Myriocin

Myriocin is a potent immunosuppressant and also a specific serine palmitoyltransferase inhibitor with Ki value of 0.28 nM [1][2].

Serine palmitoyltransferase catalyzes the first step in de novo sphingolipid biosynthesis. Sphingolipids are involved in the regulation of apoptosis, cell proliferation, cell migration, senescence and inflammation [2].

Myriocin is a specific serine palmitoyltransferase inhibitor. In lung cancer A549 and NCI-H460 cells, myriocin (10, 20, and 50 ?M) inhibited cell proliferation in a concentration-dependent manner. Myriocin inhibited A549 and NCI-H460 cell growth with IC50 values of 30 ?M and 26 ?M, respectively [4].

In melanoma mice, myriocin (1 mg/kg, every other day for 3 weeks) administered intradermally or intraperitoneally significantly inhibited tumor formation. Myriocin also reduced the expression of Cdc25C, Cdc2 and cyclin B1 in tumor tissues, and increased the expression of p53 and p21waf1/cip1. Myriocin also decreased the levels of sphingolipids in serum, liver and tumor tissue [3]. In BALB/c mice, myriocin increased dopamine (DA) in striatum and hippocampus and reduced it in cortex [2].

References:
Miyake Y, Kozutsumi Y, Nakamura S, et al.  Serine palmitoyltransferase is the primary target of a sphingosine-like immunosuppressant, ISP-1/myriocin. Biochem Biophys Res Commun. 1995 Jun 15;211(2):396-403.
Osuchowski MF, Johnson VJ, He Q, et al.  Myriocin, a serine palmitoyltransferase inhibitor, alters regional brain neurotransmitter levels without concurrent inhibition of the brain sphingolipid biosynthesis in mice. Toxicol Lett. 2004 Feb 28;147(1):87-94.
Lee YS, Choi KM, Lee S, et al.  Myriocin, a serine palmitoyltransferase inhibitor, suppresses tumor growth in a murine melanoma model by inhibiting de novo sphingolipid synthesis. Cancer Biol Ther. 2012 Jan 15;13(2):92-100.
Choi KE, Jung YS, Kim DH, et al.  Myriocin induces apoptotic lung cancer cell death via activation of DR4 pathway. Arch Pharm Res. 2014 Apr;37(4):501-11.