Delivery Systems For Drug And Gene Therapy

Delivery systems for drug and gene therapy are particularly attractive targets in uro-logical practice.

Novel drug delivery for prostate cancer using ceramic nanoparticles, carbon magnetic nanoparticles, protospheres and nanogold particles has been investigated in prostate cancer. Paclitaxel loaded biodegradable nanoparticles have been shown to be effective inhibitors of human prostate cancer cell lines in a murine model (4). In addition, enhanced cellular uptake of a triplex-forming oligonucleotide by nanoparticle formation in the presence of polypropylenimine dendrimers has also been found in metatstatic prostate cancer cell lines, indicating their potential use for delivering therapeutic oligonucleotides in cancer cells in vivo (5). Furthermore, Thomas et al. (6) have shown in vitro targeting of synthesized antibody against prostate-specific membrane antigen with conjugated dendrimer nanoparticles as a suitable platform for targeted molecule delivery into appropriate antigen-expressing cells. Studies investigating gene therapy in prostate cancer, have also shown enhanced in vitro DNA transfection efficiency by novel folate-linked nanoparticles (7), and similarly a human transferrin-targeted cationic liposome-DNA complex, Transferrin-lipoplex, has shown enhanced stability, improved in vivo gene transfer efficiency, and long-term efficacy for systemic p53 gene therapy when used in combination with conventional radiotherapy (8). Anderson et al. (9) have recently demonstrated that a polymer, termed C32, is capable of delivering genes to cancer cells more efficiently and with less toxicity than other polymers that have been tested in the field to date. Therapeutic genes delivered to cells in this manner are able to drive cellular production of a gene-encoded protein through normal processes. By genetically engineering the normal diphtheria toxin gene, a toxin was created that would be produced only in prostate cells. When injected into prostate tumors in animals with C32 nanoparticles, tumour growth was suppressed or reversed, relative to untreated tumors. Research is also being carried out to explore whether nanoparticles can be delivered intravenously to attack metastatic tumor cells, which are found throughout the body in advanced stages of cancer (10).

With the obvious financial potential of a drug delivery system, this particular aspect of nanotechnology is receiving considerable attraction from the commercial sector, specifically the pharmaceutical industry.

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