Rethinking biology: What role does physical structure play in the development of cells?
|November 10, 2017||Posted by News under Cell biology, Evolution, Intelligent Design|
That’s structuralism, in part. Further to Evelyn Fox Keller’s comment that the landscape of biological thought is being “radically reconfigured,” a cancer geneticist writes to say that a tumor’s physical environment fuels its growth and causes treatment resistance:
The forces of cancer
In vitro experiments showing that cancer cells actively migrate in response to fluid flow have supported the hypothesis that fluid escaping from the boundary of a tumor may guide the invasive migration of cancer cells toward lymphatic or blood vessels, potentially encouraging metastasis. There remains controversy over how the fluid forces induce the migration; the cells may respond to chemical gradients created by the cells and distorted by the flowing fluid,8 or the fluid may activate cell mechanosensors. Because of the potential for new therapeutic interventions, the transduction of mechanical fluid forces into biochemical signals by cell mechanosensors is an active area of investigation. In a more direct manner, the fluid flow can physically carry cancer cells to lymph nodes.
And fluid pressure is just one of the many forces in a tumor that can influence its development and progression. Tumors also develop increased solid pressure, as compared with normal tissue, stemming from the uncontrolled division of cancer cells and from the infiltration and proliferation of stromal and immune cells from the surrounding tissue and circulation. High-molecular-weight polysaccharides known as hydrogels found in the extracellular matrix (ECM) also add pressure on a tumor. The most well-studied of these hydrogels is hyaluronan; when the polysaccharide absorbs water, it swells, pressing on surrounding cells and structural elements of the tissue. More. (The Scientist, April 1, 2016)
The dissection of how cells sense and propagate physical forces is leading to exciting new tools and discoveries in mechanobiology and mechanomedicine.
Of course, mechanical properties and forces aren’t just important in disease, but in health as well. Almost all living cells and tissues exert and experience physical forces that influence biological function. The magnitudes of those forces vary among different cell and tissue types, as do cells’ sensitivities to changes in magnitudes, frequencies, and durations of the forces. Touch, hearing, proprioception, and certain other senses are well-known examples of specialized force sensors. But force detection and sensing are not limited to these special cases; rather, they are shared by all living cells in all tissues and organs. The underlying mechanisms of force generation and detection are not well understood, however, leaving many open questions about force dynamics; the distance over which a force exerts its impact; and how cells convert mechanical signals into biochemical signals and changes in gene expression (The Scientist, February 1, 2017)More.
We may come to understand evolution better if we see what can and can’t happen in physics terms.
See also: Keller: Landscape of biological thought is being “radically reconfigured”