I. The Utility of Activation Domain Mimics as Targeted Inhibitors of Transcription II. The Design and Implementation of a Peer-Lead Module in Practical Research Ethics.

Abstract

Because of the central role that transcription plays in regulating cell function and fate, the ability to cause a targeted increase or decrease in particular transcription programs has tremendous potential as both a therapeutic approach, and as a tool for biochemical investigations. However, the design of small molecules that target transcription has proven difficult. Only a handful of such molecules are known, and at the time this project was initiated, no clear rationale for their design had emerged.

Our results indicate that small molecules which mimic activation domains can be used as scaffolds for the development of transcriptional inhibitors. A small molecule designed to mimic the activation domain of the transcriptional activator ESX is able to inhibit transcription of erbB2, an oncogene whose expression is mediated by ESX. This molecule reduces erbB2 mRNA and protein levels, and inhibits the proliferation of erbB2 over-expressing cancer cells. However, as with other known inhibitors of transcription, it requires low micromolar doses to be effective, and has modest selectivity for erbB2 over-expressing cells when compared to non tumorigenic cells. In order to solve these recurring problems with interventions that target transcription, we combined this small molecule transcriptional inhibitor with other agents that target the activity and lifetime of the erbB2 protein. These combinations show dramatically increased potency, with simultaneous IC50 reductions of higher than 10-fold in the case of some combinations. They also have increased selectivity for erbB2 over-expressing cancer cells. On the whole, these results validate a rationale for the design of small molecule inhibitors of transcription, and a strategy for overcoming the problems with potency and selectivity that are endemic to such molecules.

The final portion of this thesis concerns the important issue of education in research practices. A growing body of work suggests the widespread use of questionable practices by research scientists. As a local solution to potential issues, we designed, wrote, and led a discussion module for incoming graduate students about research ethics, data interpretation, and conflict management. This module was well-received by both students and the broader chemical eduction community as a method for research ethics education.