Neural Tumor-Initiating Cells Have Distinct Telomere Maintenance and Can be Safely Targeted for Telomerase Inhibition by Pedro Castelo-Branco and 12 co-authors, including Uri Tabori, Clin Cancer Res 2011(Jan 1); 17(1): 111-121 [Full text]. Translational Relevance:

Pediatric neural tumors (brain tumors and neuroblastoma) are the leading cause of morbidity and mortality in childhood cancer. This is due to their ability to recur after minimal disease is achieved. Telomerase is active in most malignant pediatric neural tumors. Therefore, telomerase inhibition may offer an effective treatment option for such patients. Because normal stem cells may require telomerase for continuous self-renewal, this therapy may have devastating effects on normal nervous system development and maintenance.

This study reveals that telomerase activation exists only in the tumor-initiating cancer subpopulation and is critical to sustain their survival and self-renewal potential. Importantly, normal neural or neural crest stem cells do not require telomerase for their self-renewal. Furthermore, as opposed to conventional chemoradiation therapies, telomerase inhibition results in irreversible loss of self-renewal capacity of tumor initiating cells in vitro and in vivo.

These observations uncover a difference between normal and cancer stem cell biology in the nervous system and suggest that telomerase inhibition may offer a specific and safe therapeutic approach for these devastating tumors.

For a commentary on this article, see: Anita B Hjelmeland and Jeremy N Rich, Clin Cancer Res 2011(Jan 1); 17(1): 3-5 (unlike the article, the commentary is not publicly accessible). Abstract:

Telomerase is an important mechanism by which cancers escape replicative senescence. In neural tumors, cancer stem cells express telomerase, suggesting that this may explain their preferential tumorigenesis. Oligonucleotide telomerase targeting selectively disrupts cancer stem cell growth through the induction of differentiation, adding to the armamentarium of anticancer stem cell therapies.