BioFiles Volume 5, Number 8 — Cell-Based Assays

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Apoptosis is a highly regulated program of cell death that is critical for normal homeostasis, development, wound repair and the removal of pathogen-infected cells. Abnormalities in apoptosis contribute to pathologies in disorders as diverse as Amyotrophic Lateral Sclerosis (ALS), AIDS, cancer, and ischemia. The ability to circumvent the normal induction of apoptosis is often utilized by tumor cells and viruses as a method of increased survival to normal host defenses. Conversely, excessive levels of apoptosis underlie the depletion of T-helper CD4+ cells during HIV progression and neurons in Parkinson's and Alzheimer's disease.

The molecular mechanisms of apoptosis have been extensively characterized and involve multiple energy-dependent steps which culminate in DNA fragmentation, protein cleavage, alternations in membrane asymmetry, organelle degradation, and the breakdown of the cell into vesicles called apoptotic bodies. At least three major pathways are known to initiate apoptosis, the extrinsic (death receptor) pathway, the intrinsic (mitochondrial) pathway, and the perforin-granzyme pathway. However, the majority of apoptosis-initiating processes converge at the execution pathway initiated by caspase-3 cleavage.

The choice of a kit or reagent depends on multiple parameters including which pathway induces the apoptotic cascade, the type and number of cells used, and the desired method of analysis. Sigma® offers a wide variety of kits and reagents used for the study of and measurement of apoptosis including assays for caspase activation, DNA fragmentation, loss of mitochondrial integrity, and the induction of membrane asymmetry. Our collection of products also includes the most complete selection of inhibitors and inducers of apoptosis in the industry.

Apoptosis Detecting Kits

Reagents for Monitoring Mitochondrial Function

Reagents for Monitoring Apoptosis

Apoptosis-Inhibiting Compounds

Apoptosis-Inducing Compounds

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