22 research outputs found
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TRAIL Enhances Apoptosis of Human Hepatocellular Carcinoma Cells Sensitized by Hepatitis C Virus Infection: Therapeutic Implications
Hepatitis C virus (HCV) infection causes chronic liver diseases leading to hepatocellular carcinoma (HCC) and liver failure. We have previously shown that HCV sensitizes hepatocytes to mitochondrial apoptosis via the TRAIL death receptors DR4 and DR5. Although TRAIL and its receptors are selective targets for cancer therapy, their potential against HCC with chronic HCV infection has not been explored yet. Here we show that HCV induces DR4/DR5-dependent activation of caspase-8 leading to elevation of apoptotic signaling in infected cells and also present TRAIL effect in HCV-induced apoptotic signaling. HCV induced proteolytic cleavage of caspase-9 by stimulating DR4 and DR5, resulting in subsequent cleavage of caspase-3. Further, HCV-induced proteolytic cleavage in caspase-8, caspase-9, and caspase-3 was enhanced in the presence of recombinant TRAIL. HCV-induced cleavage in caspase-9 and increase in caspase-3/7 activity was completely suppressed by silencing of either DR4 or DR5. Perturbing DR4/DR5-caspase-8 signaling complex by silencing DR4 and DR5 or by chemical inhibitor specific to caspase-8 led to decrease of HCV-induced cleavage of poly(ADP-ribose) polymerase (PARP), a substrate for caspase-3 during apoptosis, indicating the functional role of caspase-8 in HCV-induced apoptotic signaling network. Furthermore, TRAIL enhanced PARP cleavage in apoptotic response induced by HCV infection, indicating the effect of TRAIL for the induction of selective apoptosis of HCC cells infected with HCV. Given the importance of apoptosis in HCC development, our data suggest that HCV-induced DR4 and DR5 may be considered as an attractive target for TRAIL therapy against HCC with chronic HCV infection
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Influence of water content on ion sorption and transport in cross-linked polymer membranes
Polymer membrane-based technologies have been successfully utilized for a variety of desalination applications, including reverse osmosis (RO), forward osmosis (FO), electrodialysis (ED), and others. In these applications, separation of water and ions is possible because of differences in their transport rates through the membrane. Generally, high water permeability through a membrane can be achieved by using more hydrophilic (i.e., highly water swollen) polymers. However, increasing water permeability often leads to a decrease in water/ion selectivity in hydrophilic polymers, rendering controlling water content of a polymer a key factor to achieve desirable ion separation properties. Thus, a fundamental understanding of ion transport in polymers with various water contents is essential for designing and optimizing polymer membranes.
The relationship between ion size and sorption/diffusion properties in water swollen uncharged polymers was investigated as a model system for understanding ion sorption and transport in more complex systems (i.e., charged polymer networks). Alkali metal chloride (e.g., LiCl, NaCl, and KCl) sorption and diffusion coefficients in a series of cross-linked poly(ethylene glycol) diacrylate (XLPEGDA) polymer membranes were measured as a function of external salt concentrations ranging from 0.01-1.0 M. Generally, ion sorption and diffusion coefficients increase as polymer water content increases. Salt activity coefficients in the polymers were quantified to better understand the thermodynamic non-ideality of ions in polymer networks. The Flory-Rehner theory was used to predict water volume fraction in the polymers equilibrated with salt solution, based on salt sorption measurements.
A series of cross-linked cation exchange membranes (CEMs) were synthesized with different water uptake values and similar fixed charge group concentrations to study the effect of water content on ion sorption. Equilibrium co-ion sorption data were interpreted using a thermodynamic model based on Donnan’s theory and Manning’s counter-ion condensation theory. The inhomogeneous morphology of the membranes was characterized by small angle X-ray scattering (SAXS). The Manning parameter was used as an adjustable constant to account for morphological heterogeneity.
