Sphingosine Kinase 1 Inhibitor II, PF-543

A cell-permeable hydroxymethylpyrrolidine compound that acts as a high affinity (K_d = 5 nM, k_offt_1/2 = 8.5 min), but poor, sphingosine kinase-1/SphK1 substrate (1/1,500 of sphingosine processivity) and potently inhibits against SphK1-catalyzed sphingosine-to-S1P conversion (IC₅₀ = 2.0 nM; [sphingosine] = 3 µM) in a reversible, sphingosine-, but not ATP-, competitive manner (K_i = 3.6 nM), exhibiting 132-fold selectivity over SphK2, no affinity toward S1P receptors (S1P1, S1P2, S1P3, S1P5), and much reduced or no inhibitory activity against a panel of 46 other lipid and protein kinases (IC₅₀ >10 µM), including the structurally related diacylglyerol kinase α/DAGKα (3.7% inhibition at 10 µM). PF-543 exposure in 1483 squamous cultures is reported to result in intracellular S1P depletion (by 90% upon 1 h 200 nM or 7 d 1 µM drug exposure) with concomitant elevation of sphingosine level and no detectable cytotoxicity (1 µM for 7 to 9 d in 1483, A549, Jurkat, LN229, MCF7, or U937 cultures). Also active in human whole blood assays in the presence human & bovine serum proteins (IC₅₀ = 26.7 nM against cellular C₁₇-S1P formation from exogenously added 20 µM C₁₇-sphingosine in 10 min with 30 min drug preincubation).

A cell-permeable hydroxymethylpyrrolidine compound that inhibits sphingosine kinase-1/SphK1-catalyzed Sphingosine phosphorylation (IC₅₀ = 2.0 nM; [sphingosine] = 3 µM) in a reversible and sphingosine-competitive manner (K_i = 3.6 nM), exhibiting no affinity toward S1P receptors and much reduced inhibitory activity against Sphk2 (6.8% inhibition at 10 µM) or 46 other lipid and portein kinases (IC₅₀ >10 µM). Effectively depletes cellular S1P (by 90% with 1 h 200 nM or 7 d 1 µM drug exposure in 1483 cultures) with concomitant elevation of sphingosine level and no detectable cytotoxicity.

Packaged under inert gas

Toxicity: Standard Handling (A)

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 3 months at -20°C.

Schnute, M.E., et al. 2012. Biochem. J.444, 79.

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