-
Mutation Research Nov 1985The ability of N-nitrosodimethylamine (DMN) and methyl methanesulfonate (MMS) to induce DNA damage in primary cultures of human hepatocytes was examined by the alkaline...
The ability of N-nitrosodimethylamine (DMN) and methyl methanesulfonate (MMS) to induce DNA damage in primary cultures of human hepatocytes was examined by the alkaline elution technique. Both the agents induced a dose-dependent increase in DNA elution rate, but appreciable differences in the degree of response to the procarcinogen DMN were observed among cultures obtained from the livers of four patients. A comparative analysis of DNA fragmentation indicated a substantial similarity between human and concurrently studied rat hepatocytes in their response to both DMN and MMS.
Topics: Aged; Cells, Cultured; Chemical Phenomena; Chemistry; DNA; Dimethylnitrosamine; Female; Humans; Liver; Male; Methyl Methanesulfonate; Middle Aged; Mutagenicity Tests; Mutation
PubMed: 4058441
DOI: 10.1016/0165-7992(85)90142-3 -
Mutation Research Apr 1989Two different mechanisms for mutagenesis following treatment with methyl methanesulfonate (MMS) are suggested from the dose-response curve that is best fit by the linear...
Dosage-response relationships for methyl methanesulfonate in Drosophila melanogaster spermatozoa: DNA methylation per nucleotide vs. sex-linked recessive lethal frequency.
Two different mechanisms for mutagenesis following treatment with methyl methanesulfonate (MMS) are suggested from the dose-response curve that is best fit by the linear quadratic model where m = 0.130D + 0.038D2 (D = dose measured as alkylations per nucleotide X 10(3), APdN; m = percent sex-linked recessive lethals, SLRL). A predominant component of the dose-response curve at moderate to high dose is the quadratic component which is interpreted as the result of two single-strand breaks. The distribution of methyl adducts in vivo is consistent with the previously determined in vitro distribution of methyl adducts on DNA following treatment with MMS. With the use of HPLC, 82% of the 3H-labeled adducts are found on the N-7 of guanine. It has previously been shown by both in vitro studies and in vivo correlation with mutagenesis that the N-7 alkyl guanine is not itself a predominately genotoxic lesion; however, N-7 alkyl guanine destabilizes guanine resulting in an increased rate of hydrolysis producing apurinic sites. In data presented in this paper, the loss of labeled adducts is shown to be at a rate consistent with hydrolysis of the destabilized alkyl guanine. The apurinic site thus produced should be converted to single-strand breaks by AP endonucleases once sperm has fertilized the egg. Single-strand breaks are repaired by excision repair which is not error-prone; however, multiple breaks producing a proximity effect should lead to double-strand breaks that are repaired by an error-prone process. Mutations that are induced by a proximity effect would account for the quadratic term. It is hypothesized that a proximity effect is produced when two breaks are sufficiently close together to prevent using the complementary strand as a template. The linear component of the dose-response curve is probably due to alkylation of oxygens in the purine or pyrimidine ring leading to mispairing. However, due to the low frequency of ring-oxygen alkylation following treatment with MMS, this important genotoxic site is not the predominant one observed at experimental levels normally used in the laboratory. From the dose-response curve, it is calculated that at mutation frequencies of 10 times the spontaneous frequency or higher, the predominant mechanism is the multi-hit component; however, at mutation induced frequencies of 0.1 of the spontaneous frequency, which are levels more likely to be encountered in man's exposure to environmental mutagens, the dominant mechanism is the linear component.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Animals; DNA; Dose-Response Relationship, Drug; Drosophila melanogaster; Genes, Lethal; Genes, Recessive; Male; Methyl Methanesulfonate; Methylation; Spermatozoa
PubMed: 2494441
DOI: 10.1016/0027-5107(89)90007-9 -
Mutation Research Feb 1998Resistance to the cytotoxic effects of S(N)1 alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-methyl-N-nitrosourea (MNU) is well established...
Resistance to the cytotoxic effects of S(N)1 alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-methyl-N-nitrosourea (MNU) is well established in mismatch repair-defective cells, however, little is known about the cellular response to S(N)2 alkylating agents in these cells. Here we describe the cytotoxic response and the mutagenic response at the hypoxanthine-guanine phosphoribosyl transferase (HPRT) locus to the S(N)2 alkylating agent methyl methanesultfonate (MMS) in human cancer cell lines defective in mismatch repair (MMR). Our findings suggest that cytotoxicity to MMS is mediated through MMR, as indicated by an increased resistance to MMS in MMR-deficient cells. Cells in which specific MMR-gene defects were complemented by chromosome transfer were generally more sensitive to the cytotoxic effects of MMS. Additionally, the induced mutant frequency at HPRT following exposure to MMS is significantly increased in MMR-deficient lines. These findings suggest that resistance to S(N)2 alkylation damage is mediated by MMR genes, and that resistance to such damage in MMR-defective cells correlates with an increase in genomic mutations. The results are consistent with the hypothesis that abasic sites may be substrates for repair involving MMR-gene products in human cells.
