Expression In HepG2 Cells Research Articles

Nonsynonymous C1653T Mutation of Hepatitis B Virus X Gene Enhances Malignancy of Hepatocellular Carcinoma Cells.

PurposeFunctional analysis was performed to elucidate the mechanism by which hepatocellular carcinoma (HCC) outcome-associated mutation in the hepatitis B virus X (HBx) gene modifies the HCC process.MethodsProliferation, invasion, migration, and apoptosis assays were performed, and changes in fibrosis, intracellular reactive oxygen species (ROS), and cytokine levels were measured. The differences between variables were evaluated by Student’s t-test.ResultsThe influence of two previously identified nonsynonymous mutation, C1653T and T1753C, on HCC cells was assessed. With regard to HBX-induced promotion of proliferation (p < 0.01), invasion (p < 0.01) and migration (p < 0.01), the C1653T mutation displayed a significant additive effect in these assays (P < 0.05). The subsequent apoptosis assay indicated that HBX could inhibit apoptosis (P < 0.01), whereas the C1653T mutation markedly amplified this effect in HCC cells (P < 0.01). Furthermore, the tumor growth-promoting effect of HBX was confirmed in a mouse xenograft model of HCC (P < 0.05), and the C1653T mutation was observed to amplify this effect (P < 0.05). To further investigate the mechanism by which the C1653T mutation enhances malignancy in HCC cells, fibrosis, intracellular ROS, and cytokine levels were measured. The C1653T mutant increased fibrosis and intracellular ROS level, and altered monocyte chemotactic protein-1 and interleukin-18 expression in HepG2 cells. Drug sensitivity test revealed that the C1653T mutation is sensitive to apatinib treatment and that overexpression of vascular endothelial growth factor might be involved in this process.ConclusionOur data indicate that the C1653T mutation of HBx promotes HCC malignancy by altering the levels of fibrosis, ROS, and some cytokines. This mutation could serve as a potential biomarker for screening HCC patients to determine apatinib treatment efficacy.

MicroRNA-20a-5p Downregulation by Atorvastatin: A Potential Mechanism Involved in Lipid-Lowering Therapy

The treatment of hypercholesterolemia is mainly based on statins. However, the response to pharmacological therapy shows high inter-individual variability, resulting in variable effects in both lipid lowering and risk reduction. Thus, a better understanding of the lipid-lowering mechanisms and response variability at the molecular level is required. Previously, we demonstrated a deregulation of the microRNA expression profile in HepG2 cells treated for 24 h with atorvastatin, using a microarray platform. In the present study, we evaluated the expression of hsa-miR-17-5p, hsa-miR-20a-5p and hsa-miR-106a-5p in hypercholesterolemic patients before and after atorvastatin treatment and in HepG2 cells treated for 24 h with atorvastatin The miRNA hsa-mir-20a-5p was repressed after atorvastatin treatment in hypercholesteremic subjects and in HepG2 cells in culture. Repression of hsa-mir-20a-5p increased LDLR gene and protein expression in HepG2 cells, while hsa-mir-20a-5p overexpression reduced LDLR gene and protein expression.

Antrodia cinnamomea and its compound dehydroeburicoic acid attenuate nonalcoholic fatty liver disease by upregulating ALDH2 activity

