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Altered protein tyrosine kinase levels in human colon carcinoma
Author(s) -
Sakanoue Youichirou,
Kusunoki Masato,
Hatada Takuya,
Sakiyama Tooru,
Yamamura Takehira,
Utsunomiya Joji
Publication year - 1991
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/1097-0142(19910201)67:3<590::aid-cncr2820670312>3.0.co;2-y
Subject(s) - cytosol , tyrosine , tyrosine kinase , biochemistry , tyrosine phosphorylation , biology , endocrinology , enzyme , signal transduction
To further understand the molecular mechanisms and the biological indicators of colonic tumorigenesis, the authors examined tyrosine kinase activity in the cytosol and in the particulate fraction of the homogenates of specimens from 20 human colonic carcinomas and compared them with the adjacent normal mucosal tissues. Total protein tyrosine kinase activity could be precisely detected using miniphosphocellulose column purification and a synthetic peptide, Glu–asparagine (Asp)–alanine (Ala)–Glu–tyrosine (Tyr)–Ala–Ala–arginine (Arg)–Arg–Arg–glycine (Gly) (E 11 ‐G 1 ), as an artificial substrate. Tyrosine kinase activity of colonic carcinoma and normal mucosa was reduced in the cytosol fraction whereas activity in the particulate fraction was elevated with respect to protein concentration. The average specific activity ratios were 1.95 ± 0.27 (normal cytosolic/carcinoma cytosolic) and 0.57 ± 0.01 (normal particulate/carcinoma particulate) for tyrosine kinase activity. Cellular distribution (% cytosol) of tyrosine kinase activity in normal mucosa and in carcinoma varied from 21.0% to 91.2% and from 7.0% to 61.4%, respectively. In nearly all cases the percentage of cytosolic tyrosine kinase activity in carcinoma tissues was lower than in normal tissues. There was no difference due to histologic type or the presence of adenomatous components. A significant decrease of cytosolic tyrosine kinases was correlated with Dukes' Stage A. With advancing Dukes' stage, the average specific activity ratios (normal cytosol/carcinoma cytosol) were decreased. This study indicates that colonic carcinogenesis might be associated with alterations in cellular levels of tyrosine kinase activity and that the average specific activity ratio (normal cytosol/carcinoma cytosol) had a possible correlation with colonic tumor growth.