New Nano Drug Delivery System Eliminates Tumors after Single Treatment

Bioengineers at Duke University have created a way to load cancer drugs into nano-scale delivery modules for targeted delivery to tumors. Their research shows the possibility of destroying tumors in only one treatment. The method is inexpensive and simple. Once the delivery of the drug to the tumor is complete the delivery module dissolves harmlessly in the body.

There have been several breakthroughs reported recently using nanotechnology for more effective drug delivery. Research using nano size systems is making headway due to the ability to more specifically target tumors and other diseased tissue. With cancer treatment, the small size allows delivery systems to move through blood vessels in tumors as they are more porous than normal blood vessels, allowing for higher doses of a drug to be delivered, with fewer side effects than from chemotherapy.

This latest research from Duke involved the use of doxorubicin, used frequently in treating cancers of the blood, ovaries, breast, and other organs. Mice were injected with tumors implanted under their skin with either a chimeric polypeptide-doxorubicin combination or doxorubicin by itself. Those treated with only doxorubicin had an average tumor size 25 times greater than those treated with the new combination. The mice treated with the new formation had an average survival time of 66 days compared to the doxorubicin-treated mice of only 27 days.

Researchers reported that the dose of anti-cancer drugs could be increased four times beyond what would be previously tolerated as blood vessels in tumors are more porous allowing for the drugs to reach their intended target of tumor cells. Without the nano delivery system the drugs tested had only a nominal effect on shrinking of tumors.

Scientists expect their findings will improve the effectiveness of other existing cancer drugs as well, but further testing is needed. Not only did their findings show clear improvement in treatment, but they also created a unique way of creating the drug. They can produce large quantities of the formulation simply and inexpensively.

An important part of the new method of delivery is how the drug is attached to its polypeptide delivery system and whether or not a drug can be dissolved in water.

The delivery system uses the bacterium E. coli, which has been genetically altered to produce a specific artificial polypeptide known as a chimeric polypeptide. Protein production commonly uses E. coli as it is a simple and reliable manufacturing vessel for producing these specific polypeptides with high yield. By attaching the drug to the chimeric polypeptides it takes on new characteristics not currently held and makes the drug water soluble. This is important in that most drugs, particularly chemotherapeutic drugs, do not dissolve in water, which limits their ability to be assimilated by cells. The new procedure brings the size to 50 nanometers, which is perfect for cancer therapy according to scientists.

Additional research is planned by Duke researchers who expect to test the new combination on different types of cancers, as well as tumors growing within different organs. They will also try combining these chimeric polypeptides with other insoluble drugs and test their effectiveness against tumors.

The results of the study were published in the journal Nature Materials. Research was supported by the National Institutes of Health.