Advanced oxidation protein products induce hepatocyte epithelial–mesenchymal transition via a ROS‐dependent, TGF‐β/Smad signaling pathway

Park

et al. 2019

Biology

Recent studies showed that melatonin, a well-known pineal hormone that modulates the circadian rhythm, exerts beneficial effects against liver fibrosis. However, mechanisms for its protective action against the fibrotic processes remain incompletely understood. Here, we aimed to explore the effects of the hormone on transforming growth factor-β1 (TGF-β1)-stimulated epithelial–mesenchymal transition (EMT) in AML12 hepatocytes. Pretreatment with melatonin dose-dependently reversed downregulation of an epithelial marker and upregulation of mesenchymal markers after TGF-β1 stimulation. Additionally, melatonin dose-dependently suppressed an increased phosphorylation of Smad2/3 after TGF-β1 treatment. Besides the canonical Smad signaling pathway, an increase in phosphorylation of extracellular signal-regulated kinase 1/2 and p38 was also dose-dependently attenuated by melatonin. The suppressive effect of the hormone on EMT stimulated by TGF-β1 was not affected by luzindole, an antagonist of melatonin membrane receptors, suggesting that its membrane receptors are not required for the inhibitory action of melatonin. Moreover, melatonin suppressed elevation of intracellular reactive oxygen species (ROS) levels in TGF-β1-treated cells. Finally, TGF-β1-stimulated EMT was also inhibited by the antioxidant N-acetylcysteine. Collectively, these results suggest that melatonin prevents TGF-β1-stimulated EMT through suppression of Smad and mitogen-activated protein kinase signaling cascades by deactivating ROS-dependent mechanisms in a membrane receptor-independent manner.

Section: Discussionsupporting

confidence: 82%

Melatonin Inhibits Transforming Growth Factor-β1-Induced Epithelial–Mesenchymal Transition in AML12 Hepatocytes

Park

et al. 2019

Biology

“…Immunohistochemical (IHC) analysis was performed as previously described [ 21 , 22 ]. Briefly, HCC and matched adjacent non-cancerous tissues were fixed in 4% paraformaldehyde, embedded in paraffin wax, and sectioned at 4-μm thickness.…”

Section: Methodsmentioning

confidence: 99%

Expression of Allograft Inflammatory Factor-1 (AIF-1) in Hepatocellular Carcinoma

et al. 2018

Self Cite

BackgroundAllograft inflammatory factor-1 (AIF-1) is a cytoplasmic protein cloned from activated macrophages in human and rat allografts. AIF-1 has been identified as a modulator of inflammatory response, and recently published studies have shown its increased expression in carcinogenesis. However, there are still limited data on the potential functional role of AIF-1 in hepatocellular carcinoma (HCC).Material/MethodsWe evaluated the expression of AIF-1 in 104 cases of paired HCC and adjacent non-cancerous liver tissues using immunohistochemistry, Western blotting, and qPCR analysis, and sought to determine whether its expression was correlated with clinicopathological features. In vitro assays, including cell proliferation and migration assays, were used to study the effects of AIF-1 knockdown in L02 human hepatocyte, and Huh7 and SMMC7721 liver cancer cell lines.ResultsExpression of AIF-1 was increased in HCC compared to adjacent normal liver tissues and was positively correlated with median tumor size (p=0.046), number of tumor deposits (p=0.009), the Barcelona Clinic Liver Cancer (BCLC) stage (p=0.004), and portal vein tumor thrombus (PVTT) (p<0.001). Huh7 and SMMC7721 human HCC cells demonstrated upregulated AIF-1 expression compared to normal hepatocytes. Small interfering RNA (siRNA)-mediated silencing of AIF-1 expression resulted in a reduction in cell proliferation and migration in human HCC cells.ConclusionsThese findings suggest AIF-1 may have roles as a diagnostic or prognostic biomarker and a promising therapeutic target in HCC.

“…However, in the case of continuous activation of inflammatory response, the EMT process will also exist continuously, and eventually cause organ fibrosis[ 18 , 19 ]. Nowadays, although the role and regulation mechanism of EMT in CD intestinal fibrosis has not been fully understood, the transforming growth factor-β (TGF-β)/Smad/MAPK signaling pathway has been confirmed to play an important role in regulating EMT in organs such as lung, liver, kidney and so on[ 20 - 22 ]. Therefore, studying the role of EMT in the formation of intestinal fibrosis based on the TGF-β/Smad/MAPK signaling pathway, may provide a new target for the treatment of CD intestinal fibrosis.…”

Section: Introductionmentioning

confidence: 99%

Total flavone of Abelmoschus manihot suppresses epithelial-mesenchymal transition via interfering transforming growth factor-β1 signaling in Crohn’s disease intestinal fibrosis

Yang¹,

Zhu²,

Li³

et al. 2018

WJG

AIMTo explore the role and mechanism of total flavone of Abelmoschus manihot (TFA) on epithelial-mesenchymal transition (EMT) progress of Crohn’s disease (CD) intestinal fibrosis.METHODSFirst, CCK-8 assay was performed to assess TFA on the viability of intestinal epithelial (IEC-6) cells and select the optimal concentrations of TFA for our further studies. Then cell morphology, wound healing and transwell assays were performed to examine the effect of TFA on morphology, migration and invasion of IEC-6 cells treated with TGF-β1. In addition, immunofluorescence, real-time PCR analysis (qRT-PCR) and western blotting assays were carried out to detect the impact of TFA on EMT progress. Moreover, western blotting assay was performed to evaluate the function of TFA on the Smad and MAPK signaling pathways. Further, the role of co-treatment of TFA and si-Smad or MAPK inhibitors has been examined by qRT-PCR, western blotting, morphology, wound healing and transwell assays.RESULTSIn this study, TFA promoted transforming growth factor-β1 (TGF-β1)-induced (IEC-6) morphological change, migration and invasion, and increased the expression of epithelial markers and reduced the levels of mesenchymal markers, along with the inactivation of Smad and MAPK signaling pathways. Moreover, we revealed that si-Smad and MAPK inhibitors effectively attenuated TGF-β1-induced EMT in IEC-6 cells. Importantly, co-treatment of TFA and si-Smad or MAPK inhibitors had better inhibitory effects on TGF-β1-induced EMT in IEC-6 cells than either one of them.CONCLUSIONThese findings could provide new insight into the molecular mechanisms of TFA on TGF-β1-induced EMT in IEC-6 cells and TFA is expected to advance as a new therapy to treat CD intestinal fibrosis.