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

PARP: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)