Smad3 reduces susceptibility to hepatocarcinoma by sensitizing hepatocytes to apoptosis through downregulation of Bcl-2

Hepatitis B virus X protein and TGF-β: partners in the carcinogenic journey of hepatocellular carcinoma

Hepatitis B infection is substantially associated with the development of liver cancer globally, with the prevalence of hepatocellular carcinoma (HCC) cases exceeding 50%. Hepatitis B virus (HBV) encodes the Hepatitis B virus X (HBx) protein, a pleiotropic regulatory protein necessary for the transcription of the HBV covalently closed circular DNA (cccDNA) microchromosome. In previous studies, HBV-associated HCC was revealed to be affected by HBx in multiple signaling pathways, resulting in genetic mutations and epigenetic modifications in proto-oncogenes and tumor suppressor genes. In addition, transforming growth factor-β (TGF-β) has dichotomous potentials at various phases of malignancy as it is a crucial signaling pathway that regulates multiple cellular and physiological processes. In early HCC, TGF-β has a significant antitumor effect, whereas in advanced HCC, it promotes malignant progression. TGF-β interacts with the HBx protein in HCC, regulating the pathogenesis of HCC. This review summarizes the respective and combined functions of HBx and TGB-β in HCC occurrence and development.

The Role of TGF-β/SMAD Signaling in Hepatocellular Carcinoma: from Mechanism to Therapy and Prognosis

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, with high incidence and mortality, accounting for approximately 90% of liver cancer. The development of HCC is a complex process involving the abnormal activation or inactivation of multiple signaling pathways. Transforming growth factor-β (TGF-β)/Small mothers against decapentaplegic (SMAD) signaling pathway regulates the development of HCC. TGF-β activates intracellular SMADs protein through membrane receptors, resulting in a series of biological cascades. Accumulating studies have demonstrated that TGF-β/SMAD signaling plays multiple regulatory functions in HCC. However, there is still controversy about the role of TGF-β/SMAD in HCC. Because it involves different pathogenic factors, disease stages, and cell microenvironment, as well as upstream and downstream relationships with other signaling pathways. This review will summary the regulatory mechanism of the TGF-β/SMAD signaling pathway in HCC, involving the regulation of different pathogenic factors, different disease stages, different cell populations, microenvironments, and the interaction with microRNAs. In addition, we also introduced small molecule inhibitors, therapeutic vaccines, and traditional Chinese medicine extracts based on targeting the TGF-β/SMAD signaling pathway, which will provide future research direction for HCC therapy targeting the TGF-β/SMAD signaling pathway.

Strategic Replication of the Hepatic Zonation In Vitro Employing a Biomimetic Approach

The varied functions of the liver are dependent on the metabolic heterogeneity exhibited by the hepatocytes within the liver lobule spanning the porto-central axis. This complex phenomenon plays an important role in maintaining the physiological homeostasis of the liver. Standard in vitro culture models fail to mimic this spatial heterogeneity of hepatocytes, assuming a homogeneous population of cells, which leads to inaccurate translation of results. Here, we demonstrate the development of an in vitro model of hepatic zonation by mimicking the microarchitecture of the liver using a 3D printed mini bioreactor and decellularized liver matrix to provide the native microenvironmental cues. There was a differential expression of hypoxic and metabolic markers across the developed mini bioreactor, showing the establishment of gradients of oxygen, Wnt/β-catenin pathway, and other metabolic pathways. The model also showed the establishment of zone-dependent toxicity on treatment with acetaminophen. The developed model would thus be a promising avenue in the field of tissue engineering for understanding the liver physiology and pathophysiology and for drug screening to evaluate the potential of new pharmaceutical interventions.

Development and evaluation of a risk score model based on a WNT score gene-associated signature for predicting the clinical outcome and the tumour microenvironment of hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC) is currently one of the most life-threatening diseases worldwide. However, the factors, genes, and processes involved in the mechanisms of HCC initiation, development, and metastasis remain to be identified.Methods: WNT signalling pathways may play important roles in cancer initiation and progression. Thus, it would be informative to construct a WNT signature-based gene model for the prognosis of HCC and the prediction of therapeutic efficacy. We curated genomic profiles for HCC from The Cancer Genome Atlas (TCGA) and divided them into training and internal validation datasets. We also used samples from GSE14520 and HCCDB18 as validation datasets and clustered them by ConsensusClusterPlus analysis. We applied WebGestaltR to the WNT score-associated differentially expressed genes (DEGs) and conducted a signalling pathway enrichment analysis. We assessed the tumour immune microenvironment with ESTIMATE, Microenvironment Cell Populations (MCP)-counter, single-sample gene set enrichment analysis (ssGSEA), and tumour immune dysfunction and exclusion (TIDE).Results: We performed a least absolute shrinkage and selection operator (LASSO) regression analysis to identify the prognosis-related hub genes, identified the risk and protective factor genes associated with HCC, classified them into two clusters, and found that Cluster 2 had a significantly better prognosis than Cluster 1. Moreover, the latter had advanced clinical features compared with the former. Uridine-cytosine kinase 1 (UCK1), myristoylated alanine-rich C-kinase substrate-like protein 1 (MARCKSL1), P-antigen family member 1 (PAGE1), and killer cell lectin-like receptor B1 (KLRB1) were detected and used to construct a simplified prognostic model for HCC. The high risk score subgroup showed a poorer prognosis than the low risk score subgroup, and the model assessed HCC prognosis consistently and effectively.Conclusions: The WNT score-related gene-based model designed and evaluated herein had strong prognostic and predictive ability for HCC and could, therefore, facilitate decision-making in the prognosis and therapeutic efficacy assessment of HCC.

Modulation of the p38 MAPK Pathway by Anisomycin Promotes Ferroptosis of Hepatocellular Carcinoma through Phosphorylation of H3S10

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor worldwide. Ferroptosis is emerging as an effective target for tumor treatment as it has been shown to potentiate cell death in some malignancies. However, it remains unclear whether histone phosphorylation events, an epigenetic mechanism that regulates transcriptional expression, are involved in ferroptosis. Our study found that supplementation with anisomycin, an agonist of p38 mitogen-activated protein kinase (MAPK), induced ferroptosis in HCC cells, and the phosphorylation of histone H3 on serine 10 (p-H3S10) was participated in anisomycin-induced ferroptosis. To investigate the anticancer effects of anisomycin-activated p38 MAPK in HCC, we analyzed cell viability, colony formation, cell death, and cell migration in Hep3B and HCCLM3 cells. The results showed that anisomycin could significantly suppress HCC cell colony formation and migration and induce HCC cell death. The hallmarks of ferroptosis, such as abnormal accumulation of iron and elevated levels of lipid peroxidation and malondialdehyde, were detected to confirm the ability of anisomycin to promote ferroptosis. Furthermore, coincubation with SB203580, an inhibitor of activated p38 MAPK, partially rescued anisomycin-induced ferroptosis. And the levels of p-p38 MAPK and p-H3S10 were successively increased by anisomycin treatment. The relationship between p-H3S10 and ferroptosis was revealed by ChIP sequencing. The reverse transcription PCR and immunofluorescence results showed that NCOA4 was upregulated both in mRNA and protein levels after anisomycin treatment. And by C11-BODIPY staining, we found that anisomycin-induced lipid reactive oxygen species was reduced after NCOA4 knockdown. In conclusion, the anisomycin-activated p38 MAPK promoted ferroptosis of HCC cells through H3S10 phosphorylation.

Berberine Suppressed the Progression of Human Glioma Cells by Inhibiting the TGF-β1/SMAD2/3 Signaling Pathway

Background:

Previous studies have shown that berberine can inhibit glioma progression, although the underlying molecular mechanisms needed to be explored further. The aim of this study was to evaluate the suppressive effects of berberine on human glioma cells, and identify the underlying signaling pathways.

Material and Methods:

The cytotoxic effect of different concentrations of berberine against normal human glial cells (HEB) and 4 glioma cell lines was evaluated by the CCK-8 assay. Apoptosis was assayed by flow cytometry. In vitro migration and invasion were analyzed by the wound healing and transwell assays. The expression levels of specific proteins were measured by western blotting and ELISA.

Results:

Berberine significantly inhibited the proliferation of human glioma U-87 cells, and induced apoptosis in the U-87 and LN229 cells by downregulating Bcl-2, and upregulating Bax and caspase-3. In addition, berberine also inhibited migration and invasion of the glioma cells. Furthermore, berberine exerted its effects on the proliferation, migration, invasion, and apoptosis of glioma cells by inhibiting the TGF-β1/SMAD2/3 signaling pathway, and exogenous TGF-β abrogated the pro-apoptotic and anti-oncogenic effects of berberine.

Conclusions:

Berberine inhibits glioma progression by targeting the TGF-β1/SMAD2/3 signaling pathway.

