Document Detail


Increased expression of neprilysin (neutral endopeptidase 24.11) in rat and human hepatocellular carcinomas.
MedLine Citation:
PMID:  8302012     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Neprilysin (EC 3.4.24.11) (NEP), a membrane metallopeptidase, is identical with common acute lymphoblastic leukemia antigen or cluster differentiation antigen 10. This antigen is present in blast cells in acute lymphoblastic leukemias and is implicated in differentiation of B lymphocytes. NEP cleaves a variety of peptides including bradykinin, substance P, bombesin, enkephalins, and atrial natriuretic peptide. We investigated its expression in several variants of rat hepatomas and a human hepatocellular carcinoma cell line. Normal rat and human livers were used as controls. EXPERIMENTAL DESIGN: The expression of NEP (common acute lymphoblastic leukemia antigen) was determined with: (a) enzyme assays; (b) high performance liquid chromatography analysis of bradykinin metabolism; (c) immunoprecipitation; and (d) mRNA characterization. RESULTS: NEP activity increased by 2 to 3 orders of magnitude in all rat hepatomas and in the human SK-HEP1 cell line, compared with normal tissues. Antiserum against rat NEP precipitated 93% of endopeptidase activity in rat hepatomas, whereas monoclonal antibody to common acute lymphoblastic leukemia antigen immunoprecipitated 99% of that in human hepatocarcinoma cells. Solubilized rat hepatoma membranes cleaved bradykinin to a hepta- and dipeptide; the reaction was inhibited by an NEP inhibitor. Activity of three other membrane peptidases did not increase in rat hepatomas. Northern hybridization revealed the presence of NEP mRNA in rat hepatoma, but not in normal liver. Reverse transcriptase-polymerase chain reaction showed that hepatomas have higher amounts of NEP mRNA than normal liver of the same strain. CONCLUSIONS: Rat hepatomas and a human hepatocarcinoma cell line express high amounts of NEP, in contrast to normal rat and human livers, which have very little. The increase in NEP activity could be due to increased transcription by tumor cells and may signal malignant transformation of liver cells.
Authors:
T Dragović; P A Deddish; F Tan; G Weber; E G Erdös
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Laboratory investigation; a journal of technical methods and pathology     Volume:  70     ISSN:  0023-6837     ISO Abbreviation:  Lab. Invest.     Publication Date:  1994 Jan 
Date Detail:
Created Date:  1994-03-09     Completed Date:  1994-03-09     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0376617     Medline TA:  Lab Invest     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  107-13     Citation Subset:  IM    
Affiliation:
Laboratory of Peptide Research/Department of Pharmacology, University of Illinois College of Medicine, Chicago.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blotting, Northern
Blotting, Southern
Bradykinin / analysis,  metabolism
Carcinoma, Hepatocellular / chemistry,  enzymology*,  pathology
Cell Membrane / chemistry,  enzymology,  ultrastructure
Chromatography, High Pressure Liquid
DNA Probes
Gene Expression Regulation, Neoplastic / genetics
Humans
Liver / chemistry,  enzymology
Liver Neoplasms / chemistry,  enzymology*,  pathology
Liver Neoplasms, Experimental / chemistry,  enzymology*,  pathology
Neprilysin / analysis*,  genetics
Polymerase Chain Reaction
Precipitin Tests
RNA, Neoplasm / analysis,  genetics
Rats
Rats, Inbred ACI
Rats, Inbred BUF
Tumor Cells, Cultured
Grant Support
ID/Acronym/Agency:
HL36081/HL/NHLBI NIH HHS; HL36082/HL/NHLBI NIH HHS; HL36473/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/DNA Probes; 0/RNA, Neoplasm; 58-82-2/Bradykinin; EC 3.4.24.11/Neprilysin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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