Using Heat-Seeking Bubbles To Destroy Cancer

A cancer cell dying. Credit: Dr. Raowf Guirguis. National Cancer Institute

We have plenty of chemicals that can kill cancer cells, but they often hit healthy ones too. The search has therefore been on for a targeted approach, that delivers a fatal payload to tumours without harming surrounding tissue. 

Enter liposomes

Liposomes can deliver lots of different types of molecules, including drugs and DNA. They can also be used for gene therapy.

Liposomes are essentially bubbles, encoated in a layer of lipids. Our cells are similar in structure, so liposomes can do a great job of delivering material inside cells that doesn’t normally enter.  Combined with a targeting molecule on the outer coating, the fatty bubble can merge with a cell membrane and push its contents into the host. 

Revamping cancer therapy

Researchers at Manchester University have now honed these liposome structures to inject chemotherapy drugs directly into tumours, and sparing other tissue. Chemotherapy is really good at fighting cancer, but it causes large scale damage to other organs too. By delivering it specifically to cancer cells, there’s less collateral damage along the way. 

“These liposomes could be an effective way of targeting treatment towards cancer cells while leaving healthy cells unharmed”

Heat activated

We’ve had liposomal technology for a while now, but the real challenge is making it specific. This time the research team added a novel approach – attaching a heat responsive element. This requires heating up a tumour to 42 degrees with a probe, ultrasound or a heat pad to differentiate them. These deadly spheres then travel through the body until they reach a hotspot and ‘explode’ – hitting the tumours with toxic drugs. 

“Once they reach a ‘hotspot’ of warmed-up cancer cells, the pin is effectively pulled and the drugs are released. This allows us to more effectively transport drugs to tumours, and should reduce collateral damage to healthy cells”

The main challenges has been developing the heat responsive element, so that it doesn’t ‘leak’ at 37 degrees (the body’s normal temperature). These liposomes remain intact below 42 degrees, but begin to break apart at higher temperatures. In early trials on melanone in mice results are looking positive, but the technology is still in its early days. The hope is that with more refinement, it could be a relatively simple way to destroy tumours that aren’t surgically possible to remove; as well as having potentially fewer side effects.

Read more at The Telegraph