March 20, 2006
Targeted Magnetic Nanoparticles Accumulate in Breast Tumors and Metastases
Magnetic iron oxide nanoparticles are among the most promising nanomaterials being developed as targeted imaging and therapeutic agents for use in detecting and treating cancer. Little is known, however, about how these nanoparticles interact with cancer cells in a living animal, so a team of investigators decided to remedy that knowledge deficit. The results of their work has been published in the journal Biomaterials.
A team led by Winston Soboyejo, Ph.D., of Princeton University and Carola Leuschner, Ph.D., at the Pennington Biomedical Research Center in Baton Rouge, LA, used magnetic iron oxide particles coated with luteinizing hormone releasing hormone (LHRH), a peptide that binds to a receptor found on most breast cancer cells. Earlier work by Leuschner and Soboyejo’s team had shown that this nanoparticle will target breast tumors and metastatic lesions in the lung.
After determining that these nanoparticles did not aggregate under physiological conditions – aggregation would prevent cells from taking up the nanoparticles – the investigators injected the LHRH-labeled nanoparticles into mice with implanted breast cancer tumors. Twenty hours later, close to 60 percent of the injected nanoparticles had accumulated in the primary tumor and another 20 percent had accumulated within metastatic lesions in the animals’ lungs. In contrast, only 9 percent of a similar nanoparticle lacking the LHRH targeting agent had accumulated in tumors over the same time period.
Closer examination of individual cells showed that the nanoparticles had accumulated inside cells, where at least some of the nanoparticles formed clusters. The researchers also detected nanoparticles in the cell nucleus, suggesting that these nanoparticles could serve as a tool for delivering anticancer genes and anticancer agents that interact with a tumor cell’s genes into a cancer cell’s nucleus.
This work is detailed in a paper titled, “Sub-cellular accumulation of magnetic nanoparticles in breast tumors and metastases.” Investigators from the Louisiana State University in Baton Rouge, LA, and the Lawrence Livermore National Laboratory, in Livermore, CA, also participated in this study. An abstract of this paper is available through PubMed.