Topics: Cell Line; DNA Repair; Humans; Methyl Methanesulfonate; Mutagens; Mutation; Nucleic Acid Heteroduplexes; Tumor Cells, Cultured
PubMed: 9626980
DOI: 10.1016/s0027-5107(98)00004-9 -
Environmental Research Jan 2021The genotoxic and antigenotoxic potential of BP-C2, a novel lignin-derived polyphenolic composition with ammonium molybdate, was investigated as a...
The genotoxic and antigenotoxic potential of BP-C2, a novel lignin-derived polyphenolic composition with ammonium molybdate, was investigated as a radioprotector/radiomitigator for civil applications and as a medical countermeasure for radiation emergencies. Using the alkaline comet assay and methyl methanesulfonate (MMS, 40 mg/kg) as the DNA-damaging agent, these effects of BP-C2 on liver, bone marrow cells and blood leukocytes in rats were studied. The DNA damage was estimated by the DNA content in the comet tail (TDNA, %) 1, 6 and 18 h post exposure to MMS. BP-C2 at doses of 20, 200 and 2000 mg/kg did not exert genotoxic activity in the tested tissues in rats. BP-C2 administered at doses of 20, 100 and 200 mg/kg 1 h before MMS significantly (p < 0.01) mitigated MMS-induced DNA damage, showing a strong genoprotective effect in the liver. In blood leukocytes and bone marrow samples of animals treated with BP-C2, the TDNA % was slightly higher than in the negative control (vehicle) but significantly lower than in the positive control (MMS). Thus, BP-C2 exerted a genoprotective effect against MMS-induced DNA damage to a greater extent towards liver cells, requiring further evaluation of this substance as a genoprotective agent.
Topics: Animals; Comet Assay; DNA Damage; Lignin; Methyl Methanesulfonate; Mutagens; Protective Agents; Rats
PubMed: 33075358
DOI: 10.1016/j.envres.2020.110321 -
Mutation Research Jan 1978
Evaluation of genetic risks of alkylating agents IV. Quantitative determination of alkylated amino acids in haemoglobin as a measure of the dose after-treatment of mice with methyl methanesulfonate.
Topics: Amino Acid Sequence; Animals; Chromatography, Gas; Dose-Response Relationship, Drug; Hemoglobins; Male; Mesylates; Methyl Methanesulfonate; Mice; Mice, Inbred CBA; Models, Biological; Mutagens
PubMed: 202871
DOI: 10.1016/0027-5107(78)90079-9 -
Journal of Virology Dec 1984Experiments were conducted to determine whether phage T7 treated with methyl methanesulfonate used multiplicity reactivation to repair alkylation lesions. This type of...
Experiments were conducted to determine whether phage T7 treated with methyl methanesulfonate used multiplicity reactivation to repair alkylation lesions. This type of repair was found to be operative at high multiplicities in actively growing wild-type Escherichia coli B cells.
Topics: DNA Repair; Escherichia coli; Methyl Methanesulfonate; Methylation; Recombination, Genetic; T-Phages; Virus Replication
PubMed: 6387176
DOI: 10.1128/JVI.52.3.1009-1010.1984 -
Pharmacology & Toxicology Oct 1995Ethanol extract of Senokot tablets (Cassia senna concentrate used as vegetable laxative), was found to be non-mutagenic while it inhibited the mutagenicity of...
Ethanol extract of Senokot tablets (Cassia senna concentrate used as vegetable laxative), was found to be non-mutagenic while it inhibited the mutagenicity of benzo[a]pyrene, shamma, aflatoxin B1 and methyl methanesulfonate in the Ames histidine reversion assay using the Salmonella typhimurium tester strain TA98. While the Senokot extract completely inhibited the mutagenicity of promutagens (i.e. metabolic activation dependent) like benzo[a]pyrene and shamma, it reduced the mutagenic activity of the direct acting mutagen methyl methanesulfonate by only 58%. The mutagen aflatoxin B1 showed a 25-fold increase in the number of histidine revertants per plate at low concentrations (1.0-4.0 micrograms/plate) in the presence of metabolic activation system while at high concentrations (10.0-30.0 micrograms/plate) it proved to be weakly mutagenic (with a 5-fold increase in the number of histidine revertants/plate) without metabolic activation. The Senokot extract completely inhibited the mutagenic effect of low concentrations of aflatoxin B1 in the presence of metabolic activation but not that resulting from higher concentrations without metabolic activation. The results obtained with benzo[a]pyrene, shamma and aflatoxin B1 indicated that the antimutagenic effects of Senokot extract could be largely due to an interaction with the metabolic process involved in the activation of procarcinogens. However, the results obtained with methyl methanesulfonate suggested that factors in Senokot may also interact with direct mutagens to produce some antimutagenic effects. An ethanol extract of crude senna leaves found to be weakly mutagenic also inhibited (though less than Senokot) the mutagenic effect of benzo[a]pyrene suggesting that the antimutagenic principle is present in the complex plant material itself.
