Scientists try to hit cancer with heat-triggered drug delivery

The method worked with mice in the lab, however the researchers said ideal methods for heating liposomes to deliver drugs are still being sought.

By Stephen Feller

MANCHESTER, England, Nov. 2 (UPI) -- Scientists at the University of Manchester created the equivalent of anti-cancer grenades using liposomes to deliver drugs to cancer cells when their temperature is slightly increased.

The method may allow doctors to load their "cancer drug of choice" into the bubble-like structures and "pull the pin" on the drug grenades when they reach tumors in the body using heating methods already in clinical use.


Two studies describing the design of heat-activated liposomes and their testing in the lab with mice are being presented at the National Cancer Research Institute's 2015 conference in London.

"These studies demonstrate for the first time how they can be built to include a temperature control, which could open up a range of new treatment avenues," Dr. Charles Swanton, chair of the conference, said in a press release. "This is still early work but these liposomes could be an effective way of targeting treatment towards cancer cells while leaving healthy cells unharmed."

Scientists started by creating liposomes -- spheres created from cell membranes used to deliver nutrients or drugs to cells in the body -- that, after entering a cell, explode when heated to 42 degrees Celsius.


In the first study, researchers tested delivering the liposomes to human melanoma cells grafted to mice. They found the liposomes remained stable in the body and delivering the drugs with heat had a moderate effect on the rodent's survival.

The second study, using mice that had human colorectal cancer cells grafted onto their bodies, tested the difference between two methods of heating liposomes. Both heating options were shown to be effective, which the scientists said could allow for doctors to have options, and growth of tumors in the mice was slowed compared to mice in a control group.

While the research was somewhat successful in the lab, Kostas Kostarelos, a professor at the University of Manchester, said the work is still early because more needs to be done to find more precise methods of heating liposomes and cause them to release their payloads.

"The difficulty is, how do you release them when they reach their target?" Kostarelos, told the BBC. "The challenge for us is to try to develop liposomes in such a way that they will be very stable at 37 degrees [Celsius, the normal temperature of the human body] and not leak any cancer drug molecules and then abruptly release them at 42 degrees."


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