排序方式: 共有123条查询结果,搜索用时 15 毫秒
11.
H-C Chi S-L Chen C-J Liao C-H Liao M-M Tsai Y-H Lin Y-H Huang C-T Yeh S-M Wu Y-H Tseng C-Y Chen C-Y Tsai I-H Chung W-J Chen K-H Lin 《Cell death and differentiation》2012,19(11):1802-1814
Although accumulating evidence has confirmed the important roles of thyroid hormone (T3) and its receptors (TRs) in tumor progression, the specific functions of TRs in carcinogenesis remain unclear. In the present study, tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) was directly upregulated by T3 in TR-overexpressing hepatoma cell lines. TRAIL is an apoptotic inducer, but it can nonetheless trigger non-apoptotic signals favoring tumorigenesis in apoptosis-resistant cancer cells. We found that TR-overexpressing hepatoma cells treated with T3 were apoptosis resistant, even when TRAIL was upregulated. This apoptotic resistance may be attributable to simultaneous upregulation of Bcl-xL by T3, because (1) knockdown of T3-induced Bcl-xL expression suppressed T3-mediated protection against apoptosis, and (2) overexpression of Bcl-xL further protected hepatoma cells from TRAIL-induced apoptotic death, consequently leading to TRAIL-promoted metastasis of hepatoma cells. Moreover, T3-enhanced metastasis in vivo was repressed by the treatment of TRAIL-blocking antibody. Notably, TRAIL was highly expressed in a subset of hepatocellular carcinoma (HCC) patients, and this high-level expression was significantly correlated with that of TRs in these HCC tissues. Together, our findings provide evidence for the existence of a novel mechanistic link between increased TR and TRAIL levels in HCC. Thus, TRs induce TRAIL expression, and TRAIL thus synthesized acts in concert with simultaneously synthesized Bcl-xL to promote metastasis, but not apoptosis. 相似文献
12.
13.
Background
α-Actinins cross-link actin filaments, with this cross-linking activity regulating the formation of focal adhesions, intracellular tension, and cell migration. Most non-muscle cells such as fibroblasts express two isoforms, α-actinin-1 (ACTN1) and α-actinin-4 (ACTN4). The high homology between these two isoforms would suggest redundancy of their function, but recent studies have suggested different regulatory roles. Interestingly, ACTN4 is phosphorylated upon growth factor stimulation, and this loosens its interaction with actin.Methodology/Principal Findings
Using molecular, biochemical and cellular techniques, we probed the cellular functions of ACTN4 in fibroblasts. Knockdown of ACTN4 expression in murine lung fibroblasts significantly impaired cell migration, spreading, adhesion, and proliferation. Surprisingly, knockdown of ACTN4 enhanced cellular compaction and contraction force, and increased cellular and nuclear cross-sectional area. These results, except the increased contractility, are consistent with a putative role of ACTN4 in cytokinesis. For the transcellular tension, knockdown of ACTN4 significantly increased the expression of myosin light chain 2, a element of the contractility machinery. Re-expression of wild type human ACTN4 in ACTN4 knockdown murine lung fibroblasts reverted cell spreading, cellular and nuclear cross-sectional area, and contractility back towards baseline, demonstrating that the defect was due to absence of ACTN4.Significance
These results suggest that ACTN4 is essential for maintaining normal spreading, motility, cellular and nuclear cross-sectional area, and contractility of murine lung fibroblasts by maintaining the balance between transcellular contractility and cell-substratum adhesion. 相似文献14.
Species of Lophiidae collected from the western South Pacific Ocean are examined. Nine nominal species are recognized, all but one species with their distributions extended eastwards and southwards from the western Pacific Ocean. Two new species are described from Polynesia. Lophiodes iwamotoi n. sp. is described from five specimens collected from Savannah Seamount. It is characterized by a relatively long third dorsal-fin spine (56.9-70.8% standard length, L(S)) that extends (when retracted) to between the end of the soft dorsal fin and caudal-fin base; a relatively short fifth dorsal-fin spine (10.5-13.1% L(S)); a relatively short and narrow head; 19-20 pectoral-fin rays. Lophiodes maculatus n. sp. is described from 20 specimens collected from Marquesas Islands. It is characterized by an extremely long third dorsal-fin spine (71.9-87.2% L(S)), extending well beyond the caudal-fin base; a relatively short fifth dorsal-fin spine (11.4-16.5% L(S)); 17-18 pectoral-fin rays. A key to the lophiids in the western South Pacific Ocean is provided. 相似文献
15.
