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Pyrimidine nucleotide metabolism in human colon carcinomas: Comparison of normal tissues, primary tumors and xenografts
Author(s) -
Luccioni C.,
Beaumatin J.,
Bardot V.,
Lefrançois D.
Publication year - 1994
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910580411
Subject(s) - metabolism , nucleotide , pathology , pyrimidine metabolism , primary (astronomy) , biology , cancer research , medicine , biochemistry , gene , enzyme , purine , physics , astronomy
The activities of 5 enzymes involved in the pyrimidine metabolism were measured in xenografts of 8 human colon adenocarcinomas and in the corresponding primary tumors and normal tissues. The enzymes studied were thymidine kinase, thymidine phosphorylase, uridine kinase, uridine phosphorylase and thymidylate synthase. With the exception of the phosphorylases in one tumor, all enzyme activities were higher in primary tumors than in the corresponding normal tissues. The average activities of thymidine kinase and thymidylate synthase were of the same order of magnitude in xenografts and in primary tumors. The uridine metabolizing enzymes tend to have a higher activity in xenografts than in primary tumors. The most consistent and significant change was a sharp decrease in thymidine phosphorylase activity in xenografts as compared to primary tumors. Whether or not the difference in thymidine phosphorylase activity between xenografts and primary tumors is related to the contribution of non‐cancerous cells in primary tumors remains to be determined. However, these results raise questions concerning the representativeness of xenografts with reference to primary tumors and suggest that care should be taken in the application of this model.