Aug 17, 2012 |
Gold nanorods hitch ride on immune cells that target breast tumors
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(Nanowerk News) One of the challenges in treating cancer, whether using nanotechnology or not, is that tumors can often be inaccessible to the therapies designed to kill them. Mostafa El-Sayed, of the Georgia Institute of Technology, and his colleagues are attempting to overcome this obstacle by designing drug-loaded gold nanorods that attract the attention of tumor-associated immune cells known as macrophages. The researchers believe that these macrophages will then deliver the nanorods to the tumors, crossing the normally impermeable blood-brain barrier to do so.
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Dr. El-Sayed, who is a co-principal investigator of a Cancer Nanotechnology Platform Partnership held jointly by Georgia Tech and Emory University, and his colleagues have synthesized gold nanorods that target tumor-associated macrophages. The investigators have published the initial results of their work in the journal Small ("Small Molecule–Gold Nanorod Conjugates Selectively Target and Induce Macrophage Cytotoxicity towards Breast Cancer Cells").
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To attract the attention of tumor-associated macrophages, Dr. El-Sayed’s team coated them with an antibiotic belonging to a family of molecules called macrolides. These broad-spectrum antibiotics are known to accumulate at very high concentrations inside macrophages. Therefore, when macrolide-coated nanorods were added to macrophages growing in culture along with breast tumor cells, the macrophages quickly took up the nanorods. When the investigators then irradiated the nanorod-loaded macrophages with light from a near-infrared laser, they found that the co-cultured breast tumor cells, which were not directly exposed to the nanorods, were killed. The researchers hypothesize that the light-activated gold nanorods enhanced the innate tumor-killing activity of the macrophages.
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The investigators note that “the ability of tumor-associated macrophages to migrate freely in circulation, bypass the blood–brain barrier, and preferentially accumulate and infiltrate into solid tumors make macrolide-functionalized gold nanoparticles promising candidates for targeted cancer drug delivery to breast and brain tumors.” They also hypothesize that this type of therapy could operate synergistically with conventional chemotherapy.
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