title: The osteoclast-associated protease cathepsin K is expressed in human breast carcinoma.
abstract: Human cathepsin K is a novel cysteine protease previously reported to be restricted in its expression to osteoclasts. Immunolocalization of cathepsin K in breast tumor bone metastases revealed that the invading breast cancer cells expressed this protease, albeit at a lower intensity than in osteoclasts. In situ hybridization and immunolocalization studies were subsequently conducted to demonstrate cathepsin K mRNA and protein expression in samples of primary breast carcinoma. Expression of cathepsin K mRNA was confirmed by reverse transcription PCR and Southern analysis in a number of human breast cancer cell lines and in primary human breast tumors and their metastases. As this protease is known to degrade extracellular matrix, including bone matrix proteins, it is possible that cathepsin K may contribute to the invasive potential of breast cancer cells, including those that metastasize to bone. Thus, cathepsin K may be a potential target leading to the design of novel drugs for cancer therapy.
authors.affiliation: Novartis Pharma AG, Basel, Switzerland. littlam1@fmi.ch
authors.forename: A J
authors.initials: AJ
authors.lastname: Littlewood-Evans
authors.forename: G
authors.initials: G
authors.lastname: Bilbe
authors.forename: W B
authors.initials: WB
authors.lastname: Bowler
authors.forename: D
authors.initials: D
authors.lastname: Farley
authors.forename: B
authors.initials: B
authors.lastname: Wlodarski
authors.forename: T
authors.initials: T
authors.lastname: Kokubo
authors.forename: T
authors.initials: T
authors.lastname: Inaoka
authors.forename: J
authors.initials: J
authors.lastname: Sloane
authors.forename: D B
authors.initials: DB
authors.lastname: Evans
authors.forename: J A
authors.initials: JA
authors.lastname: Gallagher
mesh_terms: D015139:Blotting, Southern; D001859:Bone Neoplasms / Q000201:enzymology / Q000473:pathology / Q000556:secondary; D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000201:enzymology* / Q000473:pathology; D056657:Cathepsin K; D002403:Cathepsins / Q000032:analysis / Q000096:biosynthesis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D010010:Osteoclasts / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D012333:RNA, Messenger; D002403:Cathepsins; C534130:CTSK protein, human; D056657:Cathepsin K