Ethnopharmacological relevanceNonalcoholic fatty liver disease (NAFLD) is a prevalent liver disease, but currently has no specific medication in clinic. Antrodia cinnamomea (AC) is a medicinal fungus and it has been shown that AC can inhibit high fat diet (HFD)-induced lipid deposition in mouse livers, but the effective monomer in AC and mechanism against NAFLD remain unclear. It has been reported that aldehyde dehydrogenase 2 (ALDH2) activation shows protective effects on NAFLD. Our previous study demonstrates that AC and its monomer dehydroeburicoic acid (DEA) can upregulate the ALDH2 activity on alcoholic fatty liver disease mouse model, but it is not clear whether the anti-NAFLD effects of AC and DEA are mediated by ALDH2. Aim to studyTo elucidate the active compound in AC against NAFLD, study whether ALDH2 mediates the anti-NAFLD effects of AC and its effective monomer. Materials and methodsWT mice, ALDH2−/− mice and ALDH2−/− mice re-expressed ALDH2 by lentivirus were fed with a methionine-choline deficient (MCD) diet or high fat diet (HFD) to induce NAFLD, and AC at the different doses (200 and/or 500 mg/kg body weight per day) was administrated by gavage at the same time. Primary hepatocytes derived from WT and ALDH2−/−mice were stimulated by oleic acid (OA) to induce lipid deposition, and the cells were treated with AC or DEA in the meantime. Lentivirus-mediated ALDH2-KD or ALDH2-OE were used to knock down or overexpress ALDH2 expression in HepG2 cells, respectively. Finally, the effects of DEA against NAFLD as well as its effects on upregulating liver ALDH2 and removing the harmful aldehyde 4-hydroxynonenal (4-HNE) were studied in the MCD diet-induced NAFLD mouse model. ResultsIn WT mice fed with a MCD diet or HFD, AC administration reduced hepatic lipid accumulation, upregulated ALDH2 activity in mouse livers, decreased 4-HNE contents both in mouse livers and serum, inhibited lipogenesis, inflammation and oxidative stress and promoted fatty acid β-oxidation. These effects were abolished in ALDH2 KO mice but could be restored by re-expression of ALDH2 by lentivirus. In primary hepatocytes of WT mice, AC and DEA inhibited OA-induced lipid accumulation and triglyceride (TG) synthesis, promoting the β-oxidation of fatty acid in the meantime. However, these effects were lost in primary hepatocytes of ALDH2 KO mice. Moreover, the expression level of ALDH2 significantly affected the inhibitory effects of AC and DEA on OA-induced lipid deposition in HepG2 cells. The effects of AC and DEA on suppressing lipid deposition, inhibiting mitochondrial ROS levels, reducing TG synthesis, and promoting β-oxidation of fatty acid were all enhanced with the overexpression of ALDH2 and reduced with the knockdown of ALDH2 expression. DEA showed dose-dependent effects on inhibiting liver lipid deposition, elevating ALDH2 activity and reducing 4-HNE levels in the livers of MCD diet-induced NAFLD mice. ConclusionDEA is the effective compound in AC against NAFLD. The related anti-NAFLD mechanisms of AC and DEA were through upregulating ALDH2 expression and activity, thus enhancing the elimination of 4-HNE in the livers, and sequentially alleviating oxidative stress and inflammation, promoting fatty acid β-oxidation and decreasing lipogenesis.

Transcriptomic analysis reveals a novel regulatory factor of ECHDC1 involved in lipid metabolism of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the highest incidence of chronic liver disease worldwide characterized by lipid accumulation in the liver. The full understanding of the lipogenesis of NAFLD is extreme importance. Here, whole-genome transcriptome analysis was performed on liver tissues of NAFLD patients and healthy controls to identify the differentially expressed genes and find new pathways and target genes related to the lipogenesis of NAFLD. Combined with the Gene Expression Omnibus (GEO) database, we found 86 overlapping genes, many of which are related to lipid metabolism of NAFLD. ECHDC1 is one of 86 overlapping genes, and its role in NAFLD has not been reported. The expression of ECHDC1 was significantly increased in liver tissue of patients with NAFLD than that of healthy controls, and oil Red O intensity was positively correlated with the expression levels of ECHDC1. Inhibition of ECHDC1 expression in HepG2 cells by RNAi significantly reduced intracellular lipid droplet number in vitro. In summary, this study analyzed pathogenic factors related to NAFLD at the whole-genome level and demonstrated that ECHDC1 may be involved in the occurrence and development of NAFLD by regulating hepatic lipid metabolism.

Use of cellular metabolomics and lipidomics to decipher the mechanism of Huachansu injection-based intervention against human hepatocellular carcinoma cells

