Preclinical Development of Selective PKC_epsilon Inhibitors to Treat Alcoholism

DESCRIPTION (provided by applicant): Alcoholism and alcohol abuse are the most common forms of drug abuse and effect about 8% of the U.S. population at a cost of approximately $184 billion a year. Current treatment generally consists of psychosocial therapies aimed at rehabilitation and reducing alcohol-associated problems and pharmacotherapy with a limited number of approved drugs. While current treatment can be effective in reducing alcohol consumption, it is estimated that 40-70% of patients return to excessive drinking within a year after treatment. This is partly due to the modest effectiveness of currently approved medications and their side effects, which contribute to poor compliance with their use. Clearly, there is a need to develop more effective drugs. A large body of preclinical data available through studies of mice deficient in PKC_epsilon and rats treated with a peptide inhibitor of PKC_epsilon provides a strong case for development of PKC_epsilon inhibitors to reduce alcohol self-administration and pain associated with alcoholic polyneuropathy. In addition, evidence indicates that PKC_epsilon inhibitors could be useful for the treatment of anxiety, which is commonly associated with alcoholism and may contribute to excessive drinking. This proposal is focused on the preclinical development of a novel class of small organic compounds that act as inhibitors of the enzyme PKC_epsilon. Currently, there are no selective inhibitors of PKC_epsilon that can be administered systemically and cross the blood-brain barrier. Based on combined multi-property computational modeling and wet-lab verification in our Phase I SBIR study, a water soluble small organic molecule, VMD-C620 was identified as an effective and relatively selective "allosteric" PKC_epsilon inhibitor acting reversibly and noncompetitively with ATP and substrate. VMD-C620 was also shown to be efficacious in an experimental animal model of alcoholic polyneuropathy and exhibited high specificity when assayed against related kinases, including the highly related PKC_epsilon. Its distinctive molecular scaffold is very amenable to modification and optimization by medicinal and computational chemistries. These unique properties make VMD-C620 an excellent candidate to be further derived, optimized and developed for the potential treatment of alcohol use disorders. The project proposed here is to develop more potent derivatives of VMD-C620 and study them in preclinical pharmacokinetic and animal disease models relevant to alcohol use disorders. This work will form the basis for future studies, which will complete preclinical development to allow testing of a novel PKC_epsilon inhibitor in humans as a new and improved agent for treatment of alcohol use disorders.