Injured cancer cells eat their own membranes to survive and spread
Cancer uses all kinds of cunning trickery to thrive in the human body, and scientists in Denmark have just uncovered a new one that tells a familiar but interesting tale of survival. The researchers have found that cancer cells use a technique seen in other cell types that involves patching up injured membranes and consuming the damaged materials, which presents some promising opportunities to intervene and kill them off.
The study was conducted by cancer researchers at the University of Copenhagen, who focused their attention on the membranes that play an important role in containing and protecting the contents of cells, cancerous or otherwise. A rupture to this membrane can cause the fluid inside to escape and cause the cell to die.
When cells incur these types of injuries to their membranes, one of the techniques they use to repair the damage is what's known as macropinocytosis. This sees the cells cover the damaged area with an intact section of membrane, sealing away the hole in mere minutes. The damaged section of the membrane is then busted apart into small spheres that are passed along to the cell's lysosomes, which act as the "stomach" to break them down.
This had never been observed in cancer cells before. The researchers were studying cancer cells in the lab, and blasted them with a laser to shoot small holes in their membranes. The team indeed found that this triggered macropinocytosis, and also discovered that they could interfere in the process with substances that block the formation of the small spheres. This prevents the digestion process, stops the cancer cells from repairing themselves and causes them to die.
"Our research provides very basic knowledge about how cancer cells survive," says group leader Jesper Nylandsted. "In our experiments, we have also shown that cancer cells die if the process is inhibited, and this points towards macropinocytosis as a target for future treatment. It is a long-term perspective, but it is interesting."
The results also suggest that more aggressive cancer cells that tend to spread through the body might lean more heavily on macropinocytosis, owing to the fact that they typically incur more damage to their membranes as they move through tissues. This would therefore provide them with plenty of damaged materials for recycling and the energy they need to rapidly divide.
"We continue to work and investigate how cancer cells protect their membranes," says study author Stine Lauritzen Sønder. "In connection with macropinocytosis in particular, it is also interesting to see what happens after the membrane is closed. We believe that the first patching is a bit rough and that a more thorough repair of the membrane is needed afterwards. It can be another weak point in the cancer cells, and is something we want to examine closer."
The research was published in the journal Science Advances.
Source: University of Copenhagen