Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related deaths world-wide. In spite of its relatively low occurrence in the U.S., its incidence is predicted to accelerate during the next decades. Research is proposed to evaluate in vivo a newly designed, targeted, prodrug therapy for cancers that overexpress the carboxylesterase, CES2, with focus on HCC. The therapy is based upon doxazolidine, a formaldehyde conjugate of doxorubicin that is more than an order of magnitude more active against a variety of both sensitive and resistant (MDR phenotype) cancer cells than doxorubicin. Doxazolidine induces cancer cell death by a different mechanism and is less toxic to cardiomyocytes than doxorubicin. The prodrug of doxazolidine, N-(pentyloxycarbonyl-p-aminobenzyloxycarbonyl)doxazolidine (pentyl PABC- Doxaz, PPD), is activated by CES2 present in liver, colon, lung, kidney, thyroid, and pancreatic cancer cells. The drug is inactive until cleaved by CES2. Critical to specificity is stability in human plasma predicting stability in the vascular system. The therapy is designed to maximize efficacy and minimize side effects including cardiotoxicity. Very little CES2 is expressed in rat cardiomyocytes and the prodrug is two orders of magnitude less toxic to rat cardiomyocytes than doxorubicin which is commonly used for treatment of HCC. Experiments are designed to improve the synthesis and formulation, to establish a bystander effect for PPD, to measure the pharmacokinetics, and to evaluate the efficacy and toxicity in orthotopic mouse models of HCC. Efficacy endpoints will include tumor growth, survival and pharmacodynamic endpoints of cell proliferation, apoptosis in tumor sections collected after treatment, and Comet assay for DNA crosslinks. Toxicity endpoints will include echocardiogram examination, measures of gross toxicity, white blood cell counts and pathological evaluation of organ tissues following treatment. Preliminary subcutaneous xenograft experiments indicate tumor growth inhibition in mouse models of liver cancer and non-small cell lung cancer using cancer cells that express CES2.

Public Health Relevance

Hepatocellular carcinoma (HCC) is diagnosed in over 14,000 patients and leads to approximately 9,500 deaths per year in the U.S., and it is a major cause of cancer-related deaths worldwide with incidence in the U.S. predicted to accelerate during the next two to three decades. Research is proposed to evaluate in vivo a newly designed, targeted, cytotoxic therapeutic for HCC that should be effective against metastatic and resistant disease with minimal side effects. Its use in combination with new cell signaling inhibitors such as sorafenib should improve therapy for HCC.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21CA143549-01A1
Application #
8184992
Study Section
Drug Discovery and Molecular Pharmacology Study Section (DMP)
Program Officer
Forry, Suzanne L
Project Start
2011-08-01
Project End
2013-07-31
Budget Start
2011-08-01
Budget End
2012-07-31
Support Year
1
Fiscal Year
2011
Total Cost
$197,708
Indirect Cost
Name
University of Colorado at Boulder
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
007431505
City
Boulder
State
CO
Country
United States
Zip Code
80309
Ganesh, Ahil N; Logie, Jennifer; McLaughlin, Christopher K et al. (2017) Leveraging Colloidal Aggregation for Drug-Rich Nanoparticle Formulations. Mol Pharm 14:1852-1860
Barthel, Benjamin L; Mooz, Erin L; Wiener, Laura Elizabeth et al. (2016) Correlation of in Situ Oxazolidine Formation with Highly Synergistic Cytotoxicity and DNA Cross-Linking in Cancer Cells from Combinations of Doxorubicin and Formaldehyde. J Med Chem 59:2205-21
Xiao, Da; Shi, Deshi; Yang, Dongfang et al. (2013) Carboxylesterase-2 is a highly sensitive target of the antiobesity agent orlistat with profound implications in the activation of anticancer prodrugs. Biochem Pharmacol 85:439-47
Barthel, Benjamin L; Rudnicki, Daniel L; Kirby, Thomas Price et al. (2012) Synthesis and biological characterization of protease-activated prodrugs of doxazolidine. J Med Chem 55:6595-607