Purinostat mesylate is a selective inhibitor of HDAC. This compound inhibits class I and class IIb HDACs with IC₅₀s from 0.81 to 11.5 nM. Purinostat mesylate (1-10 μM) inhibits HDAC1, 2, 3, and 8. And the IC₅₀s are 0.81, 1.4, 1.7, and 3.8 nM, respectively. It also inhibits HDAC6 and 10, the IC₅₀s are 11.5 and 1.1 nM. Besides, the IC₅₀s are 1072, 426, 690, 622, and 3348 nM for HDAC4, 5, 7, 9, and 11, respectively. Purinostat mesylate induces apoptosis and affects the cell cycle of LAMA84 and 188 BL-2 cells. And this compound dose-dependently blocked cell cycle progression at G0/G1 phase.

Nextly, Purinostat mesylate effectively suppresses leukemia progression in vivo.

In Non-irradiated C57BL/6 recipient mice, the mice are treated with 5 and 10 mg/kg dosages three times a week for five weeks. As a result, Purinostat mesylate significantly prolonged the overall survival rate. Additionally, it suppressed the leukemia progression in mice. In Non-irradiated C57BL/6 recipient mice with BL-2 secondary transplantation, Purinostat mesylate shows potently anti-leukemia effects in BCR-ABL(T315I)-induced primary B-ALL mice. What's more, in this model, Purinostat mesylate completely eliminates GFP⁺B220⁺ cells in spleens on day 3 with two times treatments. A and this complete inhibition were maintained for 26 days duration of treatment. Purinostat mesylate significantly prolongs the overall survival rate and suppresses leukemia progression in mice. In Non-irradiated C57BL/6 recipient mice with BL-2 secondary transplantation, Purinostat mesylate completely eliminated GFP⁺B220⁺ cells in spleens on day 3 with two times treatments. Besides, this complete inhibition maintains for 26 days duration of treatment. In B-ALL mouse model with BCR-ABL (T315I)-induced leukemia. Purinostat mesylate significantly prolonged the survival rate of BCR-ABL(T315I)-induced B-ALL mice. Survived all mice after treatment for 42 days. In conclusion, Purinostat mesylate induces apoptosis and affects the cell cycle in vitro. Furthermore, it shows potently anti-leukemia effects in vivo. Purinostat mesylate has the potential for the research of lymphoblastic leukemia.