The cell cycle is a defining characteristic of living organisms. In multicellular organisms, including humans, the cell cycle governs the duplication of cells in a manner that assures accurate DNA replication and cell division. Cell cycle regulation is considered such an essential element of biology that Leland H. Hartwell, R. Timothy Hunt and Paul M. Nurse were recognized with the 2001 Nobel Prize in Physiology for their discoveries of "key regulators of the cell cycle."

Dysregulation of the cell cycle can lead to uncontrolled cell division and tumor formation. Cell cycle inhibitors, particularly those that target cyclin-dependent kinase (CDK), are being tested in clinical trials as novel cancer therapies.

Flow cytometry has emerged as a rapid and robust approach for cell cycle analysis and has become a powerful tool in the development of experimental therapies that target the cell cycle.

Several strategies exist for monitoring the cell cycle by flow cytometry.

1. DNA Analysis:

Fluorescent dyes, such as propidium iodide, can be used to stain cells and will bind to DNA molecules. The level of fluorescence can be used to distinguish different phases of the cell cycle. Bromodeoxyuridine (BrdU) can be incorporated into DNA during replication and anti-BrdU antibodies can be used for staining in order to measure level of DNA synthesis by flow cytometry.

2. Protein Analysis:

Proteins involved with cell cycle regulation, such as CDK, retinoblastoma, p53 and other cell cycle proteins, can be measured by flow cytometry and can be used to characterize levels of cell cycle dysregulation in a sample.

3. Protein Modification:

Proteins undergo post-translational modifications like phosphorylation during the cell cycle and this can also be dysregulated in tumor cells. Flow cytometry can be used to measure specific post-translational modifications with antibodies that bind to specific molecular modifications.

Consider using one of these approaches in your next study to evaluate cell cycle by flow cytometry.