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Caspases in apoptosis

Wang J, Lenardo MJ. Roles of caspases in apoptosis, development, and cytokine maturation revealed by homozygous gene deficiencies. J Cell Sci 2000 113 753-757. [Pg.36]

Pro-caspases are activated by cleavage at the same consensus site, either by themselves or by other caspases. Those that activate other caspases, including themselves, are initiator caspases (caspases-8, -9, and -10) and those that cleave other protein substrates are effector caspases (caspases-3, -6 and -7). The likely roles of effector caspases in apoptosis are ... [Pg.422]

Mitochondrial permeability transition involves the opening of a larger channel in the inner mitochondrial membrane leading to free radical generation, release of calcium into the cytosol and caspase activation. These alterations in mitochondrial permeability lead eventually to disruption of the respiratory chain and dqDletion of ATP. This in turn leads to release of soluble intramito-chondrial membrane proteins such as cytochrome C and apoptosis-inducing factor, which results in apoptosis. [Pg.776]

Proteasomal inhibition represents a novel strategy in cancer treatment and the small molecule Bortezomid (PS-341, Velcade ) has been approved for the treatment of refractory and relapsed multiple myeloma, a proliferative disease of plasma cells. Bortezomid inhibits an active site in a proteasome subunit and remarkably shows selective cytotoxicity to cancer cells. Although the underlying mechanisms are not completely understood bortezomid apparently induces a cell stress response in these tumor cells followed by caspase-dependent apoptosis. Whether bortezomid is beneficial for the treatment of other proliferative disease is currently being tested in clinical trials. [Pg.1266]

Topo inhibitors are found to be the most efficient inducers of apoptosis. The main pathways leading from topo-mediated DNA damage to cell death involve activation of caspases in the cytoplasm by pro-apoptotic molecules released from mitochondria. In some cells, the apoptotic response also involves the death receptor Fas (APO-1/CD95). The engagement of these apoptotic ef-... [Pg.45]

Many of the morphological and biochemical changes that occur in cells that die by necrosis are very different from those that occur in apoptosis. During necrosis cells swell, mitochondria and endoplasmic reticulum lose their structure and become dysfunctional and the nuclear membrane becomes disrupted (Fig. 35-1). Necrotic death is independent of premitochondrial apoptotic proteins such as Bax, cytochrome c release and caspase activation. Necrosis is further distinguished from apoptosis by the fact that necrosis usually occurs as the result of a traumatic physical injury or stroke and cells die en masse, whereas apoptosis typically occurs in individual cells within a population of surviving neighbors. [Pg.604]

High doses of trichothecenes promote rapid onset of leukocyte apoptosis which likely contributes to immunosuppression. DON and other trichothecenes cause apoptosis in vitro in primary T-cells, B-cells and IgA+ B cells20 as well as HL-60,53 U937 and RAW 264.7 cell lines43 via caspase-mediated mechanisms.54 These in vitro findings are relevant to the intact animal since in vivo administration of trichothecenes to rodents results in apoptosis in thymus, spleen and bone marrow.55-56 Capacity of a trichothecene to induce apoptosis corresponds to ability to inhibit translation.57... [Pg.297]

In apoptosis a series of events takes place in an orderly sequence involving the activation of various proteases which are called caspases, for cysteine and aspartate proteases. Several distinct caspases act in a cascade vaguely reminiscent of the blood-clotting cascade of complement proteins. If one wishes to interfere with the apoptotic process, then one strategy would be to develop drugs that inhibit various caspases, a current effort underway in the pharmaceutical industry. [Pg.71]

Caspases are a family of evolutionary conserved cysteine proteases that cleave their substrates after an aspartic acid residue within a defined consensus sequence (Alnemri et al, 1996). They play a cracial role in the apoptotic program, as most of the characteristic features observed in apoptosis are attributable to their action (Eamshaw et al, 1999). They are... [Pg.288]

