title: IGF-I receptor phosphorylation is impaired in cathepsin X-deficient prostate cancer cells.
abstract: The cysteine-type peptidase cathepsin X is highly upregulated in several cancers and presumably promotes tumor invasion through bypassing cellular senescence. Here, we present first evidence that the underlying mechanism may involve the regulation of the insulin-like growth factor (IGF) system, a well-known activator of proliferating tumor cells. Cathepsin X deficiency leads to a reduced phosphorylation of the IGF-I receptor in response to IGF-I stimulation. In addition, downstream signaling through focal adhesion kinase was also affected. Taken together, our results indicate that cathepsin X is able to assist in IGF signaling, which may be an important progress toward understanding cathepsin X-dependent tumorigenesis.
authors.affiliation: Division of Clinical Chemistry and Clinical Biochemistry, Department of Surgery, Ludwig-Maximilians-University, D-80336 Munich, Germany
authors.forename: Steffen
authors.initials: S
authors.lastname: Kraus
authors.forename: Maximilian
authors.initials: M
authors.lastname: Fruth
authors.forename: Thea
authors.initials: T
authors.lastname: Bunsen
authors.forename: Dorit K
authors.initials: DK
authors.lastname: Nägler
mesh_terms: D056663:Cathepsin Z / Q000235:genetics* / Q000378:metabolism; D002403:Cathepsins / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D016922:Cellular Senescence; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D006801:Humans; D008297:Male; D010766:Phosphorylation; D011467:Prostate / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D017526:Receptor, IGF Type 1 / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D011498:Protein Precursors; D017526:Receptor, IGF Type 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D002403:Cathepsins; C516795:procathepsin X, human; C534182:CTSZ protein, human; D056663:Cathepsin Z