Researchers involved in a national effort to develop cancer treatments that harness nanotechnology are recommending pivotal changes in the field because experiments with laboratory animals and efforts based on current assumptions about drug delivery have largely failed to translate into successful clinical results.
The assessment was advanced in a perspective piece that appeared in the National Cancer Institute's "Cancer Nanotechnology Plan 2015", a 10-year roadmap concerning the use of nanotechnology to attack cancer.
Researchers are trying to perfect "targeted delivery" methods using various agents, including an assortment of tiny nanometer-size structures, to selectively attack tumor tissue. However, the current direction of research has brought only limited progress, according to the authors of the article.
One approach pursued by researchers has been to design nanoparticles small enough to pass through pores in blood vessels surrounding tumors but too large to pass though the pores of vessels in healthy tissue. The endothelial cells that make up healthy blood vessels are well organized with tight junctions between them. However, the endothelial cells in blood vessels around tumors are irregular and misshapen, with loose gaps between the cells.
"We should realize that having a specific nanosize or functionality alone is not enough to guarantee good drug delivery to target tumors," said Kinam Park, a professor of pharmaceutics and Purdue's Showalter Distinguished Professor of Biomedical Engineering. "The tumor microenvironment is just too complex to overcome using this strategy alone."
No comments:
Post a Comment