Synthesis of proflavine derivatives and study of how they bind to DNA as potential chemotherapeutic agents

Cancer is caused by cellular malfunction resulting in unchecked cell growth. When cells grow uncontrollably, they can crowd out nearby cells and spread to other parts of the body. The major cause of cancer is gene mutations, often caused by external carcinogens, which alter the DNA and other biological machinery required to keep our cell growth balanced.  Many cancers are hard to treat, and researchers are still trying to find selective anticancer drugs with mild or no side effects.

My research focused on proflavine, a common candidate for being a chemotherapeutic agent studied by many scientists to understand how cancer drugs bind to DNA and stop transcription processes to kill cancer cells. Proflavine is a mutagenic acridine-type molecule that can intercalate- (insert itself between adjacent DNA base pairs), which forces the DNA base pairs to separate, causing the double helix of the DNA to unwind. This process results in interference in the transcription and translation of DNA, preventing cancer cells from replicating. In order to understand how proflavine intercalates and how to improve its intercalating property, my research aimed at synthesizing proflavine derivatives by attaching other small molecules with subtly different electronic and steric properties, giving us in-depth understanding of DNA-drug interactions. During the first 3 weeks of my summer research, I managed to synthesize 3 proflavine derivatives that will be tested with the DNA this coming year. Since the molecules I synthesized don’t dissolve well in water (which is a problem if you are studying cells and DNA), I also investigated methylation strategy to increase water solubility.

Due to several limitations when building off of proflavine (e.g. cost, difficulty of some proposed chemical reactions), I switched to synthesizing acridine derivatives from simple molecules like aniline and o-iodobenzoic acid, which are cheap and readily available. I developed methods to make acridine derivatives with several different molecular fragments coming off of the acridine core, including nitrile, nitro, amine, pyridine, methyl, and a carboxylic acid at different positions on acridine rings.  While several of the attempted reactions did not work as well as expected, or failed completely, I successfully synthesized one acridine derivative. In future, I hope to be able to complete several more of my proposed acridine syntheses and to synthesize proflavine with more functional groups coming off of it. All of the molecules I make will be tested with DNA in the future for their intercalating properties. The characterization methods used to determine the structure of the synthesized compounds are proton and carbon-13 NMR spectroscopy. Future characterization will include melting point, viscosity studies, and circular dichroism spectroscopy to understand the binding mode of the synthesized compounds to DNA.