2. Academic Validation
  3. ATM regulates 3-methylpurine-DNA glycosylase and promotes therapeutic resistance to alkylating agents

ATM regulates 3-methylpurine-DNA glycosylase and promotes therapeutic resistance to alkylating agents

  • Cancer Discov. 2014 Oct;4(10):1198-213. doi: 10.1158/2159-8290.CD-14-0157.
Sameer Agnihotri 1,  Kelly Burrell 1,  Pawel Buczkowicz 1,  Marc Remke 1,  Brian Golbourn 1,  Yevgen Chornenkyy 1,  Aaron Gajadhar 2,  Nestor A Fernandez 1,  Ian D Clarke 1,  Mark S Barszczyk 1,  Sanja Pajovic 1,  Christian Ternamian 1,  Renee Head 1,  Nesrin Sabha 1,  Robert W Sobol 3,  Michael D Taylor 1,  James T Rutka 1,  Chris Jones 4,  Peter B Dirks 1,  Gelareh Zadeh 5,  Cynthia Hawkins 6
Affiliations

Affiliations

  • 1 Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Canada.
  • 2 Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts.
  • 3 Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania. Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, Pennsylvania.
  • 4 The Institute of Cancer Research, London, United Kingdom.
  • 5 Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Canada. Division of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, Canada.
  • 6 Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Canada. Division of Pathology, The Hospital for Sick Children, University of Toronto, Toronto, Canada. [email protected].
PMID: 25100205 DOI: 10.1158/2159-8290.CD-14-0157
Abstract

Alkylating agents are a first-line therapy for the treatment of several aggressive cancers, including pediatric glioblastoma, a lethal tumor in children. Unfortunately, many tumors are resistant to this therapy. We sought to identify ways of sensitizing tumor cells to alkylating agents while leaving normal cells unharmed, increasing therapeutic response while minimizing toxicity. Using an siRNA screen targeting over 240 DNA damage response genes, we identified novel sensitizers to alkylating agents. In particular, the base excision repair (BER) pathway, including 3-methylpurine-DNA glycosylase (MPG), as well as ataxia telangiectasia mutated (ATM), were identified in our screen. Interestingly, we identified MPG as a direct novel substrate of ATM. ATM-mediated phosphorylation of MPG was required for enhanced MPG function. Importantly, combined inhibition or loss of MPG and ATM resulted in increased alkylating agent-induced cytotoxicity in vitro and prolonged survival in vivo. The discovery of the ATM-MPG axis will lead to improved treatment of alkylating agent-resistant tumors.

Significance: Inhibition of ATM and MPG-mediated BER cooperate to sensitize tumor cells to alkylating agents, impairing tumor growth in vitro and in vivo with no toxicity to normal cells, providing an ideal therapeutic window.

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