By Yun Xie | Published: July 10, 2008 - 09:34AM CT
Cancer metastasis, the spread of cancer cells from their origin to other parts of the body, is often deadly and makes treatments more difficult, as simply removing the primary tumor is often not enough because the cancer cells have circulated to other parts of the body. Metastasis isn't the only problem; surgical procedures can also leave some cells behind, and cancer cells may develop resistance to chemotherapy. All of these issues allow tumors to grow again and increase cancer fatalities. A method of extracting residual and metastatic cancer cells could dramatically improve the long-term survival rate of patients.
Since magnets can function through intervening space and material, magnetic nanoparticles may be the solution to capturing cancer cells. Researchers at the Georgia Institute of Technology investigated the biomedical potential of magnetic nanoparticles for treating ovarian cancer and published their results in July in the Journal of the American Chemical Society.
The new therapeutic approach involves biologically modifying CoFe2O4 (cobalt spinel ferrite) nanoparticles. CoFe2O4 has been used before for hyperthermia cancer treatment studies, and it responds well to magnetic fields at body temperature. To prevent an immune response, CoFe2O4 nanoparticles are layered with polygalacturonic acid, which forms a biocompatible coating. A specific polypeptide, a sequence of amino acids that binds to ovarian cancer cells, was added to the CoFe2O4 nanoparticles to ensure selectivity in targeting cells for extraction.
Image Credit: ACS © The American Chemical Society.
To test the efficacy of these modified nanoparticles, the researchers injected ovarian cancer cells into the abdominal cavities of mice. Then, they injected the mice with the magnetic nanoparticles and allowed the nanoparticles to bind to the cancer cells. By using an external magnet (2600 Gauss), the cancer cells could be moved to different locations in the abdominal cavity. Furthermore, when the researchers extracted and magnetically filtered fluids from the abdominal cavity, they found that the nanoparticles selectively targeted ovarian cancer cells.
These results show that magnetic nanoparticles are capable of capturing and removing cancer cells from a live animal, a trick that may nicely complement their ability to deliver drugs to those same cells. Besides ovarian cancer, the nanoparticles can be modified by different types of polypeptides to target a variety of cancers. This approach, when combined with surgery and chemotherapy, has the potential of saving more patients
J. Am. Chem. Soc., 2008. DOI: 10.1021/ja801969b