Cytotoxic effects of caffeic acid undecyl ester are involved in the inhibition of telomerase activity in NALM-6 human B-cell leukemia cells

Our previous study reported that caffeic acid undecyl ester (CAUE) has a potent cytotoxic effect and induces apoptosis in NALM-6 cells, but not in normal human lymphocytes. The majority of normal human cells have no detectable telomerase activity, however, activity is commonly detected in cancer cells. Thus, inhibiting telomerase activity and inducing apoptosis may have a selective effect on cancer cells. The aim of the present study was to investigate the inhibitory effects of telomerase activity by CAUE in a NALM-6 cell culture system. CAUE was shown to preferentially damage DNA synthesis compared with RNA or protein synthesis. In addition, telomerase activity was significantly suppressed and the activity of human telomerase reverse transcriptase (hTERT), a subunit of telomerase, was decreased following treatment with CAUE, each in a concentration-dependent manner. These results indicated that the cytotoxic effects of CAUE are mediated by the inhibition of DNA synthesis and telomerase activity. The present study is the first to identify the cytotoxic mechanisms of CAUE in leukemia cells.