Changes in telomerase activity decreases in MCF-7 cells during apoptosis induced by sodium butyrate
Xi, L.; Wu, M-Fu.; Wu, J-Hong.; Li, F-Jun.; Lu, Y-Ping.; Zhou, J-Feng.; Ma, D.
Zhonghua Zhong Liu Za Zhi 27(1): 9-12
2005
ISSN/ISBN: 0253-3766 PMID: 15771789 Document Number: 588419
To investigate telomerase activity of MCF-7 mammary cancer cells during apoptosis induced by sodium butyrate (SB) in vitro and its mechanism. The proliferative activity of MCF-7 cells was assessed by morphology and MTT assay. Cell apoptosis was confirmed by DNA fragmentation and phosphatidylserine (PS) externalization. Telomerase activity was examined by TRAP-ELISA. The expression status of telomerase subunits was analyzed by RT-PCR. A time- and dose-dependent inhibition was detected in MCF-7 cells treated with SB. At 72 hr after SB (2.5 mmol/L) treatment, MCF-7 cells were apoptotic with a rate of 84.3% by flow cytometric assay (AnnexinV/PI double staining). Apoptosis was also confirmed by DNA fragmentation. Telomerase activity and expression level of hTERT, the key subunit of telomerase, decreased at 24-hour time point after SB treatment. No significant changes were observed in the expression of hTR and hTP, the other two subunits of telomerase. Telomerase activity decreases in MCF-7 cells during apoptosis induced by sodium butyrate. The underlying mechanism might be related to the down regulation of hTERT transcription.