Targeting tumors: Researchers develop more precise approach to delivery of chemotherapy drugs

October 12, 2009 by Tom Vasich
Kenneth Longmuir, left, and Richard Robertson inserted the anti-cancer drug doxorubicin into liposomes (orange globules shown in background) and attached a protein that targets only the liver. Image: Daniel A. Anderson

( -- Chemotherapy is one of the most effective ways to fight cancer, but the toxic medicine can cause collateral damage to healthy tissue. UC Irvine's Kenneth Longmuir, physiology & biophysics associate professor, and Richard Robertson, anatomy & neurobiology professor, believe they have developed a way for these drugs to reach specific tumors with increased precision, thereby limiting side effects.

In a study appearing online in the International Journal of Pharmaceutics, the researchers show that doxorubicin — commonly used to treat a number of cancers — can be directed almost entirely to a particular spot in the body with virtually no spread to other organs.

"Although doxorubicin is a potent anti-cancer agent, its usefulness is compromised by its serious side effects on normal tissue," Longmuir says. "When administered in a chemotherapeutic regimen, the drug distributes widely in the body, including the heart, rather than just in tumor regions. This chance of heart damage restricts the amount of doxorubicin that a patient can receive."

He notes that less than a quarter — and in many cases less than 10 percent — of the medicine typically reaches its target. The remainder is dispersed throughout normal organs, resulting in considerable toxicity.

To overcome this, the researchers focused on the fact that all tissue, even a tumor, is surrounded by a dense area of sugar-containing molecules called polysaccharides. The chemical composition of these polysaccharides differs for each type of tissue.

"We knew that if we could find a molecular guide to a specific polysaccharide coating, we could create a highly targeted drug delivery system," Robertson says. "Fortunately, such a guide exists in the malaria microorganism Plasmodium."

Plasmodium has the exceptional ability to only recognize the liver's polysaccharide coating. So Robertson and Longmuir isolated the protein that allows Plasmodium to do this and built a doxorubicin delivery system around it.

They inserted the drug into fatty, tubelike structures called liposomes that are staples of nanomedicine. Then they bonded Plasmodium's targeting protein to these liposome packages, in essence "addressing" them to the liver.

In tests on mice, the research team demonstrated that doxorubicin was conveyed to the liver, and away from the heart, with a specificity rate of more than 99 percent.

The next step is to try the drug transport system in several experimental models, Longmuir says. He and Robertson are developing new liposome packages with targeting proteins that only recognize the unique polysaccharide features of tumors.

"By rapidly and accurately delivering chemotherapeutic agents to tumor regions, treatments can become safer and more effective," Longmuir says. "This promising approach opens up a new avenue to helping people survive cancer."

More information:

Provided by UC Irvine

Related Stories

Recommended for you

One in five young colon cancer patients have genetic link

December 13, 2017
As doctors grapple with increasing rates of colorectal cancers in young people, new research from the University of Michigan may offer some insight into how the disease developed and how to prevent further cancers. Researchers ...

New strategy for unleashing cancer-fighting power of p53 gene

December 13, 2017
Tumor protein p53 is one of the most critical determinants of the fate of cancer cells, as it can determine whether a cell lives or dies in response to stress. In a new study published today in the journal Nature Communications, ...

Researchers develop test that can diagnose two cancer types

December 12, 2017
A blood test using infrared spectroscopy can be used to diagnose two types of cancer, lymphoma and melanoma, according to a study led by Georgia State University.

Cancer-causing mutation suppresses immune system around tumours

December 12, 2017
Mutations in 'Ras' genes, which drive 25% of human cancers by causing tumour cells to grow, multiply and spread, can also protect cancer cells from the immune system, finds a new study from the Francis Crick Institute and ...

Atoh1, a potential Achilles' heel of Sonic Hedgehog medulloblastoma

December 12, 2017
Medulloblastoma is the most common type of solid brain tumor in children. Current treatments offer limited success and may leave patients with severe neurological side effects, including psychiatric disorders, growth retardation ...

MRI scans predict patients' ability to fight the spread of cancer

December 12, 2017
A simple, non-invasive procedure that can indicate how long patients with cancer that has spread to the brain might survive and whether they are likely to respond to immunotherapy has been developed by researchers in Liverpool.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.