Mutational signatures representative transcriptomic perturbations in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary malignancy with increasing incidence and poor prognosis. Heterogeneity originating from genomic instability is one of the critical reasons of poor outcomes. However, the studies of underlying mechanisms and pathways affected by mutations are still not intelligible. Currently, integrative molecular-level studies using multiomics approaches enable comprehensive analysis for cancers, which is pivotal for personalized therapy and mortality reduction. In this study, genomic and transcriptomic data of HCC are obtained from The Cancer Genome Atlas (TCGA) to investigate the affected coding and non-coding RNAs, as well as their regulatory network due to certain mutational signatures of HCC. Different types of RNAs have their specific enriched biological functions in mutational signature-specific HCCs, upregulated coding RNAs are predominantly associated with lipid metabolism-related pathways, and downregulated coding RNAs are enriched in axonogenesis for tumor microenvironment generation. Additionally, differentially expressed miRNAs are inclined to concentrate in cancer-related signaling pathways. Some of these RNAs also serve as prognostic factors that help predict the survival outcome of HCCs with certain mutational signatures. Furthermore, deregulation of competing endogenous RNA (ceRNA) regulatory network is identified, which suggests a potential therapy via interference of miRNA activity for mutational signature-specific HCC. This study proposes a projection approach to reduce therapeutic complexity from genomic mutations to transcriptomic alterations. Through this method, we identify genes and pathways critical for mutational signature-specific HCC and further discover a series of prognostic markers indicating patient survival outcome.

Research Progress on the Microenvironment and Immunotherapy of Advanced Non-Small Cell Lung Cancer With Liver Metastases

Lung cancer is a malignant tumor with the highest morbidity and mortality, and more than 75% of patients are diagnosed at an advanced stage. Liver metastases occur in 20% of non-small cell lung cancer patients, and their prognosis are poor. In recent years, immune checkpoint inhibitor monotherapy and combination therapy have made breakthrough progress in advanced Non-small cell lung cancer (NSCLC) patients. However, compared with the overall population, the liver metastases population was an independent prognostic factor for poor immunotherapy response. Whether and how immunotherapy can work in NSCLC patients with liver metastases is a major and unresolved challenge. Although more and more data have been disclosed, the research progress of NSCLC liver metastasis is still limited. How liver metastasis modulates systemic antitumor immunity and the drug resistance mechanisms of the liver immune microenvironment have not been elucidated. We systematically focused on non-small cell lung cancer patients with liver metastases, reviewed and summarized their pathophysiological mechanisms, immune microenvironment characteristics, and optimization of immunotherapy strategies.

Tumor Microenvironment of Hepatocellular Carcinoma: Challenges and Opportunities for New Treatment Options

The prevalence of liver cancer is constantly rising, with increasing incidence and mortality in Europe and the USA in recent decades. Among the different subtypes of liver cancers, hepatocellular carcinoma (HCC) is the most commonly diagnosed liver cancer. Besides advances in diagnosis and promising results of pre-clinical studies, HCC remains a highly lethal disease. In many cases, HCC is an effect of chronic liver inflammation, which leads to the formation of a complex tumor microenvironment (TME) composed of immune and stromal cells. The TME of HCC patients is a challenge for therapies, as it is involved in metastasis and the development of resistance. However, given that the TME is an intricate system of immune and stromal cells interacting with cancer cells, new immune-based therapies are being developed to target the TME of HCC. Therefore, understanding the complexity of the TME in HCC will provide new possibilities to design novel and more effective immunotherapeutics and combinatorial therapies to overcome resistance to treatment. In this review, we describe the role of inflammation during the development and progression of HCC by focusing on TME. We also describe the most recent therapeutic advances for HCC and possible combinatorial treatment options.

The Molecular Interaction of Collagen with Cell Receptors for Biological Function

Collagen, an extracellular protein, covers the entire human body and has several important biological functions in normal physiology. Recently, collagen from non-human sources has attracted attention for therapeutic management and biomedical applications. In this regard, both land-based animals such as cow, pig, chicken, camel, and sheep, and marine-based resources such as fish, octopus, starfish, sea-cucumber, and jellyfish are widely used for collagen extraction. The extracted collagen is transformed into collagen peptides, hydrolysates, films, hydrogels, scaffolds, sponges and 3D matrix for food and biomedical applications. In addition, many strategic ideas are continuously emerging to develop innovative advanced collagen biomaterials. For this purpose, it is important to understand the fundamental perception of how collagen communicates with receptors of biological cells to trigger cell signaling pathways. Therefore, this review discloses the molecular interaction of collagen with cell receptor molecules to carry out cellular signaling in biological pathways. By understanding the actual mechanism, this review opens up several new concepts to carry out next level research in collagen biomaterials.

The Bright and the Dark Side of TGF-β Signaling in Hepatocellular Carcinoma: Mechanisms, Dysregulation, and Therapeutic Implications

Simple Summary

Transforming growth factor β (TGF-β) signaling is a preeminent regulator of diverse cellular and physiological processes. Frequent dysregulation of TGF-β signaling has been implicated in cancer. In hepatocellular carcinoma (HCC), the most prevalent form of primary liver cancer, the autocrine and paracrine effects of TGF-β have paradoxical implications. While acting as a potent tumor suppressor pathway in the early stages of malignancy, TGF-β diverts to a promoter of tumor progression in the late stages, reflecting its bright and dark natures, respectively. Within this context, targeting TGF-β represents a promising therapeutic option for HCC treatment. We discuss here the molecular properties of TGF-β signaling in HCC, attempting to provide an overview of its effects on tumor cells and the stroma. We also seek to evaluate the dysregulation mechanisms that mediate the functional switch of TGF-β from a tumor suppressor to a pro-tumorigenic signal. Finally, we reconcile its biphasic nature with the therapeutic implications.

Abstract

Hepatocellular carcinoma (HCC) is associated with genetic and nongenetic aberrations that impact multiple genes and pathways, including the frequently dysregulated transforming growth factor β (TGF-β) signaling pathway. The regulatory cytokine TGF-β and its signaling effectors govern a broad spectrum of spatiotemporally regulated molecular and cellular responses, yet paradoxically have dual and opposing roles in HCC progression. In the early stages of tumorigenesis, TGF-β signaling enforces profound tumor-suppressive effects, primarily by inducing cell cycle arrest, cellular senescence, autophagy, and apoptosis. However, as the tumor advances in malignant progression, TGF-β functionally switches to a pro-tumorigenic signal, eliciting aggressive tumor traits, such as epithelial–mesenchymal transition, tumor microenvironment remodeling, and immune evasion of cancer cells. On this account, the inhibition of TGF-β signaling is recognized as a promising therapeutic strategy for advanced HCC. In this review, we evaluate the functions and mechanisms of TGF-β signaling and relate its complex and pleiotropic biology to HCC pathophysiology, attempting to provide a detailed perspective on the molecular determinants underlying its functional diversion. We also address the therapeutic implications of the dichotomous nature of TGF-β signaling and highlight the rationale for targeting this pathway for HCC treatment, alone or in combination with other agents.

Comparative Metabolomics and Proteomics Reveal Vibrio parahaemolyticus Targets Hypoxia-Related Signaling Pathways of Takifugu obscurus

Coronavirus disease 2019 (COVID-19) raises the issue of how hypoxia destroys normal physiological function and host immunity against pathogens. However, there are few or no comprehensive omics studies on this effect. From an evolutionary perspective, animals living in complex and changeable marine environments might develop signaling pathways to address bacterial threats under hypoxia. In this study, the ancient genomic model animal Takifugu obscurus and widespread Vibrio parahaemolyticus were utilized to study the effect. T. obscurus was challenged by V. parahaemolyticus or (and) exposed to hypoxia. The effects of hypoxia and infection were identified, and a theoretical model of the host critical signaling pathway in response to hypoxia and infection was defined by methods of comparative metabolomics and proteomics on the entire liver. The changing trends of some differential metabolites and proteins under hypoxia, infection or double stressors were consistent. The model includes transforming growth factor-β1 (TGF-β1), hypoxia-inducible factor-1α (HIF-1α), and epidermal growth factor (EGF) signaling pathways, and the consistent changing trends indicated that the host liver tended toward cell proliferation. Hypoxia and infection caused tissue damage and fibrosis in the portal area of the liver, which may be related to TGF-β1 signal transduction. We propose that LRG (leucine-rich alpha-2-glycoprotein) is widely involved in the transition of the TGF-β1/Smad signaling pathway in response to hypoxia and pathogenic infection in vertebrates as a conserved molecule.