Huachansu (HCS) injection has been used for the clinical treatment of hepatocellular carcinoma (HCC) patients in China for more than thirty years. However, the underlying mechanisms of HCS injection in inhibiting HCC remains unclear. In this study, we aimed to evaluate the effects of HCS injection on HCC both in vitro and in vivo and to systematically explore the underlying mechanisms of HCS’s actions against HCC using an ultrahigh-performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS)-based cellular metabolomics and lipidomics approach. MTT and DAPI staining were performed to evaluate the effects of HCS injection on cell proliferation and apoptosis, respectively, in human HepG2 HCC cells with and without HCS treatment. An H22 hepatoma-bearing mouse model was employed to investigate the anti-HCC action of HCS injection in vivo. A UPLC-HRMS-based cellular metabolomics and lipidomics method was employed to characterize cellular metabolite fingerprinting, to identify potential biomarkers associated with the effect of HCS injection on the inhibition of HCC and to explore the anti-HCC mechanisms of HCS injection from the perspective of cellular metabolism. As a result, HCS injection inhibited the proliferation of HepG2 cells and induced their apoptosis. Body weight loss, sarcoma weights and volumes of H22 hepatoma-bearing mice in the HCS treatment group were significantly attenuated compared to those in the model group. Twenty-five biomarkers responsible for the intervention effect of HCS were screened and annotated using UPLC-HRMS-based cellular metabolomics and lipidomics. Among these biomarkers, two cellular metabolites, uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) and glutathione, were confirmed unambiguously using the reference substances. Metabolic pathway analysis revealed that the anti-HCC effects of HCS injection primarily involved the metabolism of glutathione, cysteine and methionine, sphingolipid, fatty acid biosynthesis, amino sugar and nucleotide sugars. As evidenced by western blotting experiments, the changes in UDP-GlcNAc content in response to HCS injection were linked to the inhibition of UDP-GlcNAc pyrophosphorylase 1 (UAP1) expression in HepG2 cells. In conclusion, HCS injection has a curative anti-HCC effect, and a UPLC-HRMS-based cellular metabolomics and lipidomics approach combined with further confirmatory experiments is a promising means of discovering its underlying mechanisms.

Deacetylated-poly-N-acetylglucosamine-folic Acid as a Nanocarrier for Delivering miR-196a Inhibitor to Anticancer Activity

Background:MiR-196a is particularly noticeable in the development of liver cancer. However, the rapid degradation by ribonuclease (RNase) imposes a limit on the miRNA gene therapy applications.Aims:To design a novel gene-targeting nano system for liver cancer treatment.Study Design:Cell culture study and animal experimentation.Methods:Deacetylated (DEAC)-poly-N-acetylglucosamine (PNAG)-folic acid (FA) was prepared via ethyl (dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide reaction, and miR-196a inhibitor (miR-196a I)/DEAC-PNAG-FA was prepared through self-assembly. The characterization and nucleic acid protection of the self-assembly system were also determined. The biological function and related mechanism of the prepared system were studied at cellular and molecular levels. Mice were established as a xenotransplantation model to evaluate the anticancer capacity of miR-196a I/DEAC-PNAG-FA in vivo.Results:The morphology of miR-196a I/DEAC-PNAG-FA was uniform, and its particle size was approximately 70–100 nm. A nanocarrier with an N/P ratio of 200:1 can maximize the nucleic acid carrying capacity of the self-assembly system. The nanosystem can protect miRNA from RNase degradation and could be internalized rapidly within 4 h. The self-assembly system significantly enhanced the apoptosis-inducing effect of miR-196a I on HepG2 cells (P = 0.003). Molecular biological analyses confirmed that the apoptosis-inducing effect of the nanosystem was due to the inhibition of miR-196a gene expression in HepG2 cells, which upregulate the expression of pro-apoptotic proteins FOXO1 (P < 0.001), Bax (P < 0.001), Ki67 (P < 0.001), and proliferating cell nuclear antigen (P < 0.001), and inhibit the expression of apoptosis inhibitory protein Bcl-2 (P < 0.001). Moreover, compared with free miR-196a inhibitor or miR-196a I/DEAC-PNAG, miR-196a I/DEAC-PNAG-FA can more effectively inhibit tumor growth in vivo (P = 0.026).Conclusion:The newly prepared self-assembly targeting system can effectively induce apoptosis and abrogate tumor growth, which may open a new approach for liver cancer treatment.

DA-1241, a Novel GPR119 Agonist, Improves Hyperglycaemia by Inhibiting Hepatic Gluconeogenesis and Enhancing Insulin Secretion in Diabetic Mice.

