[Effects of 3'-azido-deoxythymidine on telomerase activity and protein expression of hepatocarcinoma cell line SMMC-7721].

BACKGROUND & OBJECTIVE: The mechanism of inhibiting telomerase activity by telomerase inhibitors is very complex, and involves common actions of many proteins. This study was to investigate the effects of 3'-azido-deoxythymidine (AZT) on telomerase activity and protein expression of hepatocarcinoma cell line SMMC-7721, and explore possible mechanism of inhibiting telomerase activity in SMMC-7721 cells by AZT.

METHODS

Optimized concentration and treatment time of AZT were detected by MTT assay. After treatment with AZT, the telomerase activity in SMMC-7721 cells was detected by real-time fluorescent quantitative TRAP (FQ-TRAP) assay; the apoptosis of SMMC-7721 cells was detected by TUNEL assay and flow cytometry (FCM); the changes of specific proteins were monitored by raman spectra assay and surface-enhanced laser desorption time of flight-mass spectrum (SELDI-TOF-MS) with protein chip assay.

RESULTS

The optimized treatment time of AZT was 48 h, and the optimized concentration of AZT was 20 mmol/L. When treated with 20 mmol/L AZT for 48 h, the telomerase activity in SMMC-7721 cells was inhibited by 53.85% of control (P<0.001); apoptotic morphologic changes of SMMC-7721 cells were observed; the apoptosis rate of SMMC-7721 cells was 13.5%; 7 spectral peak of proteins were changed; 24 proteins were up-regulated and 8 were down-regulated in SMMC-7721 cells. All of the 32 distinct proteins were small molecular proteins.

CONCLUSION

AZT can inhibit the telomerase activity and induce apoptosis of SMMC-7721 cells, which is related to specific small molecular proteins.