Brain tumor cell lines resistant to O6-benzylguanine/1,3-bis(2-chloroethyl)-1-nitrosourea chemotherapy have O6-alkylguanine-DNA alkyltransferase mutations

Manny D. Bacolod, Stewart P. Johnson, Anthony E. Pegg, M. Eileen Dolan, Robert C. Moschel, Nancy S. Bullock, Qingming Fang, O. Michael Colvin, Paul Modrich, Darell D. Bigner, Henry S. Friedman

Research output: Contribution to journalArticle

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Abstract

The chemotherapeutic activity of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU or carmustine) may be improved by the addition of O6 -benzylguanine (O6-BG). The reaction of O6-BG with O6-alkylguanine-DNA alkyltransferase (AGT) prevents the repair of O6-chloroethyl lesions caused by BCNU. In clinics, the combination of O6-BG and BCNU is now being tested for the treatment of brain tumors. However, the effectiveness of this drug regimen may be limited by drug resistance acquired during treatment. To understand the possible mechanisms of resistance of brain tumor cells to the O6-BG/BCNU combination, we generated medulloblastoma cell lines (D283 MED, D341 MED, and Daoy) resistant to the combination of O6-BG and BCNU [O6-BG/BCNU resistant (OBR)]. DNA sequencing showed that all of the parent cell lines express wild-type AGTs, whereas every OBR cell line exhibited mutations that potentially affected the binding of O6-BG to the protein as evidenced previously by in vitro mutagenesis and structural studies of AGT. The D283 MED (OBR), Daoy (OBR), and D341 MED (OBR) cell lines expressed G156C, Y114F, and K165T AGT mutations, respectively. We reported previously that rhabdomyosarcoma TE-671 (OBR) also expresses a G156C mutation. These data suggest that the clonal selection of AGT mutants during treatment with O6-BG plus an alkylator may produce resistance to this intervention in clinical settings.

Original languageEnglish (US)
Pages (from-to)1127-1135
Number of pages9
JournalMolecular cancer therapeutics
Volume3
Issue number9
StatePublished - Sep 1 2004

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Carmustine
Tumor Cell Line
Brain Neoplasms
Drug Therapy
Mutation
Cell Line
O(6)-benzylguanine
DNA alkyltransferase
Medulloblastoma
Rhabdomyosarcoma
Alkylating Agents
DNA Sequence Analysis
Drug Resistance
Mutagenesis

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research

Cite this

Bacolod, Manny D. ; Johnson, Stewart P. ; Pegg, Anthony E. ; Dolan, M. Eileen ; Moschel, Robert C. ; Bullock, Nancy S. ; Fang, Qingming ; Colvin, O. Michael ; Modrich, Paul ; Bigner, Darell D. ; Friedman, Henry S. / Brain tumor cell lines resistant to O6-benzylguanine/1,3-bis(2-chloroethyl)-1-nitrosourea chemotherapy have O6-alkylguanine-DNA alkyltransferase mutations. In: Molecular cancer therapeutics. 2004 ; Vol. 3, No. 9. pp. 1127-1135.
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title = "Brain tumor cell lines resistant to O6-benzylguanine/1,3-bis(2-chloroethyl)-1-nitrosourea chemotherapy have O6-alkylguanine-DNA alkyltransferase mutations",
abstract = "The chemotherapeutic activity of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU or carmustine) may be improved by the addition of O6 -benzylguanine (O6-BG). The reaction of O6-BG with O6-alkylguanine-DNA alkyltransferase (AGT) prevents the repair of O6-chloroethyl lesions caused by BCNU. In clinics, the combination of O6-BG and BCNU is now being tested for the treatment of brain tumors. However, the effectiveness of this drug regimen may be limited by drug resistance acquired during treatment. To understand the possible mechanisms of resistance of brain tumor cells to the O6-BG/BCNU combination, we generated medulloblastoma cell lines (D283 MED, D341 MED, and Daoy) resistant to the combination of O6-BG and BCNU [O6-BG/BCNU resistant (OBR)]. DNA sequencing showed that all of the parent cell lines express wild-type AGTs, whereas every OBR cell line exhibited mutations that potentially affected the binding of O6-BG to the protein as evidenced previously by in vitro mutagenesis and structural studies of AGT. The D283 MED (OBR), Daoy (OBR), and D341 MED (OBR) cell lines expressed G156C, Y114F, and K165T AGT mutations, respectively. We reported previously that rhabdomyosarcoma TE-671 (OBR) also expresses a G156C mutation. These data suggest that the clonal selection of AGT mutants during treatment with O6-BG plus an alkylator may produce resistance to this intervention in clinical settings.",
author = "Bacolod, {Manny D.} and Johnson, {Stewart P.} and Pegg, {Anthony E.} and Dolan, {M. Eileen} and Moschel, {Robert C.} and Bullock, {Nancy S.} and Qingming Fang and Colvin, {O. Michael} and Paul Modrich and Bigner, {Darell D.} and Friedman, {Henry S.}",
year = "2004",
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Bacolod, MD, Johnson, SP, Pegg, AE, Dolan, ME, Moschel, RC, Bullock, NS, Fang, Q, Colvin, OM, Modrich, P, Bigner, DD & Friedman, HS 2004, 'Brain tumor cell lines resistant to O6-benzylguanine/1,3-bis(2-chloroethyl)-1-nitrosourea chemotherapy have O6-alkylguanine-DNA alkyltransferase mutations', Molecular cancer therapeutics, vol. 3, no. 9, pp. 1127-1135.

