Modulation of telomerase activity by zinc in human prostatic and renal cancer cells

Because the up-regulation of telomerase in most cancer tissues is considered to be responsible for the unlimited proliferation of cancer cells, suppression of telomerase activity is an attractive potential target for cancer therapy. The mechanism for the activation of telomerase in cancer cells, however, is still unclear. In the present study, we demonstrated that Zn induces an enhancement of telomerase activity in the human renal cell carcinoma (NRC-12) and prostatic cancer (DU145) cell lines. The maximum elevation of the activity was observed 6 hr after treatment with 100 mu M Zn; it was diminished by the addition of either metal chelator or cycloheximide. Other metals such as Cd and Cu also enhanced telomerase activity but to a lesser extent, anal no correlation between the activation of telomerase and the induction of metallothionein was observed. Our findings provide the first evidence that metals, especially Zn, can modulate telomerase activity in cancer cells. BIOCHEM PHARMACOL 59;4:401-405, 2000. (C) 2000 Elsevier Science Inc.