Background:

CI994 is a selective inhibitor of HDAC1 with IC50 value of 0.57 μM [1].
HDAC1 is an enzyme that encoded by HDAC1 and plays a pivotal role in regulating eukaryotic gene expression. It is also been reported that HDAC1 interacts with retinoblastoma tumor-suppressor protein which is a key element in the control of cell proliferation and differentiation. Many studies have shown that HDAC1 inhibition works as a promising therapy used for cancer treatment in clinic [2] [3].
CI994 is a selective HDAC1 and HDAC3 and is different from the reported unselective inhibitor SAHA. When tested with HeLa cervical carcinoma cells, CI994 treatment showed a selectivity inhibitory ability for HDAC1 and 3 with the IC50 was 43.5±1.2 μM [4]. In peripheral blood lymphocytes isolated from untreated male Wistar rats, administration of CI994 for 24 hours induced cells apoptosis in a dose-dependent manner (1 μM