ATM Regulates 3-Methylpurine-DNA Glycosylase and Promotes Therapeutic Resistance to Alkylating Agents

作者：Agnihotri Sameer; Burrell Kelly; Buczkowicz Pawel; Remke Marc; Golbourn Brian; Chornenkyy Yevgen; Gajadhar Aaron; Fernandez Nestor A; Clarke Ian D; Barszczyk Mark S; Pajovic Sanja; Ternamian Christian; Head Renee; Sabha Nesrin; Sobol Robert W; Taylor Michael D; Rutka James T; Jones Chris; Dirks Peter B; Zadeh Gelareh; Hawkins Cynthia^*

来源：Cancer Discovery, 2014, 4(10): 1198-1213.

DOI：10.1158/2159-8290.CD-14-0157

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 an

• 出版日期2014-10