This process is called macropinocytosis and it consists of the cancer cells pulling the intact cell membrane in over the damaged area and sealing the hole. The damaged part of the cell membrane is then separated into small spheres and transported to the cells' 'stomach' (the lysosomes). Once, there these damaged parts are broken down and essentially digested by the lysosomes.
"Our research provides very basic knowledge about how cancer cells survive. 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," said in a statement group leader Jesper Nylandsted from the Danish Cancer Society's Research Center and the University of Copenhagen, who has headed the new research and who for many years has investigated how cancer cells repair their membranes.
To study macropinocytosis, the researchers used a laser to damage the membrane of the cancer cells. They further found that if macropinocytosis was inhibited with substances blocking the formation of the small membrane spheres, the cancer cells died.
Macropinocytosis is especially useful to aggressive cancer cells partially due to the fact that the cancer cell has the opportunity to reuse the damaged membrane when it is degraded in the lysosomes. Aggressive cancer cells divide frequently, requiring large amounts of energy and material for the new cells, and macropinocytosis allows them to feed themselves the energy they need to keep on living.
"We continue to work and investigate how cancer cells protect their membranes. 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 afterward. It can be another weak point in the cancer cells, and is something we want to examine closer," said postdoc Stine Lauritzen Sønder.
The study is published in the journal Science Advances.