Expression of transforming growth factor β pathway components in chronic graft-versus-host disease after allogeneic hematopoietic cell transplantation

Chronic graft-versus-host disease (cGvHD), an immunological complication of allogeneic cell transplantation, is the principal cause of non-relapse mortality and morbidity. Even though advances have been made in understanding the pathophysiology of this disorder, many questions remain. We sought to evaluate gene expression of transforming growth factor β (TGF-β) pathway components, through quantitative RT-PCR and PCR array, in patients with cGvHD with different disease activity. We observed an upregulation of SMAD3, BMP2, CDKN1A, IL6, and TGF-β2 genes in the clinical tolerance group, which had never developed cGvHD, or which had been withdrawn from all immunosuppressive treatments (IST) for at least 1 year. In addition, SMAD5 gene upregulation was observed in cGvHD patients undergoing IST, and ordinal regression showed a correlation between SMAD5 expression and disease severity. Our data support the evidence of the important role of TGF-β effects in the pathological process of cGvHD.

Determining the function of LvSmad3 on Litopenaeus vannamei in response to acute low temperature stress

Smad3 is a key mediator of the canonical TGF-β signaling pathway and plays an important role in TGF-β1-mediated transcriptional regulation. However, the function of Smad3 in crustaceans such as shrimp, is still poorly understood and needs to be further explored. We characterized Litopenaeus vannamei Smad3 (LvSmad3) and its biological functions were investigated in response low temperature stress. Full-length LvSmad3 cDNA was 2341bp and contained an open reading frame (ORF) of 1326 bp that encoded a 441 amino acid long protein, with a predicted molecular mass of 48.35 kDa. Phylogenetic analysis revealed that LvSmad3 has a high degree of similarity with other known species. LvSmad3 mRNA was detected in all the tested tissues and highest transcription occurred mostly in gills. Further research showed that suppressing the expression of Smad3 could reduce ROS production, DNA damage and the apoptosis rate in shrimp hemocyte under low temperature compared with the dsGFP group. Thus, we speculated that Smad3 could promote the apoptosis of hemocytes. We confirmed that Smad3 could inhibit apoptosis in the hepatopancreas by suppressing the expression of pro-apoptotic genes. Taken together, the silencing of Smad3 can reduce ROS production induced by low temperature stress, weaken the damage to hemocytes and the hepatopancreas by inhibit the apoptosis.

Lepidium sativum Secondary Metabolites (Essential Oils): In Vitro and In Silico Studies on Human Hepatocellular Carcinoma Cell Lines

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and the greatest cause of cancer-related death in the world. Garden cress (Lepidium sativum) seeds have been proven to possess extraordinary antioxidant, anti-inflammatory, hypothermic, and analgesic properties. In this study, in vitro cytotoxic efficiency evaluation of L. sativum fractions was performed against two hepatocellular carcinoma cell lines (HuH-7 and HEPG-2), and the expression of some apoptotic genes was explored. In addition, the chemical composition of a potent extract of L. sativum was analyzed using gas chromatography coupled with mass spectrometry. Then, molecular docking analysis was implemented to identify the potential targets of the L. sativum components’ most potent extract. Overall, the n-hexane extract was the most potent against the two HCC cell lines. Moreover, these cytotoxicity levels were supported by the significant downregulation of EGFR and BCL2 gene expression levels and the upregulation of SMAD3, BAX, and P53 expression levels in both HuH-7 and HEPG2 cell lines. Regarding L. sativum’s chemical composition, GC–MS analysis of the n-hexane extract led to the identification of thirty compounds, including, mainly, hydrocarbons and terpenoids, as well as other volatile compounds. Furthermore, the binding affinities and interactions of the n-hexane fraction’s major metabolites were predicted against EGFR and BCL2 molecular targets using the molecular docking technique. These findings reveal the potential use of L. Sativum in the management of HCC.

TGF-β signaling: A recap of SMAD-independent and SMAD-dependent pathways

Transforming growth factor-β (TGF-β) is a proinflammatory cytokine known to control a diverse array of pathological and physiological conditions during normal development and tumorigenesis. TGF-β-mediated physiological effects are heterogeneous and vary among different types of cells and environmental conditions. TGF-β serves as an antiproliferative agent and inhibits tumor development during primary stages of tumor progression; however, during the later stages, it encourages tumor development and mediates metastatic progression and chemoresistance. The fundamental elements of TGF-β signaling have been divulged more than a decade ago; however, the process by which the signals are relayed from cell surface to nucleus is very complex with additional layers added in tumor cell niches. Although the intricate understanding of TGF-β-mediated signaling pathways and their regulation are still evolving, we tried to make an attempt to summarize the TGF-β-mediated SMAD-dependent andSMAD-independent pathways. This manuscript emphasizes the functions of TGF-β as a metastatic promoter and tumor suppressor during the later and initial phases of tumor progression respectively.

PGC-1α Protects against Hepatic Ischemia Reperfusion Injury by Activating PPARα and PPARγ and Regulating ROS Production

Peroxisome proliferator-activated receptors (PPARs) α and γ have been shown to be protective in hepatic ischemia/reperfusion (I/R) injury. However, the precise role of PPARγ coactivator-1α (PGC-1α), which can coactivate both of these receptors, in hepatic I/R injury, remains largely unknown. This study was designed to test our hypothesis that PGC-1α is protective during hepatic I/R injury in vitro and in vivo. Our results show that endogenous PGC-1α is basally expressed in normal livers and is moderately increased by I/R. Ectopic PGC-1α protects against hepatic I/R and hepatocyte anoxia/reoxygenation (A/R) injuries, whereas knockdown of endogenous PGC-1α aggravates such injuries, as evidenced by assessment of the levels of serum aminotransferases and inflammatory cytokines, necrosis, apoptosis, cell viability, and histological examination. The EMSA assay shows that the activation of PPARα and PPARγ is increased or decreased by the overexpression or knockdown of PGC-1α, respectively, during hepatic I/R and hepatocyte A/R injuries. In addition, the administration of specific antagonists of either PPARα (MK886) or PPARγ (GW9662) can effectively decrease the protective effect of PGC-1α against hepatic I/R and hepatocyte A/R injuries. We also demonstrate an important regulatory role of PGC-1α in reactive oxygen species (ROS) metabolism during hepatic I/R, which is correlated with the induction of ROS-detoxifying enzymes and is also dependent on the activations of PPARα and PPARγ. These data demonstrate that PGC-1α protects against hepatic I/R injury, mainly by regulating the activation of PPARα and PPARγ. Thus, PGC-1α may be a promising therapeutic target for the protection of the liver against I/R injury.

An Apoptotic Gene Signature for the Prognosis of Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is a major public health burden worldwide owing to high incidence and poor prognosis. Although numerous apoptotic genes were disclosed in HCC, the prognostic value and clinical utility of the genes remained unclear.

Methods

The differentially expressed genes (DEGs) were identified in the microarray and RNA sequencing data from public databases. The apoptosis-related differentially expressed genes (AR-DEGs) were selected to construct a Lasso-penalized Cox regression model. The signature including five apoptotic genes was used to calculate risk score. Then, the receiver operating characteristic (ROC) and survival analysis were conducted based on the signature. A nomogram containing the signature and clinical characteristics was plotted to visualized the prognosis prediction. Finally, the enrichment analysis was performed in the Gene Ontology (GO) to investigate the potential mechanism.

Results

Patients with high risk scores were related to worse overall survival than those with low risk. The 3-year and 5-year area under curve (AUC) values of the signature were above 0.7 in databases. And the nomogram presented reliable net benefits for the survival prediction. The nomogram was also tested by probability calibration curves and Decision Curve Analysis (DCA). Furthermore, the five differentially expressed genes were verified again in the HCC clinical specimens with real-time PCR and Western Blot.

Conclusion

Collectively, the present study formed a novel signature based on five apoptotic genes, and this possibly predicted prognosis and strengthened the communication with HCC patients about the likely treatment.

The Apoptotic Effect of Trichinella spiralis Infection Against Experimentally Induced Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the sixth most common type of cancer. Prognosis of HCC remains unsatisfactory. Therefore, developing new therapeutic modalities is still mandatory. Tumor biotherapy is a novel concept developed as a therapeutic strategy for cancer treatment. There is a similarity between the regulatory mechanism of Trichinella spiralis nurse cell formation and tumor cell apoptosis signal regulation.

OBJECTIVES

Induction of apoptosis by T. spiralis can represent a new strategy for tumor treatment.

METHODS

Experimental animals were divided in four groups; negative control (GI), T. spiralis infected (GII), induced HCC (GIII) and HCC then infected with T. spiralis (GIV). The apoptotic effect of T. spiralis infection was assessed by histopathological and immunohistochemical staining of B-cell lymphoma 2 (Bcl-2).

RESULTS

We found higher survival rate of rats and decreased weight of their livers with no nodules in HCC- T. spiralis group as compared to HCC group. Improvement of the dysplastic changes and increased apoptotic bodies which was confirmed by decreased expression of Bcl-2 reported in HCC- T. spiralis group.