BackgroundWe investigated the antidiabetic effects of DA-1241, a novel G protein-coupled receptor (GPR) 119 agonist, in vitro and in vivo.MethodsDA-1241 was administrated to high-fat diet (HFD)-fed C57BL/6J mice for 12 weeks after hyperglycaemia developed. Oral/intraperitoneal glucose tolerance test and insulin tolerance test were performed. Serum insulin and glucagon-like peptide-1 (GLP-1) levels were measured during oral glucose tolerance test. Insulinoma cell line (INS-1E) cells and mouse islets were used to find whether DA-1241 directly stimulate insulin secretion in beta cell. HepG2 cells were used to evaluate the gluconeogenesis and autophagic process. Autophagic flux was evaluated by transfecting microtubule-associated protein 1 light chain 3-fused to green fluorescent protein and monomeric red fluorescent (mRFP-GFP-LC3) expression vector to HepG2 cells.ResultsAlthough DA-1241 treatment did not affect body weight gain and amount of food intake, fasting blood glucose level decreased along with increase in GLP-1 level. DA-1241 improved only oral glucose tolerance test and showed no effect in intraperitoneal glucose tolerance test. No significant effect was observed in insulin tolerance test. DA-1241 did not increase insulin secretion in INS-1E cell and mouse islets. DA-1241 reduced triglyceride content in the liver thereby improved fatty liver. Additionally, DA-1241 reduced gluconeogenic enzyme expression in HepG2 cells and mouse liver. DA-1241 reduced autophagic flow in HepG2 cells.ConclusionThese findings suggested that DA-1241 augmented glucose-dependent insulin release via stimulation of GLP-1 secretion, and reduced hepatic gluconeogenesis, which might be associated with autophagic blockage, leading to improved glycaemic control.

A preliminary study on Fructus Aurantii extract against hepatocarcinoma via glycolysis and PD-1/PD-L1 pathway

Fructus Aurantii (FA) is a traditional herbal medicine that has been widely used for thousands of years in China and possesses a variety of pharmacological effects. FA is full of flavonoids. Several natural bioactive compounds of FA are involved in the treatment of various types of cancers, however, the beneficial effects of FA in hepatocarcinoma and the potential mechanisms of its therapeutic effects have not been fully explored. The present study investigates the anticancer role of flavonoids extracted from FA on human hepatoblastoma cell, HepG2. Eriocitrin, neoeriocitrin, narirutin, naringin, hesperidin, neohesperidin, hesperitin, poncirin, meranzin, nobiletin and tangeretin were identified in FAE. The FAE inhibit the proliferation of HepG2 cells in a dose-dependent manner. Metabolic alteration was detected by cell metabolomics and quantitative real time polymerase chain reaction. Flavonoids decreased the level of glycolysis rate-limiting enzymes gene expression in HepG2 cells. It was also observed that the PD-1 and PD-L1 gene expression level were decreased in FAE-treated cells. Collectively, these results suggest that flavonoid extracted from FA inhibits HepG2 cell proliferation by glycolysis and its downstream of PD-1/PD-L1 pathway. These findings suggest that the possible mechanism by which FA exerts its activities in the treatment of hepatocarcinoma and lays a foundation for further experiments and the development of a rational clinical application of FA, which still needs further in vivo investigation in animals and human beings.

Effect of rosiglitazone on 20-hydroxyeicosatetraenoic acid levels and CYP4F2 expression in HepG2 cells

&#x0D; &#x0D; &#x0D; &#x0D; Purpose: To determine the effect of rosiglitazone on the levels of the cardiotoxic arachidonic acid metabolite, 20-hydroxyeicosatetraenoic acid (20-HETE), in the human liver hepatocellular carcinoma cell line, HepG2.&#x0D; Methods: HepG2 cells were treated with thiazolidinedione rosiglitazone and the mRNA and protein expressions of cytochrome P450 4F2 (CYP4F2) responsible for synthesizing 20-HETE were measured using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. The levels of 20-HETE were evaluated using liquid chromatography/mass spectrometry (LC-MS).&#x0D; Results: Rosiglitazone significantly increased the levels of CYP4F2 mRNA and protein when compared with the control group (p &lt; 0.05). This was correlated with significantly increased 20-HETE levels in the culture medium of rosiglitazone-treated cells in a dose-dependent manner (p &lt; 0.05). The PPARγ antagonist, GW9662, significantly repressed the increased production of 20-HETE and CYP4F2 mRNA protein (p &lt; 0.05).&#x0D; Conclusion: Rosiglitazone increases the synthesis of 20-HETE via activation of PPARγ receptor and upregulation of CYP4F2. These findings may provide an additional explanation, at least in part, for the unwanted side effects of rosiglitazone on the cardiovascular system.&#x0D; &#x0D; &#x0D; &#x0D;

Effects of 2-Methoxyestradiol, a Main Metabolite of Estradiol on Hepatic ABCA1 Expression in HepG2 Cells.

