Cell Cycle Arrest (N/A)

Cell cycle arrest refers to a regulatory mechanism that halts or delays the progression of a cell through the cell cycle at specific checkpoints. This process is essential for maintaining genomic integrity, especially in response to cellular stresses such as DNA damage, incomplete replication, or unfavorable environmental conditions. The arrest can be temporary (reversible) or permanent (irreversible), depending on the context and underlying signals. It acts as an alarm response triggered by aberrant proliferation signals or deleterious stimuli, thereby preventing dysfunctional cells from continuing through the cell cycle. Arrest is mediated by activation of natural checkpoints within the cell-cycle control system. These checkpoints operate mainly through negative intracellular signals that inhibit cyclin-dependent kinase (CDK) activity via phosphorylation, binding of inhibitory proteins (CKIs), proteolysis of cyclins, and transcriptional regulation. Dysregulation leading to loss-of-function mutations in checkpoint components allows uncontrolled proliferation—a hallmark feature in cancer. Conversely, pharmacologically inducing cell cycle arrest has become an effective anti-cancer strategy; for example, CDK4/6 inhibitors block progression through G1/S transition in tumor therapy.

Inhibition of cyclin-dependent kinases (CDKs)