PARP-1-IN-1 is a highly selective and orally active inhibitor of the enzyme PARP-1 with an IC50 of 0.96 nM, exhibiting excellent tolerance and significant activity in a single dose in the MDA-MB-436 xenotransplantation model [1].

PARP-1-IN-1 (compound Y49) effectively inhibits various cancer cells over 48 hours, with IC50 values of 9.64, 123.5, and 106.3 μM for MX-1, MCF7, and A548 cells, respectively. At 2.5-10 μM concentrations, it significantly inhibits PARP-1 activity and reduces PAR production in A549 cells in a dose-dependent manner [1]. Western Blot Analysis confirms this, showing suppression of PARP-1 activity and decreased PAR levels at 2.5, 5, and 10 μM concentrations after 48-hour incubation [1].

PARP-1-IN-1 (Compound Y49) administered orally at a dosage of 50 mg/kg/day for 18 days significantly inhibits the growth of MDA-MB-436 tumors in female athymic BALB/c nude mice without causing a significant change in the body weight of the treated mice. This finding highlights the compound's potential as a targeted therapy for this tumor model.