Anticancer Nanochains Slow Growth of Triple-Negative Breast Cancer in Rodent Models

Novel nanoparticles comprising a short chain of magnetic particles and a liposome loaded with the drug doxorubicin were dramatically more effective than traditional chemotherapy in treating animal models of triple-negative breast cancer.

Investigators at Case Western Reserve University (Cleveland, OH, USA) were seeking a solution to the uneven distribution of drug-containing nanoparticles that resulted in most tumor cells not being exposed to the toxic agent.

They constructed a new type of “nanochain” from magnetic nanoparticles made of iron oxide that were arranged around a liposome loaded with the anticancer drug doxorubicin. The liposome prevented the drug from entering the blood stream, thereby greatly reducing its toxicity to normal tissues. Toxicity was further reduced by filling the liposomes with a dosage of the drug that was only 5% to 10% of the dose of doxorubicin used in standard chemotherapy. When the liposomes reached the target tumor, the magnetic nanoparticle chains were stimulated by an electric field that caused them to vibrate and disrupt the liposomal membrane, which dumped the toxic contents of the liposomes directly into the tumor.

Nanochains were injected into both rat and mouse models of triple-negative breast cancer. Results published in the April 9, 2012, online edition of the journal ACS Nano revealed that the nanoparticles displayed prolonged blood circulation and significant deposition into the tumors growing in the rodent. Tumor growth in rats following nanochain treatment was less than half that of rats treated traditionally. In rats that received two doses of nanochains, tumor growth was reduced to one-tenth that of rats treated traditionally. Rats that received one treatment survived an average of 25 days and those treated twice, 46 days, compared to 15 days for traditionally treated rats. In mice, nanochain treatment caused nearly a 4-fold increase in cancer cell apoptosis as compared to traditional chemotherapy.

“Other nanotechnology has been used to get a drug inside a tumor, but once the drug gets in the door, it stays by the door, missing most of the building,” said senior author Dr. Efstathios Karathanasis, professor of biomedical engineering at Case Western Reserve University. “We used a different kind of nanotechnology to smuggle the drug inside the tumor and to explode the bomb, releasing the drug in its free form to spread throughout the entire tumor.”

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