NU1025 (NSC-696807) is a potent PARP inhibitor with IC50 of 400 nM.

NU1025 (0.2 mM) treatment attenuates Water2 induced cytotoxicity. NU1025 per se does not have any effect on cell viability. NU1025 pretreatment significantly increases cell viability (82.59 4.67%) in SIN-1 (0.8 mM) exposed cells.[2] NU1025 has no detectable effect on the proliferation of D54 and U251 cells. Treatment with NU1025 markedly inhibits the enhanced activation of PARP-1 induced by TPT and RT treatment.[3] No DNA strand breakage is detected following exposure to 200 μM NU1025 alone.[4]

Treatment with NU1025 (1 and 3 mg/kg) reduces the infarction to 25% and 45% versus vehicle treated rats, respectively. NU1025 (1 and 3 mg/kg) treatment significantly reduces edema volume. NU1025 also produces significant improvement in neurological deficits.[2]

PARP activation assay: Cells are suspended in hypotonic buffer (9 mM HEPES, pH 7.8, 4.5% (v/v) dextran, 4.5 mM MgCl2 and 5 mM DTT) at 1.5 × 107/mL on ice for 30 min, then 9 vol of isotonic buffer (40 mM HEPES, pH 7.8, 130 mM KCl, 4% (v/v) dextran, 2 mM EGTA, 2.3 mM MgCl2, 225 mM sucrose and 2.5 mM DTT) is added. The reaction is started by adding 300 μL cells to 100 μL 300 μM NAD+ containing [32P]-NAD+, and terminated by the addition of 2 mL ice-cold 10% (w/v) TCA +10% (w/v) sodium pyrophosphate. After 30 min on ice the precipitated 32P-labelled ADP-ribose polymers are filtered, washed five times with 1% (v/v) TCA, 1% (v/v) sodium pyrophosphate, dried and counted.

Cells are seeded in 96-well plates at a density of 2,500 cells/well and treated with the indicated doses of NU1025. Adherent cells are irradiated in medium with 250 kVp X-rays (dose rate 0.5 Gy/min). Untreated cells are used as a control. Following an up to 5 day incubation, cell proliferation is assessed by MTT assay.(Only for Reference)