The prognosis for patients afflicted with malignant gliomas remains grim in spite of many years of intensive clinical research. Several factors contribute to this state of affairs. First, these tumors are highly invasive. This invasiveness greatly limits the effectiveness of local therapies, such as surgery, radiosurgery, and brachytherapy. Second, these tumors are very effective at generating their own blood supply. They accomplish this by secreting a variety of factors that induce endothelial cells to migrate toward and invade into tumor stroma. Finally, gliomas, like other malignancies, produce a variety of growth factors that in aggregate stimulate their mitotic activity--one that is relatively resistant to cell cycle-specific chemotherapies. While it may not seem immediately obvious, tumor invasion, angiogenesis, and mitosis have one thing in common--all depend critically on cell motility. Cell motility allows glioma and endothelial cells to crawl through the extracellular matrix of the brain. However, cell motility also includes movement of intracellular components from one location within the cell to another, such as occurs in mitosis, where chromosomes are actively translocated to the poles. All of these motile processes depend upon a class of enzymes, called """"""""molecular motors"""""""", which utilize the energy of ATP hydrolysis to generate movement. While it would seem very reasonable to treat gliomas by targeting their myosins and kinesins, the pharmacologic inhibition of molecular motors as a form of cancer therapy has been largely unexplored and unexploited. I will address this issue by proposing to identify new inhibitors of myosin II and kinesin by developing high throughput screening assays based on a series of novel spectroscopic probes developed in my laboratory. These assays will be performed at the High Throughput Screening (HTS) Laboratory at Southern Research, Inc. and will be used to identify promising compounds identified from screening several large chemical libraries (Aim 1). Compounds identified in Aim 1 will be validated by fluorescence spectroscopy and transient state kinetics to determine the mechanism of inhibition and its specificity (Aim 2). This work will serve as the basis for a future extramural funding initiative designed to take promising compounds identified by this approach into pre-clinical glioma model systems, and ultimately, into clinical trial. ? ?
