OBJECTIVETo assess the telomerase activity inhibitory effect of ham merhead ribozyme targeting the 5'-end of human telomerase reverse transcriptase mRNA (hTERT-5'RZ), to compare it with the effect of another ribozyme teloRZ, and the combine the applications of the two ribozymes.

METHODShTERT-5'RZ gene was synthesized and cloned into pcDNA3.1(+); the ribozyme was produced by in vitro transcription. The teloRZ ribozyme was produced in the same way by in vitro transcription of p(SPT19-teloRZ) which had been constructed by the present authors. The ribozymes were transiently transfected into HeLa cells by liposome every 24 hours. After 72 hours, the cells were collected and their telomerase activities were assayed.

RESULTSThe ribozyme targeting the 5'-end of hTERT mRNA exhibited a very strong telomerase-inhibitory activity, the combined use of hTERT-5'RZ and teloRZ also showed clear inhibitory activity, but the inhibitory effect of teloRZ used alone was not so strong.

CONCLUSIONThese observations suggest that the use of hTERT-5'RZ and the combined use of hTERT-5'RZ and teloRZ are more effective in telomerase inhibition as compare with the use of teloRZ alone. They may find applications in cancer therapy.