2,636 research outputs found
Aspirin Has Antitumor Effects via Expression of Calpain Gene in Cervical Cancer Cells
Aspirin and other nonsteroidal anti-inflammatory drugs show efficacy in the prevention of cancers. It is known that they can inhibit cyclooxygenases, and some studies have shown that they can induce apoptosis. Our objective in this study was to investigate the mechanism by which aspirin exerts its apoptosis effects in human cervical cancer HeLa cells. The effect of aspirin on the gene expression was studied by differential mRNA display RT-PCR. Among the isolated genes, mu-type calpain gene was upregulated by aspirin treatment. To examine whether calpain mediates the antitumor effects, HeLa cells were stably transfected with the mammalian expression vector pCR3.1 containing mu-type calpain cDNA (pCRCAL/HeLa), and tumor formations were measured in nude mice. When tumor burden was measured by day 49, HeLa cells and pCR/HeLa cells (vector control) produced tumors of 2126 mm3 and 1638 mm3, respectively, while pCRCAL/HeLa cells produced markedly smaller tumor of 434 mm3 in volume. The caspase-3 activity was markedly elevated in pCRCAL/HeLa cells. The increased activity levels of caspase-3 in pCRCAL/HeLa cells, in parallel with the decreased tumor formation, suggest a correlation between caspase-3 activity and calpain protein. Therefore, we conclude that aspirin-induced calpain mediates an antitumor effect via caspase-3 in cervical cancer cells
FDI and Its Impact on Trade in the East Asian Transition Economies
As globalization and trade liberalization have increased integration of the world economy through financial and trade flows, the role of FDI and trade on economic growth is becoming more influential. This paper investigates the impact of FDI on trade of the East Asian economic transition countries, namely the China, Cambodia, Lao PDR, and Vietnam, employing FDI flow and FDI stock data separately. The data from these four countries during the period 1990–2019 have been collected, and OLS and panel within fixed effect estimators are utilized. The main findings show that, first, when estimated using FDI flow as independent variable, there exists complementary effect between FDI and trade, and the coefficients are significant except for Cambodia. Second, when estimated using FDI stock as independent variable, the impact of FDI decreases and even substitutability effect is found in China at significant level. Third, in both cases, the coefficient of FDI is shown positive and significant in Vietnam. In addition, the paper finds the effects of human capital, GDP, and WTO accession on trade are positive, while the effects of exchange rate, financial development, and tariff rate vary among the East Asian economic transition countries
Comparison of Two Mice Strains, A/J and C57BL/6, in Caspase-1 Activity and IL-1β Secretion of Macrophage to Mycobacterium leprae Infection
A/J mice were found to have amino acid differences in Naip5, one of the NOD-like receptors (NLRs) involved in the cytosolic recognition of pathogen-associated molecular patterns and one of the adaptor proteins for caspase-1 activation. This defect was associated with a susceptibility to Legionella infection, suggesting an important role for Naip5 in the immune response also to other intracellular pathogens, such as Mycobacterium leprae. In this study, the immune responses of macrophages from A/J mice against M. leprae were compared to those of macrophages from C57BL/6 mice. Infection with M. leprae induced high levels of TNF-α production and NF-κB activation in A/J and C57BL/6 macrophages. Caspase-1 activation and IL-1β secretion were also induced in both macrophages. However, macrophages from A/J mice exhibited reduced caspase-1 activation and IL-1β secretion compared to C57BL/6 macrophages. These results suggest that NLR family proteins may have a role in the innate immune response to M. leprae
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Mitochondrial Dysfunction Induces Formation of Lipid Droplets as a Generalized Response to Stress
Lipid droplet (LD) formation is a hallmark of cellular stress. Cells attempt to combat noxious stimuli by switching their metabolism from oxidative phosphorylation to glycolysis, sparing resources in LDs for generating cellular reducing power and for anabolic biosynthesis. Membrane phospholipids are also a source of LDs. To elucidate the formation of LDs, we exposed mice to hyperoxia, hypoxia, myocardial ischemia, and sepsis induced by cecal ligation and puncture (CLP). All the above-mentioned stressors enhanced the formation of LDs, as assessed by transmission electron microscopy, with severe mitochondrial swelling. Disruption of mitochondria by depleting mitochondrial DNA (ρ0 cells) significantly augmented the formation of LDs, causing transcriptional activation of fatty acid biosynthesis and metabolic reprogramming to glycolysis. Heme oxygenase (HO)-1 counteracts CLP-mediated septic shock in mouse models. In HO-1-deficient mice, LD formation was not observed upon CLP, but a concomitant decrease in “LD-decorating proteins” was observed, implying a link between LDs and cytoprotective activity. Collectively, LD biogenesis during stress can trigger adaptive LD formation, which is dependent on mitochondrial integrity and HO-1 activity; this may be a cellular survival strategy, apportioning energy-generating substrates to cellular defense
Melittin restores proteasome function in an animal model of ALS
Amyotrophic lateral sclerosis (ALS) is a paralyzing disorder characterized by the progressive degeneration and death of motor neurons and occurs both as a sporadic and familial disease. Mutant SOD1 (mtSOD1) in motor neurons induces vulnerability to the disease through protein misfolding, mitochondrial dysfunction, oxidative damage, cytoskeletal abnormalities, defective axonal transport- and growth factor signaling, excitotoxicity, and neuro-inflammation
PG-RCNN: Semantic Surface Point Generation for 3D Object Detection
One of the main challenges in LiDAR-based 3D object detection is that the
sensors often fail to capture the complete spatial information about the
objects due to long distance and occlusion. Two-stage detectors with point
cloud completion approaches tackle this problem by adding more points to the
regions of interest (RoIs) with a pre-trained network. However, these methods
generate dense point clouds of objects for all region proposals, assuming that
objects always exist in the RoIs. This leads to the indiscriminate point
generation for incorrect proposals as well. Motivated by this, we propose Point
Generation R-CNN (PG-RCNN), a novel end-to-end detector that generates semantic
surface points of foreground objects for accurate detection. Our method uses a
jointly trained RoI point generation module to process the contextual
information of RoIs and estimate the complete shape and displacement of
foreground objects. For every generated point, PG-RCNN assigns a semantic
feature that indicates the estimated foreground probability. Extensive
experiments show that the point clouds generated by our method provide
geometrically and semantically rich information for refining false positive and
misaligned proposals. PG-RCNN achieves competitive performance on the KITTI
benchmark, with significantly fewer parameters than state-of-the-art models.
The code is available at https://github.com/quotation2520/PG-RCNN.Comment: Accepted by ICCV 202
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