SK1-I hydrochloride is the salt form of SK1-I(BML-258). SK1-I is a selective and competitive sphingosine kinase 1 (SphK1) inhibitor and sphingosine analog that is inactive against SphK2 and a variety of other protein kinases, and possesses anti-leukemic potential to inhibit tumor cell growth and promote apoptosis.

The effect of SK1-I hydrochloride on cancer cell growth, survival, and apoptosis is closely related to the TP53 status. Treatment of HCT116 cells with a defective TP53 mutation and normal HCT116 cells with SK1-I hydrochloride (0-10μM) for 24 hours revealed that the growth and survival rate of normal HCT116 cells decreased significantly. In protein blot analysis, after treating both cell types with SK1-I hydrochloride (0-20μM) for 12 hours, it was found that CASP3 cleavage was increased in normal HCT116 cells, making them more prone to apoptosis [1].

In the C57BL/6 male mouse model, pretreatment with SK1-I hydrochloride (intraperitoneal injection, 75mg/kg, a single dose administered 24 hours before baseline mean arterial pressure measurement) showed a significant hypotensive effect, significantly reducing the baseline mean arterial pressure (MAP) [2].