ATP-binding cassette transporter A1 (ABCA1) is a key regulator of lipid efflux, and the absence of ABCA1 induces hepatic lipid accumulation, which is one of the major causes of fatty liver. 2-Methoxyestradiol (2-ME2) has been demonstrated to protect against fatty liver. In this study, we investigated the effects of 2-ME2 on the hepatic lipid content and ABCA1 expression. We found that 2-ME2 dose-dependently increased ABCA1 expression, and therefore, the lipid content was significantly decreased in HepG2 cells. 2-ME2 enhanced the ABCA1 promoter activity; however, this effect was reduced after the inhibition of the PI3K pathway. The overexpression of Akt or p110 induced ABCA1 promoter activity, while dominant-negative Akt diminished the ability of 2-ME2 on ABCA1 promoter activity. Further, 2-ME2 stimulated the rapid phosphorylation of Akt and FoxO1 and reduced the nuclear accumulation of FoxO1. Chromatin immunoprecipitation confirmed that FoxO1 bonded to the ABCA1 promoter region. The binding was reduced by 2-ME2, which facilitated ABCA1 gene transcription. Furthermore, mutating FoxO1-binding sites in the ABCA1 promoter region or treatment with FoxO1-specific siRNA disrupted the effect of 2-ME2 on ABCA1 expression. All of our results demonstrated that 2-ME2 might upregulate ABCA1 expression via the PI3K/Akt/FoxO1 pathway, which thus reduces the lipid content in hepatocytes.

Activation of the aryl hydrocarbon receptor by clozapine induces preadipocyte differentiation and contributes to endothelial dysfunction

Background:The superior therapeutic benefit of clozapine is often associated with metabolic disruptions as obesity, insulin resistance, tachycardia, higher blood pressure, and even hypertension.Aims:These adverse vascular/ metabolic events under clozapine are similar to those caused by polycyclic aromatic hydrocarbons (PAHs), and clozapine shows structural similarity to well-known ligands of the aryl hydrocarbon receptor (AhR). Therefore, we speculated that the side effects caused by clozapine might rely on AhR signaling.Methods:We examined clozapine-induced AhR activation by luciferase reporter assays in hepatoma HepG2 cells and we proved upregulation of the prototypical AhR target gene Cyp1A1 by realtime-PCR (RT-PCR) analysis and enzyme activity. Next we studied the physiological role of AhR in clozapine’s effects on human preadipocyte differentiation and on vasodilatation by myography in wild-type and AhR-/- mice.Results:In contrast to other antipsychotic drugs (APDs), clozapine triggered AhR activation and Cyp1A1 expression in HepG2 cells and adipocytes. Clozapine induced adipogenesis via AhR signaling. After PGF2α-induced constriction of mouse aortic rings, clozapine strongly reduced the maximal vasorelaxation under acetylcholine in rings from wild-type mice, but only slightly in rings from AhR-/- mice. The reduction was also prevented by pretreatment with the AhR antagonist CH-223191.Conclusion:Identification of clozapine as a ligand for the AhR opens new perspectives to explain common clozapine therapy-associated adverse effects at the molecular level.

Atractylenolide III ameliorates Non-Alcoholic Fatty Liver Disease by activating Hepatic Adiponectin Receptor 1-Mediated AMPK Pathway.

Background: Nonalcoholic fatty liver disease (NAFLD) is the most frequent cause of chronic liver diseases worldwide. At present, there are no effective pharmacological therapies for NAFLD except lifestyle intervention-mediated weight loss. Atractylenolide III (ATL III), the major bioactive component found in Atractylode smacrocephala Koidz, has been shown to exert anti-oxidant, anti-tumor, anti-allergic response, anti-bacterial effects and cognitive protection. Here we investigate the therapeutic potential and underlying mechanisms of ATL III for the treatment of NAFLD.Methods: Male C57BL/6J mice were fed a high-fat diet (HFD) and treated with ATL III. Lipid accumulation was analyzed by Oil Red O staining in liver tissues and free fatty acids (FFAs)-treated hepatocytes. AMP-activated protein (AMPK) and sirtuin 1(SIRT1) signaling pathways were inhibited by Compound C and EX527 in vitro, respectively. Small-interfering RNA (siRNA) was used to knockdown adiponectin receptor 1 (AdipoR1) expression in HepG2 cells.Results: ATL III treatment ameliorated liver injury and hepatic lipid accumulation in the HFD-induced NAFLD mouse model as demonstrated by that ATL III administration significantly reduced serum levels of alanine aminotransferase, glutamic oxaloacetic transaminase, triglycerides, total cholesterol and low-density lipoprotein. Furthermore, treatment with ATL III alleviated hepatic oxidative stress, inflammation and fibrosis in the HFD feeding model. To study the underlying mechanisms, we performed Computer Aided Design assay and found that open-formed AdipoR1 and adiponectin receptor 2 were the potential receptors targeted by ATL III. Interestingly, HFD feeding or FFAs treatment only reduced hepatic AdipoR1 expression, while such reduction was abolished by ATL III administration. In addition, in vitro treatment with ATL III activated the AdipoR1 downstream AMPK /SIRT1 signaling pathway and reduced lipid deposition in HepG2 cells, which was diminished by silencing AdipoR1. Finally, inhibition of AMPK or SIRT1, the AdipoR1 downstream signaling, abolished the protective effects of ATL III on lipid deposition and oxidative stress in FFAs-treated HepG2 cells.Conclusion: Our findings suggest that ATL III is a therapeutic drug for the treatment of NAFLD and such protective effect is mediated by activating hepatic AdipoR1-mediated AMPK/SIRT1 signaling pathway.

