Morphofunctional Differences of Micronuclei in Cultures of Human p53-Positive and p53-Negative Tumor Cells

Micronuclei that are often present in tumor cells are not only the indicator of genetic instability, they also can induce DNA damage during cell progression through the cell cycle. p53 protein is the key regulator of the cell cycle. In this study we compared morphofunctional features of micronuclei depending on the presence of wild-type p53 gene: in human breast adenocarcinoma MCF-7 (p53⁺) and human epidermoid carcinoma A431 (p53^-). The number of cells with MN in these cell lines does not depend on the presence of active p53. However, micronuclei in cell culture with mutant p53 protein more often have lamina defects, carry DNA damage, and generally determine higher risk of tumor progression. Asynchronous with the main nucleus DNA replication in micronuclei in p53⁺ and p53^- cell cultures demonstrates predisposition of cells with micronuclei to chromothripsis.