Cancer is not only difficult to treat but the patients also suffer from the pain associated with anticancer treatments. Targeted chemotherapeutics can reduce the adverse effects by reducing the dose required for tumor cell kill. Cancers of various origins often have characteristic marker molecules that distinguish them from the normal tissues. Folate receptors are such marker molecules present in ovarian and cervical cancers. The hypothesis for the current study is that amphiphiles constructed out of folic acid, the natural ligand for the folate receptor, can deliver paclitaxel, a chemotherapeutic compound, to folate receptor expressing cancer cells. To test this hypothesis, amphiphilic molecules were synthesized out of folic acid and fatty acids or long chain aliphatic amines. The gamma carboxylic group of folic acid was converted to an N-alkyl substituted amide. The alkyl group had various chain lengths varying from eleven methylene groups to seventeen methylene groups giving rise to a number of amphiphiles. The amphiphiles formed micelles in aqueous solutions. The critical micellization concentrations of the amphiphiles were measured by pyrene fluorescence and were found to be in the range of 10–70μM. HeLa and Caco-2 cells were taken as in vitro tumor models. Folate receptor expression was verified in HeLa and Caco-2 cells by western blot analysis. HeLa showed more than forty fold expression of the receptor when compared to Caco-2 and was chosen as receptor positive cell line while Caco-2 served as a negative control. Uptake of the folate labeled delivery system in the cell lines was tested by a fluorescent probe (aminocoumarin) labeled amphiphile. To test the specificity of the delivery system towards the receptor positive HeLa cells, the receptors were knocked down (70%) by folate receptor specific siRNA. Fluorescent amphiphile uptake in the knockdown cells was comparable to that of the negative control, Caco-2. Finally cytotoxicity studies were performed for paclitaxel formulated with the folate labeled amphiphiles and compared to free drug treatment in HeLa and Caco-2. IC50 values in HeLa for formulations with the folate labeled amphiphiles were ten folds less than those observed for free drug treatment whereas in Caco-2 no significant difference was noted.
| Identifer | oai:union.ndltd.org:pacific.edu/oai:scholarlycommons.pacific.edu:uop_etds-3359 |
| Date | 01 January 2008 |
| Creators | Bhattacharya, Shiladitya |
| Publisher | Scholarly Commons |
| Source Sets | University of the Pacific |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | University of the Pacific Theses and Dissertations |
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