CONCLUSION

Trichinella-induced apoptosis can be a contributing mechanism of the anti-tumor effect of T. spiralis infection. Our results showed a certain level of decreased progression of the tumor in HCC-T. spiralis group as indicated by increased rate of apoptosis and subsequently had a positive impact on the survival of rats.
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Fatty Acids and a High-Fat Diet Induce Epithelial-Mesenchymal Transition by Activating TGFβ and β-Catenin in Liver Cells

Nonalcoholic fatty liver disease is defined as the accumulation of excessive fat in the liver in the absence of excessive alcohol consumption or any secondary cause. Although the disease generally remains asymptomatic, chronic liver inflammation leads to fibrosis, liver cirrhosis, and even to the development of hepatocellular carcinoma (HCC). Fibrosis results from epithelial–mesenchymal transition (EMT), which leads to dedifferentiation of epithelial cells into cells with a mesenchymal-like phenotype. During EMT, epithelial cells with high expression of E-cadherin, influenced by growth factors, cytokines, and inflammatory processes, undergo morphological changes via enhanced expression of, e.g., vimentin, fibronectin, and N-cadherin. An inducer of EMT and, consequently, of fibrosis development is transforming growth factor beta (TGFβ), a pleiotropic cytokine associated with the progression of hepatocarcinogenesis. However, the understanding of the molecular events that direct the development of steatosis into steatohepatitis and liver fibrosis remains incomplete. Our study revealed that both prolonged exposure of hepatocarcinoma cells to fatty acids in vitro and high-fat diet in mice (20 weeks) result in inflammation. Prolonged treatment with fatty acids increased the levels of TGFβ, MMP9, and β-catenin, important EMT inducers. Moreover, the livers of mice fed a high-fat diet exhibited features of liver fibrosis with increased TGFβ and IL-1 levels. Increased expression of IL-1 correlated with a decrease in monocyte chemoattractant protein-induced protein 1 (MCPIP1), a negative regulator of the inflammatory response that regulates the stability of proinflammatory transcripts encoding IL-1. Our study showed that a high-fat diet induced EMT by increasing the levels of EMT-activating transcription factors, including Zeb1, Zeb2, and Snail and changed the protein profile to a profile characteristic of the mesenchymal phenotype.

Alpha-fetoprotein accelerates the progression of hepatocellular carcinoma by promoting Bcl-2 gene expression through an RA-RAR signalling pathway

Previous studies have found that alpha-fetoprotein (AFP) can promote the proliferation of hepatoma cells and accelerate the progression of hepatocellular carcinoma (HCC). However, the exact mechanism of action remains unclear. Recent bioinformatics studies have predicted the possible interaction between AFP and retinoic acid receptors (RARs). Thus, the purpose of this study was to investigate the molecular mechanism through which AFP promotes tumour cell proliferation by interfering with the RA-RAR signal pathway. Our data indicated that AFP could significantly promote the proliferation and weaken ATRA-induced apoptosis of hepatoma cells. Besides, cytoplasmic AFP interacts with RAR, disrupting its entrance into the nucleus, which in turn affects the expression of the Bcl-2 gene. In addition, knockdown of AFP in HepG2 cells was synchronously associated with an incremental increase of RAR binding to DNA, as well as down-regulation of Bcl-2; the opposite effect was observed in AFP gene-transfected HLE cells. Moreover, a similar effect of AFP was detected in tumour tissues with high serum AFP, but not in adjacent non-cancerous liver tissues, or HCC tissues with low serum AFP levels. These results indicate that AFP acts as signalling molecule and prevents RAR from entering into the nucleus by interacting with RAR, thereby promoting the expression of Bcl-2. Our data reveal a novel mechanism through which AFP regulates Bcl-2 expression and further suggest that AFP may be used as a novel target for treating HCC.

The dichotomous role of TGF-β in controlling liver cancer cell survival and proliferation

Hepatocellular carcinoma (HCC) is the major form of primary liver cancer and one of the most prevalent and life-threatening malignancies globally. One of the hallmarks in HCC is the sustained cell survival and proliferative signals, which are determined by the balance between oncogenes and tumor suppressors. Transforming growth factor beta (TGF-β) is an effective growth inhibitor of epithelial cells including hepatocytes, through induction of cell cycle arrest, apoptosis, cellular senescence, or autophagy. The antitumorigenic effects of TGF-β are bypassed during liver tumorigenesis via multiple mechanisms. Furthermore, along with malignant progression, TGF-β switches to promote cancer cell survival and proliferation. This dichotomous nature of TGF-β is one of the barriers to therapeutic targeting in liver cancer. Thereafter, understanding the underlying molecular mechanisms is a prerequisite for discovering novel antitumor drugs that may specifically disable the growth-promoting branch of TGF-β signaling or restore its tumor-suppressive arm. This review summarizes how TGF-β inhibits or promotes liver cancer cell survival and proliferation, highlighting the functional switch mechanisms during the process.

PTPRε Acts as a Metastatic Promoter in Hepatocellular Carcinoma by Facilitating Recruitment of SMAD3 to TGF-β Receptor 1

BACKGROUND AND AIMS

Transforming growth factor beta (TGF-β) suppresses early stages of tumorigenesis, but contributes to the migration and metastasis of cancer cells. However, the role of TGF-β signaling in invasive prometastatic hepatocellular carcinoma (HCC) is poorly understood. In this study, we investigated the roles of canonical TGF-β/mothers against decapentaplegic homolog 3 (SMAD3) signaling and identified downstream effectors on HCC migration and metastasis.

APPROACH AND RESULTS

By using in vitro trans-well migration and invasion assays and in vivo metastasis models, we demonstrated that SMAD3 and protein tyrosine phosphatase receptor epsilon (PTPRε) promote migration, invasion, and metastasis of HCC cells in vitro and in vivo. Further mechanistic studies revealed that, following TGF-β stimulation, SMAD3 binds directly to PTPRε promoters to activate its expression. PTPRε interacts with TGFBR1/SMAD3 and facilitates recruitment of SMAD3 to TGFBR1, resulting in a sustained SMAD3 activation status. The tyrosine phosphatase activity of PTPRε is important for binding with TGFBR1, recruitment and activation of SMAD3, and its prometastatic role in vitro. A positive correlation between pSMAD3/SMAD3 and PTPRε expression was determined in HCC samples, and high expression of SMAD3 or PTPRε was associated with poor prognosis of patients with HCC.

CONCLUSIONS

PTPRε positive feedback regulates TGF-β/SMAD3 signaling to promote HCC metastasis.

Protection from β-cell apoptosis by inhibition of TGF-β/Smad3 signaling

Prevailing insulin resistance and the resultant hyperglycemia elicits a compensatory response from pancreatic islet beta cells (β-cells) that involves increases in β-cell function and β-cell mass. However, the sustained metabolic stress eventually leads to β-cell failure characterized by severe β-cell dysfunction and progressive loss of β-cell mass. Whereas, β-cell dysfunction is relatively well understood at the mechanistic level, the avenues leading to loss of β-cell mass are less clear with reduced proliferation, dedifferentiation, and apoptosis all potential mechanisms. Butler and colleagues documented increased β-cell apoptosis in pancreas from lean and obese human Type 2 diabetes (T2D) subjects, with no changes in rates of β-cell replication or neogenesis, strongly suggesting a role for apoptosis in β-cell failure. Here, we describe a permissive role for TGF-β/Smad3 in β-cell apoptosis. Human islets undergoing β-cell apoptosis release increased levels of TGF-β1 ligand and phosphorylation levels of TGF-β's chief transcription factor, Smad3, are increased in human T2D islets suggestive of an autocrine role for TGF-β/Smad3 signaling in β-cell apoptosis. Smad3 phosphorylation is similarly increased in diabetic mouse islets undergoing β-cell apoptosis. In mice, β-cell-specific activation of Smad3 promotes apoptosis and loss of β-cell mass in association with β-cell dysfunction, glucose intolerance, and diabetes. In contrast, inactive Smad3 protects from apoptosis and preserves β-cell mass while improving β-cell function and glucose tolerance. At the molecular level, Smad3 associates with Foxo1 to propagate TGF-β-dependent β-cell apoptosis. Indeed, genetic or pharmacologic inhibition of TGF-β/Smad3 signals or knocking down Foxo1 protects from β-cell apoptosis. These findings reveal the importance of TGF-β/Smad3 in promoting β-cell apoptosis and demonstrate the therapeutic potential of TGF-β/Smad3 antagonism to restore β-cell mass lost in diabetes.