Topics: Aflatoxin B1; Benzo(a)pyrene; Biotransformation; Cathartics; Dose-Response Relationship, Drug; Histidine; Methyl Methanesulfonate; Mutagenicity Tests; Mutation; Salmonella typhimurium; Senna Extract
PubMed: 8577642
DOI: 10.1111/j.1600-0773.1995.tb01029.x -
Rapid Communications in Mass... 2005The reactions of two model mutagenic and carcinogenic alkylating agents, N-methyl-N-nitrosourea (MNU) and methyl methanesulfonate (MMS), with proteins and...
The reactions of two model mutagenic and carcinogenic alkylating agents, N-methyl-N-nitrosourea (MNU) and methyl methanesulfonate (MMS), with proteins and deoxynucleosides in vitro, were investigated. The protein work used an approach involving trypsin digestion and high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS). This technique permitted identification of the specific location of protein adduction by both MNU and MMS with commercial apomyoglobin and human hemoglobin, under physiological conditions. MNU treatment resulted in predominantly carbamoylation adducts on the proteins, but in contrast only methylated protein adducts were found following treatment with MMS. Further analyses, using TurboSequest, and the Scoring Algorithm for Spectral Analysis (SALSA), revealed that MNU carbamoylation was specific for modification of either the N-terminal valine or the free amino group in lysine residues of apomyglobin and human hemoglobin. However, MMS methylation modified the N-terminal valine and histidine residues of the proteins. Despite their clear differences in protein modifications, MNU and MMS formed qualitatively the same methylated deoxynucleoside adduct profiles with all four deoxynucleosides in vitro under physiological conditions. In light of their different biological potencies, where MMS is considered a 'super clastogen' while MNU is a 'super mutagen', these differences in reaction products with proteins vs. deoxynucleosides may indicate that these two model alkylating agents work via different mechanisms to produce their mutagenic and carcinogenic effects.
Topics: Amino Acid Sequence; Apoproteins; Chromatography, High Pressure Liquid; Deoxyribonucleosides; Hemoglobins; Humans; Methyl Methanesulfonate; Methylnitrosourea; Molecular Sequence Data; Mutagens; Myoglobin; Proteins; Sequence Analysis, Protein; Spectrometry, Mass, Electrospray Ionization
PubMed: 15655799
DOI: 10.1002/rcm.1806 -
Infection and Immunity May 1985A UV-sensitive derivative was obtained from Streptococcus sanguis Challis. The organism could be transformed with a number of small streptococcal plasmids at frequencies...
A UV-sensitive derivative was obtained from Streptococcus sanguis Challis. The organism could be transformed with a number of small streptococcal plasmids at frequencies equal to, or 1 logarithm below, the transformation frequencies for the parent organism. However, transformation with chromosomal DNA was greatly impaired in the UV-sensitive derivative.
Topics: Methyl Methanesulfonate; Mutation; Plasmids; Recombination, Genetic; Streptococcus sanguis; Transformation, Bacterial; Ultraviolet Rays
PubMed: 3988349
DOI: 10.1128/iai.48.2.584-586.1985 -
Aging Jan 2021The naked mole rat (NMR), is the longest-living rodent species, and is extraordinarily resistant to cancer and aging-related diseases. The molecular basis for these...
The naked mole rat (NMR), is the longest-living rodent species, and is extraordinarily resistant to cancer and aging-related diseases. The molecular basis for these unique phenotypic traits of the NMR is under extensive research. However, the role of regulated cell death (RCD) in the longevity and the protection from cancer in the NMR is still largely unknown. RCD is a mechanism restricting the proliferation of damaged or premalignant cells, which counteracts aging and oncotransformation. In this study, DNA damage-induced cell death in NMR fibroblasts was investigated in comparison to RCD in fibroblasts from . The effects of methyl methanesulfonate, 5-fluorouracil, and etoposide in both cell types were examined using contemporary cell death analyses. Skin fibroblasts from were found to be more resistant to the action of DNA damaging agents compared to fibroblasts from . Strikingly, our results revealed that NMR cells also exhibit a limited apoptotic response and seem to undergo regulated necrosis. Taken together, this study provides new insights into the mechanisms of cell death in NMR expanding our understanding of longevity, and it paves the way towards the development of innovative therapeutic approaches.
Topics: Animals; Cells, Cultured; DNA Damage; Fibroblasts; Longevity; Methyl Methanesulfonate; Mice; Mole Rats; Regulated Cell Death
PubMed: 33510044
DOI: 10.18632/aging.202577