77 research outputs found

    Arecoline induces HA22T/VGH hepatoma cells to undergo anoikis - involvement of STAT3 and RhoA activation

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    <p>Abstract</p> <p>Background</p> <p>Our previous study showed that, in basal cell carcinoma cells, arecoline reduces levels of the tumor cell survival factor interleukin-6 (IL-6), increases levels of tumor suppressor factor p53, and elicits cell cycle arrest, followed by apoptosis. In preliminarily studies, we observed that arecoline induces detachment of the human-derived hepatoma cell line HA22T/VGH from the extracellular matrix. In the present study, we explored the fate of the detached HA22T/VGH cells and investigated the underlying mechanism.</p> <p>Methods</p> <p>HA22T/VGH cells or primary cultured rat hepatocytes were treated with arecoline, then changes in morphology, viability, apoptosis, and the expression of surface β1-integrin, apoptosis-related proteins, and IL-6 were examined. Furthermore, activation of the signal transducer and activator of transcription 3 (STAT3) pathway and the RhoA/Rock signaling pathway, including p190RhoGAP and Src homology-2 domain-containing phosphatase SHP2, was examined.</p> <p>Results</p> <p>A low concentration of arecoline (≤ 100 μg/ml) caused cytoskeletal changes in HA22T/VGH cells, but not hepatocytes, and this was accompanied by decreased β1-integrin expression and followed by apoptosis, indicating that HA22T/VGH cells undergo anoikis after arecoline treatment. IL-6 expression and phosphorylation of STAT3, which provides protection against anoikis, were inhibited and levels of downstream signaling proteins, including Bcl-X<sub>L </sub>and Bcl-2, were decreased, while Bax expression, mitochondrial cytochrome c release, and caspase-3 activity were increased. In addition, phosphorylation/activation of p190RhoGAP, a RhoA inhibitor, and of its upstream regulator, SHP2, was inhibited by arecoline treatment, while Rho/Rock activation was increased. Addition of the RhoA inhibitor attenuated the effects of arecoline.</p> <p>Conclusions</p> <p>This study demonstrated that arecoline induces anoikis of HA22T/VGH cells involving inhibition of STAT3 and increased RhoA/Rock activation and that the STAT3 and RhoA/Rock signaling pathways are connected.</p

    Alterations in IL-6, IL-8, GM-CSF. TNF-α, and IFN-γ Release by Peripheral Mononuclear Cells in Patients with Active Vitiligo

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    The purpose of this study was to clarify the relationship between the cellular and humoral immune components in the pathogenesis of vitiligo vulgaris. By using cytokines as indicators of peripheral mononuclear cell (MNC) function, we compared the effects of phytohemagglutinin (PHA) and purified IgG on MNCs derived from patients suffering from active vitiligo with those from normal controls. The results revealed (i) a significant increase in spontaneous production of 11-6 and IL-8 in patients; (ii) PHA, purified IgG from patients (IgG-anti-MC), or IgG from normal controls (N-IgG) induced a significant increase in IL-6 but diminished GM-CSF, TNF-α, and IFN-γ release in patients; and (iii) IgG-anti-MC brought about a significantly higher stimulatory effect on IL-1β and IFN-γ production than N-IgG in normal controls. Immunologically, IL-6 can enhance melanocyte ICAM-1 expression, which may increase leukocyte-melanocyte attachment and cause melanocyte damage in vitiligo. A decrease in GM-CSF (an intrinsic growth factor for melanocyte) production may retard recovery from vitiligo by checking the proliferation of surviving melanocytes. A significant decrease in TNF-α and IFN-γ production may partially explain the reduced inflammatory reaction in vitiliginous lesions. That IgG-anti-MC stimulates an increase in IL-1β and IFN-γ production in controls suggests that IgG-anti-MC may play a role in melanocyte destruction mediated by monocytes

    Progesterone Increases Apoptosis and Inversely Decreases Autophagy in Human Hepatoma HA22T/VGH Cells Treated with Epirubicin

