Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.23.5 (cathepsin D)
 4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Type-2 insulin-like growth factor receptor (IGF2R) mediates the transport of lysosomal hydrolases to lysosomes and the clearance of insulin-like growth factor II (IGF-II). Mutant mice lacking IGF2R usually die perinatally, but are completely rescued from lethality in the absence of IGF-II. IGF2R/IGF-II-deficient mice have elevated levels of circulating IGF binding protein (IGFBP)-3 and show a strong IGFBP-6 immunoreactivity in all pancreatic islet cells and in secretory granules of different size in acinar cells and interlobular connective tissue of exocrine pancreas. Fibroblasts derived from double mutant mice missort the lysosomal protease cathepsin D, and are able to degrade endocytosed (125I)IGFBP-3 intracellularly, however, with lower efficiency than in control cells. These results show that the deficiency of IGF2R and IGF-II affects the expression and metabolism of IGFBPs in a tissue- and cell type-specific manner.
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PMID:Alteration in pancreatic immunoreactivity of insulin-like growth factor (IGF)-binding protein (IGFBP)-6 and in intracellular degradation of IGFBP-3 in fibroblasts of IGF-II receptor/IGF-II-deficient mice. 1022 7

Insulin-like growth factor (IGF)-II is a potent growth factor, normally controlled by a number of other factors, including IGF binding proteins and IGF binding protein proteases. In general, the latter increase the bioavailability of IGF by cleaving IGF binding proteins. Cathepsin D (an IGF binding protein protease) was also implicated in tumor invasion. Although IGF-II was implicated in the pathogeneses of various childhood neoplasms, its significance in the pathogenesis of atypical teratoid/rhabdoid tumor of the central nervous system (ATRT-CNS) was not studied to date. We present clinicopathologic features of two cases of ATRT-CNS. In addition, formalin-fixed, paraffin-embedded tissue sections were stained immunohistochemically for IGF-II, IGF receptor type 1, cathepsin D, and Ki-67. Both tumors demonstrated diffuse strong cytoplasmic positivity for IGF-II, diffuse cytoplasmic and focal membranous positivity for IGF receptor type I, and diffuse cytoplasmic positivity for cathepsin D. The Ki-67 labeling indices were 10.0% and 1.4%. We conclude that ATRT-CNS cells express both IGF-II and IGF receptor type 1, supporting the hypothesis that autocrine/paracrine stimulation of cell growth by IGF-II might be one mechanism involved in ATRT-CNS tumorigenesis. Cathepsin D expressed by the tumor cells might also be involved in both tumor cell invasion and growth. The exact pathogenesis of ATRT-CNS remains to be elucidated.
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PMID:Atypical teratoid/rhabdoid tumor of the CNS: cytopathology and immunohistochemistry of insulin-like growth factor-II, insulin-like growth factor receptor type 1, cathepsin D, and Ki-67. 1022 2

Perturbations of the insulin-like growth factor (IGF) axis, including the autocrine production of IGFs, IGF binding proteins (IGFBPs) and IGFBP proteases such as prostate specific antigen (PSA), and cathepsin D have been identified in prostate, lung and breast cancer cells and tissues. Serum IGFBP-3 levels have been found to be negatively correlated to the risk of cancer. Interestingly, IGFBP-3 is a potent inhibitor of IGF action and also mediates apoptosis via an IGF-independent mechanism. Recent case-control studies have found an approximately 10% increase in the serum levels of IGF-I in patients with prostate, breast and lung cancers, which are among the most frequently diagnosed cancers. While the studies indicate an association between serum IGF-I levels and cancer risk, causality has not been established. Thus, serum IGF-I level may actually be a confounding variable, serving as a marker for autocrine tissue IGF-I production. Growth hormone (GH) therapy raises both IGF-I and IGFBP-3 levels in serum. However, the role of GH in controlling prostate, breast and lung growth and carcinogenesis remains unclear from animal studies. Increased GH levels as seen in acromegaly have been associated with benign prostatic hyperplasia but not with prostate, breast or lung cancers, although colon cancer mortality may be increased. Should serum IGF-I levels be proven to play a causal role in the pathogenesis of cancer, interpreting the risk associated with therapies such as GH replacement must take into account both the duration of exposure and the risk magnitude associated with the degree of serum IGF-I elevation. Since GH-deficient patients often have a subnormal IGF-I serum level, which normalizes on therapy, their cancer risk on GH therapy probably does not increase substantially above that of the normal population. Until further research in the area dictates otherwise, ongoing surveillance and routine monitoring of IGF-I levels in GH recipients should become standard of care.
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PMID:IGFs and human cancer: implications regarding the risk of growth hormone therapy. 1059 43