RNA PCR quantitation method was developed to determine DNA Topoisomerase I(Topo I)-specific mRNA in order to study its gene expression in CPT-11 sensitive, acquired- or native-resistant human pancreatic tumor cell lines. The results were supported by Northern blotting and Western blotting analyses. Acquired-resistant cells have shown decreased levels of Topo I mRNA, compared with their parental cells. On the contrary, in the wild type cells no correlation was shown between sensitivity and gene expression. On the other specific Topo I activity of the native resistant cell lines was fairly lower than that of sensitive cell lines, suggesting that immunoreactive Tope I protein contains low levels of active form enzyme which could be targets of CPT-11 in these native-resistant ones. Finally, the different mechanisms might be operative between acquired- and native-resistant tumor cells.
|ジャーナル||Biochemical and Biophysical Research Communications|
|出版ステータス||Published - 1992 4月 30|
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