PHPS1

PHPS1 inhibits Shp2-dependent cellular events such as hepatocyte growth factor/scatter factor (HGF/SF)-induced epithelial cell scattering and branching morphogenesis. PHPS1 also blocks Shp2-dependent downstream signaling, namely HGF/SF-induced sustained phosphorylation of the Erk1/2 MAP kinases and dephosphorylation of paxillin. Furthermore, PHPS1 efficiently inhibits activation of Erk1/2 by the leukemia-associated Shp2 mutant, Shp2-E76K, and blocks the anchorage-independent growth of a variety of human tumor cell lines.^[1]

PHPS1 decreases the number of atherosclerotic plaques without significantly affecting body weight, serum glucose levels or lipid metabolism. Plaque composition analysis shows a significant decrease in the number of VSMCs in atherosclerotic lesions of Ldlr^−/− mice treated with PHPS1. Stimulation with oxLDL induces a dose-dependent increase in the number of VSMCs and in SHP2 and ERK phosphorylation levels, and these effects are blocked by PHPS1.^[2]

MDCK cells are either untreated or treated with 20 μM PHPS1 and stimulated with 1 unit/ml of HGF/SF. Paxillin is immunoprecipitated from total cell lysates and immunoblotted with antibodies specific for paxillin and for phosphotyrosine. NIH 3T3 cells are transfected with an expression vector for RasV12 and either untreated or treated with 10 μM PHPS1 for 2 days, respectively. Total cell lysates are immunoblotted with antibodies specific for phospho-Erk1/2 (P-Erk1/2) and Erk1/2. HEK293 cells are transfected with expression vectors for HA-GAB2, HA-SHP2-E76K, or ERBB2 and either untreated or treated with 20 μM PHPS1. Total cell lysates are immunoblotted with antibodies specific for hemagglutinin epitope (HA), phospho-Erk1/2 (P-Erk1/2), and Erk1/2.

• [1] Klaus Hellmuth , et al. Proc Natl Acad Sci U S A. 2008 May 20;105(20):7275-80.
• [2] Jia Chen, et al. BMC Cardiovasc Disord. 2018 Apr 27;18(1):72.