LncRNA SNHG3 Promotes Hepatocellular Tumorigenesis by Targeting miR-326

Small nucleolar RNA host gene 3 (SNHG3), a long noncoding RNA (lncRNA), acts as an oncogene in hepatocellular carcinoma (HCC), whereas microRNA (miR)-326 plays an inhibitory role in some types of human cancers, including melanoma, osteosarcoma, and gastric cancer. In the present study, by analyzing 47 tissue specimens of human HCC, we found that the relative expression levels of SNHG3 were significantly higher in HCC tissues than those in the adjacent noncancerous tissues, whereas the relative expression levels of miR-326 were significantly lower in HCC tissues. Furthermore, the relative mRNA levels of Sma and Mad Related Family 3 (SMAD3) and zinc finger E-box binding homeobox 1 (ZEB1) were significantly higher in HCC tissues compared with the adjacent noncancerous tissues. In human HCC cell lines, SNHG3 overexpression promoted the proliferation, migration, and epithelial-mesenchymal transition and inhibited apoptosis, whereas knockdown of SNHG3 expression exerted the opposite effects. Importantly, miR-326 or miR-326 inhibitor restored the aforementioned effects of SNHG3 overexpression or SNHG3 knockdown. We thus found that the miR-326-response element is present in SNHG3 and the 3'-untranslated region of SMAD3 mRNA. In fact, SNHG3 overexpression increased the expression levels of SMAD3 and ZEB1, while miR-326 decreased the expression levels of SMAD3. These results suggest that SNHG3 may function as a competing endogenous RNA (ceRNA) for miR-326, which in turn enhances SMAD3 and ZEB1 expression. In conclusion, we propose that SNHG3 promotes HCC progression via the miR-326/SMAD3/ZEB1 signaling pathway. The findings may provide novel targets for the diagnosis and treatment of HCC.

Conditional knockout of TGF-βRII /Smad2 signals protects against acute renal injury by alleviating cell necroptosis, apoptosis and inflammation

Rationale: TGF-β/Smad signaling is the central mediator for renal fibrosis, however, its functional role in acute kidney injury (AKI) is not fully understood. We previously showed Smad2 protects against renal fibrosis by limiting Smad3 signaling, but details on its role in acute phase are unclear. Recent evidence showed that TGF-β/Smad3 may be involved in the pathogenesis of AKI, so we hypothesized that Smad2 may play certain roles in AKI due to its potential effect on programmed cell death.

Methods: We established a cisplatin-induced AKI mouse model with TGF-β type II receptor or Smad2 specifically deleted from renal tubular epithelial cells (TECs). We also created stable in vitro models with either Smad2 knockdown or overexpression in human HK2 cells. Importantly, we evaluated whether Smad2 could serve as a therapeutic target in both cisplatin- and ischemic/reperfusion (I/R)-induced AKI mouse models by silencing Smad2 in vivo.

Results: Results show that disruption of TGF-β type II receptor suppressed Smad2/3 activation and attenuated renal injury in cisplatin nephropathy. Furthermore, we found that conditional knockout of downstream Smad2 in TECs protected against loss of renal function, and alleviated p53-mediated cell apoptosis, RIPK-mediated necroptosis and p65 NF-κB-driven renal inflammation in cisplatin nephropathy. This was further confirmed in cisplatin-treated Smad2 knockdown and overexpression HK2 cells. Additionally, lentivirus-mediated Smad2 knockdown protected against renal injury and inflammation while restoring renal function in established nephrotoxic and ischemic AKI models.

Conclusions: These findings show that unlike its protective role in renal fibrosis, Smad2 promoted AKI by inducing programmed cell death and inflammation. This may offer a novel therapeutic target for acute kidney injury.

Contextual Regulation of TGF-β Signaling in Liver Cancer

Primary liver cancer is one of the leading causes for cancer-related death worldwide. Transforming growth factor beta (TGF-β) is a pleiotropic cytokine that signals through membrane receptors and intracellular Smad proteins, which enter the nucleus upon receptor activation and act as transcription factors. TGF-β inhibits liver tumorigenesis in the early stage by inducing cytostasis and apoptosis, but promotes malignant progression in more advanced stages by enhancing cancer cell survival, EMT, migration, invasion and finally metastasis. Understanding the molecular mechanisms underpinning the multi-faceted roles of TGF-β in liver cancer has become a persistent pursuit during the last two decades. Contextual regulation fine-tunes the robustness, duration and plasticity of TGF-β signaling, yielding versatile albeit specific responses. This involves multiple feedback and feed-forward regulatory loops and also the interplay between Smad signaling and non-Smad pathways. This review summarizes the known regulatory mechanisms of TGF-β signaling in liver cancer, and how they channel, skew and even switch the actions of TGF-β during cancer progression.

Cathepsin L-mediated resistance of paclitaxel and cisplatin is mediated by distinct regulatory mechanisms

BACKGROUND

Cathepsin L (CTSL) is a cysteine protease known to have important roles in regulating cancer cellular resistance to chemotherapy. However mechanism underlying which regulates CTSL-mediated drug resistance remain largely unknown.

METHODS

We used NSCLC cell lines: A549, A549/TAX (paclitaxel-resistant), A549/DDP (cisplatin-resistant), H460 and PC9 cells, to evaluate CTSL and drug resistance changes. Tumor specimens from 53 patients with NSCLC and Xenograft models was also utilized to explore the regulatory relationship of CTSL, TGF-β, Egr-1 and CREB.

RESULTS

TGF-β and smad3 were overexpressed only in A549/TAX cells, silencing TGF-β or smad3 in A549/TAX cells decreased the expression of CTSL and enhanced their sensitivity to paclitaxel. Smad3 binds to the Smad-binding-element(SBE) of the CTSL promoter, resulting in increased activity of the CTSL promoter and subsequent CTSL. Egr-1 and CREB were overexpressed only in A549/DDP cells, and silencing Egr-1 or CREB reduced the expression of CTSL and increased cisplatin cytotoxicity. CREB could affect the activity of the CTSL promoter by binding to it. And the potential regulatory factors of CTSL were consistent in vivo and in human lung cancer. These different regulatory mechanisms of CTSL-mediated drug resistance exist in two other NSCLC cell lines.

CONCLUSION

CTSL-mediated drug resistance to paclitaxel and cisplatin may be modulated by different mechanisms. The results of our study identified different mechanisms regulating CTSL-mediated drug resistance and identified smad3 as a novel regulator of CTSL.

HEY2 acting as a co-repressor with smad3 and smad4 interferes with the response of TGF-beta in hepatocellular carcinoma

The HEY2 (hairy and enhancer of split-related with YRPW motif 2) is reported to play potential roles in tumorigenesis. However, the underlying mechanism in tumorigenesis is remain elusive. The present study aims to investigate the molecular mechanism of biological function of HEY2 in hepatocellular carcinoma (HCC). Dysfunction of the transforming growth factor-beta (TGF-β) pathway plays a critical role in HCC pathogenesis. Here, we identified HEY2 as a suppressor for TGF-β biological response. We demonstrated that HEY2 protein in tumor cytoplasm was up-regulated in HCC. Further, HEY2 overexpression inhibited TGF-β-induced growth arrest of HCC cells and inhibited TGF-β-induced downregulation of c-Myc, both in mRNA and in protein levels. While knockdown of HEY2, by small interfering RNA, was shown to enhance the TGF-β-mediated biological response of HCC cells. Moreover, HEY2 could form complexes with Smad3 and Smad4 and repress Smad3/Smad4 transcriptional activity. In conclusion, our findings indicate a novel role of HEY2 in mediating the TGF-β/Smad signaling pathway in HCC tumorigenesis.

A Transforming Growth Factor-β and H19 Signaling Axis in Tumor-Initiating Hepatocytes That Regulates Hepatic Carcinogenesis

Functions of transforming growth factor-β (TGF-β) in the liver vary depending on specific cell types and their temporal response to TGF-β during different stages of hepatocarcinogenesis (HCG). Through analysis of tumor tissues from hepatocellular carcinoma (HCC) patients, we were able to cluster hepatic epithelial cell-derived TGF-β gene signatures in association with distinct clinical prognoses. To delineate the role of hepatic epithelial TGF-β signaling in HCC development, we used an experimental system in which tumor-initiating hepatocytes (TICs) were isolated from TGF-β receptor II floxed mice (Tgfbr2^fl/fl ) and transplanted into syngeneic C57BL/6J mice by splenic injection. Recipient mice were then administered Cre-expressing adenovirus (Ad-Cre) to inactivate Tgfbr2 in transplanted TICs. After latency, Tgfbr2-inactivated TICs formed larger and more tumor nodules in recipient livers compared to TICs without Tgfbr2 inactivation. In vitro analyses revealed that treatment of cultured TICs with TGF-β inhibited expression of progenitor cell factors (including SRY (sex determining region Y)-box 2 [Sox2]). RNA sequencing (RNA-seq) analysis identified H19 as one of the most up-regulated long noncoding RNA (lncRNA) in association with Tgfbr2 inactivation in TICs. Tgfbr2 inactivation by Ad-Cre led to a 5-fold increase of H19 expression in TICs. Accordingly, TGF-β treatment reduced H19 expression. We observed that forced overexpression of Sox2 in TICs increased transcription of H19, whereas knockdown of Sox2 decreased it. Furthermore, depletion of H19 reduced the progenitor property of TICs in vitro and decreased their tumorigenic potential in vivo. Finally, we observed a low level of H19 mRNA expression in human HCC tissues from patients with the epithelial TGF-β gene signature in association with favorable prognosis. Conclusion: Our findings describe a TGF-β and H19 signaling axis by Sox2 in TICs that importantly regulates HCG.

