Duke researchers fight cancer with nanoparticles

Duke scientists have discovered a breakthrough method of delivering cancer drugs that drastically improves their efficiency.

This summer, a team led by Ashutosh Chilkoti—Theo Pilkington professor of biomedical engineering and chair of the biomedical engineering department—published a study describing the new technique, in which nanoparticles are modified to package and deliver a common chemotherapy drug called paclitaxel. Although nanoparticles have been used before in treating cancer, the Chilkoti group, which studies biomolecular materials, devised a system that allows the drug to reach and destroy tumors nearly twice as effectively as current methods approved by the Food and Drug Administration. The success of the new nanoparticle packaging system has been demonstrated in mice, and the team is also focused on adapting their discovery to other chemotherapy treatments and other cancers.

“We have demonstrated this platform for only one drug, but this is not only true for one—you can use it for any drug,” said Jayanta Bhattacharyya, senior research scientist and lead author of the recently published study. “This is actually a robust technology for using different kinds of chemotherapy drugs.”

The project launched three and a half years ago, when the group of researchers realized that the current nanoparticle packaging system used for delivering cancer-fighting drugs was not as efficient or safe as it could be.

“The main problem of cancer chemotherapy drugs is that they are not water-soluble. So when you administer them in humans, you have to use some solubilizing agents—which can be very toxic,” Bhattacharyya said.

Current nanoparticle methods that deliver paclitaxel—commonly used to treat ovarian, breast and lung cancers—use foreign and synthetic materials that can be harmful when released in the body. The drug also has problems with dissolving in blood.

To address these common issues, the team was able to link the paclitaxel drug to amino acids, which are essential building blocks of many other molecules in the body. Once released, these new nanoparticles allowed the drug to more effectively move through the bloodstream, and the amino acids did not harm the body in the process.

Bhattacharyya added that another major problem with current chemotherapy drugs is that they are often not tumor-specific and can therefore damage healthy parts of the body.

“If you inject them, there is no guarantee that they will reach the tumor,” he explained. “You are getting less drug in the place you want, but you are getting drugs in all the other healthy organs.”

With this challenge in mind, the scientists engineered the nanoparticles to respond to changes in acidity, causing the drug to only be released and delivered to tumor cells—which are more acidic than normal cells in the body.

In the mice they studied, Chilkoti’s system resulted in much longer survival with both breast and prostate cancer. Some mice even saw complete tumor regression, demonstrating the clinical possibilities of this technology and its effectiveness over current methods.

Although this particular study focused on packaging paclitaxel, Bhattacharyya and the Chilkoti group are now working on applying the packaging system to deliver other chemotherapy drugs. By designing different combinations of drugs and packaging materials, they hope to effectively treat more types of cancer and target specific ones.