Macropinocytosis is a cellular process that occurs in cancer cells. Even though this process may help cancer as it spreads through the body, new research also gives hope for treatment.

What is Macropinocytosis?

All cells, including cancer cells, have a membrane that serves as a protective layer. The membrane has to be intact because the cell is full of fluid. However, if damage does occur, the entire cell will die unless it can sanction the damaged and restore the membrane.

There are several processes that cells use to repair themselves. Macropinocytosis is just one of them, and it occurs in other cell types. The recently published study done by a research team from Denmark shows that specific cancer cells also use this process.

Macropinocytosis is a process in which the healthy cell membrane surrounds the damaged area and envelopes it. After this, the lysosomes ‘digested’ the broken pieces of the membrane. The process is often described as recycling because the cell reuses mater to grow or divide.

In this experiment, the researchers damaged the cellular membrane of a specific type of cancer cells (MCF-7) with a laser. After this, they observed as the cancer cells initiated macropinocytosis to repair the damage. But they also used chemicals to stop the repair process, resulting in the death of the cell.

Commenting on their findings, the lead researcher Jesper Nylandsted, Danish Cancer Society’s Research Center and the University of Copenhagen, said:

“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”.

Fig. Proposed model for membrane restructuring by LAM after initial plasma membrane repair (from original research article

Implications of Research

One of the reasons cancers are dangerous is because they cause damage as they spread through the body. As this occurs, the disease becomes difficult to treat. However, research also indicates that as cancer cells spread through the body, they become more prone to membrane damage. Such findings help in forming treatment strategies that will be better at stopping cancer.

In previous research, the team from Denmark demonstrated one more method cancer cells use for membrane repair. They can discard the damaged area similarly to how a lizard discards its tail. That is, the cell isolates the site and throws it off. However, it seems more aggressive cancer cells prefer macropinocytosis.

Cancer cells often divide to increase their spread through the body. Cellular division requires a lot of energy, which may be why certain cancers prefer to recycle themselves. However, much of our knowledge in this area is still in the domain of speculation.

Stine Lauritzen Sønder, a postdoc member of the research team, best describes the future of cancer research and the significance of their findings.

“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 afterwards. It can be another weak point in the cancer cells, and is something we want to examine closer.”