There chemotherapy enhances the spread of cancer beyond the primary tumor. A chemotherapy drug allows the cells of the cancer breast sticking to the linings of blood vessels in the lungs: this new oncological evidence is revealed by a developed study Tsonwin Hai, professor of biological chemistry and pharmacology at Ohio State University. (1)
There Research was recently published online onInternational Journal of Molecular Sciences.
Is chemotherapy always the right way to treat certain cancers?
Research carried out on mice leaves no doubt that chemotherapy drugs cause changes to non-cancerous cells which enable this process. The scientists pretreated healthy mice with a chemotherapy agent and gave them intravenous injections of breast cancer cells four days later.
Within three hours of the injection, the cancerous cells were able to penetrate the weakened junctions between the blood vessel cells in the lungs and attach themselves to the underscore structure of those vessels, avoiding being washed out of the bloodstream..
“This is the key step that gives cancer cells a passage through the door to a secondary site “, he said Tsonwin Hai, professor of biological chemistry and pharmacology at theOhio State University and senior author of the study. “The focus of our pre-treatment model is to ask the question: does chemotherapy affect healthy cells in a way that helps cancer cells? The answer is yes.It is a cautionary note for the use of chemotherapy ”.
The basics of cancer metastasis have been observed for years, discovering that the activation of a specific gene in immune cells is a crucial link between stress and the spread of cancer and that the chemotherapy drug paclitaxel it triggers molecular changes in immune cells that allow breast cancer cells to “escape” from a tumor.
This new study focused on the effects of the chemotherapy drug cyclophosphamide on non-cancerous cells before cancer is present, focusing on the lungs as the site of metastasis.
The researchers injected a dose of the chemotherapy into the mice and waited four days for the animals to metabolize and excrete the drug. The scientists then gave the mice intravenous injections of breast cancer cells, allowing them to travel to the lungs.
Once in the lungs, cancer cells are more likely to attach to blood vessel walls if animals have been pretreated with the chemotherapy. The researchers identified two reasons: First, there are open interstitions between cells in the vessel lining. In addition to this, a second material under those cells, called the basement membrane, changed properties in such a way that it allowed the cancer cells to attach themselves so that they were not carried away from the bloodstream.
“The endothelial cells lining the inside of the blood vessel are like a brick wall, and each brick is tightly adhered to the next“, has explained You have, researcher at the Comprehensive Cancer Center of Ohio. “What we found when we treated the mice with chemotherapy is that it makes the vessel permeable, so the tight junction is no longer as tight and cancer cells can slip through the brick layer. “
“We also found out that chemotherapy changed the basement membrane below, so once the cancer cells pass through, they find a place to hang on “, continued the scholar.
In control mice that did not receive chemotherapy, adhesion of cancer cells to blood vessel walls was relatively minimal., the researchers stated.
The study team determined that the presence of cyclophosphamide led to an increase in the levels of an enzyme in the blood called MMP-2 and that the increase induced changes to the basement membrane that allowed cancer cells to attach to the lining of the blood vessels.
For decades, scientists have focused on chemo’s effects on the intrinsic properties of cancer cells that allow cells to survive, resist chemotherapy, and spread. Only in the last 10 years or so have researchers discovered the effects of chemotherapy on non-cancerous cells and their contribution to metastasis.
“We focused on how there chemotherapy affects non-cancerous cells in the lung, the second site in our model, rather than primary tumors, because the escape of cancer cells from a primary tumor is not a late event: it can actually happen very soon “Hai said.
“Our data revealed that chemo acts on non-cancerous cells and sets in motion changes in the lung so that within three hours of the cancer cells arriving, they can already adhere very well. The effect of chemotherapy on non-cancerous cells actually changes those cells, and those changes help the cancer cells progress“.
How does chemotherapy work?
Chemotherapy circulates throughout the body through the bloodstream, so it can treat cancer cells almost anywhere in the body itself. This is known as a systemic treatment.
Chemotherapy kills cells that are about to divide into 2 new cells. The tissues of the body are made up of billions of individual cells. Once the organism has completed the formation phase, most of the cells in the body do not divide and multiply but the cells divide only if they are called to repair any damage.
When the cells divide, they divide into 2 new identical cells. So where there was 1 cell, now there are 2, it goes without saying that these divide into 4, then 8 and so on.
In cancer, cells continue dividing until a mass of cells is created. This mass of cells becomes a lump, called a tumor. Since cancer cells divide much more often than most healthy cells, chemotherapy is much more likely to suppress them.
Some drugs kill dividing cells by damaging the part of the cell’s control center that causes it to divide. Other drugs disrupt the chemical processes involved in cell division.
Chemotherapy damages cells as they divide. At the center of every living cell is a dark spot called the nucleus. The nucleus is the control center of the cell. Contains chromosomes, which are made up of genes. These genes must be copied exactly every time a cell divides into 2 to create new cells: Chemotherapy damages genes inside the cell nucleus.
Some drugs damage cells at the point of cleavage. Some damage cells while making copies of all their genes before they divide. Chemotherapy is far less likely to damage resting cells, like most cells healthy. A combination of several chemotherapy drugs will include drugs that damage cells at different stages of the cell division process. This means there are more chances of killing more cells.
The fact that chemotherapy drugs kill dividing cells helps explain why chemotherapy causes side effects. It affects healthy body tissues where cells are constantly growing and dividing, such as:
The hair, which always grows;
The bone marrow, which constantly produces blood cells;
The skin and the lining of the digestive system, which are constantly renewed;
Since these tissues have dividing cells, chemotherapy can damage them. But normal cells can replace or repair healthy cells damaged by chemotherapy.
So the damage to healthy cells is usually not permanent. Most of the side effects disappear when the treatment is finished. Some side effects such as diarrhea may only occur during the days that you are actually having chemotherapy.
Chemotherapy is given as:
An injection into the bloodstream (through a vein)
A drip (intravenous infusion) into the bloodstream
Tablets or capsules;
The chemotherapy drugs administered in this way circulate throughout the body through the bloodstream and can reach cancer cells almost anywhere in the body. This is known as systemic treatment.
Whether chemotherapy will cure cancer depends on the type of cancer being treated. With some types of cancer, most people are treated with chemotherapy; with other types of cancer, fewer people recover completely.
Examples of cancers where chemotherapy works very well are testicular cancer and Hodgkin’s lymphoma.
With some cancers, chemotherapy alone cannot cure the cancer. But it can help in combination with other types of treatment. For example, many people with breast or bowel cancer have chemotherapy after surgery to help reduce the risk of the cancer returning.
With some cancers, if a cure is unlikely, the specialist may still suggest chemotherapy for:
Reduce cancer;
Relieve symptoms
Allowing for life extension by controlling cancer or putting it into remission.
Remission is a word doctors often use when talking about cancer. It means that there is no sign of cancer after the treatment. Remission can be complete or partial: complete when cancer cannot be detected on scans, x-rays, blood tests, or other tests. Doctors sometimes call this a complete response or may say there is no evidence of disease; partial here when the treatment killed some cells, but not all. The cancer has shrunk, but it can still be detected on scans and does not appear to grow.
Another term used by doctors is stable disease. This may mean that the cancer has remained the same size or may even have grown by a small amount.
There are many different types of anticancer drugs. Some treat cancer and others help relieve symptoms such as illness and pain. The type of drugs that the patient needs for his specific cancer depends on the type of cancer developed by the patient. It could also be a combination of drugs. Knowing more about how these drugs work, about their possible side effects can help the patient cope with the treatment.
#chemotherapy #potentiate #spread #cancer