Biophysical Characterization of Synthetic Imidazole and Pyrrole Containing Analogues of Netropsin and Distamycin that Target Specific DNA Sequences for the Treatment of Various Diseases

The development of small-molecules which target nucleic acids, more specifically the minor groove of DNA, in a sequence specific manner and control gene expression are currently being investigated as potential therapeutic compounds for the treatment of various diseases, including cancer, as well as viral and bacterial infections. The naturally occurring compounds netropsin and distamycin have been shown to demonstrate antitumor and antibacterial properties. Currently, there are synthetic efforts to create pyrrole and imidazole-containing polyamide derivatives of netropsin and distamycin that show potential as medicinal agents. Synthetic pyrrole and imidazole-containing polyamides are potentially useful for targeting and modulating the expression of genes, including those associated with cancer cell growth. The key challenges that must be overcome to realize this goal of using synthetic polyamides in the treatment of disease are the development of polyamides with low molar mass so the molecules can readily diffuse into cells and concentrate in the nucleus. In addition, the molecules must have appreciable water solubility, bind DNA sequence specifically, and with high affinity. As part of a systematic study within the authors’ laboratory, our goal is to develop polyamides which can be synthesized readily yet possess excellent sequence specificity, stronger binding affinity, high solubility in biological media and enhanced cell penetration and nuclear localization properties. There is a need to develop a library of modified polyamides which target DNA and exhibit improved biological properties. The present study is a systematic examination of the binding properties of various modified synthetic polyamide compounds. The synthetic polyamide derivatives presented have more potential as therapeutic candidates over other synthetic polyamides because of their increased water solubility, smaller molecular weights, and molecular design, thus, allowing them to penetrate into cells and localize in the nucleus. INDEX WORDS: DNA, minor groove, polyamides, netropsin, distamycin, imidazole, pyrrole, sequence specificity, gene control, surface plasmon resonance, isothermal titration calorimetry BIOPHYSICAL CHARACTERIZATION OF SYNTHETIC IMIDAZOLE AND PYRROLE CONTAINING ANALOGUES OF NETROPSIN AND DISTAMYCIN THAT TARGET SPECIFIC DNA SEQUENCES FOR THE TREATMENT OF VARIOUS DISEASES