Is telomerase a novel target for metastatic colon cancer?

Most current therapies for advanced colon cancer lead to the emergence of drug-resistant cells and tumor recurrences. Targeted cancer therapeutics seek to identify pathways that are more tumor specific, resulting in fewer side effects, and that may produce long-term durable responses. Telomerase is a cellular reverse transcriptase that maintains the ends of chromosomes (telomeres). Telomerase is activated in the vast majority of human cancers, including colon cancer, and telomeres are maintained at short but stable lengths. In normal tissues, telomerase is not expressed or is expressed at very low levels that do not fully maintain telomeres. This suggests that telomerase may be a novel cancer target, and approaches to inhibit telomerase for cancer therapy are an attractive option because of its distinct pattern of expression. This article reviews the background of telomeres and telomerase in colon cancer and the use of telomerase inhibitors in the treatment of cancer.