O-(6)-methylguanine

09/01/2008 - "Correlation of O6-methylguanine methyltransferase (MGMT) promoter methylation with clinical outcomes in glioblastoma and clinical strategies to modulate MGMT activity."
04/01/2013 - "The efficacy of treatment for glioblastoma multiforme is currently limited by the development of resistance, particularly, but not exclusively, due to the expression of the DNA repair enzyme O6-methylguanine methyltransferase (MGMT) in a significant proportion of astrocytic tumors. "
08/01/2014 - "This also applies to O(6)-methylguanine DNA methyltransferase (MGMT)-mediated myeloprotection, a concept recently proven clinically effective in the context of glioblastoma therapy. "
05/01/2007 - "Recent data suggest that methylation of the DNA repair gene O(6)-methylguanine DNA methyltransferase (MGMT), by increasing the chemosensitivity of glioblastoma multiforme, is significantly associated with improved prognosis. "
10/06/2015 - "Although O(6)-methylguanine DNA methyltransferase (MGMT) promoter methylation status is an important marker for glioblastoma multiforme (GBM), there is considerable variability in the clinical outcome of patients with similar methylation profiles. "

05/01/2010 - "However, improved survival is observed in a minority of patients, most frequently those whose tumors display CpG methylation of the O(6)-methylguanine (O(6)-meG)-DNA methyltransferase (MGMT) promoter, and adult GBMs remain invariably fatal. "
08/01/2001 - "Previous studies indicated that O(6)-methylguanine (O(6)-mG) persistence is critical for lung tumor formation in A/J mice. "
01/01/2015 - "However, therapeutic benefits of TMZ can be compromised by the expression of O6-methylguanine methyltransferase (MGMT) in tumor tissue. "
01/01/2015 - "Drug pharmacokinetic (PK) analysis, tumor gene expression, methylation status of the O6-methylguanine methyltransferase (MGMT) promoter, and MGMT expression were evaluated. "
06/01/2014 - "By analogy to O(6)-methylguanine, O(6)-CMG is expected to be mutagenic, inducing G-to-A mutations that may be the molecular basis of increased cancer risk. "

01/01/2009 - "Brca2/Xrcc2 dependent HR, but not NHEJ, is required for protection against O(6)-methylguanine triggered apoptosis, DSBs and chromosomal aberrations by a process leading to SCEs."
04/01/2004 - "Loss of ATM sensitizes against O6-methylguanine triggered apoptosis, SCEs and chromosomal aberrations."
01/01/1993 - "The probability that O6-methylguanine is converted into cytogenetic effects has been estimated to be about 1:30 for SCEs, and 1:147,000 and 1:22,000 for chromosomal aberrations in the first and second post-treatment mitosis, respectively. "
03/01/1983 - "O6-methylguanine, but not N7-methylguanine or N3-methyladenine, induces gene mutations, sister-chromatid exchanges and chromosomal aberrations in Chinese hamster cells."
02/03/1997 - "O6-Methylguanine (O6MeG) is important in induction of chromosome aberrations (abs), with the unusual property that new abs are produced in the second cycle after treatment; cells lacking repair by O6-alkylguanine DNA-alkyltransferase (AGT) have more abs at the second division (M2) than at the first (M1). "

11/01/2012 - "Epigenetic silencing of the O6-methylguanine methyltransferase (MGMT) gene by promoter methylation plays an important role in regulating MGMT expression in gliomas and this is an established independent prognostic factor. "
10/01/2002 - "The enhancing effect exerted by PARP inhibitor was particularly evident in glioma cells characterized by a defective expression of MR, since these cells are tolerant to O(6)-methylguanine damage and show low sensitivity to TZM. "
08/01/2009 - "Correlation of chromosomes 1p and 19q status and expressions of O6-methylguanine DNA methyltransferase (MGMT), p53 and Ki-67 in diffuse gliomas of World Health Organization (WHO) grades II and III: a clinicopathological study."
05/01/2015 - "Clinical and molecular prognostic factors in gliomas include age, IDH mutation, the glioma CpG island methylator phenotype (G-CIMP+) and promoter methylation of the O(6)-methylguanine DNA-methyltransferase (MGMT) gene. "
10/01/2013 - "The DNA repair enzyme O6-methylguanine methyltransferase (MGMT) is a major determinant of glioma resistance to alkylating agents. "

01/01/1989 - "The effect of O6-methylguanine treatment on AGT activity was measured in mouse tissues as well as human colonic carcinoma tumors (HT29 and BE) grown in Swiss athymic nude mice. "
03/01/1977 - "Excision of O6-methylguanine from hepatic DNA was significantly slower in A/J than in C3HeB/FeJ mice; both strains habe been found to develop hepatic carcinomas following MNU administration. "
11/15/2007 - "In this study, we demonstrated that treatment of human colorectal HT-29 carcinoma cells with tamoxifen decreased the repair activity and expression level of O(6)-methylguanine DNA methyltransferase (MGMT) protein in a concentration- and time-dependent manner. "
04/01/1989 - "This increased formation of the mutagenic DNA adduct O6-methylguanine may explain the increased incidence of dialkylnitrosamine-induced carcinomas observed with dietary zinc deficiency. "
07/01/1984 - "In view of the possible involvement of N-nitroso compounds in the etiology of gastric carcinoma in man, we have examined the abilities of extracts of human gastric mucosa for the removal from DNA of O6-methylguanine, the primary precarcinogenic lesion induced in DNA by methylating carcinogenic N-nitroso compounds. "