Impact of Soy β-Conglycinin Peptides on PCSK9 Protein Expression in HepG2 Cells.

Background: Dyslipidaemias, particularly elevated plasma low-density lipoprotein cholesterol (LDL-C) levels, are major risk factors for cardiovascular disease (CVD). Besides pharmacological approaches, a nutritional strategy for CVD prevention has gained increasing attention. Among functional foods, the hypocholesterolemic properties of soy are driven by a stimulation of LDL-receptor (LDL-R) activity. Aim: To characterize the effect of two soy peptides, namely, β-conglycinin-derived YVVNPDNDEN and YVVNPDNNEN on the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), one of the key-regulators of the LDL-R. Methods: PCSK9 promoter activity (luciferase assay), PCSK9 protein expression (WB) and secretion (ELISA), PCSK9 interaction with LDL-R (binding assay) and human HepG2 cells were the objects of this investigation. Results: Treatment with YVVNPDNNEN peptide has led to a rise in PCSK9 gene expression (90.8%) and transcriptional activity (86.4%), and to a decrement in PCSK9 intracellular and secreted protein (−42.9%) levels. YVVNPDNNEN peptide reduced the protein expression of transcriptional factor HNF1α. Most changes driven by YVVNPDNDEN peptide were not statistically significant. Neither peptide inhibited the PCSK9–LDLR interaction. Conclusions: Although sharing a common effect on LDL-R levels through the inhibition of 3-hydroxy-3-methylglutaryl CoA reductase activity, only the YVVNPDNNEN peptide has an additional mechanism via the downregulation of PCSK9 protein levels.

Gallic Acid Improves Diabetic Steatosis by Downregulating MicroRNA-34a-5p through Targeting NFE2L2 Expression in High-Fat Diet-Fed db/db Mice.

Type 2 diabetes mellitus (T2DM) has become epidemic worldwide and is strongly associated with nonalcoholic fatty liver disease (NAFLD). The molecular mechanisms of microRNAs in NAFLD and T2DM development and the corresponding therapies remain unclear. We performed microRNA microarray validation to determine whether hepatic miR-34a-5p was significantly upregulated in db/db mice fed with a high-fat diet (HFD), a mouse model of T2DM with steatohepatitis. The potential role of miR-34a-5p and gallic acid (GA) in regulating hepatic lipid metabolism and diabetic steatosis was explored. GA improved the activities of antioxidant enzymes and suppressed lipid accumulation in the HFD-induced steatotic liver of db/db mice. In vitro, the silencing of miR-34a-5p in hepatocyte HepG2 cells ameliorated high glucose + oleic acid/palmitic acid mixture–induced accumulation of cellular triglycerides. We identified nuclear factor erythroid-derived 2-like 2 (NFE2L2) as a direct target of miR-34a-5p. Reduction in intracellular triglyceride and the expression levels of sterol regulatory element-binding protein 1 and fatty acid synthase by GA were mediated by the inhibition of miR-34a-5p expression in HepG2 cells. The findings suggest that GA improves hepatic lipogenesis by downregulating miR-34a-5p by suppressing NFE2L2 expression, indicating the potential therapeutic role of GA or an NFE2L2-activating agent in diabetic fatty liver disease.

