22 patients with AML, to a variety of agents +/- 15 microM aphidicolin for 48 hours. Cell survival was measured using the MTT assay. Overall, there was no significant effect of aphidicolin on sensitivity to daunorubicin, doxorubicin, etoposide or fludarabine. However, there was a marked increase in sensitivity to ara-C with a median 4.75-fold increase overall (range 0.8-80-fold;P< 0.005). The effect of aphidicolin was significantly greater in blast cells found resistant in vitro to ara-C (8.9-fold compared to 2.12-fold, P< 0.01). This observation was further validated by the correlation between ara-C LC(50)and extent of modulation effect (P< 0.05). Cells isolated from 10 cord blood samples were also tested in order to establish the haematological toxicity of combining ara-C and aphidicolin. The therapeutic index (LC(50)normal cells/tumour cells) for ara-C + aphidicolin was higher than that for ara-C alone suggesting no increased myelotoxicity for the combination. Increased cytotoxicity without increased haematotoxicity makes the combination of ara-C plus aphidicolin ideal for inclusion in future clinical trials.
Topics: Antimetabolites, Antineoplastic; Aphidicolin; Cell Survival; Cytarabine; DNA; Drug Resistance; Drug Screening Assays, Antitumor; Enzyme Inhibitors; Fetal Blood; Formazans; Humans; Lethal Dose 50; Leukemia, Myeloid, Acute; Tetrazolium Salts; Tumor Cells, Cultured
PubMed: 11237390
DOI: 10.1054/bjoc.2000.1639 -
Current Opinion in Genetics &... Jun 1995Fragile sites on chromosomes have been classified into a number of groups according to their frequency and the conditions required to induce them. A number of the rare... (Review)
Review
Fragile sites on chromosomes have been classified into a number of groups according to their frequency and the conditions required to induce them. A number of the rare folate-sensitive fragile sites have been characterized and shown to be amplified methylated CCG trinucleotide repeats. One common fragile site has been partly characterized and appears to be a region of fragility, rather than a single site.
Topics: Aphidicolin; Chromosome Fragile Sites; Chromosome Fragility; Chromosomes, Human; Culture Techniques; Gene Expression Regulation; Genes; Humans; Mutation; Repetitive Sequences, Nucleic Acid; Sequence Analysis, DNA
PubMed: 7549426
DOI: 10.1016/0959-437x(95)80046-8