UPF 1069 is a PARP inhibitor, with IC₅₀s of 8 and 0.3 μM for PARP-1 and PARP-2, respectively. IC50 & Target: IC50: 8 μM (PARP-1), 0.3 μM (PARP-2)^[1][2] In Vitro: UPF 1069 (Compound 55) is a PARP inhibitor, with IC₅₀s of 8 and 0.3 μM for PARP-1 and PARP-2, respectively^[1]. UPF 1069 (1 µM) reduces the residual PARP activity by approximately 80% of PARP-1-deficient fibroblasts, but only slightly inhibits the enzymic activity in wild-type fibroblasts. UPF 1069 (0.1-1 µM) markedly enhances CA1 hippocampal damage. UPF 1069 (10 µM) also exacerbates oxygen-glucose deprivation (OGD) damage in organotypic hippocampal slices. However, UPF 1069 alleviates the damage cuased by OGD in mixed cortical cell cultures, shows a potent neuroprotective activity both at a concentration (1 µM) selectively acting on PARP-2 and at a concentration (10 µM) inhibiting both PARP-1 and PARP-2 activities^[2].