Cancer tricks your body’s healthy cells, known as fibroblasts, into protecting it from your own immune system. This new genetically modified virus (called enadenotucirev) attacks both the tumors, and these fibroblasts that have been turned against you. The scientists from Oxford University that produced it claim that it is the first time cancer-associated fibroblasts within solid tumors have been specifically targeted in this way.
Up to now, any existing treatment that kills these ‘tricked’ fibroblasts, might also destroy those in the bone marrow and skin, but not this virus. The researchers tested it on samples of healthy human bone marrow and found it did not cause toxicity. This is very exciting news. Lead researcher Dr Kerry Fisher, from the University of Oxford’s department of oncology, said:
“Even when most of the cancer cells in a carcinoma are killed, fibroblasts can protect the residual cancer cells and help them to recover and flourish. Until now, there has not been any way to kill both cancer cells and the fibroblasts protecting them at the same time, without harming the rest of the body…Our new technique to simultaneously target the fibroblasts while killing cancer cells with the virus could be an important step towards reducing immune system suppression within carcinomas and should kick-start the normal immune process.”
How The Virus Works:
- A protein, called a bi-specific T-cell engager, is attached to the virus.
- One end of the protein is targeted to bind to fibroblasts,
- The other end specifically stuck to T-cells – a type of immune cell that is responsible for killing defective cells.
- By binding the two together, it triggered the T-cells to kill the fibroblasts that are attached to tumors.
The head of molecular and cellular medicine at the Medical Research Council (MRC), Dr Nathan Richardson, who was involved in funding the study, says:
“Immunotherapy is emerging as an exciting new approach to treating cancers. This innovative viral delivery system, which targets both the cancer and surrounding protective tissue, could improve outcomes for patients whose cancers are resistant to current treatments.”
How Immunotherapy Works
Immunotherapy uses our own immune system to fight cancer by helping the immune system recognise and attack cancer cells. Normally, our immune system (lymph glands, spleen and white blood cells) will naturally protect us from the development of cancer without any assistance. That is, after all, its sole purpose – to protect our body against infection, illness and disease. It can, and does, spot and destroy faulty cells in the body, stopping cancer from developing.
But, sometimes, there are cells that outsmart our immune system. Those are the cells that develop into cancer. That might happen when:
- The immune system is weak – It recognizes the cancer cells but it is not strong enough to kill them.
- The cancer cells trick the immune system by producing signals that stop the immune system from attacking it.
- The cancer cells manage to hide or escape from the immune system.
At the moment, surgery, chemotherapy, and radiation therapy are more widely used treatments than Immunotherapy. What is the difference between these kinds of treatment?
- Surgery is the physical removal of the cancer.
- Chemotherapy uses medication to kill cancer cells.
- Radiotherapy means the use of radiation, usually X-rays, to treat illness.
- Immunotherapy uses the natural power of your immune system to fight illnesses.
There are actually different types of immunotherapy (aka targeted therapies or biological therapies). Hasan Jasim describes the different types as follows:
Monoclonal antibodies (MABs)
Monoclonal antibodies are laboratory-produced molecules engineered to serve as substitute antibodies that can restore, enhance or mimic the immune system’s attack on cancer cells. They are designed to bind to antigens that are generally more numerous on the surface of cancer cells than healthy cells. This process is called antibody dependent cell mediated cytotoxicity (ADCC).
Normally, vaccines help to protect us from disease, and researchers are looking at whether vaccines can be used as a treatment to help the immune system to recognise and attack cancer cells. When you have the vaccine, it stimulates the immune system into action. The immune system makes antibodies that can recognise and attack the harmless versions of the disease. Once the body has made these antibodies it can recognise the disease if you come into contact with it again. So you’re protected from it.
Cytokines are a group of proteins in the body that play an important part in boosting the immune system. Interferon and interleukin are types of cytokines found in the body. Scientists have developed man-made versions of these to treat some types of cancer.
Adoptive Cell Transfer
Adoptive cell transfer changes the genes in a person’s white blood cells (T cells) to help them recognise and kill cancer cells. Changing the T cell in this way is called genetically engineering the T cell. This treatment is only available as part of a clinical trial in the UK. An example of a type of adoptive cell transfer is CAR T cell therapy.
Apart from successful testing on healthy human bone marrow, the scientists also tested this therapy on mice and fresh human cancer samples collected from patients. All these tests resulted in positive outcomes. The virus is already used in clinical trials for treating cancers that start in the pancreas, colon, lungs, breasts, ovaries or prostate. The team has published all their findings in the journal Cancer Research.