WRN Helicase Inhibitor, NSC 19630

A cell-permeable maleimide compound selectively inhibits Werner syndrome WRN helicase activity (IC₅₀ = 20 µM) over its ATPase and exonuclease activities (19% and <10% inhibition, respectively, at 50 µM), while exhibiting no effect against the helicase activity of two other human RecQ family DNA helicases (RECQ1 and Werner syndrome BLM), Fanconi anemia group J helicase FANCJ, as well as three other E. coli helicases, RecQ, UvrD, and DnaB. The WRN-dependent antiproliferation activity of MIRA-1/NSC 19630 in HeLa 1.2.11 cultures (0% vs. 95% inhibition with or without siRNA-mediated WRN-depletion, respectively, after 48 h 3 µM treatment) is shown to be a direct result of apoptosis induction due to replication forks blockage (20-fold increase in PCNA foci staining after 72 h 2 µM treatment), enhanced DSB (17-fold increase in γ-H2AX foci staining after 72 h 2 µM treatment), and increased S-phase population (from 24% to 42% after 72 h 2 µM treatment). In some cells, MIRA-1/NSC 19630 appears to also exert its apoptotic effect, at least in part, by restoring DNA-binding and transactivation function of some, but not all, p53 mutants.

Toxicity: Standard Handling (A)

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 6 months at -20°C.

Aggarwal, M., et al. 2011. Proc. Natl. Acad. Sci USA108, 1525.
Bykov, V.J.N., et al. 2005. J. Biol. Chem.280, 30384.

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