In new variation of ways to use nanotech to treat cancer, scientists have shown that using a scorpion toxin to target nanoparticles to brain cancer cells depletes the amount on the cancer cell surface of a protein required to make the cells invasive. From the National Cancer Institute’s Alliance for Nanotechnology in Cancer “Toxin-nanoparticle combo inhibits brain cancer invasion while imaging tumors“:
Working with a nanoparticle designed to target and image glioblastoma, a form of brain cancer, investigators at the University of Washington in Seattle have found that these same nanoparticles inhibit tumor cell invasion, one of the key events that leads to the metastatic spread of cancer. The investigators have also determined how the nanoparticles exert this potentially beneficial effect.
Miqin Zhang, Ph.D., principal investigator of the Nanotechnology Platform for Pediatric Brain Cancer Imaging and Therapy project, and her colleagues had shown previously … that chlorotoxin, a small peptide toxin produced by the death stalker scorpion, is highly effective as a tumor-targeting agent when chemically linked to a variety of nanoparticles. In this work, whose results appear in the journal Small [abstract], Dr. Zhang’s team linked chlorotoxin to magnetic iron oxide nanoparticles, which can act as tumor imaging agents in conjunction with magnetic resonance imaging (MRI).
When added to glioblastoma cells growing in culture, the chlorotoxin-targeted nanoparticles were rapidly taken up by the tumor cells. This internalization occurs when chlorotoxin binds to a surface protein known as MMP-2 that is overexpressed by many highly invasive tumors, including glioblastoma. As a consequence of nanoparticle binding and internalization, the amount of MMP-2 remaining on the surface of the tumor cells drops significantly, which greatly reduces the invasive properties of the treated cells.
Quantifying this effect, the investigators showed that the nanoparticle produced a 98% inhibition of cell invasiveness. By way of comparison, invasiveness fell by less than 50% when cells were treated with chlorotoxin alone.
—Jim
