Inhibitor of the human telomerase reverse trancriptase (hTERT) gene promoter induces cell apoptosis via a mitochondrial-dependent pathway.

Telomerase is aberrantly expressed in many cancers and plays an important role in the development of cellular immortality and oncogenesis, which makes it a potential cancer therapeutic target for drug discovery. Here, we constructed a firefly luciferase reporter driven by the human telomerase reverse trancriptase (hTERT) gene promoter to screen for inhibitory compounds. Compound 5c was discovered and shown to significantly inhibit the promoter activity of hTERT gene. Furthermore, five analogs of compound 5c were synthesized, and compound 8b was shown to be a more potent inhibitor of hTERT gene promoter activity and subsequent expression of hTERT mRNA and protein. The viability of HeLa cells was inhibited by a knockdown of hTERT gene expression, and the same effect was also observed by treating with compound 8b. Moreover, our results indicated that compound 8b induced apoptosis of HeLa cells, and activated caspase-9 and caspase-3 enzymes. Taken together, these results suggested that compound 8b down-regulates the expression of hTERT and induces mitochondrial-dependent apoptosis.