Discovery and biological evaluation of the anticancer properties of novel curcumin analogs

Curcumin, a spice used extensively in curries as a coloring and flavoring agent, is remarkable for its range of therapeutic properties and low toxicity. Of most interest is the compound's anticancer activity, which includes growth suppression and apoptosis induction in vitro, as well as inhibition of tumorigenesis in vivo. Despite these favorable properties, its use is limited due to low potency and poor absorption characteristics. Furthermore, the molecular target(s) of curcumin has not been fully characterized. However, curcumin remains a solid lead compound for the design of derivatives with a similar safety profile, but increased activity and solubility.; The goal of this thesis was to discover novel curcumin analogs, determine their in vitro and in vivo anticancer activity, and characterize their cellular effects and possible molecular targets.; Derivatives of curcumin were discovered by 2D database searching and synthetic chemistry and tested for their in vitro anticancer and anti-angiogenic activity. The anticancer assays demonstrated that many of the compounds effectively inhibit tumor cell proliferation and are more potent than curcumin. The same analogs were also effective in the anti-angiogenesis assays. The most active derivative, EF24, was identified and tested for its ability to inhibit the growth of human breast tumors in immunocompromised mice. The compound significantly reduced the size of the tumors and showed little side effects.; After determining the in vitro and in vivo anticancer activity of the analogs, studies were performed to elucidate the mechanism of cell death that is induced by the compounds and their possible molecular targets. Experiments with EF24 indicated that this compound induces apoptosis and growth arrest in two highly malignant cancer cell lines. Features of apoptosis included exposure of phosphatidylserine (PS) residues on the cell surface, mitochondrial membrane depolarization, caspase-3 activation, and DNA fragmentation. In addition, it was demonstrated that EF24 modulates the DNA binding activity of AP-1 and NF-κB, which may contribute to the apoptosis-inducing effects of the analog and its ability to alter the expression of important cancer-related genes. Finally, immunohistochemical studies using biotinylated derivatives of EF24 showed that this compound localizes in the nucleus, suggesting the possibility of a nuclear target.