Isolation of Factors That Disrupt Critical Protein/Protein Interactions Within the Telomerase Holoenzyme for Use in Breast Cancer Therapies

Telomerase activity is required to maintain telomere integrity on chromosomes of proliferating cells and thus is critically involved in regulating cellular replicative lifespan. Telomerase is repressed in most adult somatic cells, and activation of telomerase activity is an early event associated with tumor progression. Expression of telomerase is sufficient to greatly prolong proliferative lifespan of human cells in culture. Because telomerase activity is not required to maintain viability of post-mitotic somatic cells, but is required to maintain the proliferative capacity of tumor cells, telomerase is an ideal target for anti-cancer therapies. Here we have produced mammalian expression vectors containing Pollll- driven short-hairpin sIRNA precursors targeting hTERT mRNA. We show that these vectors dramatically repress telomerase activity when delivered to telomerase positive immortal human tumor cells, resulting in dramatic telomere shortening and a limited replicative life-span in culture.