March 24, 2011

Cancer cells have taught biologists about a lot of wacky things that can happen when things don’t go merrily along for a cell. Entosis is a process in which a living cell is internalized into a neighboring cell, and has been found to occur in some tumors. A recent paper describes exactly what can go wrong here.

Aneuploidy refers to a cell having an incorrect number of chromosomes, and is a feature of many cancers. Typically, aneuploidy occurs from a failure in cytokinesis, the physical division of a cell after mitosis, due to misregulation or mutation of genes involved in cell division. Sometimes, however, aneuploidy can occur from a non-genetic failure of cytokinesis, according to a recent paper. In this paper, Krajcovic and colleagues look at cytokinesis failures due to entosis, a process in which living cells are internalized by their neighboring cells. These cell-in-cell structures are found in some tumors, and the outer “host” cell is frequently aneuploid. This aneuploidy occurs when the internalized cell physically disrupts the constriction required to cleave two cells during cytokinesis, as seen in the images above. Cytokinesis of the cell-in-cell structure (left) is not going well compared with a normal cell (right). Red labels (and in black and white insets) mark active constriction during cytokinesis, and should be symmetric around the cells. The mitotic spindle is labeled in green, and chromosomes in blue.

BONUS!! Movie of above cell, attempting cytokinesis, can be found here. More cool movies from this paper can be found here.

Krajcovic, M., Johnson, N., Sun, Q., Normand, G., Hoover, N., Yao, E., Richardson, A., King, R., Cibas, E., Schnitt, S., Brugge, J., & Overholtzer, M. (2011). A non-genetic route to aneuploidy in human cancers Nature Cell Biology, 13 (3), 324-330 DOI: 10.1038/ncb2174
Adapted by permission from Macmillan Publishers Ltd, copyright 2011