Inhibition Of Human Telomerase By Targeting Its Transitory Rna Dna Heteroduplex

Download or read book Inhibition of Human Telomerase by Targeting Its Transitory RNA/DNA Heteroduplex written by Rawle Francis and published by . This book was released on 2005 with total page 708 pages. Available in PDF, EPUB and Kindle. Book excerpt: Telomerase is a target of intense scientific interest largely because of its implicated role in human carcinogenesis. The inactivation of this enzyme is widely believed to be a promising method to selectively destroy neoplastic cells, while leaving normal cells mostly unaffected. In this dissertation work, the inactivation of human telomerase by molecules based on nucleic acid intercalator structures is presented. The process of cell division shortens the distal portion of linear chromosomes (the telomere). Human telomerase, a special DNA polymerase which functions to maintain telomere length, is composed of RNA and protein subunits. Upon binding to its telomeric DNA substrate, a RNA/DNA heteroduplex is formed. The working hypothesis pursued here is that molecules which target this specific RNA/DNA heteroduplex will stabilize this structure and effectively stall telomerase polymerase activity. Since telomere maintenance is paramount for the survival of rapidly dividing cancer cells, the prevention of telomere maintenance, via inhibition of the telomerase enzyme, is a promising approach to cancer treatment. There are several other approaches to telomerase inhibition presented in the literature. However, targeting the RNA/DNA heteroduplex with the use of modified DNA intercalating agents is a novel and attractive approach to telomerase inhibition. A multifaceted methodology was undertaken to achieve the goal of producing specific inhibitors of human telomerase. First, commercially available nucleic acid intercalators were tested to obtain lead compounds with good inhibitory effect on telomerase activity. Secondly, utilizing techniques of enzyme kinetics, investigations were carried out to determine whether the telomerase RNA/DNA heteroduplex was the target of these lead compounds. Finally, the generation of more potent inhibitors of telomerase was attempted through the use of combinatorial peptide synthesis using lead intercalator(s) as the base structure. It was demonstrated in vitro, that more potent inhibitors of human telomerase could be developed by this approach. Using previously existing assay methods, in addition to original methods developed, relevant experiments were carried out to investigate the stated working hypothesis. During the course of these experiments many interesting observations were made, some of which were pursued and dealt with in these chapters.