I. Design, synthesis, and biological evaluation of new analogs of bryostatin. II. Investigations into the mode of action of apoptolidin A

The bryostatins are a family of marine natural products with a unique combination of potency and activity. Bryostatin 1 has shown the ability to inhibit cancer cell growth, induce apoptosis, synergize with existing chemotherapeutics, reverse multi-drug resistance, stimulate immune function, improve memory and learning, and reduce amyloid plaque formation. Results from clinical trials indicate bryostatin 1 is active at doses of 25--50 mug/m 2. The natural abundance of bryostatin is too low to provide material for widespread use and the structural complexity of the natural product prevents its practical synthesis. Bryostatin is also unoptimized for therapeutic use. The design of molecules with bryostatin like function that can be produced in a practical fashion provides a reliable source of material and also provides a method of generating optimized therapeutics.; A practical synthesis of the most potent bryostatin analog reported to date has been achieved. This synthesis has also provided simple access to advanced materials that have been used in the preparation of additional analogs. Analogs of bryostatin with changes to the C-ring recognition domain have been prepared. A macrocyclic lactam analog bearing a modified pharmacophore was found to be inactive. The C20 position of bryostatin was identified as a non-pharmacophoric region of the molecule and analogs were prepared by a late stage-diversification strategy. These compounds bound potently to PKC, a known receptor for bryostatin, and retained functional activity. A receptor-docking model has been developed for analog design, producing a new hypothesis for the bryostatin-C1 domain interaction and successfully explains known SAR.; A series of functional assays have been developed to measure the ability of bryostatin analogs to activate PKC. These experiments demonstrate that the analogs have bryostatin-like effects and are more potent in some systems than the natural product. A-ring modifications result in selective activation of PKC isozymes. The use of fluorescent compounds has allowed observation of the uptake and distribution of analogs.; Apoptolidin, a natural product with selective growth inhibition of cancer cell lines, has been investigated using new fluorescent biosensors, revealing that in H292 and HeLa cells apoptolidin induces arrest of the cell cycle in G1 phase.