TP53 is the most commonly mutated gene in human cancer for which no effective targeted anti-cancer drug exists. We identified NSC319726 (726) as a mutant p53 reactivating compound, and a lead compound for mutant p53 targeted drug development . Prior evidence indicated that the effects of 726 were allele-specific, by restoring wildtype structure and function to the third most common p53 mis-sense mutant (p53-R175H). This effect was dependent on the zinc-chelating and redox modulating properties of 726. The p53 protein binds a single zinc ion, which is necessary for proper p53 structure and function. The p53-R175H mutation impairs the protein from binding zinc causing it to mis-fold and lose transcriptional function. The mechanism of 726 mutant p53 reactivation is unknown. We provide preliminary data that describe a novel "dual" mechanism where 726 restores wild-type structure to the p53-R175H using a zinc-metallochaperone function to provide an optimal concentration of zinc to facilitate proper folding. We also demonstrate that the redox modulating properties of 726 function to transactivate the newly conformed p53-R175 and induce an apoptotic program. We also demonstrate that this zinc-metallochaperone function applies to other p53 mis-sense mutants with impaired zinc binding. In this K08 Career Development Award, Dr Darren Carpizo and his collaborators plan to explore this compound in two major directions.
Aim #1 is to dissect the molecular mechanism by which the compound reactivates the p53-R175 mutant protein and other p53 zinc-binding mutants.
Aim #2 is conduct pre-clinical studies of the compound to evaluate its potential for clinical development as a mutant p53 targeted anti-cancer drug. Dr. Carpizo is a surgical oncologist specializing in hepatobiliary and pancreatic cancers currently appointed as an assistant professor of surgery at The Cancer Institute of New Jersey (CINJ), an NCI designated Comprehensive Cancer Center. He has obtained formalized training in research at the University of California at Los Angeles, earning a PhD in molecular and cell biology during his general surgical residency training. Dr. Arnold Levine whose laboratory discovered the p53 tumor suppressor and Dr. Joseph Bertino, an internationally recognized expert in the field of Developmental Therapeutics in cancer, are currently mentoring him. Dr. Carpizo's immediate and long term career goals are to 1) Build an independent NIH Research Project Grant supported research program focusing on pancreatic cancer, 2) Become a leader of a dedicated group of clinicians and scientists that focus on pancreatic cancer at an NCI designated Comprehensive Cancer Center and 3) To develop a niche of Developmental Therapeutics within the broader discipline of Surgical Oncology. The Career Development Plan designed by Dr. Carpizo and his Mentor/Co-Mentor will accomplish these goals with three major components: 1) Laboratory research: The candidate will execute the research plan outlined above under the mentorship of Drs. Levine and Bertino. He will receive further instruction from several collaborators including Dr. Stewart Loh, a biochemist who will conduct biophysical experiments with NSC319726. Dr. Gaetano Montelione, an NMR structural biologist who will attempt to use NMR techniques to study drug-p53-R175 protein interactions and Dr. Ken Olive, a molecular biologist who runs a NIH funded pancreatic cancer laboratory with expertise in the transgenic mouse model of pancreas cancer that will be used to test NSC319726. Dr. Carpizo will also receive specialized instruction in using RNAi technologies in mouse cancer modeling from Dr. Scott Lowe, (Memorial Sloan-Kettering cancer center). 2) Experience in Translational Clinical Trials: Dr. Carpizo will gain experience in translational clinical trials through the conduct of small pilot study designed to study the mechanism of action of the Novartis Hedgehog inhibitor (LDE-225) in patients with surgically resectable pancreas cancer. Dr. Carpizo is the principal investigator of this clinical trial that is being funded by Novartis. Dr. Bertino will mentor him through the conduct of this trial. 3) Didactics: Dr. Carpizo will take attend several courses at Cold Spring Harbor including 1) Advanced Sequencing Technologies, and 2) Mechanisms and Models of Cancer and 3) Workshop on Pancreatic Cancer.
Decades of research have defined p53 as one of the most critical tumor suppressors in human cancer yet to date there are no effective p53 targeted anti- cancer drugs. We have discovered a lead compound for mutant p53 targeted drug development that selectively kills cancer cells that contain mutant p53, while leaving normal cells undisturbed. Through the research in this proposal, we will understand the mechanism of action of this compound as well as assess its potential for clinical development as a mutant p53 targeted anti-cancer drug.
|Yu, Xin; Narayanan, Sumana; Vazquez, Alexei et al. (2014) Small molecule compounds targeting the p53 pathway: are we finally making progress? Apoptosis 19:1055-68|
|Yu, Xin; Blanden, Adam R; Narayanan, Sumana et al. (2014) Small molecule restoration of wildtype structure and function of mutant p53 using a novel zinc-metallochaperone based mechanism. Oncotarget 5:8879-92|