Open AccessEffect of Hammerhead Ribozyme against Human Thymidylate Synthase on the Cytotoxicity of Thymidylate Synthase Inhibitors
Author(s) -
Kobayashi Hiroyuki,
Takemura Yuzuru,
Miyachi Hayato,
Skelton Lorraine,
Jackman Ann L.
Publication year - 1995
Publication title -
japanese journal of cancer research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 0910-5050
DOI - 10.1111/j.1349-7006.1995.tb03014.x
Subject(s) - thymidylate synthase , hammerhead ribozyme , ribozyme , microbiology and biotechnology , biology , transfection , rna , cell culture , enzyme , lymphoblast , messenger rna , biochemistry , gene , cancer , genetics , fluorouracil
One of the resistance mechanisms to folate‐based thymidylate synthase (TS) inhibitors is the increase in TS activity in tumor cells. Human B lymphoblastoid cell line (W1L2) was made resistant to a lipophilic non‐polyglutamatable TS inhibitor (ZM249148), and the subline (W1L2:R179) showed a 20‐fold increase in TS enzyme activity with concomitant overexpression of TS mRNA. To overcome the resistance, we designed a ribozyme that can cleave the CUC sequences in a triple tandemly repeated sequence of TS mRNA. Expression of this ribozyme in W1L2:R179 cells transfected with Epstein Barr virus‐based expression vector resulted in sensitization to TS inhibitors concomitantly with a decrease of TS expression. The ribozyme expressed in transfectants was shown to be functional in cleaving artificial TS RNA in vitro.