Role and mechanism of miRNA-181a in nonalcoholic fatty liver disease

Objective: To investigate the role and probable mechanism of miRNA-181a in nonalcoholic fatty liver disease. Methods: HepG2 cells were treated with palmitic acid to construct a nonalcoholic fatty liver disease cell model, and the expression of miR-181a and lipidosis in the cells were measured. Transforming growth factor-β (TGF-β) was used to examine the effect of miR-181a expression in HepG2 cells. The miR-181a, lipidosis, reduced glutathione and reactive oxygen species (ROS) were determined by controlling and regulating the miR-183 expression levels after transfection with miR-181 mimics and inhibitors in HepG2 cells. The miR-181a target genes were predicted by bioinformatics analysis, and verified by real-time fluorescent quantitative PCR and western blotting. The independent sample t-test was used for the comparison between the two independent samples, and the comparison between multiple groups were accorded with the normal distribution, homogeneity of variance, and one-way analysis of variance. Results: Lipidosis was significantly increased after palmitic acid treatment in HepG2 cells, and the expression level of miR-181a was significantly increased than control group. After HepG2 cells were transfected with miR-181a inhibitors, the expression of miR-181a, triglycerides and reactive oxygen species were down-regulated, and reduced glutathione, predicting the mRNA and protein expression of target gene silencing information regulator 2 related enzyme 1 were up-regulated. However, the results were contrary to the above changes after transfection with miR-181a mimics. Conclusion: miR-181a participates in lipidosis and promotes lipid peroxidation in nonalcoholic fatty liver disease. miR-181a may affect the pathogenesis and progression of nonalcoholic fatty liver disease by inhibiting the expression of silencing information regulator 2 related enzyme 1.

PXR Suppresses PPARα-Dependent HMGCS2 Gene Transcription by Inhibiting the Interaction between PPARα and PGC1α.

Background: PXR is a xenobiotic-responsive nuclear receptor that controls the expression of drug-metabolizing enzymes. Drug-induced activation of PXR sometimes causes drug–drug interactions due to the induced metabolism of co-administered drugs. Our group recently reported a possible drug–drug interaction mechanism via an interaction between the nuclear receptors CAR and PPARα. As CAR and PXR are structurally and functionally related receptors, we investigated possible crosstalk between PXR and PPARα. Methods: Human hepatocyte-like HepaRG cells were treated with various PXR ligands, and mRNA levels were determined by quantitative reverse transcription PCR. Reporter assays using the HMGCS2 promoter containing a PPARα-binding motif and mammalian two-hybrid assays were performed in HepG2 or COS-1 cells. Results: Treatment with PXR activators reduced the mRNA levels of PPARα target genes in HepaRG cells. In reporter assays, PXR suppressed PPARα-dependent gene expression in HepG2 cells. In COS-1 cells, co-expression of PGC1α, a common coactivator of PPARα and PXR, enhanced PPARα-dependent gene transcription, which was clearly suppressed by PXR. Consistently, in mammalian two-hybrid assays, the interaction between PGC1α and PPARα was attenuated by ligand-activated PXR. Conclusion: The present results suggest that ligand-activated PXR suppresses PPARα-dependent gene expression by inhibiting PGC1α recruitment.

Drug resistance via radixin-mediated increase of P-glycoprotein membrane expression during SNAI1-induced epithelial-mesenchymal transition in HepG2 cells.

Epithelial-mesenchymal transition (EMT) plays a role in cancer metastasis as well as in drug resistance through various mechanisms, including increased drug efflux mediated by P-glycoprotein (P-gp). In this study, we investigated the activation mechanism of P-gp, including its regulatory factors, during EMT in hepatoblastoma-derived HepG2 cells. HepG2 cells were transfected with SNAI1 using human adenovirus serotype 5 vector. We quantified mRNA and protein expression levels using qRT-PCR and western blot analysis, respectively. P-gp activity was evaluated by uptake assay, and cell viability was assessed by an MTT assay. P-gp protein expression on plasma membrane was higher in SNAI1-transfected cells than in Mock cells, although there was no difference in P-gp protein level in whole cells. Among the scaffold proteins such as ezrin, radixin and moesin (ERM), only radixin was increased in SNAI1-transfected cells. Uptake of both Rho123 and paclitaxel was decreased in SNAI1-transfected cells, and this decrease was blocked by verapamil, a P-gp inhibitor. The reduced susceptibility of SNAI1-transfected cells to paclitaxel was reversed by elacridar, another P-gp inhibitor. Increased expression of radixin during SNAI1-induced EMT leads to increased P-gp membrane expression in HepG2 cells, enhancing P-gp function and thereby increasing drug resistance.

