New Mechanisms of Anti-tumor Activity of A-type PACs from Cranberries

Weill Medical Coll Of Cornell Univ, New York NY

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Abstract

DESCRIPTION (provided by applicant): There has been limited effort to study the role of iron in association with inflammation and treatment or prevention of cancer, especially from dietary sources or complementary medicines. A unique class of compounds from cranberries, known as A-type proanthocyanidins (A-PACs), have iron chelating properties and are the major component of cranberry fractions that have exhibited anti-tumor effects against several human cancer cell lines. Cranberry A-PAC fractions have also inhibited the inflammatory mediator Interleukin(IL)-6, a cytokine that affects iron metabolism and contributes to anemia of inflammation from chronic disease. The proposed research project will investigate the anti-tumor activities of A-PACs and their effects on anemia in relation to inflammation, and iron metabolism. The iron biomarkers, hepcidin, ferroportin, transferrin receptor and the inflammatory cytokines, IL-1alpha and IL-6 are of particular interest for this project. The anti-tumor activity of A-PACs will be tested at three different levels in vitro and in vivo with melanoma and leukemia cell lines. Tumor cells and mice implanted with tumors, will be treated with 1) a cranberry supplement with high A-PAC content 2) an A-PAC mixture consisting of mostly A-PAC dimers/trimers; 3) an A-PAC dimer or trimer. Iron metabolism and inflammation markers will be evaluated by qPCR, immunohistochemistry or other methods after treatment with A-PACs. An anemia of inflammation model recently developed by our lab will prolong the life of mice with tumors by an inducible suicide gene and provide systemic effects more similar to humans. Several hematological parameters, iron, and inflammation biomarkers will be analyzed in this model with and without the treatment of A-PACs. In addition, structural studies of A-PACs and their anti-tumor effects will be conducted in vitro by comparison of an A-PAC dimer with a similar compound lacking the ether bond. Changes in reactive oxygen species (ROS) and prosurvival factors of tumor cells treated with A-PACs in vitro will also be assessed to better understand the pathways involved in anti-tumor activity. Results from this research will provide more information about the mechanisms of A- PACs in relation to anti-tumor activities, altered iron metabolism and anemia of inflammation. These studies will also provide medical research training in hematology/oncology and further characterize the association of cancer with iron metabolism and inflammatory states.