Over the past several decades lots of different treatments have been developed to fight against cancer. For a long time these treatments focused on making drugs that are very good at killing cancer cells. The problem with these drugs was that they had no way of telling the difference between healthy cells and cancer cells. This meant that they would also kill healthy cells, which led to severe side effects for the patients. Now scientists are focusing on how to deliver these drugs to only the cancer cells and not healthy cells. This should reduce the number of side effects of anti-cancer treatments and improve its effectiveness.
Targeting Cancer Cells
If we want to make drugs that only attack cancer cells we need to find some marker that helps us tell the difference between healthy cells and cancer cells. This isn’t always straight forward since for a number of reasons. Firstly cancer cells were once normal cells, which means they share a lot of similarities with healthy cells. Secondly cancer cells actively try to hide any differences so that the bodies immune system doesn’t attack them. Finally all cancers are unique meaning that if we find a marker on one type of cancer, it might not exist on another type.
Luckily scientists have found one difference that is very common. Lots of cancers like to travel around the body. To do this they have to make lots of a protein called CD44, which helps pull the cells around the body. Importantly it does this by grabbing on to a sugar called hyaluronan, which can be found all over the body.
This week a research group in Shanghai, China published a study in which they made so-called hyaluronan nanoparticles to tackle cancer. The paper can be found here.
They started with a drug made from a metal called iridium. This drug, like other cancer drugs, is very good at killing cancer cells, but it also damages healthy cells. Then they found a way to attach it to hyaluronan so that it formed a ball with the drug on the inside and the hyaluronan on the outside. They also equipped it with a trigger so that the particle could fall apart and release the drug once inside the cancer cell.
The idea then is as follows. The toxic iridium drug is wrapped up inside a ball of hyaluronan so that it cannot do any damage to the body. If the ball comes into contact with a cancer cell, the CD44 will grab the ball and pull it into the cancer cell. Once inside the ball will fall apart, releasing the drug and killing the cancer cell.
Most importantly the scientists managed to show that it really works. In their experiment, they treated an fast growing tumour with the hyaluronan nanoparticles. Their results showed that the treatment was able to stop the growth of this tumour completely. They also showed that the treatment did almost no damage to healthy cells. This is a big step forward for cancer treatment and with every step cancer is becoming more and more survivable.