[Study on telomerase inhibition by ribozyme targeted to telomerase RNA component].
OBJECTIVE
To evaluate the possibility of using ribozyme technology for telomerase inhibition and cancer therapy.


METHODS
A hammer head ribozyme (telomerase ribozyme, teloRZ) directed against the RNA component of human telomerase (hTR) was designed and synthesized to serve as a telomerase inhibitor. An in vitro transcription plasmid and a eukaryotic expression plasmid containing teloRZ gene were constructed. In vitro cleavage reaction was carried out by mixing the ribozyme RNA with DIG-labeled-hTR in different reaction conditions. Cleavage bands were detected by digoxin chemilumines- cent assay. The eukaryotic expression plasmid was inducted into HeLa cells by lipofectamine; the telomerase activities and bio-characteristics of HeLa cells were detected continuously.


RESULTS
teloRZ showed a specific cleavage activity against the telomerase RNA component used as template. The in vitro cleavage ratio reached about 60%. The telomerase activities of cells expressing teloRZ dropped to eight times; the doubling times became longer and apoptosis ratios became higher with increasing population doublings (PDS); at 19-20 PDS 95% cells showed apoptosis.


CONCLUSIONS
These findings support the potential use of this ribozyme against immortalized cancer cells.
Qu
Y
Y
Laboratory of Medical Molecular Biology, West China University of Medical Sciences, Chengdu, 610041 P. R. China. QuY@hotmail.com
OuYang
X
X
Liu
S
S
Peng
X
X
Liu
B
B
D017209:Apoptosis; D001483:Base Sequence; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016337:RNA, Catalytic / Q000494:pharmacology*; D019098:Telomerase / Q000037:antagonists & inhibitors*
D016337:RNA, Catalytic; D019098:Telomerase