Drugs that generate DNA crosslinks are among the most effective cancer chemotherapeutic agents. These drugs fall in several classes of bi-functional molecules that generate DNA mono-adducts, intrastrand and interstrand crosslinks and are the standard of care for many malignancies. Interstrand crosslinks (ICLs) block many DNA transactions and are thought to be the cytotoxic lesions responsible for most crosslinking drug efficacy. Their efficacy however, varies among cell types or patients. There are two major challenges associated with these compounds: 1) dose-limiting toxicity, primarily in the blood, and 2) acquired resistance. The goal of this proposal is to characterize the mechanisms of ICL repair to better understand and ultimately improve the mode of action of crosslinking agent-based chemotherapy. ICLs are repaired during and outside of S-phase. Replication-independent ICL repair (RIR) is robust and critical for survival in treated mammalian cells. The proposed studies specifically address the mechanism of ICL repair in the absence of other DNA lesions and therefore focus on the most clinically relevant repair reaction triggered by crosslinking drugs. Specifically, we propose to identify the nucleases (Aim 1) and DNA polymerases (Aim 2) involved in RIR. Finally, we propose to evaluate the impact of replication-dependent and -independent ICL repair on crosslinking drugs efficacy. We hypothesize that targeting these factors could increase the sensitivity of tumor cells to crosslinking agents and reduce the incidence of resistance. Our approach will combine biochemistry in cell-free extracts with innovative ICL repair assays in normal and tumor cells. We anticipate that a better understanding of the molecular mechanisms of ICL repair will shed light on the contribution of ICL lesions to crosslinking drug toxicity and on the impact of DNA repair on resistance to crosslinking therapy.
The proposed research is highly relevant to public health. A better understanding of the enzymes responsible for DNA interstrand crosslink (ICL) repair is warranted to unravel the mechanism of action of drugs that generate ICLs work. It will also provide insight into why these drugs, which are routinely used in chemotherapeutic protocols, have variable efficacy among cell types or patients. It can help explain how resistance to these drugs arises. Finally, the proposed research will identify potential targets to sensitize cells and to prevent resistance to crosslinking drugs.
|Aparicio, Tomas; Baer, Richard; Gottesman, Max et al. (2016) MRN, CtIP, and BRCA1 mediate repair of topoisomerase II-DNA adducts. J Cell Biol 212:399-408|
|Sato, Mai; Rodriguez-Barrueco, Ruth; Yu, Jiyang et al. (2015) MYC is a critical target of FBXW7. Oncotarget 6:3292-305|
|Aparicio, Tomas; Baer, Richard; Gautier, Jean (2014) DNA double-strand break repair pathway choice and cancer. DNA Repair (Amst) 19:169-75|
|Dominguez-Sola, David; Gautier, Jean (2014) MYC and the control of DNA replication. Cold Spring Harb Perspect Med 4:|
|Peterson, Shaun E; Li, Yinyin; Wu-Baer, Foon et al. (2013) Activation of DSB processing requires phosphorylation of CtIP by ATR. Mol Cell 49:657-67|
|Williams, Hannah L; Gottesman, Max E; Gautier, Jean (2013) The differences between ICL repair during and outside of S phase. Trends Biochem Sci 38:386-93|
|Rozier, Lorene; Guo, Yige; Peterson, Shaun et al. (2013) The MRN-CtIP pathway is required for metaphase chromosome alignment. Mol Cell 49:1097-107|
|Srinivasan, Seetha V; Dominguez-Sola, David; Wang, Lily C et al. (2013) Cdc45 is a critical effector of myc-dependent DNA replication stress. Cell Rep 3:1629-39|
|Williams, Hannah L; Gottesman, Max E; Gautier, Jean (2012) Replication-independent repair of DNA interstrand crosslinks. Mol Cell 47:140-7|