Two-stage nanoparticle smart bomb targets lung, breast cancer cells

An international team made up of U.S. and Chinese scientists has developed a two-stage nanoparticle delivery system that has successfully targeted drug-resistant lung and breast cancer in mice. 

Nanoparticle delivery systems have been tested in a variety of ways in recent years, but this new study took a two-prong approach which begins by encapsulating the chemotherapy cisplatin inside relatively large particles 100 nanometers wide to gain entry to tumors through leaky blood vessels. Once inside the tumors' acidic microenvironment, the bigger nanoparticles explode into tiny packages of cisplatin which are then activated by a second chemical process, damaging DNA and killing cancer cells. The work was published in the Proceedings of the National Academy of Sciences.

"The negative side effects of cisplatin are a long-standing limitation for conventional chemotherapy," says Jinzhi Du. "In our study, the delivery system was able to improve tumor penetration to reach more cancer cells, as well as release the drugs specifically inside cancer cells through their size-transition property."

In mouse models for lung cancer, a regular dose of cisplatin provided a small, 10% growth inhibition. The same dose delivered in their nanoparticles spurred 95% growth inhibition, the researchers report. And this new approach promises to help spare healthy tissue from the damaging effects of chemo.

In the metastatic breast cancer model, 50% of the mice were alive at 54 days with the nanoparticles, compared with 37 days for a regular dose of the chemotherapy. And the same technology could be used against other cancer targets as well.

The scientific team was led by professor Jun Wang at the University of Science and Technology of China and professor Shuming Nie in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory.

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