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    Hepatocellular carcinoma (HCC) is the leading cause of cancer-related deaths worldwide. Epirubicin can induce intracellular reactive oxygen species and is widely used to treat unresectable HCC. Progesterone has been found to inhibit the proliferation of hepatoma cells. This study was designed to test the combined effects of epirubicin and progesterone on human hepatoma cell line, HA22T/VGH. These cells were treated with different concentrations of epirubicin with or without the coaddition of 30 μM progesterone and then analyzed for apoptosis, autophagy, and expressions of apoptotic-related proteins and multidrug-resistant gene. Epirubicin treatment dose-dependently inhibited the growth of HA22T/VGH cells. Addition of 30 μM progesterone, which was inactive alone, augmented the effect of epirubicin on the inhibition of growth of HA22T/VGH cells. Cotreatment with progesterone enhanced epirubicin-induced apoptosis, as evidenced by greater increase in caspase-3 activity and in the ratio of the apoptosis-regulating protein, Bax/Bcl-XL. The combination also caused a decrease in autophagy and in the expression of multidrug resistance-related protein 1 mRNA compared to epirubicin alone. This study shows the epirubicin/progesterone combination was more effective in increasing apoptosis and inversely decreasing autophagy on HA22T/VGH cells treated with epirubicin alone, suggesting that this combination can potentially be used to treat HCC

    A Real World Report on Intravenous High-Dose and Non-High-Dose Proton-Pump Inhibitors Therapy in Patients with Endoscopically Treated High-Risk Peptic Ulcer Bleeding

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    Background and Study Aims. The optimal dose of intravenous proton-pump inhibitor (PPI) therapy for the prevention of peptic ulcer (PU) rebleeding remains controversial. This study aimed to understand the real world experiences in prescribing high-dose PPI and non-high-dose PPI for preventing rebleeding after endoscopic treatment of high-risk PU. Patients and Methods. A total of 220 subjects who received high-dose and non-high-dose pantoprazole for confirmed acute PU bleeding that were successfully treated endoscopically were enrolled. They were divided into rebleeding (n = 177) and non-rebleeding groups (n = 43). Randomized matching of the treatment-control group was performed. Patients were randomly selected for non-high-dose and high-dose PPI groups (n = 44 in each group). Results. Univariate analysis showed, significant variables related to rebleeding were female, higher creatinine levels, and higher Rockall scores ( 6). Before case-control matching, the high-dose PPI group had higher creatinine level, higher percentage of shock at presentation, and higher Rockall scores. After randomized treatment-control matching, no statistical differences were observed for rebleeding rates between the high-dose and non-high-dose groups after casecontrol matching. Conclusion. This study suggests that intravenous high-dose pantoprazole may not be superior to non-high-dose regimen in reducing rebleeding in high-risk peptic ulcer bleeding after successful endoscopic therapy

    Effects of Gallium on Immune Stimulation and Apoptosis Induction in Human Peripheral Blood Mononuclear Cells

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    Gallium is commonly used in the semiconductor industry and medical field. Biologically, gallium is able to interrupt iron metabolism. Exposure to gallium has been shown to affect the human immune system. The purpose of this study was to investigate the in vitro biological effects of different gallium concentrations on cultured human peripheral blood mononuclear cells (PBMCs) in terms of cell growth, cytokine release, and apoptosis induction. In addition, the in vivo effects of gallium were analyzed by Wistar rat model. Our results revealed that low concentrations (1-10 mug/ ml) of gallium promoted cells to enter the S phase of cell cycle and enhanced cellular release of tumor necrosis factor-alpha, interleukin-1 beta, and interferon-gamma, both in vitro and in vivo. In contrast , high concentrations of gallium (50-100 mug/ml) induced apoptosis. Furthermore, gallium-induced cytokine release and apoptosis could be inhibited by iron- saturated transferrin( Tf-Fe). These results suggest that the concentration- dependent effects of gallium on PBMCs are related to iron metabolism. (C) 2003 Elsevier Inc. All rights reserved
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