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Mechanistic Distinctions between CHK1 and WEE1 Inhibition Guide the Scheduling of Triple Therapy with Gemcitabine.

Accepted version
Peer-reviewed

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Authors

Wallez, Yann 
Bernaldo de Quirós Fernández, Sandra 
Bapiro, Tashinga E 

Abstract

Combination of cytotoxic therapy with emerging DNA damage response inhibitors (DDRi) has been limited by tolerability issues. However, the goal of most combination trials has been to administer DDRi with standard-of-care doses of chemotherapy. We hypothesized that mechanism-guided treatment scheduling could reduce the incidence of dose-limiting toxicities and enable tolerable multitherapeutic regimens. Integrative analyses of mathematical modeling and single-cell assays distinguished the synergy kinetics of WEE1 inhibitor (WEE1i) from CHEK1 inhibitor (CHK1i) by potency, spatiotemporal perturbation, and mitotic effects when combined with gemcitabine. These divergent properties collectively supported a triple-agent strategy, whereby a pulse of gemcitabine and CHK1i followed by WEE1i durably suppressed tumor cell growth. In xenografts, CHK1i exaggerated replication stress without mitotic CDK hyperactivation, enriching a geminin-positive subpopulation and intratumoral gemcitabine metabolite. Without overt toxicity, addition of WEE1i to low-dose gemcitabine and CHK1i was most effective in tumor control compared with single and double agents. Overall, our work provides quantitative insights into the mechanisms of DDRi chemosensitization, leading to the rational development of a tolerable multitherapeutic regimen.Significance: Multiple lines of mechanistic insight regarding DNA damage response inhibitors rationally guide the preclinical development of a tolerable multitherapeutic regimen.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/11/3054/F1.large.jpg Cancer Res; 78(11); 3054-66. ©2018 AACR.

Description

Keywords

Animals, Antineoplastic Combined Chemotherapy Protocols, Cell Cycle Proteins, Cell Line, Tumor, Cell Proliferation, Checkpoint Kinase 1, DNA Damage, DNA Replication, Deoxycytidine, Drug Synergism, Female, Humans, Mice, Mice, Inbred BALB C, Mice, Nude, Nuclear Proteins, Protein-Tyrosine Kinases, Xenograft Model Antitumor Assays, Gemcitabine

Journal Title

Cancer Res

Conference Name

Journal ISSN

0008-5472
1538-7445

Volume Title

78

Publisher

American Association for Cancer Research (AACR)
Sponsorship
Cancer Research UK (C14303/A17197)
Pancreatic Cancer UK (FutureLeaders)
Cancer Research UK (CB4270)
Pancreatic Cancer UK (FLF2015_03_Cambridge)
Cancer Research UK (15678)