Towards the contribution of the p38MAPK pathway to the dual role of TGFβ in cancer: A boolean model approach

The transforming growth factor-beta (TGF-β) pathway is involved in the regulation of cell growth and differentiation. In normal cells or in the early stages of cancer, this pathway can control proliferation stimuli by inducing cell cycle arrest or apoptosis (through the MAP-kinase protein p38MAPK), while in late stages it seems to act as a tumor promoter. This feature is known as the TGF-β dual role in cancer and it is not completely explained. This seems to arise through the accumulation of mutations in cancer development that affect the normal function of these pathways. In this work we propose a Boolean model of the crosstalk between the TGF-β, p38 MAPK and cell cycle checkpoint pathways which qualitatively describes this dual behavior. The model shows that for the wild type case, TGF-β acts as tumor supressor by inducing cell cycle arrest or apoptosis, as expected. However, the loss of function (LoF) of its two signaling proteins: SMAD2 and SMAD3 has immortalization effects due to the activation of the PI3K/AKT pathway that contributes to inhibit apoptosis. In silico mutations of the model elements were compared with cell phenotypes in experiments presenting agreement. In addition, we performed a series of double gene perturbations (that simulate random deleterious mutations) to determine the main regulators of the network. The results suggest that SMAD2/3 and p38MAPK are key players in processing the network input. In addition, when the LoF of SMAD2/3 is combined with the LoF of p38MAPK and p53, cell cycle arrest is completely abrogated. In conclusion, the model allows to visualize, through in silico mutations, the dual role of TGF-β: for the wild-type case TGF-β is able to block proliferation, however deleterious mutations can impair cell cycle arrest promoting cellular proliferation.

Prevention of acute liver injury by suppressing plasma kallikrein-dependent activation of latent TGF-β

Acute liver injury (ALI) is highly lethal acute liver failure caused by different etiologies. Transforming growth factor β (TGF-β) is a multifunctional cytokine and a well-recognized inducer of apoptotic and necrotic cell death in hepatocytes. Latent TGF-β is activated partly through proteolytic cleavage by a serine protease plasma kallikrein (PLK) between the R58 and L59 residues of its propeptide region. Recently, we developed a specific monoclonal antibody to detect the N-terminal side LAP degradation products ending at residue R58 (R58 LAP-DPs) that reflect PLK-dependent TGF-β activation. This study aimed to explore the potential roles of PLK-dependent TGF-β activation in the pathogenesis of ALI. We established a mouse ALI model via the injection of anti-Fas antibodies (Jo2) and observed increases in the TGF-β1 mRNA level, Smad3 phosphorylation, TUNEL-positive apoptotic hepatocytes and R58-positive cells in the liver tissues of Jo2-treated mice. The R58 LAP-DPs were observed in/around F4/80-positive macrophages, while macrophage depletion with clodronate liposomes partly alleviated the Jo2-induced liver injury. Blocking PLK-dependent TGF-β activation using either the serine proteinase inhibitor FOY305 or the selective PLK inhibitor PKSI-527 or blocking the TGF-β receptor-mediated signaling pathway using SB431542 significantly prevented Jo2-induced hepatic apoptosis and mortality. Furthermore, similar phenomena were observed in the mouse model of ALI with the administration of acetaminophen (APAP). In summary, R58 LAP-DPs reflecting PLK-dependent TGF-β activation may serve as a biomarker for ALI, and targeting PLK-dependent TGF-β activation has potential as a therapeutic strategy for ALI.

Hepatocellular Carcinoma: Causes, Mechanism of Progression and Biomarkers

Hepatocellular Carcinoma (HCC) is one of the most common malignant tumours in the world. It is a heterogeneous group of a tumour that vary in risk factor and genetic and epigenetic alteration event. Mortality due to HCC in last fifteen years has increased. Multiple factors including viruses, chemicals, and inborn and acquired metabolic diseases are responsible for its development. HCC is closely associated with hepatitis B virus, and at least in some regions of the world with hepatitis C virus. Liver injury caused by viral factor affects many cellular processes such as cell signalling, apoptosis, transcription, DNA repair which in turn induce important effects on cell survival, growth, transformation and maintenance. Molecular mechanisms of hepatocellular carcinogenesis may vary depending on different factors and this is probably why a large set of mechanisms have been associated with these tumours. Various biomarkers including α-fetoprotein, des-γ-carboxyprothrombin, glypican-3, golgi protein-73, squamous cell carcinoma antigen, circulating miRNAs and altered DNA methylation pattern have shown diagnostic significance. This review article covers up key molecular pathway alterations, biomarkers for diagnosis of HCC, anti-HCC drugs and relevance of key molecule/pathway/receptor as a drug target.

Significance of pSmad2/3 and Smad4 in hepatitis C virus-related liver fibrosis and hepatocellular carcinoma

Chronic hepatitis C (CHC) is a major public health problem, especially in Egypt. Risk of hepatocellular carcinoma (HCC) development increases as hepatitis C virus (HCV)-related liver diseases progress. Smads act as substrates for the transforming growth factor-beta (TGF-β) family of receptors. This study aims to assess hepatic expression of pSmad2/3 and Smad4 in CHC with different stages of fibrosis and grades of necro-inflammation as well as in HCC on top of CHC. This study was done on 33 core liver biopsies from patients with CHC (15 with early fibrosis and 18 with late fibrosis), 15 liver specimens from HCC cases on top of CHC, as well as five normal controls. pSmad2/3 and Smad4 show more immunopositivity, higher percentage of positive hepatocytes and stronger staining intensity in CHC with late fibrosis compared to early fibrosis. pSmad2/3 shows increase of the previous parameters in CHC with high grade activity than those with low activity. Smad4 shows increase of the previous parameters in HCC compared to CHC cases. pSmad2/3 and Smad4 can be used as diagnostic and/or prognostic markers for progression of HCV-related fibrosis to cirrhosis and further progression to HCC.

Clinico-Pathological Importance of TGF-β/Phospho-Smad Signaling during Human Hepatic Fibrocarcinogenesis

Chronic viral hepatitis is a global public health problem, with approximately 570 million persons chronically infected. Hepatitis B and C viruses increase the risk of morbidity and mortality from liver cirrhosis, hepatocellular carcinoma (HCC), and extrahepatic complications that develop. Hepatitis virus infection induces transforming growth factor (TGF)-β, which influences microenvironments within the infected liver. TGF-β promotes liver fibrosis by up-regulating extracellular matrix production by hepatic stellate cells. TGF-β is also up-regulated in patients with HCC, in whom it contributes importantly to bringing about a favorable microenvironment for tumor growth. Thus, TGF-β is thought to be a major factor regulating liver fibrosis and carcinogenesis. Since TGF-β carries out regulatory signaling by influencing the phosphorylation of Smads, we have generated several kinds of phospho-specific antibodies to Smad2/3. Using these, we have identified three types of phospohorylated forms: COOH-terminally phosphorylated Smad2/3 (pSmad2C and pSmad3C), linker phosphorylated Smad2/3 (pSmad2L and pSmad3L), and dually phosphorylated Smad3 (pSmad2L/C and pSmad3L/C). TGF-β-mediated pSmad2/3C signaling terminates cell proliferation; on the other hand, cytokine-induced pSmad3L signaling accelerates cell proliferation and promotes fibrogenesis. This review addresses TGF-β/Smad signal transduction in chronic liver injuries and carcinogenic processes. We also discuss the reversibility of Smad signaling after antiviral therapy.

Genomic Profiling and Metabolic Homeostasis in Primary Liver Cancers

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA), the two most common primary liver cancers, represent the second most common cancer-related cause of death worldwide, with most cases being diagnosed at an advanced stage. Recent genome-wide studies have helped to elucidate the molecular pathogenesis and genetic heterogeneity of liver cancers. This review of the genetic landscape of HCC and iCCA discusses the most recent findings from genomic profiling and the current understanding of the pathways involved in the initiation and progression of liver cancer. We highlight recent insights gained from metabolic profiling of HCC and iCCA. This knowledge will be key to developing clinically useful diagnostic/prognostic profiles, building targeted molecular and immunologic therapies, and ultimately curing these complex and heterogeneous diseases.

