Effects of Curcumin and Its 25 Kinds of Structural Analogs on Antiproliferation, Antimetastasis, Solubility Improvements, and Related Mechanism Investigations

The main purposes of this three-year proposal will be focused on the selection of curcumin structural analogs better than the starting material (curcumin) in anti-proliferation and anti-metastasis using human fibrosarcoma HT 1080 cancer cells as models. There are 25 different kinds of curcumin structural analogs used in this study. The selected curcumin analogs will further investigate the possible anti-proliferative and anti-metastatic mechanisms in cells and animal models compared to curcumin. Applicant had found that some amino acid hydroxamates exhibited blood pressure regulatory and anti-metastatic activities which the latter was applied as Taiwan patent (pending). In our preliminary results (please see the proposal section), it was found that (1) several structural analogs had better matrix metalloproteinase inhibitory activities than curcumin under none cytotoxic concentration using gelatin-SDS-PAGE gel assay, and (2) several structural analogs had better cytotoxic activities than curcumin in the same screening concentration using the cell viability assay, and Therefore, the three-year proposal in the screenings of structural analogs better than curcumin will include as follows. In the first year, platforms will be set up to screen and investigate mechanisms of anti-metastasis, including cell viability assay, gelatin-SDS zymography, western blot assay, ELISA assay, and RT-PCR assay to determine the protein and mRNA expressions in MMP-2, MMP-9; wound healing and transwell assays for investigating migration and invasion activity; the use of fibrin-SDS zymography assay to determine the role of uPA (urokinase-type plasminogen activator) in MMP activation; correlations among ROS, HO-1 and MMP activities. In the second year, platforms will be set up to screen and investigate mechanisms of anti-proliferation, including cell cytotoxicity assay, hall marks of apoptosis were examined (including Hoechst 33342 fluorescent dye stains, Annexin-V-FITC fluorescence, Annexin-V-FITC/PI double stains), cell cycle distribution by flow cytometry, changes of mitochondrial membrane potentials, activities and expressions of caspase-3, -8, -9, and related apoptotic proteins in the intrinsic pathway and the extrinsic pathway, roles of ROS in apoptosis. In the third year, the selected candidates of curcumin structural analogs from the first two years will be used in animal models, including (1) the use of nude mice for anticancer and anti-proliferation, and (2) the use of intraperitoneal administration of B16-F10 cells to set up the anti-metastasis in C57BL/6 mice. Several reports concerned that the uses of β-cyclodextrin, or bovine serum albumin to complex with curcumin or the preparation of curcumin nanoemulsions to improve the solubility of curcumin. These modified methods will be used in selected candidates of curcumin analogs and curcumin in above-mentioned two topics in the past two years. These results from curcumin and its structural analogs in this proposal will provide useful data in researches and utilities in caner prevention or cancer treatment.