Although the human body feels very strong, in fact, the water content in the human body can reach 50% - 80%, and the cells in the human body are mostly in a state of being wrapped by body fluids, and there is also a large amount of liquid in the cells. If we want to make an analogy, it is equivalent to filling a balloon with water and putting it into a water tank full of water - this balloon is equivalent to a cell, and this water tank is equivalent to human body fluid environment.
Cell model (image source: pixabay official website)
Imagine if you poke a hole in this balloon? Obviously, the balloon will break, spit out the water inside, and then surface. As for cells, a thin membrane (cell membrane) outside the cells protects the integrity of the cells. If the cell membrane is damaged, the cells cannot escape the fate of being cleared or apoptosis automatically.
Even for cancer cells, a hole in the cell membrane will endanger the survival of cancer cells, but it is unexpected that cancer cells will escape death by "eating themselves". This special mechanism is the "megapinocytosis" effect of tumors. The latest study was published in the journal science advances.
Source: Official Website of science advances
In February 2021, an article published in nature communications magazine had found that megapinocytosis of cancer cells played a huge role in the occurrence and development of cancer cells.
Source: nature communications official website
In fact, the use of various targeted drugs can cut off the supply and demand path of cancer cells. Cancer cells will continue to divide, and the division of cancer cells requires sufficient material and energy supply, but if these materials and energy supply are cut off, cancer cells will have no raw materials. What should we do?
What should I do? Eat other dead cancer cells!
Although both of them are cancer cells, when fighting with drugs and immune cells, many cancer cells will be killed, and these killed cancer cells will become nutrients for other living cancer cells - living cancer cells will use macropinocytosis to devour the fragments of dead cancer cells, and obtain the necessary nutrients from them to ensure their own safety and replication. This makes cancer cells resistant to some drugs.
Living cancer cells become resistant to drugs that inhibit fatty acids by ingesting fatty acids from dead cancer cells (image source: Reference 1)
In the latest research, when cancer cells themselves face the threat of death, cancer cells once again use the "macropinocytosis" function. When researchers used laser to drill a small hole in the cell membrane of cancer cells, this triggered the megapinocytosis of cancer cells - cancer cells need to repair the damage in a short time, how to do it?
The study found that cancer cells will pull the cell membrane near the damaged part into the damaged part to realize the closure and repair of the cell membrane. Moreover, cancer cells will not waste damaged cell membranes, which will be transported to lysosomes and decomposed into raw materials for later use.
Further studies have confirmed that invasive cancer cells will use macropinocytosis more, which may be related to the fact that invasive cancer cells need more material and energy to replicate and divide.
Cancer cells repair their damaged cell membranes (image source: reference 2)
However, macropinocytosis also plays an important role in immune function. Both macrophages and DC cells play an immune role through macropinocytosis, which can help these immune cells absorb and analyze antigens.
However, such functions fall into the hands of cancer cells and become the helper of cancer cell replication and division. Fortunately, researchers found that if the megapinocytosis of cancer cells is prevented, the cancer cells will die due to cell membrane damage.
With the more and more in-depth study of cancer cells, we found that cancer cells are not only very cunning, but also very "ferocious" to the same kind or ourselves. Although a single drug can treat some patients, for most advanced cancer patients, they still face the risk of recurrence. Therefore, in recent years, scientists have also found a new anti-cancer treatment technology, that is, immunotherapy technology.
Source: Shanghai cell therapy group
In the human body, immune cells are responsible for destroying cancer cells. Although cancer cells continue to mutate in the human body and escape the monitoring and elimination of immune cells, in the laboratory, immune cells can play the function of killing cancer cells again by removing the inhibition of immune cells or enhancing the function of immune cells. Moreover, immune cells have memory function after destroying cancer cells, which can produce memory immune cells, which makes the treatment effect more lasting.
Although cancer cells are cunning, we believe that with the continuous emergence of new treatment technologies, we will have more ways to defeat cancer cells and prolong the survival of cancer patients.
Reference material:
1.NVaishali Jayashankar, et al. Macropinocytosis confers resistance to therapies targeting cancer anabolism. Nature Communications. 28 Feb, 2020
2.Restructuring of the plasma membrane upon damage by LC3-associated macropinocytosis
Cancer cells eat themselves to survive
3.巨胞饮的机制及功能的研究进展
Article source:
https://www.cn-healthcare.com/articlewm/20210804/content-1249521.html
