End suppression of the immune system

Otto Warburg was one of the most respected biochemists of his time, receiving the Nobel Prize in Medicine in 1931, among others. He is also considered a role model and mentor to numerous later Nobel laureates. As part of his research work, Warburg made an exciting discovery about a hundred years ago: tumors have a high concentration of lactate. This happens because the cancer cells require large amounts of glucose and glutamine. Lactate is then created as a by-product during metabolism. Since then, much research has focused on lactic acid in cancer cells. However, the focus was mainly on the primary tumor. However, a team of German scientists has now gone a step further. They looked at the so-called tumor-draining lymph nodes. Also known as sentinel nodes, these are the first to come into contact with the fluid secreted by the tumors.

cancer cells
T cells attacking a cancer cell. Photo: Killer T cells surround a cancer cell, NIH Image Gallery, Flickr, CC BY-SA 2.0

The lactic acid suppresses the immune system response

In fact, the lymph nodes should therefore activate the immune system and deploy protective T cells. But that’s exactly what doesn’t happen. This is because the T cells in the affected lymph nodes are inhibited. Until now, however, it was still unclear exactly how this happens. The researchers have now looked at the so-called fibroblasts. These are cells that are important for the construction of the lymph nodes and provide a connection between the dendritic cells and the T cells. The dendritic cells have the task of activating the T cells in an emergency and thus setting the immune system in motion. In experiments in the laboratory and in mice, the researchers have now been able to demonstrate that the connecting element of the fibroblasts is affected by lactic acid. Simply put, the metabolism of glucose not only makes the tumor grow, but also suppresses the body’s immune system at the same time.

The first promising approaches will be pursued further

Various findings for the fight against cancer can now be derived from this knowledge. On the one hand, the focus is on the subject of nutrition. Too much sugar and fat therefore increases the risk of breast cancer and subsequent metastases. At the same time, this weakens the body’s immune system. Not eating at all is of course not a solution either. In parallel, there are also possible approaches to cancer treatment. For example, measures to neutralize the effect of lactic acid in the lymph nodes are conceivable. For example, the first tests showed that the negative effects no longer occurred as soon as the pH value in the cells was increased. The researchers now want to experiment further and mainly work with human cells. Ideally, at some point, the suppression of the immune system can be prevented.