Computer-assisted molecular design and structure activity relationship study of tocotrienol-based breast cancer proliferation and migration inhibitors

Breast cancer is the most frequently diagnosed cancer and the second leading cause of cancer mortality in women in the United States. However, despite significant advances in detection and treatment, more than 40,000 patients die each year in the United States from breast cancer. The overall objective of this dissertation was to evaluate, optimize, and discover new anticancer hits with activity against breast cancer. The bioactive phenolic natural products like tocotrienols and oleocanthal play crucial roles in breast cancer prevention. Vitamin E (VE) is a generic term that represents a family of phenolic compounds composed of various tocopherol and tocotrienol isoforms. Tocotrienols display potent anti-angiogenic and antiproliferative activities. Redox-silent tocotrienol analogues also display potent anticancer activity. Twenty-eight semisynthetically C-6-modified redox-silent tocotrienol analogues were prepared and showed enhanced antiproliferative activity against the breast cancer +SA and MCF7 cell lines and anti-invasive activity against MDA-MB-231 cell line compared to their parent compounds. Three-dimensional quantitative structure-activity relationship (3D QSAR) studies were performed using Comparative Molecular Field (CoMFA) and Comparative Molecular Similarity Indices Analyses (CoMSIA) to better understand the structural basis for biological activity and guide the future design of more potent VE analogues.;Oleocanthal is a naturally occurring minor phenolic ester isolated from extra virgin olive oil (EVOO) at a range yield of 22-190 mug/g. Oleocanthal showed potent anti- inflammatory activity via its ability to inhibit COX-1 and COX-2. It alters the structure of neurotoxic proteins believed to contribute to the debilitating effects of Alzheimer's disease. Computer-Assisted Molecular Design (CAMD) identified oleocanthal as a potential virtual c-Met inhibitor hit. c-Met is the proto-oncogene receptor tyrosine kinase. Dysregulation of the HGF-c-Met pathway plays a significant oncogenic role in many tumors. Oleocanthal potently inhibited the proliferation, migration, and invasion of the epithelial human breast and prostate cancer cell lines MCF7, MDA-MB-231, and PC-3, respectively, with IC50 range of 10-20 muM. Oleocanthal effectively inhibited the phosphorylation of c-Met kinase in vitro in Z'-LYTE(TM) assay, with an IC50 value of 4.8 muM. Oleocanthal and its natural source EVOO can have potential use for the control and chemoprevention of c-Me-dependent malignancies.;Furthermore, virtual screening of the National Cancer Institute (NCI) (260,071 chemical structures) and ZINC (13 million chemical structures) databases was carried out to search for new hits that most likely to bind the c-Met ATP binding site. This CAMD screening led to the identification of 25 compounds as potential virtual c-Met inhibitors. Of these, seven compounds were commercially available. Their c-Met phosphorylation inhibition potency, antiproliferative, and anti-migratory effects were evaluated in vitro. N-(4-((3,6-diamino-9-acridinyl)amino)-3-methoxyphenyl)urea, and (Z)-N'-((2-hydroxynaphthalen-1-yl)methylene)-4-(piperidin-1 -ylsulfonyl)benzohydrazide inhibited the phosphorylation of c-Met kinase in vitro in Z'-LYTE(TM) assay, with IC50 values of 16 muM and 39 muM, respectively. The predicted binding modes of these compounds are discussed. In conclusion, C-6-modified redox-silent tocotrienol analogues and EVOO-derived oleocanthal demonstrated enhanced anti-cancer activity against different breast cancer cell lines. CAMD has been effectively used in tocotrienols 3D QSAR design, and discovery new c-Met inhibitor scaffolds.