[siRNA targeting telomerase--effective tool in anti-cancer therapy?]

Telomeres are guanine-rich repeated sequences located at the ends of chromosomes. The loss of telomeric repeats after each cell division may function as a biological clock limiting the cell proliferation ability. Telomerase is a RNA-dependent DNA polymerase that synthesisezes telomeric DNA and thus enables cancer cells an unlimited proliferative potential. Human telomerase is a ribonucleoprotein complex composed of reverse transcriptase-hTERT, RNA component-hTR (functioning as a template for the telomeric DNA addition) and associated proteins. Telomerase activity is present in most malignant cells but undetectable in most normal cells. The enzyme and its altered activity distinguishing cancer cells, is an attractive molecular target for anti-cancer therapy. One of the most promising methods for modulation of the telomerase activity is RNA interference. Many investigators showed that targeting different subunits of telomerase (mainly hTERT) with siRNA had inhibitory effects on expression and activity of the enzyme and cells proliferation. siRNA targeting telomerase has the possibility to became effective anti-cancer agent especially in an adjuvant therapy.