Sanguinarine chloride is a potent and specific inhibitor of PP2C with Ki value of 0.68 μM, and is also a selective and cell-active inhibitor of MKP-1 with IC50 value of 10 μM. Sanguinarine is also an allosteric activator of AMPK [1][2][3].
Protein phosphatase 2C (PP2C) is a serine/threonine-specific phosphatase, the activity of which is dependent on Mg2+ or Mn2+. PP2C dephosphorylates a number of substrates such as cyclin-dependent kinase, mitogen-activated kinase (MAPK) and Bad. Mitogen-activated protein kinase phosphatase-1 (MKP-1) is a dual specificity phosphatase. AMP-activated protein kinase (AMPK) plays an important role in the regulation of cellular metabolism [1][2][3].
Sanguinarine chloride is an inhibitor of PP2C and MKP-1, and also an allosteric activator of AMPK with antibiotic and antitumor activity. Sanguinarine competed with α-casein to inhibit PP2C and exhibited selectivity for PP2C as compared with PP1, PP2A and PP2B. In human promyelocytic leukemia cell line HL60, sanguinarine exhibited cytotoxicity with IC50 value of 0.37 μM and induced apoptosis via a caspase-3/7-dependent mechanism involving the phosphorylation of p38, a PP2C substrate [1]. Sanguinarine inhibited MKP-1 and MKP-L with IC50 values of 17.3 and 12.5 μM. In PANC-1 human pancreatic cancer cells, sanguinarine increased ERK and JNK/SAPK phosphorylation [2]. In the MDA MB-231 cell line, sanguinarine caused AMPK and the downstream acetyl-CoA carboxylase (ACC) phosphorylation [3]. In LNCaP and DU145 cells, sanguinarine inhibited cell growth, induced G0/G1 phase arrest and apoptosis [4].
References:
[1]. Aburai N, Yoshida M, Ohnishi M, et al. Sanguinarine as a potent and specific inhibitor of protein phosphatase 2C in vitro and induces apoptosis via phosphorylation of p38 in HL60 cells. Biosci Biotechnol Biochem, 2010, 74(3): 548-552.
[2]. Vogt A, Tamewitz A, Skoko J, et al. The benzo[c]phenanthridine alkaloid, sanguinarine, is a selective, cell-active inhibitor of mitogen-activated protein kinase phosphatase-1. J Biol Chem, 2005, 280(19): 19078-19086.
[3]. Choi J, He N, Sung MK, et al. Sanguinarine is an allosteric activator of AMP-activated protein kinase. Biochem Biophys Res Commun, 2011, 413(2): 259-263.
[4]. Adhami VM, Aziz MH, Reagan-Shaw SR, et al. Sanguinarine causes cell cycle blockade and apoptosis of human prostate carcinoma cells via modulation of cyclin kinase inhibitor-cyclin-cyclin-dependent kinase machinery. Mol Cancer Ther, 2004, 3(8): 933-940.
