The alkylation products formed by in vitro treatment of DNA with tritium-labeled 1,3-bis(2-chloroethyl)-1-nitrosourea ((3)H-BCNU) were identified and quantified. Twelve adducts were resolved by high-performance liquid chromatography (HPLC). The principal DNA adducts formed by BCNU treatment corresponded to N-7-(2-hydroxyethyl)guanine (N7-HOEtG) (26%), N-7-(2-chloroethyl)guanine (15%), and phosphotriesters (19%). In addition, several minor products were identified as 1,2-(diguan-7-yl)ethane, N-1-(2-hydroxyethyl)-2-deoxyguanosine, 1-(N-1-2-deoxyguanosinyl), 2-(N-3-2-deoxycytidyl)ethane cross-link, and O-6-(2-hydroxyethyl)-2-deoxyguanosine, and individually they represented 1% to 5% of the total alkylation. An HPLC-electrochemical method was applied to quantify the levels of N7-HOEtG in samples treated with BCNU. Treatment of either purified DNA or U87MG cells with various amounts of BCNU produced a linear increase in the amount of N7-HOEtG. These results demonstrated that the levels of N7-HOEtG formed by BCNU treatment could be used as a molecular dosimeter of BCNU treatment dose. We measured the levels of N7-HOEtG in DNA isolated from tumor samples taken from four patients with GBM tumors following stereotactic intratumoral injection with DTI-015 (BCNU-ethanol). The level of N7-HOEtG in these samples ranged from 14.7 to 121.9 micromol N7-HOETG/mol DNA within 1 cm of the site of injection. As the distance from the site of injection increased, the levels of N7-HOEtG in tumor DNA decreased. In two of the samples, the levels of N7-HOEtG were 0.2 to 0.3 micromol N7-HOETG/mol DNA at 3.5 to 3.9 cm from the site of injection, demonstrating significant distribution of BCNU in the tumor. The levels of N7-HOEtG in these tumor samples corresponded to BCNU treatment concentrations of 0.02 to 43.0 mM. These studies demonstrate that stereotactic intratumoral injection of DTI-015 into human GBM tumors produces high concentrations of BCNU up to 2.5 cm from the site of injection in some of the tumors. These observations suggest that intratumoral injection of DTI-015 may be of benefit in the treatment of primary and recurrent GBM tumors.
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http://dx.doi.org/10.1215/15228517-2006-014 | DOI Listing |
J Neurooncol
February 2009
Laboratory of Molecular Therapeutics, Brain Tumor Research Center of the Department of Neurological Surgery, University of California-San Francisco, San Francisco, CA, 94143-0555, USA.
This study has investigated if individual DNA adducts formed in human glioma cells treated with (3)H-1-(2-chloroethyl)-1-nitrosourea ((3)H-CNU) could be used as molecular dosimeters of response after CENU treatment. The levels of individual DNA alkylation products were compared with the induction of cytotoxicity in six human glioma cell lines after treatment with (3)H-CNU. The levels of seven DNA adducts N7-(2-hydroxyethyl)guanine, (N7-HOEtG); N7-(2-chloroethyl)guanine, (N7-ClEtG); 1,2-[diguan-7-yl]-ethane, (N7-bis-G); N1-(2-hydroxyethyl)-2-deoxyguanosine, N1-HOEtdG; 1-[N1-2-deoxyguanosinyl], 2-[N3-2-deoxycytidyl]-ethane, dG-dC; O(6)-(2-hydroxyethyl)-2-deoxyguanosine, O(6)-HOEtdG and phosphotriesters (PTE), were quantified in each of the cell lines following treatment with (3)H-CNU.
View Article and Find Full Text PDFNeuro Oncol
January 2007
Laboratory of Molecular Therapeutics, Brain Tumor Research Center, Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA.
The alkylation products formed by in vitro treatment of DNA with tritium-labeled 1,3-bis(2-chloroethyl)-1-nitrosourea ((3)H-BCNU) were identified and quantified. Twelve adducts were resolved by high-performance liquid chromatography (HPLC). The principal DNA adducts formed by BCNU treatment corresponded to N-7-(2-hydroxyethyl)guanine (N7-HOEtG) (26%), N-7-(2-chloroethyl)guanine (15%), and phosphotriesters (19%).
View Article and Find Full Text PDFJ Neurooncol
May 2003
Laboratory of Molecular Therapeutics, Department of Neurological Surgery, Brain Tumor Research Center, University of California, San Francisco, CA 94143-0555, USA.
Intratumoral (IT) administration of DTI-015 (BCNU in 100% ethanol) utilizes solvent facilitated perfusion for the treatment of tumors. RIF-1 tumors were treated by IT injection of either ethanol alone or 0.05-1.
View Article and Find Full Text PDFMutat Res
December 2001
Brain Tumor Research Center of the Department of Neurological Surgery, University of California, Box-0555, San Francisco, CA 94143-0555, USA.
We have investigated the genotoxic effects of 1-(2-hydroxyethyl)-1-nitrosourea (HENU). We have chosen this agent because of its demonstrated ability to produce N7-(2-hydroxyethyl) guanine (N7-HOEtG) and O(6)-(2-hydroxyethyl) 2'-deoxyguanosine (O(6)-HOEtdG); two of the DNA alkylation products produced by 1,3-bis (2-chloroethyl)-1-nitrosourea (BCNU). For these studies, we have used the Big Blue Rat-2 cell line that contains a lambda/lacI shuttle vector.
View Article and Find Full Text PDFNeuro Oncol
October 2001
Brain Tumor Research Center of the Department of Neurological Surgery, University of California, San Francisco 94143-0555, USA.
The level of N7-(2-hydroxyethyl)guanine (N7-HOEtG), one of the DNA alkylation products formed by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) treatment, was measured in human brain tumor samples by high performance liquid chromatography with electrochemical detection. The tumors from 6 recurrent chemotherapy-naive patients with recurrent glioblastoma multiforme were analyzed as controls. The mean level of N7-HOEtG in DNA of these specimens was 0.
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