title: Localization of nuclear cathepsin L and its association with disease progression and poor outcome in colorectal cancer.
abstract: Previous in vitro studies have identified a nuclear isoform of Cathepsin L. The aim of this study was to examine if nuclear Cathepsin L exists in vivo and examine its association with clinical, pathological and patient outcome data. Cellular localization (nuclear and cytoplasmic) and expression levels v of Cathespin L in 186 colorectal cancer cases using immunohistochemistry. The molecular weight and activity of nuclear and cytoplasmic Cathepsin L in vivo and in vitro were assessed by Western blotting and ELISA, respectively. Epithelial nuclear staining percentage (p = 0.04) and intensity (p = 0.006) increased with advancing tumor stage, whereas stromal cytoplasmic staining decreased (p = 0.02). Using multivariate statistical analysis, survival was inversely associated with staining intensity in the epithelial cytoplasm (p = 0.01) and stromal nuclei (p = 0.007). In different colorectal cell lines and in vivo tumors, pro- and active Cathepsin L isoforms were present in both the cytoplasm and nuclear samples, with pro-Cathepsin L at 50 kDa and active Cathepsin L at 25 kDa. Purified nuclear and cytoplasmic fractions from cell lines and tumors showed active Cathepsin L activity. The identification of nuclear Cathepsin L may play an important prognostic role in colorectal disease progression and patient outcome. Moreover, these findings suggest that altering active nuclear Cathepsin L may significantly influence disease progression.
authors.affiliation: Centre for Colorectal Disease, St. Vincent's University Hospital, Dublin, Dublin, Ireland.
authors.forename: Shane
authors.initials: S
authors.lastname: Sullivan
authors.forename: Miriam
authors.initials: M
authors.lastname: Tosetto
authors.forename: David
authors.initials: D
authors.lastname: Kevans
authors.forename: Alan
authors.initials: A
authors.lastname: Coss
authors.forename: Laimun
authors.initials: L
authors.lastname: Wang
authors.forename: Diarmuid
authors.initials: D
authors.lastname: O'Donoghue
authors.forename: John
authors.initials: J
authors.lastname: Hyland
authors.forename: Kieran
authors.initials: K
authors.lastname: Sheahan
authors.forename: Hugh
authors.initials: H
authors.lastname: Mulcahy
authors.forename: Jacintha
authors.initials: J
authors.lastname: O'Sullivan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D056668:Cathepsin L; D002403:Cathepsins / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism* / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D015996:Survival Rate; D046888:Tissue Array Analysis; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; D002403:Cathepsins; D003546:Cysteine Endopeptidases; C534281:CTSL protein, human; D056668:Cathepsin L