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Cell death requires coordinated intracellular signalling before disassembly of cell architecture by degradative enzymes. Although the death signalling cascades that involve the mitochondria, the ER and the plasma membrane have been extensively characterized, only a handful of studies have examined the functional and structural alterations of the nuclear pore complex (NPC) during neuronal death. Here, we show that during excitotoxic neuronal degeneration calpains redistributed across the nuclear envelope and mediated the degradation of NPC components causing altered permeability of the nuclear membrane. In primary dissociated neurons, simultaneous recording of cytosolic [Ca2+] and localization of fluorescent proteins showed that the onset of Ca2+ overload signalled a progressive increase in the diffusion of small reporter molecules across the nuclear envelope. Later, calpain-mediated changes in nuclear pore permeability allowed accumulation of large proteins in the nucleus. Further, in a model of excitotoxic neuronal degeneration in Caenorhabditis elegans, we found similar nuclear changes and redistribution of fluorescent probes across the nuclear membrane in dying neurons. Our findings strongly suggest that increased leakiness of the nuclear barrier affects nucleocytoplasmic transport, alters the localization of proteins across the nuclear envelope and it is likely to be involved in Ca2+-dependent cell death, including ischemic neuronal demise. [ABSTRACT FROM AUTHOR]

Despite tremendous advances over the last 15 years in understanding fundamental mechanisms of apoptosis, this has failed to translate into improved cancer therapy for patients. However, there may now be light at the end of this long tunnel. Antiapoptotic Bcl-2 family members may be divided into two subclasses, one comprising Bcl-2, Bcl-XL and Bcl-w and the other Mcl-1 and Bcl2A1. Neutralization of both subclasses is required for apoptosis induction. Solution of the structure of antiapoptotic Bcl-2 family proteins has led to the design of novel small molecule inhibitors. Although many such molecules have been synthesized, rigorous verification of their specificity has often been lacking. Further studies have revealed that many putative Bcl-2 inhibitors are not specific and have other cellular targets, resulting in non-mechanism based toxicity. Two notable exceptions are ABT-737 and a related orally active derivative, ABT-263, which bind with high affinity to Bcl-2, Bcl-XL and Bcl-w and may prove to be useful tools for mechanistic studies. ABT-263 is in early clinical trials in lymphoid malignancies, small-cell lung cancer and chronic lymphocytic leukemia, and some patients have shown promising results. In in vitro studies, primary cells from patients with various B-cell malignancies are exquisitely sensitive to ABT-737, exhibiting novel morphological features of apoptosis including marked outer mitochondrial membrane rupture.Cell Death and Differentiation (2009) 16, 360–367; doi:10.1038/cdd.2008.137; published online 19 September 2008 [ABSTRACT FROM AUTHOR]

Proteasome inhibitors, including lactacystin and MG132 (carbobenzoxyl-leucinyl-leucinyl-leucinal), potently induce apoptosis in leukaemic B cells from patients with B cell chronic lymphocytic leukaemia (B-CLL). This pro-apoptotic effect occurs in cells from patients at all stages of the disease, including those resistant to conventional chemotherapy, suggesting that proteasome inhibitors may be useful for treatment of B-CLL. Following initial inhibition of proteasomal activity, these agents induce mitochondrial cytochrome c release and caspase-dependent apoptosis, involving cleavage/activation of caspases -2, -3, -7, -8 and -9. Pre-treatment with the cell permeable caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp (OMe)fluoromethyl ketone (Z-VAD.fmk), did not prevent the release of cytochrome c or partial processing of caspase-9 but prevented activation of effector caspases and the induction of apoptosis. These results suggest that the release of cytochrome c is caspase independent and that caspase-9 is the initiator caspase in proteasome inhibitor-induced apoptosis of B-CLL cells. Activation of B-CLL lysates with dATP results in the formation of an approximately 700 kDa caspase-activating apoptosome complex containing Apaf-1. We describe for the first time the formation of a similar approximately 700 kDa caspase-activating apoptosome complex in B-CLL cells induced to undergo apoptosis by proteasome inhibitors. [ABSTRACT FROM AUTHOR]

Some Aspects of the Toxicology of Trimethyl and Triethyl Phosphorothioates. ALDRIDGE, W. N., DINSDALE, D., NEMERY, B., AND VERSCHOYLE, R. D. (1985). 5, S47–S60. The pharmacokinetics (disposal curves) of trimethyl and triethyl phosphorothioates have been determined. The concentrations to which the lung has been exposed at the LD50 dose of different chemical structures have been compared with the dose administered to the animal; the variation of LD50 of different chemical structures is little reduced. The kinetics of the reaction of -trimethyl phosphorodithioate or -triethyl phosphorothioate with plasma cholinesterase and carboxylesterase and brain acetylcholinesterase have been determined. The relation between inhibition and circulating concentrations have been examined. Changes in Clara cells reported by others seem to be physiological rather than pathological. -Trimethyl phosphorodithioate is metabolised by rat lung and liver slices and microsomes. From these studies and the effect of various pretreatments of the rats on toxicity to the lung, it is probable that the proximal toxin is produced in the lung by oxidative attack on the alkylthio moeity of the compounds. [ABSTRACT FROM PUBLISHER]