A new study has revealed that the constant contractions of the heart may inherently suppress tumor growth within cardiac tissue. Scientists have found that the mechanical stress generated by the heart's continuous operation can alter gene activity in cancer cells and literally prevent them from multiplying, reports News Medical Life Sciences.
The study addresses one of medicine’s long-standing mysteries: why primary heart cancer is extremely rare. Researchers note that cardiac tissue in mammals has a very low turnover rate, with heart muscle cells regenerating at a rate of only about 1% per year. Simultaneously, the heart is under immense, constant mechanical load as it pumps blood at high pressure.
The authors of the new study hypothesized that this persistent physical exertion creates an environment hostile to tumor growth.
To test this hypothesis, scientists used genetically modified mice and artificially introduced human cancer cells into their cardiac tissue. They then developed a unique model: transplanting a donor heart into the neck region of another mouse. This transplanted heart continued to receive blood supply but experienced virtually no mechanical load and did not fully participate in the pumping process.
The comparison showed a stark difference. In the "unloaded" hearts, tumor cells multiplied rapidly, whereas in the normally functioning hearts, tumor growth was significantly suppressed.
The researchers discovered that a key role is played by a protein called Nesprin-2—a component of the cellular system that transmits mechanical signals from the cell surface to its nucleus. This protein helps cells "sense" the physical tension of their environment.
Under the influence of constant mechanical load, Nesprin-2 altered the structure of chromatin—the complex of DNA and proteins within the cell nucleus. This, in turn, decreased the activity of genes associated with the division and growth of tumor cells. When researchers artificially disabled Nesprin-2 in cancer cells, they began forming tumors again, even in an actively beating heart.
The authors believe this work opens a new frontier in oncology—studying how mechanical forces and the physical environment of tissues influence cancer development. This could lead to the development of new therapies based not only on pharmaceuticals but also on mechanical impacts on tumor cells.
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