Unravel some of the mysteries! Nature: How exactly does cancer metastasis occur?
January 24, 2018 Source: Biological Exploration of: Chen
Window._bd_share_config={ "common":{ "bdSnsKey":{ },"bdText":"","bdMini":"2","bdMiniList":false,"bdPic":"","bdStyle":" 0","bdSize":"16"},"share":{ }};with(document)0[(getElementsByTagName('head')[0]||body).appendChild(createElement('script')) .src='http://bdimg.share.baidu.com/static/api/js/share.js?v=89860593.js?cdnversion='+~(-new Date()/36e5)];How does the transfer happen? This has always been one of the core issues in cancer biology. Recently, in a study published in the journal Nature, the team of scientists from the United States seems to have solved some of the mysteries.
Image source: Nature (DOI:10.1038/nature25432)
In the study, scientists from institutions such as Weill Cornell Medicine and Memorial Sloan Kettering Cancer Center tracked a series of complex events caused by chromosomal instability, a common feature of cancer cells. Using breast and lung cancer models, they found that cancer metastasis may be caused by chronic leakage of DNA in tumor cells.
Dr. Samuel Bakhoum, co-first author of the paper, explained: "Chromosomal instability causes DNA to leak from the nucleus of cancer cells, triggering a chronic inflammatory response in the cell, allowing cells to spread to distant organs."
Dr. Samuel Bakhoum (Source: Memorial Sloan Kettering Cancer Center)
â–‹ 1 , more than 1500 genes are abnormally elevated
The transfer caused 90% of cancer deaths. Previously, studies have linked chromosomal instability to cancer metastasis, but the mechanisms behind this association have not been clarified. In the study, scientists began the hypothesis that chromosomal instability produces a large number of different tumor cells, and Darwin's natural selection process causes cells that can metastasize and form distant tumors to survive.
In the study, when they injected chromosomal unstable tumor cells into mice, it was found that these cells were more likely to spread and form new tumors than "tumor cells with suppressed chromosome instability."
Subsequently, the researchers investigated the genetic activities of these two groups of tumor cells. It was found that more than 1,500 genes were abnormally elevated in cells with high chromosomal instability, especially those associated with inflammation and immune responses against viral infections.
Dr. Bakhoum said: "We are very surprised about this and want to know what caused this inflammatory response."
â–‹ 2 , "mistaken" the leaked DNA "viral DNA"
Some recent studies from other laboratories have also provided clues to scientists that chromosomes in unstable tumor cells sometimes leak from the nucleus (where the chromosomes usually "live"). These leaked, mis-located chromosomes compress themselves to form a micronuclei. However, micronuclei eventually tend to rupture, releasing naked DNA into the cytosol.
The cell "mistakes" this leaked DNA as a sign of infection. Because the virus attacks its cells for the first time, it tends to release its DNA into the cytoplasm. However, human cells have evolved a way to combat this viral infection, using the cGAS-STING pathway. Once activated, this pathway triggers an inflammatory antiviral procedure.
DNA (green) residing in fluid outside of cells' main nuclei.
Image credit: Wenjing Wu/Memorial Sloan Kettering Cancer Center/Nature
Dr. Bakhoum and colleagues analyzed chromosomal-stable tumor cells and found that these cells did contain large amounts of cytosolic DNA and showed evidence of chronic activation of the antiviral cGAS-STING protein. In addition, studies have shown that lowering cGAS-STING levels reduces inflammation and prevents the ability of invasive tumor cells to metastasize after injection into mice.
▋ 3 , How do “escape†cancer cells metastasize?
In normal cells, an antiviral response stimulated by nuclear DNA leakage can quickly lead to cell death. However, the researchers found that tumor cells not only successfully inhibited the "fatal principle" of the cGAS-STING response, but also used the other parts of the response to get rid of the tumor and become available. Move in the body.
This is because tumor cells that want to "escape" will initially behave as if they were some type of immune cell. These immune cells are usually activated by infection and then quickly moved to the infected or injured part of the body. By "learning" this behavior of immune cells, cancer cells undergo a deadly mimicry.
â–‹ 4 , is expected to have a long-term impact on cancer drug development
Researchers estimate that about half of human cancer metastases occur through the above pathways based on recent research on the nature of metastatic tumors. Now they are investigating strategies to block this process. Scientists believe that although this discovery is mainly based on advances in basic science, it is expected to have a long-term impact on the development of cancer drugs.
Reference: How cancer metastasis happens: Researchers reveal a key mechanism
Dried Squids are a popular snack in many Asian countries, especially in Japan, Korea, and Thailand. They are made by cleaning and drying fresh squids until all the moisture is removed, resulting in a chewy and flavorful snack.
Pure dried squids are made without any additional flavorings or seasonings, so they have a natural taste that is slightly salty and briny. They are often served as a bar snack or as a topping for rice dishes, noodles, or salads.
Dried squids are a good source of protein and low in fat, making them a healthier snack option than many other processed snacks. They are also rich in vitamins and minerals, including vitamin B12, selenium, and phosphorus.
Overall, dried squids are a tasty and nutritious snack that can be enjoyed on their own or used as a flavorful ingredient in many dishes.
Zhoushan Fudan Tourism CO., LTD , https://www.fudanfood.com