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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6 Suppl 19
pubmed:dateCreated
2003-2-10
pubmed:abstractText
Strong clinical and experimental evidence indicates that amifostine confers cytoprotection in normal, but not in tumor, tissues. However, the mechanism of such selective action is poorly understood. Intestinal-type alkaline phosphatase (IAP) is a major isoenzyme involved in the hydrolysis of amifostine (WR-2721) to its active thiol form WR-I065. Could differences in IAP expression between normal and malignant tissues account for amifostine's selectivity? Paraffin-embedded material from normal breast, lung, colon, and head and neck tissues, together with their malignant counterparts, were retrieved and stained immunohistochemically for human IAP (antibody 7324, Abcam, Cambridge, UK) and endothelial cell CD31 antigen. Normal tissues (epithelium, fibroblasts, and vessels) consistently displayed strong nuclear and cytoplasmic IAP reactivity. The vascular density (number of positive vessels per x 200 optical field), whether assessed in anti-IAP or anti-CD31 stained sections, was very similar, indicating a strong IAP content for the entire normal vasculature. Therefore, amifostine hydrolysis is ensured in normal tissues and may occur at both vascular and interstitial levels. By contrast, 60% of the tumors analyzed showed a loss of IAP expression in both epithelial cells and stroma, and only 10% to 15% of them demonstrated nuclear/cytoplasmic reactivity, which was confined to the epithelial cells. Similarly, the percentage of tumor vessels exhibiting some IAP reactivity was very low (6% to 17%). This dramatic loss of IAP expression from tumor stroma/vasculature may form a strong basis for explaining amifostine selectivity. In contrast, the abundance of IAP expression in normal tissues, stromal and vascular, ensures an intense hydrolysis of WR-2721 and rapid intracellular accumulation of WR-1065.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0093-7754
pubmed:author
pubmed:copyrightInfo
Copyright 2002, Elsevier Science (USA). All rights reserved.
pubmed:issnType
Print
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14-21
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed-meshheading:12577238-Alkaline Phosphatase, pubmed-meshheading:12577238-Amifostine, pubmed-meshheading:12577238-Antigens, CD31, pubmed-meshheading:12577238-Antigens, Neoplasm, pubmed-meshheading:12577238-Breast, pubmed-meshheading:12577238-Breast Neoplasms, pubmed-meshheading:12577238-Colon, pubmed-meshheading:12577238-Colonic Neoplasms, pubmed-meshheading:12577238-Cytoprotection, pubmed-meshheading:12577238-Down-Regulation, pubmed-meshheading:12577238-Epithelial Cells, pubmed-meshheading:12577238-GPI-Linked Proteins, pubmed-meshheading:12577238-Head and Neck Neoplasms, pubmed-meshheading:12577238-Humans, pubmed-meshheading:12577238-Immunohistochemistry, pubmed-meshheading:12577238-Lung, pubmed-meshheading:12577238-Lung Neoplasms, pubmed-meshheading:12577238-Microcirculation, pubmed-meshheading:12577238-Neoplasms, pubmed-meshheading:12577238-Radiation-Protective Agents, pubmed-meshheading:12577238-Reference Values, pubmed-meshheading:12577238-Stromal Cells, pubmed-meshheading:12577238-Tumor Markers, Biological
pubmed:year
2002
pubmed:articleTitle
Down-regulation of intestinal-type alkaline phosphatase in the tumor vasculature and stroma provides a strong basis for explaining amifostine selectivity.
pubmed:affiliation
Tumour and Angiogenesis Research Group, Departments of Pathology, Internal Medicine, and Radiotherapy/Oncology, Democritus University of Thrace, Alexandroupolis, Greece.
pubmed:publicationType
Journal Article