Abstract
AIM: To study the effects of doxorubicin on telomerase activity and telomere length in hepatocellular carcinoma. METHODS: Telomerase activity was assayed with a non-radioisotopic quantitative telomerase repeat amplification protocol-based method. The effect of doxorubicin (DOX) on the growth of BEL-7404 human hepatoma cells was determined by microculture tetrazolium assay. Mean telomere length (terminal restriction fragment) was detected by Southern blot method. The expression of telomerase subunits genes was investigated by RT-PCR. Cell apoptosis and cell cycle distribution were evaluated by flow cytometry. RESULTS: Telomerase activity was inhibited in a dose and time-dependent manner in BEL-7404 human hepatoma cells treated with DOX for 24, 48 or 72 h in concentrations from 0.156 to 2.5 microM which was correlated with the inhibition of cell growth. No changes were found in the mRNA expression of three telomerase subunits (hTERT, hTR and TP1) after drug exposure for 72 h with indicated concentrations. The cells treated with DOX showed shortened mean telomere length and accumulated at the G(2)/M phase. However, there was almost no effects on cell apoptosis by DOX. CONCLUSION: The telomerase inhibition and the telomere shortening by DOX may contribute to its efficiency in the treatment in hepatocellular carcinoma.