Finally, the classic Merten and Lonsdale transport model for reverse osmosis membranes was reformulated to explicitly demonstrate the effects of concentration polarization and solution phase thermodynamic non-idealities on salt transport. A framework presented here accounts for the concentration dependence of ion activity coefficients in salt solutions, which was not explicitly included in the classic model.Chemical Engineerin
Partitioning of mobile ions between ion exchange polymers and aqueous salt solutions: importance of counter-ion condensation
Equilibrium partitioning of ions between a membrane and a contiguous external solution strongly influences transport properties of polymeric membranes used for water purification and energy generation applications. This study presents a theoretical framework to quantitatively predict ion sorption from aqueous electrolytes (e.g., NaCl, MgCl2) into charged (i.e., ion exchange) polymers. The model was compared with experimental NaCl, MgCl2, and CaCl2 sorption data in commercial cation and anion exchange membranes. Ion sorption in charged polymers was modeled using a thermodynamic approach based on Donnan theory coupled with Manning\u2019s counter-ion condensation theory to describe non-ideal behavior of ions in the membrane. Ion activity coefficients in solution were calculated using the Pitzer model. The resulting model, with no adjustable parameters, provides remarkably good agreement with experimental values of membrane mobile salt concentration. The generality of the model was further demonstrated using literature data for ion sorption of various electrolytes in charged polymers, including HCl sorption in Nafion
Predictive Factors for Complete Response and Recurrence after Transarterial Chemoembolization in Hepatocellular Carcinoma
Background/AimsTo investigate the predictive factors for complete response (CR) and recurrence after CR in patients with hepatocellular carcinoma (HCC) treated with transarterial chemoembolization (TACE).Methods : Among 691 newly diagnosed HCC patients, 287 were treated with TACE as a first therapy. We analyzed the predictive factors for CR, recurrence after CR, and overall survival (OS).Results : Eighty-one patients (28.2%) achieved CR after TACE, and recurrence after CR was detected in 35 patients (43.2%). In multivariate analyses, tumor size (≤5 cm) and single nodularity were predictive factors for CR, with hazard ratios (HRs) of 0.35 (p=0.002) and 0.41 (p20 ng/mL) level and multinodularity exhibited significant relationships with recurrence after CR, with HRs of 2.220 (p=0.026) and 3.887 (p5 cm), multinodularity, elevated serum AFP (>20 ng/mL) level, Child-Turcotte-Pugh score (B and C), and portal vein thrombosis were significant factors for OS.Conclusion : sIn patients treated with TACE as a first therapy, tumor size (≤5 cm) and single nodularity were predictive factors for CR, and multinodularity and elevated serum AFP (>20 ng/mL) levels were predictive factors for recurrence after CR. These factors were also significant for OS
HCV-induced DR4/DR5-mediated caspase-8 activity affects PARP cleavage.
<p>(A) Western blot analysis of cleaved PARP in HCV-infected cells. Whole cell lysates extracted from HCV-infected Huh7.5.1 cells grown in the absence or presence of recombinant TRAIL (100 ng/ml) were analyzed by Western blotting with antibodies specific to the indicated proteins. (B) Huh7.5.1 cells transfected with non-targeting (NT) or gene-specific (ST) siRNA pools targeting DR4 and DR5, respectively, were infected with HCVcc. At 3 days post-infection, whole cell lysates were analyzed by Western blotting with antibodies specific to the indicated proteins. (C) HCV-infected Huh7.5.1 cells stimulated with recombinant TRAIL (100 ng/ml) were treated with Z-VAD-FMK (pan inhibitor; 40 µM), Z-IETD-FMK (caspase-8 inhibitor; 40 µM), and Z-LEHD-FMK (caspase-9 inhibitor; 40 µM), respectively, for 72 h before harvest. The expression level of PARP was analyzed by Western blotting with anti-cleaved PARP antibody. (D) Western blot analysis showing dose-dependent effects of recombinant TRAIL on PARP cleavage in HCV-infected cells. HCV-infected Huh7.5.1 cells were treated with recombinant TRAIL for 72 h at the indicated dose points. Whole cell lysates were analyzed by Western blotting with anti-cleaved PARP antibody. Samples: MC, media control. (A-D) β-actin was used as an internal loading control.</p
