Targeted delivery of drugs to specific regions of the body, or even to specific regions of the cell, promises enhanced drug efficacy and reduced systemic toxicity. By covalently coupling targeting ligands, the smart drug delivery systems are capable of targeting specific cell types exclusively through ligand-receptor interactions. The main goal of the project is to create a polymeric nanoparticle drug delivery system from synthesized biodegradable polymers and modify the polymeric nanoparticles using targeting antibodies for targeted delivery of anticancer drugs.
A new biodegradable copolymer poly(2-methyl, 2-carboxy trimethylene carbonate-co-D,L-lactide)-graft-poly(ethylene glycol)-furan (poly(TMCC-co-LA)-g-PEG-furan) was synthesized and characterized. The copolymers self-assembled into spherical nanoparticles in aqueous environments with the hydrodynamic diameters controlled over a broad size range. Immuno-polymeric nanoparticles were created by coupling maleimide-modified anti-human epidermal growth factor receptor 2 (anti-HER2) antibodies to the self-assembled nanoparticles through Diels-Alder (DA) chemistry. This new coupling methodology was demonstrated to be relatively rapid, highly efficient and specific under mild conditions. In vitro studies showed that the immuno-nanoparticles bound specifically and efficiently with SKBR3 breast cancer cells that overexpress HER2 receptors.
Anticancer drugs were incorporated into the immuno-nanoparticle system and the drug delivery via an antibody-mediated targeting mechanism was investigated in vitro. First, a protein anticancer drug, interleukin-2 (IL-2), was physically encapsulated through polymer-drug association. The IL-2 encapsulated anti-HER2 immuno-nanoparticles exhibited a cell-binding associated IL-2 release in the extracellular space upon binding with HER2-overexpressing SKBR3 breast cancer cells. Second, a small molecule hydrophobic drug, doxorubicin (DOX), was chemically conjugated on the nanoparticle surface after the antibody coupling, using the same DA chemistry. The novel formulation localized DOX in the cell nucleus of HER2-overexpressing SKBR3 breast cancer cells and remained the biological function of conjugated DOX. Compared to the nanoparticles bearing DOX or anti-HER2 antibody alone, the nanoparticles having a combination of DOX and anti-HER2 antibody exhibited the most significant cytotoxicity and specificity against SKBR3 cells relative to healthy HMEC-1 endothelial cells, demonstrating the potential of the DOX-immuno-nanoparticles as a novel platform for intracellular DOX delivery.
This work provides a novel means for the delivery of combination immunotherapy/chemotherapy to more effectively treat certain malignancies.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/17245 |
| Date | 26 February 2009 |
| Creators | Shi, Meng |
| Contributors | Shoichet, Molly |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
| Format | 8627399 bytes, application/pdf |
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