The Effects of Smad3 on Adrenocorticotropic Hormone-Secreting Pituitary Adenoma Development, Cell Proliferation, Apoptosis, and Hormone Secretion

OBJECTIVE

Down-regulation of mothers against decapentaplegic homolog 3 (Smad3) results in the formation of tumors both in vivo and in vitro. However, little is known about the effect of Smad3 on adrenocorticotropic hormone-secreting pituitary adenomas (ACTH-PAs). Our objective was to study the expression and effect of Smad3 in ACTH-PAs and its possible mechanisms.

METHODS

Smad3, COOH-terminally phosphorylated mothers against decapentaplegic homolog 3 (pSmad3), and mothers against decapentaplegic homolog 2 proteins (Smad2) were detected in samples from 5 normal anterior pituitaries and 18 ACTH-PAs by Western blot and immunohistochemical analysis. Then, Smad3 expression was up-regulated by Smad3-CMV plasmid or down-regulated by small interfering RNA in ACTH tumor cells (AtT-20) in vitro. Cell proliferation, apoptosis, ACTH level, and pSmad3, B-cell lymphoma/lewkmia-2 (BCL-2), and pro-opiomelanocortin (POMC) protein expression in the AtT-20 cells were measured to investigate the antitumor effects of Smad3.

RESULTS

Reduced expression of Smad3 and pSmad3 but unchanged Smad2 levels were found in ACTH-PAs compared with normal pituitaries. In vitro, the overexpression of Smad3 inhibited cell proliferation, promoted cell apoptosis, and decreased ACTH secretion; in contrast, Smad3 knockdown increased cell proliferation and decreased cell apoptosis but had no significant effect on ACTH secretion. At the same time, overexpression of Smad3 increased pSmad3 but inhibited BCL-2 and POMC protein expression. On the contrary, underexpression of Smad3 inhibited pSmad3 but promoted BCL-2 and POMC protein expression.

CONCLUSIONS

Smad3 is underexpressed in ACTH-PAs. Reversing the expression of Smad3 in AtT-20 cells could suppress cell growth, promote tumor apoptosis, and decrease ACTH secretion. Tumor suppression was possibly mediated by the promotion of pSmad3 and the reduction of BCL-2 and POMC expression.

Carcinogen 7,12-dimethylbenz[a]anthracene-induced mammary tumorigenesis is accelerated in Smad3 heterozygous mice compared to Smad3 wild type mice

Previous studies based on cell culture and xenograft animal models suggest that Smad3 has tumor suppressor function for breast cancer during early stages of tumorigenesis. In this report, we show that DMBA (7,12-dimethylbenz[a]anthracene), a chemical carcinogen, induces mammary tumor formation at a significantly higher frequency in the Smad3 heterozygous mice than in the Smad3 wild type mice. This is the first genetic evidence showing that Smad3 inhibits mammary tumor formation in a mouse model. Our findings support the notion that Smad3 has important tumor suppressor function for breast cancer.

Analysis of Genomes and Transcriptomes of Hepatocellular Carcinomas Identifies Mutations and Gene Expression Changes in the Transforming Growth Factor-β Pathway

BACKGROUND & AIMS

Development of hepatocellular carcinoma (HCC) is associated with alterations in the transforming growth factor-beta (TGF-β) signaling pathway, which regulates liver inflammation and can have tumor suppressor or promoter activities. Little is known about the roles of specific members of this pathway at specific of HCC development. We took an integrated approach to identify and validate the effects of changes in this pathway in HCC and identify therapeutic targets.

METHODS

We performed transcriptome analyses for a total of 488 HCCs that include data from The Cancer Genome Atlas. We also screened 301 HCCs reported in the Catalogue of Somatic Mutations in Cancer and 202 from Cancer Genome Atlas for mutations in genome sequences. We expressed mutant forms of spectrin beta, non-erythrocytic 1 (SPTBN1) in HepG2, SNU398, and SNU475 cells and measured phosphorylation, nuclear translocation, and transcriptional activity of SMAD family member 3 (SMAD3).

RESULTS

We found somatic mutations in at least 1 gene whose product is a member of TGF-β signaling pathway in 38% of HCC samples. SPTBN1 was mutated in the largest proportion of samples (12 of 202, 6%). Unsupervised clustering of transcriptome data identified a group of HCCs with activation of the TGF-β signaling pathway (increased transcription of genes in the pathway) and a group of HCCs with inactivation of TGF-β signaling (reduced expression of genes in this pathway). Patients with tumors with inactivation of TGF-β signaling had shorter survival times than patients with tumors with activation of TGF-β signaling (P = .0129). Patterns of TGF-β signaling correlated with activation of the DNA damage response and sirtuin signaling pathways. HepG2, SNU398, and SNU475 cells that expressed the D1089Y mutant or with knockdown of SPTBN1 had increased sensitivity to DNA crosslinking agents and reduced survival compared with cells that expressed normal SPTBN1 (controls).

CONCLUSIONS

In genome and transcriptome analyses of HCC samples, we found mutations in genes in the TGF-β signaling pathway in almost 40% of samples. These correlated with changes in expression of genes in the pathways; up-regulation of genes in this pathway would contribute to inflammation and fibrosis, whereas down-regulation would indicate loss of TGF-β tumor suppressor activity. Our findings indicate that therapeutic agents for HCCs can be effective, based on genetic features of the TGF-β pathway; agents that block TGF-β should be used only in patients with specific types of HCCs.

Up-regulated miR-500a enhances hepatocarcinoma metastasis by repressing PTEN expression

It has been shown that miR-500a may play an important role in the metastasis of hepatocarcinoma. The present study is to explore the influence of miR-500a on hepatocarcinoma proliferation and metastasis, and the related molecular mechanism. The levels of miR-500a in the serum and tissues of patients with metastatic or non-metastatic hepatocarcinoma or normal people were determined by quantitative reverse transcription-PCR (qRT-PCR). The proliferation, invasion, and cloning of hepatocarcinoma cell lines SMMC-7721 after transfection with mimic miR-500a or inhibitor miR-500a were determined. Luciferase reported assay was used to explore the relationship between miR-500a and phosphatase and tensin homologue (PTEN). Then, the protein expression of PTEN, p-Akt (S473), p-Akt (T308), Akt, p-mTOR, mTOR, p-4E-BP1, 4E-BP1, p-S6K, and S6K in SMMC-7721 cells were also determined by Western blotting. The expression of miR-500a in patients with metastatic hepatocarcinoma was significantly higher than the non-metastatic hepatocarcinoma. Overexpression of miR-500a promoted the proliferation, invasion, and cloning of SMMC-7721 cells. Luciferase reported assay showed miR-500a could directly target at 3'-UTR of PTEN. Overexpression of miR-500a significantly reduced the expression of PTEN, and enhanced phosphorylation of Akt, mTOR, S6K, and 4E-BP1. In conclusion, the expression of miR-500a was related to the proliferation and metastasis of hepatocarcinoma, which may be partly because of the activation of AKT/mTOR pathway through targetting PTEN.

Transforming Growth Factor-β Promotes Liver Tumorigenesis in Mice via Up-regulation of Snail

BACKGROUND & AIMS

Transforming growth factor beta (TGF-β) suppresses early stages of tumorigenesis, but also contributes to migration and metastasis of cancer cells. A large number of human tumors contain mutations that inactivate its receptors, or downstream proteins such as Smad transcription factors, indicating that the TGF-β signaling pathway prevents tumor growth. We investigated the effects of TGF-β inhibition on liver tumorigenesis in mice.

METHODS

C57BL/6 mice received hydrodynamic tail-vein injections of transposons encoding HRAS^G12V and a short hairpin RNA (shRNA) to down-regulate p53, or those encoding HRAS^G12V and MYC, or those encoding HRAS^G12V and TAZ^S89A, to induce liver tumor formation; mice were also given injections of transposons encoding SMAD7 or shRNA against SMAD2, SMAD3, SMAD4, or SNAI1 (Snail), with or without ectopic expression of Snail. Survival times were compared, and livers were weighted and examined for tumors. Liver tumor tissues were analyzed by quantitative reverse-transcription PCR, RNA sequencing, immunoblots, and immunohistochemistry. We analyzed gene expression levels in human hepatocellular carcinoma samples deposited in The Cancer Genome Atlas. A cell proliferation assay was performed using human liver cancer cell lines (HepG2 and Huh7) stably expressing Snail or shRNA against Snail.