Brain tumor cell lines resistant to O6-benzylguanine/1,3-bis(2-chloroethyl)-1-nitrosourea chemotherapy have O6-alkylguanine-DNA alkyltransferase mutations. / Bacolod, Manny D.; Johnson, Stewart P.; Pegg, Anthony E.; Dolan, M. Eileen; Moschel, Robert C.; Bullock, Nancy S.; Fang, Qingming; Colvin, O. Michael; Modrich, Paul; Bigner, Darell D.; Friedman, Henry S.

In: Molecular cancer therapeutics, Vol. 3, No. 9, 01.09.2004, p. 1127-1135.

Research output: Contribution to journalArticle

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T1 - Brain tumor cell lines resistant to O6-benzylguanine/1,3-bis(2-chloroethyl)-1-nitrosourea chemotherapy have O6-alkylguanine-DNA alkyltransferase mutations

AU - Bacolod, Manny D.

AU - Johnson, Stewart P.

AU - Pegg, Anthony E.

AU - Dolan, M. Eileen

AU - Moschel, Robert C.

AU - Bullock, Nancy S.

AU - Fang, Qingming

AU - Colvin, O. Michael

AU - Modrich, Paul

AU - Bigner, Darell D.

AU - Friedman, Henry S.

PY - 2004/9/1

Y1 - 2004/9/1

N2 - The chemotherapeutic activity of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU or carmustine) may be improved by the addition of O6 -benzylguanine (O6-BG). The reaction of O6-BG with O6-alkylguanine-DNA alkyltransferase (AGT) prevents the repair of O6-chloroethyl lesions caused by BCNU. In clinics, the combination of O6-BG and BCNU is now being tested for the treatment of brain tumors. However, the effectiveness of this drug regimen may be limited by drug resistance acquired during treatment. To understand the possible mechanisms of resistance of brain tumor cells to the O6-BG/BCNU combination, we generated medulloblastoma cell lines (D283 MED, D341 MED, and Daoy) resistant to the combination of O6-BG and BCNU [O6-BG/BCNU resistant (OBR)]. DNA sequencing showed that all of the parent cell lines express wild-type AGTs, whereas every OBR cell line exhibited mutations that potentially affected the binding of O6-BG to the protein as evidenced previously by in vitro mutagenesis and structural studies of AGT. The D283 MED (OBR), Daoy (OBR), and D341 MED (OBR) cell lines expressed G156C, Y114F, and K165T AGT mutations, respectively. We reported previously that rhabdomyosarcoma TE-671 (OBR) also expresses a G156C mutation. These data suggest that the clonal selection of AGT mutants during treatment with O6-BG plus an alkylator may produce resistance to this intervention in clinical settings.

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