Cell Cycle and Drug Sensitivity

Induction of tumor cell death by chemotherapeutic modalities often occurs in a cell cycle-dependent manner. It has also been observed that several regulatory proteins involved in tumor chemosensitivity and apoptosis are expressed periodically during the cell cycle progres sion. However, the nature of cancer cellular chemosensitivity and mechanisms of action of anti cancer drugs in different phases of the cell cycle still remain unknown. In this chapter we describe two methods (serum deprivation and pharmacological drug treatment) to synchronize human tumor cells in specific phases of the cell cycle, followed by induction of cell death by anticancer drugs. We also describ three methods (flow cytometry, Western blot, and DNA fragmentation) to measure the cell cycle-associated cytotoxic effects of chemotherapeutic agents.