| Description |
Bryostatin 1 is a 20-member macrolactone natural product that exhibits a variety of extremely beneficial biological activities. Since it was first isolated in 1969 and characterized in 1982, bryostatin has garnered interest for its highly oxygenated complex structure and also for its potent effect on several diseases. Bryostatin 1 has been the focus of clinical trials for cancer, Alzheimer's disease, stroke, and the human immunodeficiency virus. The biological activity is traced back to bryostatin 1's nanomolar binding affinity for and ability to maintain activation of a family of isozymes, protein kinase C (PKC). Current work in this field of research focuses on the construction of structurally simplified bryostatin analogues that can mimic the biological effects, since the natural abundance of bryostatin 1 cannot support the necessary medical testing required. A new direction in bryostatin analogue design involves the removal of one of the ABC pyran rings at the core of the structure and replacing it with an aromatic phenyl or pyridine ring. Replacement of the C-ring pyran with a tetra-substituted aryl ring has helped reduce the bryostatin 1 natural C-ring synthesis of 18 steps down to a much more practical 11 steps. The major pharmacophores present in bryostatin 1 are mirrored in these aromatic analogues in a new way, therefore binding studies and biological analysis will be required to assess if they are acceptable for further analogue development. To further understand the mechanism of exogenous ligands PMA and bryostatin 1 iv on the translocation of PKC and downstream effects, a group of fluorescently labeled compounds have been synthesized. Fluorescently labeled Merle 44 and Merle 45 were synthesized to mimic two classes of analogues that tend to have opposite effects on the living system. Merle 45 has a very similar biological profile to bryostatin 1 through various cell assays. To complete the fluorescence study, a phorbol with the same BODIPY tag as Merle 44 and 45 was synthesized. Future biological studies will shed light on the rate of uptake of phorbol versus bryostatin analogues, along with the localization of PKC within the cell and translocation pathways. Förster resonance energy transfer (FRET) studies will also be performed to analyze the protein/ligand interactions, while monitoring the resulting PKC conformational change. These results will give more insight about how the high-affinity binding of these two structurally different compound classes to PKC can result in such vastly different downstream biological outcomes. |