Carmel Mothersill Richard W. Smith Lene Sørlie Heier Hans-Christian Teien Ole Christian Land Colin B. Seymour Deborah Oughton Brit Salbu 《Radiation and environmental biophysics》2014,53(1):103-114
Very little is known about the combined effects of low doses of heavy metals and radiation. However, such “multiple stressor” exposure is the reality in the environment. In the work reported in this paper, fish were exposed to cobalt 60 gamma irradiation with or without copper or aluminum in the water. Doses of radiation ranged from 4 to 75 mGy delivered over 48 or 6 h. Copper doses ranged from 10 to 80 μg/L for the same time period. The aluminum dose was 250 μg/L. Gills and skin were removed from the fish after exposure and explanted in tissue culture flasks for investigation of bystander effects of the exposures using a stress signal reporter assay, which has been demonstrated to be a sensitive indicator of homeostatic perturbations in cells. The results show complex synergistic interactions of radiation and copper. Gills on the whole produce more toxic bystander signals than skin, but the additivity scores show highly variable results which depend on dose and time of exposure. The impacts of low doses of copper and low doses of radiation are greater than additive, medium levels of copper alone have a similar level of effect of bystander signal toxicity to the low dose. The addition of radiation stress, however, produces clear protective effects in the reporters treated with skin-derived medium. Gill-derived medium from the same fish did not show protective effects. Radiation exposure in the presence of 80 μg/L led to highly variable results, which due to animal variation were not significantly different from the effect of copper alone. The results are stressor type, stressor concentration and time dependent. Clearly co-exposure to radiation and heavy metals does not always lead to simple additive effects. 相似文献
16.
17.
C Zinner M Krueger JL Reed M Kohl-Bareis H-C Holmberg B Sperlich 《Biology of sport / Institute of Sport》2016,33(1):71-76
In this study, we tested the hypothesis that breathing hyperoxic air (FinO2 = 0.40) while exercising in a hot environment exerts negative effects on the total tissue level of haemoglobin concentration (tHb); core (Tcore) and skin (Tskin) temperatures; muscle activity; heart rate; blood concentration of lactate; pH; partial pressure of oxygen (PaO2) and carbon dioxide; arterial oxygen saturation (SaO2); and perceptual responses. Ten well-trained male athletes cycled at submaximal intensity at 21°C or 33°C in randomized order: first for 20 min while breathing normal air (FinO2 = 0.21) and then 10 min with FinO2 = 0.40 (HOX). At both temperatures, SaO2 and PaO2, but not tHb, were increased by HOX. Tskin and perception of exertion and thermal discomfort were higher at 33°C than 21°C (p < 0.01), but independent of FinO2. Tcore and muscle activity were the same under all conditions (p > 0.07). Blood lactate and heart rate were higher at 33°C than 21°C. In conclusion, during 30 min of submaximal cycling at 21°C or 33°C, Tcore, Tskin and Tbody, tHb, muscle activity and ratings of perceived exertion and thermal discomfort were the same under normoxic and hyperoxic conditions. Accordingly, breathing hyperoxic air (FinO2 = 0.40) did not affect thermoregulation under these conditions. 相似文献
18.
Cell traction force and measurement methods 总被引:2,自引:0,他引:2
Cell traction forces (CTFs) are crucial to many biological processes such as inflammation, wound healing, angiogenesis, and
metastasis. CTFs are generated by actomyosin interactions and actin polymerization and regulated by intracellular proteins
such as alpha-smooth muscle actin (α-SMA) and soluble factors such as transforming growth factor-β (TGF-β). Once transmitted
to the extracellular matrix (ECM) through stress fibers via focal adhesions, which are assemblies of ECM proteins, transmembrane
receptors, and cytoplasmic structural and signaling proteins (e.g., integrins), CTFs direct many cellular functions, including
cell migration, ECM organization, and mechanical signal generation. Various methods have been developed over the years to
measure CTFs of both populations of cells and of single cells. At present, cell traction force microscopy (CTFM) is among
the most efficient and reliable method for determining CTF field of an entire cell spreading on a two-dimensional (2D) substrate
surface. There are currently three CTFM methods, each of which is unique in both how displacement field is extracted from
images and how CTFs are subsequently estimated. A detailed review and comparison of these methods are presented. Future research
should improve CTFM methods such that they can automatically track dynamic CTFs, thereby providing new insights into cell
motility in response to altered biological conditions. In addition, research effort should be devoted to developing novel
experimental and theoretical methods for determining CTFs in three-dimensional (3D) matrix, which better reflects physiological
conditions than 2D substrate used in current CTFM methods. 相似文献
19.
Anilkumar GN Selyutin O Rosenblum SB Zeng Q Jiang Y Chan TY Pu H Wang L Bennett F Chen KX Lesburg CA Duca J Gavalas S Huang Y Pinto P Sannigrahi M Velazquez F Venkatraman S Vibulbhan B Agrawal S Ferrari E Jiang CK Huang HC Shih NY George Njoroge F Kozlowski JA 《Bioorganic & medicinal chemistry letters》2012,22(1):713-717
Development of SAR at the C2 position of indole lead 1, a palm site inhibitor of HCV NS5B polymerase (NS5B IC(50)=0.053μM, replicon EC(50)=4.8μM), is described. Initial screening identified an acyl sulfonamide moiety as an isostere for the C2 carboxylic acid group. Further SAR investigation resulted in identification of acyl sufonamide analog 7q (NS5B IC(50)=0.039μM, replicon EC(50)=0.011μM) with >100-fold improved replicon activity. 相似文献
20.