A colorful chaos of melanoma cells can be seen under the microscope. The cell membranes are colored red and the cell nuclei are colored blue. In between, colored green, are small cell structures of M1 macrophages that can accelerate tumor growth. Now the mechanism behind it has been researched in more detail.
Macrophages are white blood cells that are involved in the immune system’s response to cancer cells and migrate to the tumor environment in many types of cancer. A high macrophage count is considered an indicator of an advanced stage of the disease. M1 macrophages actually have an inflammatory effect and thus against the tumor. However, too much inflammation can also promote the survival and growth of cancer cells.
Extracellular vesicles, i.e. membrane-bound particles that are secreted by cells and serve for intercellular communication, play an important role. In a study by the University of Eastern Finland, published in the specialist journal Cell Communication and Signaling, they were examined in more detail.
The researchers added green-colored extracellular vesicles from M1 macrophages to melanoma cells, which almost completely absorbed the cell components in two hours, as can be seen in the image. These extracellular vesicles of the M1 macrophages contain inflammatory mediators that enter the melanoma cells.
In addition, the cell components activate the so-called NF-κB signaling pathway, which controls the reaction of cells to external stimuli. It promotes an inflammatory environment that makes the tumor more aggressive and invasive. The immune system responds to this by migrating more M1 macrophages into the tumor environment. A cycle is created in which the cancer cells thrive.
With this study, the researchers demonstrate a key mechanism in cell communication. A precise understanding can help break the inflammatory cycle and thus find a new method of cancer therapy.