A prospective comparative assessment of the accuracy of the FibroScan in evaluating liver steatosis
<div><p>Background/aims</p><p>Recent studies have demonstrated the utility of the FibroScan<sup>®</sup> device in diagnosing liver steatosis, but its usefulness has not been thoroughly appraised. We investigated the usefulness of the controlled attenuation parameter (CAP) in detecting and quantifying liver steatosis.</p><p>Methods</p><p>A prospective analysis was applied to 79 chronic liver disease patients who underwent a liver biopsy, a FibroScan investigation, ultrasonography, and hepatic steatosis index (HSI). The presence and degree of steatosis as measured by the FibroScan device, ultrasonography and HSI were compared with the results for the liver biopsy tissue.</p><p>Results</p><p>There was substantial concordance between the liver biopsy results and the CAP as evaluated by the kappa (κ) index test for detecting liver steatosis (κ<sub>CAP</sub> = 0.77, <i>P</i><0.001; κ<sub>ultrasonography</sub> = 0.60, <i>P</i><0.001; κ<sub>HSI</sub> = 0.47, <i>P</i><0.001). The areas under the receiver operating characteristic curve (AUROCs) of the CAP, ultrasonography, and HSI were 0.899 [95% confidence interval (CI) = 0.826–0.972)], 0.859 (95% CI = 0.779–0.939), and 0.766 (95% CI = 0.655–0.877), respectively. The optimal CAP cutoff value for differentiating between normal and hepatic steatosis was 247 dB/m, which produced sensitivity and specificity values of 91.9% and 85.7%, respectively, as well as a positive predictive value of 85.0% and a negative predictive value of 92.3%.</p><p>Conclusion</p><p>The CAP produces results that are highly concordant with those of a liver biopsy in detecting steatosis. Therefore, the CAP is a noninvasive and reliable tool for evaluating liver steatosis, even in the early stages.</p></div
HCV infection activates DR4/DR5-dependent caspase cascade.
<p>(A) Western blot analysis of Bax and cleaved caspase-8, caspase-9, and caspase-3 in HCV-infected cells. Huh7.5.1 cells infected with HCVcc in the absence or presence of recombinant TRAIL (100 ng/ml) were used for Western blot analysis with antibodies against the indicated proteins. β-actin was used as an internal loading control. Samples: MC, media control. (B and D) Silencing DR4 and DR5 prevent caspase-9 cleavage and caspase-3/7 activity induced by HCV infection. Huh7.5.1 cells transfected with non-targeting (NT) or gene-specific (ST) siRNA pools targeting DR4 and DR5, respectively, were infected with HCVcc. At 3 days post-infection, the mRNA levels of DR4 and DR5 were analyzed by real-time qRT-PCR (B) (mean±SD; n = 3; *p<0.05, **p<0.01) and whole cell lysates were analyzed by Western blotting with antibodies specific to the indicated proteins (C). (D) The activity of caspase-3/7 was measured according to manufacturer's instructions (mean±SD; n = 3; *p<0.005).</p
HCV infection stimulates DR4 and DR5 expression.
<p>(A-C) Quantitative analyses of DR4 and DR5 gene expression in HCV-infected cells. Huh7.5.1 cells were infected with HCVcc. At 3 days post-infection, cells were used for analysis of DR4 and DR5 gene expression. (A and B) Intracellular mRNA level of DR4 and DR5 genes were analyzed by real-time qRT-PCR. Human GNB2L1 was used to normalize changes in DR4 and DR5 gene expression (mean±SD; n = 3; *p<0.001). (C) The protein expression levels of DR4 and DR5 were analyzed by Western blotting with anti-DR4 and DR5 antibodies. The expression of HCV core protein was analyzed by Western blotting with anti-HCV core antibody. β-actin was used as an internal loading control. The relative intensity of DR4 and DR5 expression normalized to β-actin was analyzed by ImageJ.</p