Figure 3. The many ways to lose a HAT. Decreased amounts of functional CBP protein and subsequent CBP s loss of function has been observed in different contexts of neurological disorders and neuronal apoptosis. RTS (Rubinstein-Taybi Syndrome) results from a mutation on one cbp gene allele. In several cases of polyQ diseases, CBP can be sequestred by the mutated polyQ proteins, forming aggregates in the cytoplasm or the nucleus. CBP proteasomal degradation was also shown to be favored by polyQ proteins. CBP is a caspase-6 substrate in cerebellar granule neurons (CGN) deprived of potassium modeling caspase-dependent apoptosis. Finally, cbp gene repression has been observed in oxidative stress-induced death of a motomeuronal cell line. The mechanisms by which CBP levels are reduced in motomeurons of ALS mice is still unknown... Figure 3. The many ways to lose a HAT. Decreased amounts of functional CBP protein and subsequent CBP s loss of function has been observed in different contexts of neurological disorders and neuronal apoptosis. RTS (Rubinstein-Taybi Syndrome) results from a mutation on one cbp gene allele. In several cases of polyQ diseases, CBP can be sequestred by the mutated polyQ proteins, forming aggregates in the cytoplasm or the nucleus. CBP proteasomal degradation was also shown to be favored by polyQ proteins. CBP is a caspase-6 substrate in cerebellar granule neurons (CGN) deprived of potassium modeling caspase-dependent apoptosis. Finally, cbp gene repression has been observed in oxidative stress-induced death of a motomeuronal cell line. The mechanisms by which CBP levels are reduced in motomeurons of ALS mice is still unknown...
Apoptosis or programmed cell death is one of the regulatory mechanisms for the removal of unwanted cells. Apoptosis is induced by the stimulation of several different cell surface receptors in association with caspase activation. Apoptosis of a cell is thus a complicated process and can be assayed by various methods. Among widely used methods, the TUNEL assay is described here. [Pg.92]

Figure 20.35 Mechanisms by which external or internal stress leads to cell damage resulting in apoptosis. The stress leads to activation of initiator proteolytic enzymes (caspases) that initiate activation of effector caspases. These enzymes cause proteolytic damage to the cytoskeleton, plasma membrane and DNA. The activation of DNAases in the nucleus results in cleavage of DNA chains between histones that produces a specific pattern of DNA damage which, upon electrophoresis, gives a specific pattern of DNA fragments. The major endproduct of apoptosis are the apoptolic bodies which are removed by the phagocytes. Figure 20.35 Mechanisms by which external or internal stress leads to cell damage resulting in apoptosis. The stress leads to activation of initiator proteolytic enzymes (caspases) that initiate activation of effector caspases. These enzymes cause proteolytic damage to the cytoskeleton, plasma membrane and DNA. The activation of DNAases in the nucleus results in cleavage of DNA chains between histones that produces a specific pattern of DNA damage which, upon electrophoresis, gives a specific pattern of DNA fragments. The major endproduct of apoptosis are the apoptolic bodies which are removed by the phagocytes.
Singh AV, Xiao D, Lew KL, Dhir R, Singh SV. (2004) Sulforaphane induces caspase-mediated apoptosis in cultured PC-3 human prostate cancer cells and retards growth of PC-3 xenografts in vivo. Carcinogenesis 25 83-90. [Pg.303]

In aminoglycoside-treated animals, the cells can be led to canonical apop-totic death through activation of caspases. Caspase-9 forms an apoptosome complex with cytochrome c and APAF-1 and leads to apoptosis through activation of caspase-3. Aminoglycosides activate caspases in auditory structures conversely, inhibition of caspase activity successfully blocks neomycin-induced vestibulotoxicity. In contrast, apoptotic markers were essentially absent in a mouse model of chronic kanamycin ototoxicity where death of auditory sensory cells ensued via cathepsins. The activation of cathepsin D was accompanied by the nuclear translocation of endonuclease G, necrotic cleavage of PARP, and activation of p,-calpain, all facets of necrotic cell death. [Pg.262]

The group at Pharmacyclics developed a related phenyl hydroxamic add HDACi, PCI-34051 (27e) and demonstrated this to display greater than 200-fold selectivity for HDAC8 (IC5o = 10nM) over the other HDAC isoforms [40b]. Interestingly, this compound induced caspase-dependent apoptosis in T-cell lymphomas and leukemias at low micromolar concentrations, but not in other hematopoietic or solid tumor cell lines. Furthermore, PCI-34051 does not cause detectable tubulin or histone acetylation. [Pg.197]

We will synthesize a 6,000-member focused library designed to inhibit the caspase family of cysteine proteases involved in apoptosis. [Pg.491]

Shao RG, Cao CX, Pommier Y (1997) Activation of PKC alpha downstream from caspases during apoptosis induced by 7-hydroxystaurosporine or the topoi-somerase inhibitors, camptothecin and etoposide, in human myeloid leukemia HL60 ceUs. J Biol Chem 272 31321-31325... [Pg.89]


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See also in sourсe #XX -- [ Pg.270 , Pg.273 , Pg.305 ]




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