Abstract

Glioblastoma multiforme (GBM) is the most lethal of brain tumors and is highly resistant to ionizing radiation (IR) and chemotherapy. Here, we report on a molecular mechanism by which a key glioma-specific mutation, epidermal growth factor receptor variant III (EGFRvIII), confers radiation resistance. Using Ink4a/Arf-deficient primary mouse astrocytes, primary astrocytes immortalized by p53/Rb suppression, as well as human U87 glioma cells, we show that EGFRvIII expression enhances clonogenic survival following IR. This enhanced radioresistance is due to accelerated repair of DNA double-strand breaks (DSB), the most lethal lesion inflicted by IR. The EGFR inhibitor gefitinib (Iressa) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 attenuate the rate of DSB repair. Importantly, expression of constitutively active, myristylated Akt-1 accelerates repair, implicating the PI3K/Akt-1 pathway in radioresistance. Most notably, EGFRvIII-expressing U87 glioma cells show elevated activation of a key DSB repair enzyme, DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Enhanced radioresistance is abrogated by the DNA-PKcs-specific inhibitor NU7026, and EGFRvIII fails to confer radioresistance in DNA-PKcs-deficient cells. In vivo, orthotopic U87-EGFRvIII-derived tumors display faster rates of DSB repair following whole-brain radiotherapy compared with U87-derived tumors. Consequently, EGFRvIII-expressing tumors are radioresistant and continue to grow following whole-brain radiotherapy with little effect on overall survival. These in vitro and in vivo data support our hypothesis that EGFRvIII expression promotes DNA-PKcs activation and DSB repair, perhaps as a consequence of hyperactivated PI3K/Akt-1 signaling. Taken together, our results raise the possibility that EGFR and/or DNA-PKcs inhibition concurrent with radiation may be an effective therapeutic strategy for radiosensitizing high-grade gliomas.

Original languageEnglish (US)
Pages (from-to)4252-4259
Number of pages8
JournalCancer Research
Volume69
Issue number10
DOIs
StatePublished - May 15 2009

Fingerprint

Double-Stranded DNA Breaks
Glioblastoma
DNA-Activated Protein Kinase
Epidermal Growth Factor Receptor
Phosphatidylinositol 3-Kinase
Catalytic Domain
Glioma
Ionizing Radiation
Astrocytes
Radiotherapy
Radiation
Neoplasms
2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
Survival
Brain
Brain Neoplasms
Drug Therapy
Mutation
Enzymes

ASJC Scopus subject areas

  • Cancer Research
  • Oncology

Cite this

EGFRvIII and DNA double-strand break repair : A molecular mechanism for radioresistance in glioblastoma. / Mukherjee, Bipasha; McEllin, Brian; Camacho, Cristel V.; Tomimatsu, Nozomi; Sirasanagandala, Shyam; Nannepaga, Suraj; Hatanpaa, Kimmo J.; Mickey, Bruce; Madden, Christopher; Maher, Elizabeth; Boothman, David A.; Furnari, Frank; Cavenee, Webster K.; Bachoo, Robert M.; Burma, Sandeep.

In: Cancer Research, Vol. 69, No. 10, 15.05.2009, p. 4252-4259.

Research output: Contribution to journalArticle

Mukherjee, Bipasha ; McEllin, Brian ; Camacho, Cristel V. ; Tomimatsu, Nozomi ; Sirasanagandala, Shyam ; Nannepaga, Suraj ; Hatanpaa, Kimmo J. ; Mickey, Bruce ; Madden, Christopher ; Maher, Elizabeth ; Boothman, David A. ; Furnari, Frank ; Cavenee, Webster K. ; Bachoo, Robert M. ; Burma, Sandeep. / EGFRvIII and DNA double-strand break repair : A molecular mechanism for radioresistance in glioblastoma. In: Cancer Research. 2009 ; Vol. 69, No. 10. pp. 4252-4259.
@article{2737f688087749c28a94defe591001f0,
title = "EGFRvIII and DNA double-strand break repair: A molecular mechanism for radioresistance in glioblastoma",
abstract = "Glioblastoma multiforme (GBM) is the most lethal of brain tumors and is highly resistant to ionizing radiation (IR) and chemotherapy. Here, we report on a molecular mechanism by which a key glioma-specific mutation, epidermal growth factor receptor variant III (EGFRvIII), confers radiation resistance. Using Ink4a/Arf-deficient primary mouse astrocytes, primary astrocytes immortalized by p53/Rb suppression, as well as human U87 glioma cells, we show that EGFRvIII expression enhances clonogenic survival following IR. This enhanced radioresistance is due to accelerated repair of DNA double-strand breaks (DSB), the most lethal lesion inflicted by IR. The EGFR inhibitor gefitinib (Iressa) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 attenuate the rate of DSB repair. Importantly, expression of constitutively active, myristylated Akt-1 accelerates repair, implicating the PI3K/Akt-1 pathway in radioresistance. Most notably, EGFRvIII-expressing U87 glioma cells show elevated activation of a key DSB repair enzyme, DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Enhanced radioresistance is abrogated by the DNA-PKcs-specific inhibitor NU7026, and EGFRvIII fails to confer radioresistance in DNA-PKcs-deficient cells. In vivo, orthotopic U87-EGFRvIII-derived tumors display faster rates of DSB repair following whole-brain radiotherapy compared with U87-derived tumors. Consequently, EGFRvIII-expressing tumors are radioresistant and continue to grow following whole-brain radiotherapy with little effect on overall survival. These in vitro and in vivo data support our hypothesis that EGFRvIII expression promotes DNA-PKcs activation and DSB repair, perhaps as a consequence of hyperactivated PI3K/Akt-1 signaling. Taken together, our results raise the possibility that EGFR and/or DNA-PKcs inhibition concurrent with radiation may be an effective therapeutic strategy for radiosensitizing high-grade gliomas.",
author = "Bipasha Mukherjee and Brian McEllin and Camacho, {Cristel V.} and Nozomi Tomimatsu and Shyam Sirasanagandala and Suraj Nannepaga and Hatanpaa, {Kimmo J.} and Bruce Mickey and Christopher Madden and Elizabeth Maher and Boothman, {David A.} and Frank Furnari and Cavenee, {Webster K.} and Bachoo, {Robert M.} and Sandeep Burma",
year = "2009",
month = "5",
day = "15",
doi = "10.1158/0008-5472.CAN-08-4853",
language = "English (US)",
volume = "69",
pages = "4252--4259",
journal = "Journal of Cancer Research",
issn = "0099-7013",
publisher = "American Association for Cancer Research Inc.",
number = "10",

