Why are cancer cells so, well, cancerous? It has just been discovered that one reason for their malignancy is an irregularity in their division when under physical pressure. Upon dividing, they can produce as much as 5 daughter cells compared to the normal 2.
Cancer is so hard to contain because of the rapidity with which cancerous cells spread. Now we are learning that tumour progression may not just be not a function of increased speed or frequency of cell division, but of a greater reproductive output.
Creating a Platform that Creates a Physical Stress on Cells
For the first time, researchers have been able to confine single cells in a microfluidics system with mechanical pressures to observe the effects of cellular confinement at a cellular scale on the division process. using this platform, they could microscopically observe a single cell as it divided in response to the stress. As it turns out, these effects are quite large. Cancer cells under physical duress divide irregularly and assymetrically, and half of them produce 3–5 daughter cells. Cancer cells also face mechanical pressures in the body and this response could lead to their increased malignancy.
Mitosis is the process by which a cell divides and produces two daughter cells (the dividing cell becomes one of the ‘daughters’). This is a highly regulated process because the cell’s resources have to be equally distributed between the two cells that are formed. Division of a cell into more than two cells often leads to an irregular distribution, with some cells even receiving extra copies of a chromosome, and in some cases, no copies.
Propagation of Damaged Cells
Most of these daughter cells produced under mechanical duress were viable. Normal cells, on the other hand, are constantly regulated by cellular mechanisms which leads to their death upon detection of any irregularity. This irregular cell division and lack of death could thus be a phenomenon by which cancerous cells rapidly produce more cancerous cells, some of which are genetically abnormal, and could cause the many defects cancer leads to.
Published in the journal PLoS One, this research was not conducted on normal cells, and it would be interesting to note if non-cancerous cells also respond atypically to such stresses, and if this is really what differentiates cancerous cells from non-cancerous cells.