Design, Synthesis and Evaluation of Targeted Prodigiosenes as Breast Cancer Chemotherapeutic Agents (Folates)

We are developing new drugs for breast cancer based on a naturally occurring molecule called prodigiosin found in bacteria in our homes and workplaces. Extracts containing prodigiosin were used in the USA from 1893 to 1963 to treat various cancers. However, prodigiosin was too toxic and was withdrawn from the market by the Food and Drug Administration (FDA) in 1963. We have now decreased toxicity 100-fold while maintaining broad anti-cancer activity by chemically modifying prodigiosin. Our goal is to develop prodigiosin-based drugs that have specific selectivity for breast cancer, while reducing general toxicity and side-effects. About 50% of breast cancers have a much greater ability to take in an essential vitamin called folic acid, compared to healthy cells. We will attach a compound similar to prodigiosin to a molecule that looks like folic acid: we expect that the resultant folate-prodigiosin drugs will target breast cancer cells rather than healthy cells. Ideally, this approach should reduce toxicity (side-effects) elsewhere in the body, while killing breast cancer cells more effectively. We will evaluate the compounds using cells from breast cancers, and we will also evaluate how well the compounds penetrate into solid tumours. Funding of this work will pave the way for a completely new avenue for breast cancer treatment. We anticipate that novel folate-prodigiosin drugs will fill an urgent need for new treatments for so-called triple negative breast cancers, which currently have limited treatment options and poor prognosis. Our continued ownership of our molecules and their applications will be secured (patents) so that clinical potential can be pursued. Synthesis of several series of folate-prodigiosene conjugatesWe will use medicinal chemistry to prepare several series of prodigiosenes appended to a folate moiety. We will design/optimize the preparative procedures for each step, via synthetic intermediates. We will fully characterize each synthetic intermediate and final target compound.In vitro cancer cell-line screening and evaluationIn partnership with the NCI, we will evaluate folate-prodigiosene conjugates across six human breats cancer cell lines.Correlation of selectivity/activity of folate-prodigiosene conjugates with respect to FRA-expressionWe will use tissue culture, Western blots, reverse transcriptase-PCR techniques and screening protocols to assess the correlation of selectivity/activity of folate-prodigiosene conjugates relative to the expression levels of folate receptor alpha.In vivo toxicity assays and evaluation as selective cytotoxic agents for breast cancersIn partnership with the NCI, we will assess the potential of in vivo evaluation to determine toxicity (max tolerated dose in mice) and cytotoxicity (xenograft assays, mice) of folate-prodigiosene conjugates.Studies involving models of accumulation into spheroid mimics of solid tumoursIn partnership with Dr. Ross Boyle (Hull), we will use spheroid models to mimic solid tumours. We will use confocal miscroscopy to measure the penetration and accumulation of folate-prodigiosene conjugates into these solid tumour models, with correlation to folate receptor alpha expression.Development and utilization of a structure activity relationshipThe knowledge we will gain via synthesis and cancer biology evaluation (effectiveness of our folate-prodigiosene conjugates) will be used to create a structure activity relationship that will guide the design of improved/later generation folate-prodigiosene conjugates.