Gossypol suppresses telomerase activity in human leukemia cells via regulating hTERT.

Gossypol is a polyphenolic compound originally isolated from cottonseed that has long been used successfully as a contraceptive drug for males. However, the molecular mechanism of anti-telomerase effects of gossypol is not entirely understood. In this study, we observed direct cytotoxicity and inhibition of telomerase activity with downregulation of telomerase reverse transcriptase (hTERT) expression. Gossypol treatment resulted in a decrease of c-Myc expression and binding activity. Gossypol treatment also suppressed the activation of Akt, thereby inhibiting hTERT phosphorylation and translocation into the nucleus. We conclude that gossypol regulates the loss of telomerase activity through transcriptional and posttranslational modifications of hTERT.