( ner Ph.D. at the Pennington Biomedica...)Nanoparticles, nanoshells, nanotubes: How tiny specks may provide powerful tools against cancer

They took advantage of the abundance of receptors for luteinizing hormone releasing hormone (LHRH) on breast cancer cell surfaces and created a molecular complex, combining LHRH with a 10 nm nanoparticle ?superparamagnetic ironoxide ?and a cell-killing peptide drug, Hecate.

Leuschner and her co-workers tested two different versions of the complex to see which might be the best way to treat and image tumors and metastases in breast cancer. In one version, the nanoparticle's surface was covered with alternating "sun rays" of LHRH and Hecate. In the other, the nanoparticle was bound directly to LHRH-Hecate.

They first tested the two versions in the laboratory dish in two different breast cancer cell lines and in a mouse cell control. In a proof of concept study, they found evidence that the alternating LHRH and lytic peptide on the ironoxide particle was effective at killing cancer cells, suggesting that the cell-killing peptide worked best when it came in direct contact with the cell membrane. "It is possible that if the lytic peptide has no interaction with the membrane it is targeting, it cannot kill," Leuschner says.

The research group next looked at nude mice ?mice lacking immune systems ?that carried xenografts of human breast cancer. In another proof-of-concept study, they found that if a nanoparticle-Hecate combination is injected the drug can't kill the tumor cells because it essentially couldn't find them. When LHRH is injected prior to the three-headed combination or the LHRH-drug combination, the LHRH receptors on the tumor cells were blocked. These findings suggest a receptor-mediated process.

"The take home message is that you need to have a targeted entity to kill the
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Source:American Association for Cancer Research