PF-543 is a potent, selective, reversible, and sphingosine-competitive inhibitor of SphK1 with an IC50 value of 2nM and a Ki value of 3.6 nM[1]. SphK1 is a kinase that phosphorylates sphingosine to sphingosine-1-phosphate (S1P), which promotes cell growth, survival, and migration, and regulates lymphocyte trafficking. The selectivity of PF-543 for SPHK 1 is over 100 times that of SPHK 2[2]. PF-543 induces apoptosis, necrosis, and autophagy.
In vitro, PF-543 inhibits the formation of C17-S1P in 1483 cells, with an IC50 of 1.0 nM[1]; PF-543 inhibits SphK1 leading to a dose-dependent depletion of intracellular S1P levels, with an EC50 of 8.4 nM and an accompanying increase in intracellular sphingosine levels in 1483 cells[1]; PF-543 (10-1000 nM; 24h) treatment eliminates SK expression in PASM cells[1]. Treatment with 200 nM PF-543 for 1h decreased endogenous S1P levels by tenfold in 1483 cells, with a corresponding increase in sphingosine levels[2]. PF-543 (0.1-10 μM; 24 h) treatment of PASM cells induces caspase-3/7 activity[3].
In vivo, PF-543 (1 mg/kg; intraperitoneal injection; every other day; for 3 weeks) reduces right ventricular hypertrophy in female C57BL/6 J mice, decreases the expression of p53, increases the expression of the antioxidant nuclear factor Nrf-2, but has no effect on vascular remodeling[3]. When mice were initially treated with an intraperitoneal injection of 10 mg/kg or 30 mg/kg PF-543 for 24 h, the blood sample T1/2 was 1.2 h, which could induce a decrease in SK1 expression in the pulmonary vasculature[3].
References:
[1] Schnute M E et al. , Modulation of cellular S1P levels with a novel, potent and specific inhibitor of sphingosine kinase-1. Biochem J. 2012, 444(1): 79-88.
[2] Hamada M, et al. Induction of autophagy by sphingosine kinase 1 inhibitor PF-543 in head and neck squamous cell carcinoma cells. Cell Death Discov. 2017 Aug 14;3:17047.
[3] MacRitchie N, et al. Effect of the sphingosine kinase 1 selective inhibitor, PF-543 on arterial and cardiac remodelling in a hypoxic model of pulmonary arterial hypertension. Cell Signal. 2016 Aug;28(8):946-55.
PF-543是一种强效、选择性、可逆和鞘氨醇竞争性SphK 1抑制剂，IC50值为2nM，Ki值为3.6 nM[1]。SphK1是一种将鞘氨醇磷酸化为鞘氨醇-1-磷酸（S1P）的激酶，S1P促进细胞生长、存活和迁移，并调节淋巴细胞运输。PF-543对SPHK 1的选择性是SPHK 2的100倍以上[2]。PF-543诱导细胞凋亡、坏死和自噬。
在体外，PF-543 抑制1483细胞中C17-S1P的形成，IC50 of 1.0 nM[1]；PF-543 抑制 SphK1导致细胞内S1P水平的剂量依赖性消耗，EC50 8.4 nM 的浓度和伴随的 1483细胞中鞘氨醇细胞内水平的升高[1]；PF-543 (10-1000 nM；24h) 处理PASM 细胞消除SK表达[1]。200 nM PF-543 处理 1h，1483细胞中的内源性 S1P水平降低了10倍，鞘氨醇水平相应增加[2]。PF-543 (0.1-10 μM；24 h) 处理PASM细胞诱导caspase-3/7 活性[3]。
在体内，PF-543 (1 mg/kg；腹膜内注射；每隔一天；持续3周)会减少雌性C57BL/6 J小右心室肥大，减少p53的表达，增加抗氧化核因子Nrf-2的表达，但对血管重塑没有影响[3]。当小鼠最初被腹膜注射10 mg/kg的PF-543处理24 h，血液样本中的T1/2为1.2 h，可诱导肺血管中 SK1 表达的降低[3]。