Cancer is formed when a cell mutates and develops the ability to grow uncontrollably. This uncontrollable growth means that cancer cells are energy hogs, they require copious amounts of fuel to drive their growth and movement. Many chemotherapeutics target the food supplies of cancer cells in an effort to starve them. Typically, nutrients are provided to cancer cells through blood vessels that supply the tumour. However, a recent research paper from scientists in Norway has identified a new, more subtle way that cancer cells can get the nutrients they need to grow. The cancer cells were seen tricking their neighbouring non-cancer cells to give up some of their food.
Using fruit flies, the researchers found that a cellular process known as autophagy supplies the cancer cells with this sneaky source of food. Autophagy is the cells recycling process, this process takes damaged or unused proteins and breaks them down into their basic units, amino acids. These amino acids can then be used by the cell to make new proteins for different purposes. This process is similar to how we recycle paper and plastics into new products by breaking them down to their starting materials. Autophagy is normally triggered in cells that are under stress or are short on nutrients. It is thought that the process of autophagy may help prevent age related damage to cells. In this study, the researchers saw that cancer cells secreted molecules that tricked near by cells to start autophagy and then spit out their amino acids for the cancer cell to suck up. When the researchers stopped autophagy in the neighbouring cells, the tumour started to shrink. If they turned it back on, the tumour began to grow again. Similarly, if the researchers stopped the tumour cells from sucking up the amino acids from their environment, the tumour cells began to shrink.
This work was done in house flies because they provide an easy way to manipulate the different cells. Rest assured, this process has also been seen in human cells and acts in a very similar manner. This means that we can be relatively confidents that the process of exploiting neighbouring cells for resources happens in human cancers. We don’t yet know if it happens in all cancers though. Ideally, blocking autophagy in the area surrounding the tumour will be able to prevent its growth and may help treat cancer. Realistically, autophagy is a relatively new area of interest in science and we don’t yet know what negative consequences would occur if we stopped autophagy in the human body. Some research suggests that a loss of autophagy in the brain can lead to Parkinson’s and other neurodegenerative diseases. Much more work is necessary to understand how this may be useful in our fight against cancer. However, this researcher highlights the importance of basic, fundamental research to help us understand disease processes and effectively treat disease.
Image Creit: Flickr Penn State