Search

Background & Aims: It has recently been reported that thymosin beta-4 (Tβ4) has anti-fibrogenic effects in human hepatic stellate cells (HSCs) in vitro, but the mechanisms underlying these effects remain unclear. The aim of this study was to investigate the roles of Tβ4 in the proliferation, migration, and activation of HSCs. Methods: Enzyme-linked immunosorbent assays (ELISA), immunohistochemistry, and western blot assays were utilized to determine the expression levels of Tβ4 in serum, liver tissues, and LX-2 cells. Tβ4 was depleted in LX-2 cells using small interfering RNAs (siRNAs). Cell proliferation was analyzed using cell counting kit-8 (CCK-8) viability assays, and cell migration was investigated using wound-healing and transwell migration assays. Results: The expression of Tβ4 was significantly reduced during the progression of liver fibrosis. The depletion of Tβ4 significantly promoted the proliferation and migration of LX-2 cells via the activation of the PI3K/Akt signaling pathway. The pro-migratory and pro-proliferative effects of Tβ4 depletion in LX-2 cells can be counteracted by treatment with the Akt inhibitor MK-2206. In addition, Tβ4 depletion was also associated with the activation of HSCs via the enhanced expression of α-smooth muscle actin (α-SMA) and vimentin. Conclusions: Our results suggest that Tβ4 participates in liver fibrosis by inhibiting the migration, proliferation, and activation of HSCs and that Tβ4 may be an effective target in the treatment of liver fibrosis. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background/Aims: Parenteral nutrition-associated liver disease (PNALD) is a major complication for patients who require long-term parenteral nutrition. Treatment options for PNALD are limited and its pathogenesis is poorly understood. Tribbles homolog 3 (TRB3) is a pseudokinase that modulates many signal transduction cascades and may be involved in the pathogenesis of PNALD. The aim of this study was to examine the role of TRB3 in palmitate-induced endoplasmic reticulum (ER) stress, in the human liver cell line L02. Methods: L02 cells were treated with palmitate, and its effect on cell viability, mitochondrial membrane potential, apoptosis and TRB3 expression were assessed. The role of TRB3 was also studied using transient overexpression of TRB3 in L02 cells, as well as its interaction with Akt signaling. Results: We found that palmitate induced ER stress and apoptosis in L02 cells. Palmitate-associated ER stress was accompanied by a significant induction of TRB3 expression at the mRNA and protein level. Overexpression of TRB3 potentiated the deleterious effects of palmitate, which was associated with decreased levels of phospho-Akt. Conclusions: TRB3 is an important mediator of palmitate-induced apoptosis in human liver cells, suggesting that it may also be involved in the molecular mechanism underlying PNALD. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Aims: Retinoic acid (RA) is used pharmacologically to treat neuroblastoma (NB), but its mechanism of action is unclear and it has limited use against refractory disease. This study investigated the expression of LSD1 (also known as KDM1A) in tumors, and assessed the efficacy of combining RA treatment with the inhibition of LSD1 expression. Methods: LSD1 protein expression levels were assessed semi-quantitatively in specimens of NB and ganglioneuroblastoma (GNB), along with the apoptosis markers, Bcl-2 and Bax. The combined effect of RA and LSD1 siRNA inhibition on cell death was then assessed in the human neuroblastoma cell line, SH-SY5Y. Results: LSD1 expression was higher in NB compared to GNB, and LSD1 overexpression directly correlated with Bcl-2 expression and inversely correlated with Bax expression. RA treatment or LSD1 siRNA inhibition alone inhibited the growth of SH-SY5Y cells, but did not cause significant apoptosis or cell death. Combined treatment led to higher rates of SH-SY5Y cell death, as reflected by an increased Bax/Bcl-2 ratio. Conclusions: The combined effect of RA and LSD1 siRNA inhibition had a synergistic effect on promoting the apoptosis of NB cells. This novel approach may improve the clinical treatment of NB. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background/Aims: SUZ12 and EZH2 are two main components of polycomb repressive complex 2 (PRC2) that is known to be of great importance in tumorigenesis. EZH2 has been reported to play a vital role in pathogenesis of human cancer. However, whether SUZ12 has equivalent roles in tumorigenesis has not been demonstrated. Here, we investigated a possible role of SUZ12 for the proliferation of gastric cancer cells. Methods: Western-blot analysis was used to detected the levels of SUZ12, H3K27me3, EZH2 and p27 in ten gastric cell lines. SUZ12 was depleted by RNA interference. Cell cycle was detected by flow cytometry. Luciferase assays was to analyze whether miR-200b directly regulate SUZ12. Results: We found that SUZ12 depletion mediated by RNA interference (RNAi) led to a reduction of gastric cell numbers and arrested the cell cycle at G1/S point. As an important G1/S phase inhibitory gene, p27 is re-induced to some extent by SUZ12 knockdown. Furthermore, we demonstrated that SUZ12 was directly downregulated by miR-200b. Conclusion: We provide evidence suggesting that SUZ12 may be a potential therapeutic target for gastric cancer. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]