SK1-I (BML-258), an analog of sphingosine, is an isozyme-specific competitive SPHK1 inhibitor with a Ki value of 10 µM[1]. SK1-I shows no activity at SPHK1 PKCα, PKCδ, PKA, AKT1, ERK1, EGFR, CDK2, IKKβ or CamK2β. SK1-I enhances autophagy and has antitumor activity[2].

SK1-I (0-10 μM; 24 hours) attenuates cancer cell growth and survival in a TP53-dependent manner in HCT116 cells and HCT116 cells bearing TP53 null cancer[2].SK1-I (0-20 μM; 12 hours) induces more CASP3 cleavage in HCT116 cells, compared to HCT116 cells lacking TP53, leading to a hallmark of apoptosis[2]. Cell Viability Assay[2] Cell Line: HCT116 cells and HCT116 cells bearing TP53 null cancer

Pre-treatment with SK1-I (BML-258; intraperitoneal (i.p.) injection; once; 24 hours prior to baseline mean arterial blood pressure (MAP) measurement; 75 mg/kg) before anandamide (i.v. injection; two doses; 1 and 10 mg/kg) significantly decreases the hypotensive response[3]. Animal Model: Male C57BL/6 mice (24?±?3.5?g) [3]

[1]. Melissa R Pitman, et al. Inhibitors of the sphingosine kinase pathway as potential therapeutics. Curr Cancer Drug Targets. 2010 Jun;10(4):354-67. [2]. Santiago Lima, et al. TP53 is required for BECN1- and ATG5-dependent cell death induced by sphingosine kinase 1 inhibition. Autophagy. 2018;14(6):942-957. [3]. Fiona H Greig, et al. Requirement for sphingosine kinase 1 in mediating phase 1 of the hypotensive response to anandamide in the anaesthetised mouse. Eur J Pharmacol. 2019 Jan 5;842:1-9.