Cathepsin K [SEP] found in taxon
and gelatin allows it to break down bone and cartilage. This catabolic activity is also partially responsible for the loss of lung elasticity and recoil in emphysema. Cathepsin K inhibitors show great potential in the treatment of osteoporosis. Cathepsin K is degraded by Cathepsin S, called Controlled Cathepsin Cannibalism.
Cathepsin K expression is stimulated by inflammatory cytokines that are released after tissue injury.
Clinical significance.
Cathepsin K is expressed in a significant fraction of human breast cancers, where it could contribute to tumor invasiveness. Mutations in this gene
are the cause of pycnodysostosis, an autosomal recessive disease characterized by osteosclerosis and short stature. Cathepsin K has also been found to be over-expressed in glioblastoma.
That the expression of cathepsin K is characteristic for some cancers and not others has been documented. Cathepsin K antibodies are marketed for research into expression of this enyzme by various cells.
Merck had a cathepsin K inhibitor, odanacatib, in Phase III clinical trials for osteoporosis. In September, 2016, Merck announced they were discontinuing development of odanacatib after their own