Cancer Regulation Through Splice Modulation
- Author(s): Trieger, Kelsey
- Advisor(s): Burkart, Michael
- et al.
RNA splicing plays a central role in cell regulation, development, and disease progression, but the complexity of this macromolecular assembly process has left RNA splicing underexplored in cancer. In recent years, it has become clear that alternative RNA splicing becomes mis-regulated in and plays a role in the progression of a wide range of cancers. Therefore, drugs that regulate RNA splicing could serve as powerful therapeutics for cancer. Splice modulators (SPLMs) are a class of chemotherapeutics that regulate aberrant splicing profiles in tumors, thereby inducing tumor cell apoptosis. SPLMs interfere with the overused splicing machinery that cancer cells become dependent upon for expansion, thereby limiting the tumor’s ability to produce proteins necessary for growth and survival. Understanding the relationship between splicing and cancer progression will allow for expansion of our therapeutic arsenal in tackling cancer.In my graduate studies, I evaluated splice modulator regulation of the cell cycle genes Aurora kinase (AURK) and Polo-like kinase 1 (PLK-1). Next, I leveraged the SPLM FD- 895’s regulation of the cell cycle to develop a splicing-based combination therapy capable of targeting a wide range of tumor types. This co-dosing approach relied on use of the splice modulator FD-895 to reduce cell cycle RNA, followed by treatment with a cell cycle protein inhibitor to further reduce cell cycle protein expression. This combination therapy was found to be effective against a range of tumor types, including cervical, ovarian, and colorectal tumor cell lines, indicating that this approach has wide therapeutic applications. These studies suggest the potential to engage small molecule SPLM pretreatment as a therapeutic tool to edit the levels of therapeutically targeted proteins by mis-splicing their RNAs. SPLM combination therapy may be particularly useful for enhancing clinical agents that suffer from off-target effects or dose-limiting toxicity and could therefore allow for previously abandoned lead molecules (therapeutics) to re-enter the clinic. Next, I synthesized analogs of the splice modulator FD-895 to investigate structure- activity relationships (SARs) for this class of compound. Structural differences from one SPLM to another lead to significant changes in splicing activity based on SPLM orientation within the spliceosome binding pocket. Therefore, although most SPLMs affect the splicing of the same category of genes, each SPLM affects the splicing of individual genes to a different extent. Through these efforts, we have been able to synthesize splice modulators like 17S-FD-895 with enhanced stability compared to their parent natural products [Villa 2013].