PD 150606 is a specific inhibitor of calpain with Ki value of 0.21 μM and 0.37 μM for mu- and m- calpains, respectively [1].
Calpain is an enzyme and plays an important role in a variety of physiological processes, including signaling, cytoskeletal remodeling, regulation of gene expression, apoptosis and cell cycle progression. It has been shown that calpain involves in many pathologies, like muscular dystrophies, cancer, diabetes, Alzheimer's disease and multiple sclerosis [2] [3].
PD 150606 is a potent calpain inhibitor and has similar activity as calpain inhibitor-III. When tested with A2058, A375 and HS578T cell lines infected with ΔPK(resulted the failure of cells growth in 3D culture), administration of PD 150606 in a concentration of 100 μM restored 3D growth in soft sugar culture by inhibiting calpain [2].
Treated pathogen-free adult C57BL/6 mice with PD 150606 (3 mg/kg, i.p) before LPS injection to establish sepsis mouse model that had lower myocardial calpain activity, the result showed that PD 150606 prevented the degradation of myocardial Hsp90/p-Akt protein induced by LPS and inhibited myocardial caspase-3 activation and apoptosis [3].
References:
[1].    Wang, K.K., et al., An alpha-mercaptoacrylic acid derivative is a selective nonpeptide cell-permeable calpain inhibitor and is neuroprotective. Proc Natl Acad Sci U S A, 1996. 93(13): p. 6687-92.
[2].    Colunga, A., et al., Calpain-dependent clearance of the autophagy protein p62/SQSTM1 is a contributor to DeltaPK oncolytic activity in melanoma. Gene Ther, 2014. 21(4): p. 371-8.
[3].    Li, X., et al., The role of the Hsp90/Akt pathway in myocardial calpain-induced caspase-3 activation and apoptosis during sepsis. BMC Cardiovasc Disord, 2013. 13: p. 8.