Grant: Operating Grant

Most chemotherapeutics act by associating with DNA which is being copied into messenger RNA by the cellular machinery - a process known as transcription. RNA polymerase is a multi-component protein machine that is physically bound to (touching) the DNA and catalyzes transcription. When chemotherapeutics like cis-platin, chlorambucil, and mitomycin bind to DNA, they not only damage the DNA but stall RNA polymerase on the DNA and prevent it from moving along the DNA, thus inhibiting transcription. Other cellular proteins sense that RNA polymerase is stalled and degrade it to remove it from the DNA in order to repair the damaged DNA. When there is too much damage to the DNA, cells undergo programmed cell death (called apoptosis), a desired effect of the chemotherapy. Therefore understanding how RNA polymerase stalls and is degraded will provide essential knowledge for understanding how chemotherapies cause cell death. Amanitin, a toxin that is found in mushrooms, is a specific RNA polymerase inhibitor that causes it to stall, be degraded, and ultimately kills cells. Our publications uniquely qualify us to prepare synthetic amanitins to probe RNA polymerase inhibition, degradation, and cell death. This understanding, along with our synthetic know-how, enables us to investigate amanitin as a targeted therapeutic. Targeted therapies, which link toxins to anticancer agents like antibodies (e.g. mylotarg), and bioreductive drugs (e.g. mitomycins) are now used in patient management. Although many drugs are being targeted to cancer, amanitin has not been investigated in this manner. Here, we propose a unique approach that combines both bioreduction and targeting to investigate the possibility of using amanitin to kill cancer cells. This proposal therefore will use amanitin to explore both fundamental aspects of cell death as well as investigate its potential for use in anticancer therapeutic development.