}

TY - JOUR

T1 - EGFRvIII and DNA double-strand break repair

T2 - A molecular mechanism for radioresistance in glioblastoma

AU - Mukherjee, Bipasha

AU - McEllin, Brian

AU - Camacho, Cristel V.

AU - Tomimatsu, Nozomi

AU - Sirasanagandala, Shyam

AU - Nannepaga, Suraj

AU - Hatanpaa, Kimmo J.

AU - Mickey, Bruce

AU - Madden, Christopher

AU - Maher, Elizabeth

AU - Boothman, David A.

AU - Furnari, Frank

AU - Cavenee, Webster K.

AU - Bachoo, Robert M.

AU - Burma, Sandeep

PY - 2009/5/15

Y1 - 2009/5/15

N2 - Glioblastoma multiforme (GBM) is the most lethal of brain tumors and is highly resistant to ionizing radiation (IR) and chemotherapy. Here, we report on a molecular mechanism by which a key glioma-specific mutation, epidermal growth factor receptor variant III (EGFRvIII), confers radiation resistance. Using Ink4a/Arf-deficient primary mouse astrocytes, primary astrocytes immortalized by p53/Rb suppression, as well as human U87 glioma cells, we show that EGFRvIII expression enhances clonogenic survival following IR. This enhanced radioresistance is due to accelerated repair of DNA double-strand breaks (DSB), the most lethal lesion inflicted by IR. The EGFR inhibitor gefitinib (Iressa) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 attenuate the rate of DSB repair. Importantly, expression of constitutively active, myristylated Akt-1 accelerates repair, implicating the PI3K/Akt-1 pathway in radioresistance. Most notably, EGFRvIII-expressing U87 glioma cells show elevated activation of a key DSB repair enzyme, DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Enhanced radioresistance is abrogated by the DNA-PKcs-specific inhibitor NU7026, and EGFRvIII fails to confer radioresistance in DNA-PKcs-deficient cells. In vivo, orthotopic U87-EGFRvIII-derived tumors display faster rates of DSB repair following whole-brain radiotherapy compared with U87-derived tumors. Consequently, EGFRvIII-expressing tumors are radioresistant and continue to grow following whole-brain radiotherapy with little effect on overall survival. These in vitro and in vivo data support our hypothesis that EGFRvIII expression promotes DNA-PKcs activation and DSB repair, perhaps as a consequence of hyperactivated PI3K/Akt-1 signaling. Taken together, our results raise the possibility that EGFR and/or DNA-PKcs inhibition concurrent with radiation may be an effective therapeutic strategy for radiosensitizing high-grade gliomas.

AB - Glioblastoma multiforme (GBM) is the most lethal of brain tumors and is highly resistant to ionizing radiation (IR) and chemotherapy. Here, we report on a molecular mechanism by which a key glioma-specific mutation, epidermal growth factor receptor variant III (EGFRvIII), confers radiation resistance. Using Ink4a/Arf-deficient primary mouse astrocytes, primary astrocytes immortalized by p53/Rb suppression, as well as human U87 glioma cells, we show that EGFRvIII expression enhances clonogenic survival following IR. This enhanced radioresistance is due to accelerated repair of DNA double-strand breaks (DSB), the most lethal lesion inflicted by IR. The EGFR inhibitor gefitinib (Iressa) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 attenuate the rate of DSB repair. Importantly, expression of constitutively active, myristylated Akt-1 accelerates repair, implicating the PI3K/Akt-1 pathway in radioresistance. Most notably, EGFRvIII-expressing U87 glioma cells show elevated activation of a key DSB repair enzyme, DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Enhanced radioresistance is abrogated by the DNA-PKcs-specific inhibitor NU7026, and EGFRvIII fails to confer radioresistance in DNA-PKcs-deficient cells. In vivo, orthotopic U87-EGFRvIII-derived tumors display faster rates of DSB repair following whole-brain radiotherapy compared with U87-derived tumors. Consequently, EGFRvIII-expressing tumors are radioresistant and continue to grow following whole-brain radiotherapy with little effect on overall survival. These in vitro and in vivo data support our hypothesis that EGFRvIII expression promotes DNA-PKcs activation and DSB repair, perhaps as a consequence of hyperactivated PI3K/Akt-1 signaling. Taken together, our results raise the possibility that EGFR and/or DNA-PKcs inhibition concurrent with radiation may be an effective therapeutic strategy for radiosensitizing high-grade gliomas.

UR - http://www.scopus.com/inward/record.url?scp=66249149058&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=66249149058&partnerID=8YFLogxK

U2 - 10.1158/0008-5472.CAN-08-4853

DO - 10.1158/0008-5472.CAN-08-4853

M3 - Article

VL - 69

SP - 4252

EP - 4259

JO - Journal of Cancer Research

JF - Journal of Cancer Research

SN - 0099-7013

IS - 10

ER -