T lymphocyte activation and proliferation is involved in many pathological processes. We have recently shown that carbon monoxide (CO), an enzymatic product of heme oxygenase-1 (HO-1), confers potent antiproliferative effects in airway and vascular smooth muscle cells. The purpose of this study was to determine whether CO can inhibit T lymphocyte proliferation and then to determine the mechanis...

Following activation with proliferative stimuli, including ligation of CD40, dense human tonsillar B cells (>98% cells in G(0)) have increased cleavage and activation of caspase-8 and -6 accompanied by decreased caspase-3 activation and apoptosis. Proliferation was blocked by either a broad specificity caspase inhibitor or inhibitors selective for caspase-6 or caspase-8. In contrast, an inhibit...

Background: Mesenchymal stem cells (MSCs) are undifferentiated with the ability of multi-potency, pluripotency, and self-renewal. MSCs show great promise in cancer therapy due to their unique features. MSC secrete various cytokines multifunctional properties, although roles unclear. Methods: We have investigated influence secreted from on KG-1 as a cell model acute myeloid leukemia (AML). For t...

Our previous study has found the anti-tumor activity of oleandrin in osteosarcoma cells in vitro, but the signal transduction process of cell apoptosis induced by oleandrin is uncertain, which is explored in this study. Fluorescence staining and flow cytometry (FCM) was performed to detect the cell apoptosis, intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (MMP)...

The notion that the cell death machinery is utilized during lens organelle degradation is supported by the observation that well characterized apoptotic substrates are cleaved during this process. Here, we test directly the role of executioner caspases (caspase-3, -6, and -7) in fiber cell differentiation. The distribution of mRNA, protein, and enzymatic activity for each caspase was determined...

Caspases are cysteine proteases that play critical roles in apoptosis and other key cellular processes. A mechanism of caspase regulation that has been described in mammals and nematodes involves caspase-like decoy molecules, enzymatically inactive caspase homologs that have arisen by gene duplication and acquired the ability to regulate other caspases. Caspase-like decoy molecules are not foun...

Activation of the caspase proteases represents a central point in apoptosis. The requirement for spermine for the processes leading to caspase activation has been studied in transformed embryonic fibroblasts obtained from gyro (Gy) mutant male mice. These cells lack spermine synthase activity and thus provide a valuable model to study the role of spermine in cell processes. Gy fibroblasts do no...

Calprotectin, a calcium-bound protein complex, is abundant in the cytosol of neutrophils. It has been reported that this protein has an apoptotic activity in tumor cells. Since calprotectin increases in colorectal cancer, this study was conducted to investigate, for the first time, the cytotoxicity/apoptotic effect of calprotectin on HT29/219 and SW742 colon carcinoma and adenocarcinoma cell li...

Drosophila Reaper (RPR), Head Involution Defective (HID), and GRIM induce caspase-dependent cell death and physically interact with the cell death inhibitor DIAP1. Here we show that HID blocks DIAP1's ability to inhibit caspase activity and provide evidence suggesting that RPR and GRIM can act similarly. Based on these results, we propose that RPR, HID, and GRIM promote apoptosis by disrupting ...

Two subsets of human CTL have been defined based upon phenotype and function: CD4(-) CD8(-) double-negative (DN) CTL lyse susceptible targets via Fas-Fas ligand interaction and CD8(+) CTL via the granule exocytosis pathway. CD8(+) CTL, but not DN CTL, can mediate an antimicrobial activity against Mycobacterium tuberculosis-infected target cells that is dependent on cytotoxic granules that conta...