A breakthrough in targeted cancer treatment

We've recently covered some interesting advances in cancer treatment that have called on the big promises of tiny nanoparticles to more narrowly target powerful chemotherapy drugs.

Now, in a fascinating advance in targeted drug therapy, a team of researchers at the Massachusetts Institute of Technology have demonstrated another extremely effective way of delivering cancer treatment, at least in a mouse model. (The director of the NIH recently announced that improvements in drug delivery are among his top 5 priorities.)

Immune cell therapies are being developed as a new approach to cancer treatment. The traditional approach has been to withdraw T-cells (a type of immune cell that hunts and destroys cancer cells) from a patient, tune them up so they target a specific type of tumor before re-injecting them back into the patient. The trouble with this approach is that it takes a lot of T-cells to effectively conquer cancer. So researchers have tried to boost T-cell formation with a class of drugs called interleukins. The problem with those drugs is that they are toxic in large doses.

The MIT researchers have combined these two approaches in a novel way. First, they created microscopic pockets out of fatty membranes that attach to the sides of the T-cells. Then they loaded the pockets with interleukin drugs, and injected them into their test subjects (mice suffering from lung and bone-marrow tumors.) Over the following weeks, the pockets degraded and released their immune-boosting drugs. Within 16 days, tumors disappeared in mice treated this way, and they all the lived till the end of the 100-day study period. Sick mice that received no treatment died within 25 days, and those that received just T-cells, or T-cells plus traditional drug injections died within 75 days.

The researchers are also investigating their technique as a means for refining the delivery of drugs that piggy-back on nanoparticles. "The vast majority of nanoparticles injected intravenously go into the liver or spleen," says Darrell Irvine of the MIT team, "less than 5 percent reach the tumor." If nano-delivered chemotherapy drugs could ride on T-cells engineered to search and destroy cancer cells, many more would reach their intended targets. See the August 15 issue of Nature Medicine for the research by Irvine and his colleagues.

Also see our recent story about the use of nanoparticles to fight the antibiotic-resistant infection MRSA.

Photo credit: The author