title: Alterations in cathepsin H activity and protein patterns in human colorectal carcinomas.
abstract: Our analyses of cathepsin H activity levels and protein forms in human colorectal cancers compared to matched control mucosa support the concept that altered proteinase expression patterns may reflect both cancer stage and site. Cathepsin H-specific activity was significantly increased in colorectal cancers compared to control mucosa (P = 0.003; n = 77). Highest specific activities and cancer/normal ratios (C/N) for activity were measured in Dukes' B and C stage carcinomas, cancers involved in local spread and invasion to lymph nodes. In contrast, cathepsin B and L activities analysed in the same paired extracts had been shown to be most frequently elevated in earlier stage carcinomas (Dukes' A and B), confirming that cathepsin H demonstrates a distinct pattern of expression during colorectal cancer progression. Although cathepsin H activities were most commonly elevated in Dukes' C cancers at all colon sites, both specific activity and C/N ratios were significantly higher for cancers of the left colon compared to other colon locations. A subset of 43 paired extracts analysed on Western blots also revealed consistent changes in cathepsin H protein forms in cancers. Normal mucosa typically showed a strong protein doublet at 31 and 29 kDa while cancers demonstrated decreased expression or total loss of the 31 kDa protein (90% of cases), equal or increased expression of the 29-kDa protein (67% of cases) and the new appearance or up-regulation of a cathepsin H band at 22 kDa (78% of cases). C/N ratios for cathepsin H enzyme activity correlated significantly with C/N ratios for the 29 kDa mature single-chain protein form (P < 0.001), with increased activity most commonly associated with elevated expression of 29-kDa cathepsin H but also with up-regulation of the 22-kDa band, suggesting a shift to more fully processed, mature active cathepsin H protein forms in cancers. Changes in cathepsin H expression were also detected by immunohistochemistry as elevated cathepsin H staining in tumour epithelial cells.
authors.affiliation: Department of Pathology, Boston University School of Medicine, MA 02118, USA.
authors.forename: E C
authors.initials: EC
authors.lastname: del Re
authors.forename: S
authors.initials: S
authors.lastname: Shuja
authors.forename: J
authors.initials: J
authors.lastname: Cai
authors.forename: M J
authors.initials: MJ
authors.lastname: Murnane
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D056655:Cathepsin H; D002403:Cathepsins / Q000032:analysis / Q000096:biosynthesis*; D015179:Colorectal Neoplasms / Q000737:chemistry* / Q000473:pathology; D003546:Cysteine Endopeptidases / Q000032:analysis / Q000096:biosynthesis*; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009092:Mucous Membrane; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000378:metabolism; D009367:Neoplasm Staging; D015854:Up-Regulation
chemical_list: D009363:Neoplasm Proteins; D002403:Cathepsins; D003546:Cysteine Endopeptidases; C534126:CTSH protein, human; D056655:Cathepsin H