'Smart bomb' nanoparticle strategy impacts metastasis

The study is an example of an initiative that joins researchers from UC San Diego's Health Sciences and the Jacobs School of Engineering to improve health care through innovative technologies. Engineers and oncologists working together designed a nanoparticle – a microscopic-sized particle of 100 nanometers, made of various lipid-based polymers – which delivers the cancer cell-killing drug doxorubicin to the network of blood vessels supporting the tumor that express the ανβ3 protein.

"Doxorubicin is known to be an effective anti-cancer drug, but has been difficult to give patients an adequate dose without negative side effects," Cheresh said. "This new strategy represents the first time we've seen such an impact on metastatic growth, and it was accomplished without the collateral damage of weight loss or other outward signs of toxicity in the patient."

Cancer metastasis is traditionally much more difficult to treat than the primary tumor, and is what usually leads to the patient's death. Because metastasis is more reliant on new blood vessel growth, or angiogenesis, than established tumors are, Cheresh theorized that targeting the anti-cancer drug to the sites of new blood vessel growth has a preferential effect on metastatic lesions.

"Traditional cancer therapies are often limited, or non-effective over time because the toxic side effects limit the dose we can safely deliver to the patient," said Cheresh. "This new drug delivery system offers an important advance in treating metastatic disease."

Additional contributors to the study were Eric A. Murphy, Bharat K. Majeti, Leo A. Barnes, Milan Makale, Sara M. Weis and Wolfgang Wrasidlo, all of the Department of Pathology and Moores UCSD Cancer Center. The study was supported by the National Institutes of Health and the National Cancer Institute Nanotechnology Alliance.