Control of macroautophagy by calcium, calmodulin-dependent kinase kinase-beta, and Bcl-2.

Macroautophagy is an evolutionary conserved lysosomal pathway involved in the turnover of cellular macromolecules and organelles. In spite of its essential role in tissue homeostasis, the molecular mechanisms regulating mammalian macroautophagy are poorly understood. Here, we demonstrate that a rise in the free cytosolic calcium ([Ca(2+)](c)) is a potent inducer of macroautophagy.

Apoptosome-independent activation of the lysosomal cell death pathway by caspase-9.

The apoptosome, a heptameric complex of Apaf-1, cytochrome c, and caspase-9, has been considered indispensable for the activation of caspase-9 during apoptosis. By using a large panel of genetically modified murine embryonic fibroblasts, we show here that, in response to tumor necrosis factor (TNF), caspase-8 cleaves and activates caspase-9 in an apoptosome-independent manner. Interestingly, caspase-8-cleaved caspase-9 induced lysosomal membrane permeabilization but failed to activate the effector caspases whereas apoptosome-dependent activation of caspase-9 could trigger both events.

No difference in early cellular response of the pseudo-synovial membrane after total hip arthroplasty: comparison of 3 combinations of bearing materials.

Background: Wear-resistant bearing materials may hypothetically reduce chronic inflammation in the pseudosynovial membrane as compared to less wear-resistant bearing materials such as polyethylene. We assessed the foreign body response in the pseudosynovial membrane in vivo after total hip replacement.

Methods: 37 patients from a larger prospective randomized trial of 225 patients had biopsies taken arthroscopically from the artificial hip joint (i.

Ischemia leads to apoptosis--and necrosis-like neuron death in the ischemic rat hippocampus.

Morphological evidence of apoptosis in transient forebrain ischemia is controversial. We therefore investigated the time sequence of apoptosis-related antigens by immunohistochemistry and correlated it with emerging nuclear patterns of cell death in a model of transient forebrain ischemia in CA1 pyramidal cells of the rat hippocampus. The earliest ischemic changes were found on day 2 and 3, reflected by an upregulation of phospho-c-Jun in a proportion of morphologically intact CA1 neurons, which matched the number of neurons that succumbed to ischemia at later time points.

Calcium and calpain as key mediators of apoptosis-like death induced by vitamin D compounds in breast cancer cells.

The active form of vitamin D(3) (1,25(OH)(2)D(3)) induces an increase in the intracellular free calcium ([Ca(2+)](i)) and caspase-independent cell death in human breast cancer cells. Here we show that the treatment of MCF-7 breast cancer cells with 1,25(OH)(2)D(3) or its chemotherapeutic analog, EB 1089, releases Ca(2+) from the endoplasmic reticulum. The increase in [Ca(2+)](i) was associated with the activation of a calcium-dependent cysteine protease, mu-calpain.

Epidermal growth factor receptor mutation type III transfected into a small cell lung cancer cell line is predominantly localized at the cell surface and enhances the malignant phenotype.

In the present study we transfected the epidermal growth factor receptor (EGFR)-negative small cell lung cancer cell line, GLC3, with the type III EGFR mutation (EGFRvIII). The EGFRvIII protein could be detected by Western blot analysis as a 145-kDa protein, which by immunohistochemistry appeared to be localized at the cell surface. Ultrastructurally EGFRvIII was expressed mainly at the cell surface with clusters at cell-cell contacts.