Entosis and Cell Cycle in Tumor Cell Culture

Abstract

Entosis is a type of cell cannibalism during which one tumor cell invades another. The fate of the inner cell can vary. It can leave the entotic vacuole, divide within it, or be subjected to lysosome-mediated degradation. The aim of our work was to determine whether MCF7 (p53+) human breast adenocarcinoma cells and A431 (p53-) human epidermoid carcinoma cells can pass through the cell cycle during entosis. The percentage of entotic cells was 1.01 ± 0.37% in MCF7 culture and 0.42 ± 0.27% in A431 culture. It was shown that inner cells, as well as outer cells, can synthesize DNA (BrdU incorporation) and enter mitosis. Morphometric analysis showed polyploidization of outer cells. This process is most pronounced in the A431 (p53–) cell line. In addition, polyploid cells may be the preferred targets of invasion in this culture. In the MCF-7 cell line, the number of G1-phase entotic cells was higher, probably due to p53-mediated cell cycle arrest or the preferred cell invasion in the G1-phase. Overall, in tumors with active p53 protein expression, the entosis contribution to polyploidy and genetic instability of tumor cells is less than in p53 tumor cells.