By releasing chemical signals, the primary tumor makes the “target” area adhesive, while also attracting bone marrow cells to “prepare the site” for the arrival of cancer cells.
Researchers from Cornell University in the United States have discovered how secondary tumors form and how to control them from initial cancer cells. First, the primary tumor releases growth factors that stimulate the formation of an adhesive protein called fibronectin on the surface of healthy cells in the target area. Following this, a second batch of growth factors is released to “entice” bone marrow cells to move to this area. There, the bone marrow cells cluster together, creating a nest-like structure, waiting for malignant cells to arrive and form a secondary tumor.
Based on this process, the research team believes that it is possible to control the movement of bone marrow cells using antibodies, as theoretically, this technique could be quite effective in cancer patients to prevent disease progression.
In experiments, all bone marrow cells in some mice were irradiated to destroy them, and then replaced with new bone marrow cells tagged with green fluorescent protein, allowing for easy tracking of their movement under a microscope. Subsequently, these mice were injected with skin or lung cancer cells, each tagged with red fluorescent protein for tracking purposes.
It is anticipated that the cancer cells will first form a primary tumor on the skin before spreading to the lungs. Based on this, the research team observed that the green bone marrow cells appeared in the lungs several days before the primary cancer cells arrived. Subsequently, as “planned,” they reached the exact location where the bone marrow cells had been present.
Researchers then injected the mice with cultured cancer cells. Interestingly, the green bone marrow cells also migrated to the lungs first, demonstrating that any type of cancer cell releases chemical factors into the surrounding environment to control the movement of bone marrow cells.
According to the research leader David Lyden, the metastatic process of cancer cells can be halted by controlling the bone marrow cells with antibodies. The team hopes to begin clinical trials on patients within the next year.