Inhibition of miR-15a-5p Promotes the Chemoresistance to Pirarubicin in Hepatocellular Carcinoma via Targeting eIF4E.

Chemoresistance has become a primary hurdle in the therapeutic outcome of hepatocellular carcinoma. Substantial evidences have demonstrated that microRNAs (miRNAs) are closely associated with the chemoresistance of hepatocellular carcinoma (HCC). Our investigation is aimed at testifying the influence of microRNA-15a-5p (miR-15a-5p)/eukaryotic translation initiation factor 4E (eIF4E) on hepatocellular carcinoma resistance to pirarubicin (THP). In our study, miR-15a-5p expression was increased in THP-treated HepG2 cells. Downregulation of miR-15a-5p blocked cell growth and elevated cell apoptosis of HepG2 cells treated with THP. Moreover, eIF4E was verified as a direct target of miR-15a-5p by binding its 3′-UTR, which was confirmed by luciferase report experiment. Additionally, eIF4E was negatively associated with the miR-15a-5p expression in HepG2 cells. Mechanically, eIF4E was proven as a specific downstream of miR-15a-5p and mediated the effects of miR-15a-5p on cell viability and apoptosis of HepG2 cells treated with THP. These findings supported that miR-15a-5p facilitated THP resistance of hepatocellular carcinoma cells by modulating eIF4E, thus providing an experimental basis that miR-15a-5p might act as a novel diagnostic target in hepatocellular carcinoma resistance to THP.

Experimental Study of Rhein Inhibits the Invasion and Migration of HepG2 Cells by ERK Signaling Pathway

Objective: To investigate the effectiveness of Rhein on the proliferation, invasion and migration of human hepatoma cell line HepG2 and its possible mechanism.Methods: Human hepatoma cell line HepG2 was treated with different concentrations of Rhein (Rhein treatment group) and culture in culture medium alone (control group).The proliferation activity of the cells was determined by methyl Thiazolyl Tetrazolium (MTT) colorimetry.Transwell assay detected the invasion and migration of cells in each group.Cell scratch test was used to detect the migration ability of cells in each group.Excella-phospho-excellar signal-regulated kinase (P-ERK) activity was determined by ELISA after treatment with 50μ mol/L Rhein at different times.Western blot was used to detect ERK protein expression in HepG2 cells treated with 50 μmol/L Rhein.Results: Compared with the control group, the proliferation activity, invasion and migration ability of HepG2 cells in the Rhein treatment group were all decreased (P&lt; 0.05), and the p-ERK relative activity of HepG2 cells treated with Rhein was decreased (P &lt; 0.05).Conclusion: Rhein inhibits the invasion and migration of HCC cells, possibly by inhibiting the ERK pathway

Study of the antineoplastic effect of modulating apoptosis-related noncoding RNA in human hepatocellular carcinoma cell line (HepG2)

Abstract MiR-421 is considered an important molecule that can prevent tumor growth. Bioinformatics analysis indicated that mRNA caspase-3 gene is a target gene of miR-421. The current study aimed to explore the functional role of miR-421 in hepatocellular carcinoma (HCC) and explore the interaction between miR-421 and caspase-3. To validate bioinformatics data, RT-qPCR was used to detect the expression of miR-421 and caspase-3 in 10 HCC tissues. The results showed miR-421 expression was significantly higher in HCC than non HCC liver tissues (P&amp;lt;0.01), nevertheless caspase-3 gene expression was markedly lower in HCC than non HCC liver tissues (P&amp;lt;0.01). Besides, miR-421 expression was negatively associated with caspase-3 expression. MiR-421 mimic and inhibitor was transfected into HCC cell lines (HepG2). Proliferation assay, showed that low-expression of miR-421 inhibited the proliferation of HCC cells. RT-qPCR was worked for detection the expression levels of miR-421 and caspase-3 in HepG2 cells before and after transfection. The results showed that miR-421 expression in HepG2 cells was significantly lower in miR-421 inhibitor transfected group than in mimic- transfected and control groups (Mock) (P≤ 0.05), and caspase-3 gene expression in HCC tissues was markedly higher in inhibitor transfected group than those transfected by mimic and control group (Mock) (P≤0.05). Thus, miR-421 inhibitor may inhibit the proliferation of HCC cells via over- expression of caspase-3.