RESULTS

TGF-β inhibition via overexpression of SMAD7 (or knockdown of SMAD2, SMAD3, or SMAD4) consistently reduced formation and growth of liver tumors in mice that expressed activated RAS plus shRNA against p53, or in mice that expressed activated RAS and TAZ. TGF-β signaling activated transcription of the Snail gene in liver tumors induced by HRAS^G12V and shRNA against p53, and by activated RAS and TAZ. Knockdown of Snail reduced liver tumor formation in both tumor models. Ectopic expression of Snail restored liver tumorigenesis suppressed by disruption of TGF-β signaling. In human hepatocellular carcinoma, Snail expression correlated with TGF-β activation. Ectopic expression of Snail increased cellular proliferation, whereas Snail knockdown led to reduced proliferation in human hepatocellular carcinoma cells.

CONCLUSIONS

In analyses of transgenic mice, we found TGF-β signaling to be required for formation of liver tumors upon expression of activated RAS and shRNA down-regulating p53, and upon expression of activated RAS and TAZ. Snail is the TGF-β target that is required for hepatic tumorigenesis in these models.

cPLA2α activates PI3K/AKT and inhibits Smad2/3 during epithelial-mesenchymal transition of hepatocellular carcinoma cells

Cytosolic phospholipase A2α (cPLA2α), a key phospholipase that regulates lipid metabolism, plays an important role in tumor progression. In the present study of hepatocellular carcinoma (HCC), cPLA2α was overexpressed in highly metastatic HCC cell lines. Immunohistochemical staining showed increased levels of cPLA2α at the invasive edges of HCC, and a clinicopathological analysis of samples from 111 patients revealed that its expression level was linked with micro-vascular invasion and cirrhosis. Knockdown of cPLA2α inhibited migration, probably due to its role in actin polymerization. Overexpression of cPLA2α promoted cell migration and invasion. Based on the mechanistic analysis, our data suggested that cPLA2α mediate epidermal growth factor (EGF) induced epithelial-mesenchymal transition (EMT) through PI3K/AKT/ERK pathway. cPLA2α activity was required for the transforming growth factor-(TGF)-β-induced EMT. However, cPLA2α inhibited Smad2/3 activation and promoted the activation of the PI3K/AKT/ERK pathway. A xenograft tumor transplant model confirmed the role of cPLA2α in HCC invasion and metastasis. Based on the mechanistic analysis, cPLA2α mediated both EGF- and TGF-β-induced EMT, which are essential for HCC metastasis. cPLA2α is a potentially target for novel therapies of HCC.

Genetic variants of cell cycle pathway genes predict disease-free survival of hepatocellular carcinoma

Disruption of the cell cycle pathway has previously been related to development of human cancers. However, associations between genetic variants of cell cycle pathway genes and prognosis of hepatocellular carcinoma (HCC) remain largely unknown. In this study, we evaluated the associations between 24 potential functional single nucleotide polymorphisms (SNPs) of 16 main cell cycle pathway genes and disease‐free survival (DFS) of 271 HCC patients who had undergone radical surgery resection. We identified two SNPs, i.e., SMAD3 rs11556090 A>G and RBL2 rs3929G>C, that were independently predictive of DFS in an additive genetic model with false‐positive report probability (FPRP) <0.2. The SMAD3 rs11556090G allele was associated with a poorer DFS, compared with the A allele [hazard ratio (HR) = 1.46, 95% confidential interval (95% CI) = 1.13–1.89, P = 0.004]; while the RBL2 rs3929 C allele was associated with a superior DFS, compared with the G allele (HR = 0.74, 95% CI = 0.57–0.96, P = 0.023). Additionally, patients with an increasing number of unfavorable genotypes (NUGs) of these loci had a significant shorter DFS (P_trend = 0.0001). Further analysis using receiver operating characteristic (ROC) curves showed that the model including the NUGs and known prognostic clinical variables demonstrated a significant improvement in predicting the 1‐year DFS (P = 0.011). Moreover, the RBL2 rs3929 C allele was significantly associated with increased mRNA expression levels of RBL2 in liver tissue (P = 1.8 × 10⁻⁷) and the whole blood (P = 3.9 × 10⁻¹⁴). Our data demonstrated an independent or a joint effect of SMAD3 rs11556090 and RBL2 rs3929 in the cell cycle pathway on DFS of HCC, which need to be validated by large cohort and biological studies.

miRNA-708 functions as a tumour suppressor in hepatocellular carcinoma by targeting SMAD3

Hepatocellular carcinoma (HCC) is the most frequent subtype of primary liver cancer and the third most common cause of cancer-associated mortality worldwide. Previous studies have reported that microRNAs (miRNAs) serve key roles in the carcinogenesis and progression of HCC by regulating gene expression. The present study investigated the expression patterns, biological roles and underlying mechanisms of miRNA-708 (miR-708) in HCC. The expression levels of miR-708 in HCC tissue samples and cell lines were examined. Cell proliferation, migration and invasion assays were used to evaluate the effect of miR-708 on HCC cells. In addition, bioinformatic and western blotting analyses, and dual luciferase reporter assays were performed to investigate the direct gene target of miR-708. The results of the present study demonstrated that miR-708 expression was significantly decreased in HCC tissue samples and cell lines. In addition, the expression level of miR-708 was associated with increased HCC tumour stage. Furthermore, ectopic expression of miR-708 suppressed HCC cell proliferation, migration and invasion. The results of the present study also indicated that miR-708 targets SMAD family member 3 directly in vitro. The results of the present study indicated that miR-708 may be a novel target for future HCC therapy.

Protein malnutrition during fetal programming induces fatty liver in adult male offspring rats

We evaluated the effects of protein malnutrition on liver morphology and physiology in rats subjected to different malnutrition schemes. Pregnant rats were fed with a control diet or a low protein diet (LPD). Male offspring rats received a LPD during gestation, lactation, and until they were 60 days old (MM group), a late LPD that began after weaning (CM), or a LPD administrated only during the gestation-lactation period followed by a control diet (MC). On day 60, blood was collected and the liver was dissected out. We found a decrease in MM rats' total body (p < 0.001) and liver (p < 0.05) weight. These and CM rats showed obvious liver dysfunction reflected by the increase in serum glutamic pyruvic transaminase (SGOT) (MM p < 0.001) and serum glutamic pyruvic transaminase (SGPT) (MM and CM p < 0.001) enzymes, and liver content of cholesterol (MM and CM p < 0.001) and triglycerides (MM p < 0.01; CM p < 0.001), in addition to what we saw by histology. Liver dysfunction was also shown by the increase in gamma glutamyl transferase (GGT) (MM, MC, and CM p < 0.001) and GST-pi1 (MM and CM p < 0.001, MC p < 0.05) expression levels. MC rats showed the lowest increment in GST-pi1 expression (MC vs. MM; p < 0.001, MC vs. CM; p < 0.01). ROS production (MM, CM, and MC: p < 0.001), lipid peroxidation (MM, CM, and MC p < 0.001), content of carbonyl groups in liver proteins (MM and CM p < 0.001, MC p < 0.01), and total antioxidant capacity (MM, CM, and MC p < 0.001) were increased in the liver of all groups of malnourished animals. However, MM rats showed the highest increment. We found higher TNF-α (MM and CM p < 0.001), and IL-6 (MM and CM p < 0.001) serum levels and TGF-β liver content (MM p < 0.01; CM p < 0.05), in MM and CM groups, while MC rats reverted the values to normal levels. Pro-survival signaling pathways mediated by tyrosine or serine/threonine kinases (pAKT) (MM and CM p < 0.001; MC p < 0.01) and extrasellular signal-regulated kinase (pERKs) (MM p < 0.01; CM p < 0.05) appeared to be activated in the liver of all groups of malnourished rats, suggesting the presence of cells resistant to apoptosis which would become cancerous. In conclusion, a LPD induced liver damage whose magnitude was related to the developmental stage at which malnutrition occurs and to its length.

Non-Smad Signaling Pathways of the TGF-β Family

Transforming growth factor β (TGF-β) and structurally related factors use several intracellular signaling pathways in addition to Smad signaling to regulate a wide array of cellular functions. These non-Smad signaling pathways are activated directly by ligand-occupied receptors to reinforce, attenuate, or otherwise modulate downstream cellular responses. This review summarizes the current knowledge of the mechanisms by which non-Smad signaling pathways are directly activated in response to ligand binding, how activation of these pathways impinges on Smads and non-Smad targets, and how final cellular responses are affected in response to these noncanonical signaling modes.

Non-Smad Signaling Pathways of the TGF-β Family

Transforming growth factor β (TGF-β) and structurally related factors use several intracellular signaling pathways in addition to Smad signaling to regulate a wide array of cellular functions. These non-Smad signaling pathways are activated directly by ligand-occupied receptors to reinforce, attenuate, or otherwise modulate downstream cellular responses. This review summarizes the current knowledge of the mechanisms by which non-Smad signaling pathways are directly activated in response to ligand binding, how activation of these pathways impinges on Smads and non-Smad targets, and how final cellular responses are affected in response to these noncanonical signaling modes.