New form of therapy uses exceptional approach
Oxidative stress is a phenomenon that occurs at a cellular level and which can cause healthy cells to become diseased and eventually die. Cancer uses such oxidative stress to grow and spread. Researchers are now investigating whether this phenomenon can also be used against cancer.
In their current study, the scientists at Augusta University investigated whether cancer can be combated by practically overfeeding it. The experts published the results of their analysis in the English-language journal "Cell Metabolism".
What are oxygen radicals?
Reactive oxygen species (often referred to simply as ROS or oxygen radicals) are substances that are produced naturally after oxygen metabolism. They usually play an important role in regulating biological function (homeostasis) and in signaling cells. However, if these oxygen radicals reach abnormal values, this can lead to oxidative stress, a phenomenon that leads to cell aging and aging of the organism, the experts explain.
Researchers planned to overfeed cancer
Unlike healthy cells, cancer cells require much higher ROS levels, which allows them to maintain their accelerated growth and spread. The researchers are now investigating whether they can use this effect to treat cancer through a fascinating strategy. They wanted to increase the production of oxygen radicals so much that the cancer cells die.
What is adoptive T cell therapy?
Dr. Gang Zhou and his colleagues at Augusta University used therapy that increased ROS in cancer tumors and caused the overloaded cells to self-destruct. The so-called adoptive T cell therapy is a type of immunotherapy, in which specialized immune cells or T cells are used to attack and destroy cancer tumors, the doctors explain.
Investigation was carried out on mice with colon cancer
In their study, the doctors researched mice with colon cancer. After the mice were given some type of chemotherapy that is known to support the action of T cells, the animals were exposed to immunotherapy. After the treatment, the researchers found that the treatment interrupted the production of glutathione (a natural antioxidant), which is produced at the cell level and forms the counterweight to ROS. As a result, ROS was over-accumulated and reached too high values in the cancer cells. The T cells also stimulated the production of a number of specialized proteins known as proinflammatory cytokines. These cytokines included the so-called tumor necrosis factor alpha, which is already known to play a role in both cell death and tumor progression.
Adoptive T cell therapy led to complete tumor regression
The results of the study show that the tumor necrosis factor alpha acts directly on tumor cells and can induce ROS in them, the scientists explain. Thanks to the metabolic changes induced by adoptive T cell therapy, the scientists observed a complete tumor regression in almost all mice that had received this form of treatment. Similar successes were observed when this approach was tested on models of breast cancer and cancer of the lymphatic system or lymphoma.
Combined treatment has been very successful
The researchers also found that increased tumor necrosis factor alpha production due to immunotherapy in conjunction with chemotherapy further increased oxidative stress and destroyed cancer cells. Another result of the study was that the administration of prooxidants had similar effects to adoptive T cell therapy, since these drugs also increased ROS levels.
More research is needed
The researchers found that cancer cells and T cells can compete for energy sources so that they interfere with each other. However, the T cells often starve because the required nutrients are used by the cancer cells. Adoptive T cell therapy in itself is a new type of approach that could be used to treat certain types of cancer, such as colon cancer. Therefore, more efforts should be made to better understand the effects of T cells and to improve the potential of immunotherapy to destroy cancer, the study authors explain. (as)