Cell cycle control and cell division: implications for chemically induced carcinogenesis.

Eukaryotic cells proceed through an ordered series of events constituting the cell cycle, during which their chromosomes are duplicated and one copy of each daughter chromosome segregates to each daughter cell (mitosis). A precise and stringent regulation of this cell cycle is absolutely necessary for normal development of multicellular organisms; loss of cell cycle control, however, may ultimately lead to the generation of tumors. The present article provides an overview on the molecular mechanisms constituting the two most important checkpoints within the cell cycle of eukaryotic cells, that is, the spindle/mitotic checkpoint and the DNA damage checkpoint. It will be discussed how these checkpoints may be impaired by chemical carcinogens and how these interactions may contribute to the generation of aneuploidy and accumulation of somatic mutations, two major characteristics of human tumor cells.