Targeting Wnt/β-catenin pathway in hepatocellular carcinoma treatment

Hepatocellular carcinoma(HCC) is one of the most common causes of cancer-related death worldwide. Liver cancer is generally related to hepatitis B or Cinfection and cirrhosis. Usually, patients with HCC are asymptomatic and are diagnosed at late stages when surgical treatment is no longer suitable. Limited treatment options for patients with advanced HCC are a major concern. Therefore, there is an urge for finding novel therapies to treat HCC. Liver cancer is highly heterogeneous and involved deregulation of several signaling pathways. Wnt/β-catenin pathway is frequently upregulated in HCC and it is implicated in maintenance of tumor initiating cells, drug resistance, tumor progression, and metastasis. A great effort in developing selective drugs to target components of the β-catenin pathway with anticancer activity is underway but only a few of them have reached phase Ⅰ clinical trials. We aim to review the role of β-catenin pathway on hepatocarcinogenesis and liver cancer stem cell maintenance. We also evaluated the use of small molecules targeting the Wnt/β-catenin pathway with potential application for treatment of HCC.     

Wnt-/-β-catenin pathway signaling in human hepatocellular carcinoma

The molecular basis of the carcinogenesis of hepatocellular carcinoma(HCC) has not been adequately clarified, which negatively impacts the development of targeted therapy protocols for this overwhelming neoplasia. The aberrant activation of signaling in the HCC is primarily due to the deregulated expression of the components of the Wnt-/-β-catenin. This leads to the activation of β-catenin/T-cell factor-dependent target genes that control cell proliferation, cell cycle, apoptosis, and cell motility. The deregulation of the Wnt pathway is an early event in hepatocarcinogenesis. An aggressive phenotype was associated with HCC, since this pathway is implicated in the proliferation, migration, and invasiveness of cancer cells, regarding the cell's own survival. The disruption of the signaling cascade Wnt-/-β-catenin has shown anticancer properties in HCC's clinical evaluations of therapeutic molecules targeted for blocking the Wnt signaling pathway for the treatment of HCC, and it represents a promising perspective. The key to bringing this strategy in to clinical practice is to identify new molecules that would be effective only in tumor cells with aberrant signaling β-catenin.     

ATP-citrate lyase regulates stemness and metastasis in hepatocellular carcinoma via the Wnt/β-catenin signaling pathway

Background: Hepatocellular carcinoma(HCC) is one of the most highly malignant tumors. Liver tumor-initiating cells(LTICs) have been considered to contribute to HCC progression and metastasis. ATP-citrate lyase(ACLY), as a key enzyme for de novo lipogenesis, has been reported to be upregulated in various tumors. However, its expression and role in HCC and LTICs remain unknown. Methods: The expressions of ACLY in HCC tissues were detected by quantitative real-time PCR(q RT-PCR), Western blotting and immunohistochemistry. Kaplan-Meier curves and Chi-square test were used to determine the clinical significance of ACLY expression in HCC patients. A series of assays were performed to determine the function of ACLY on stemness, migration and invasion of HCC cells. Luciferase reporter assay, Western blotting and immunoprecipitation were used to study the regulation of the Wnt/β-catenin signaling by ACLY. Rescue experiments were performed to investigate whether β-catenin was the mediator of ACLY-regulated stemness and migration in HCC cells. Results: ACLY was highly expressed in HCC tissues and LTICs. Overexpression of ACLY was significantly correlated with poor prognosis, progression and metastasis of HCC patients. Knockdown of ACLY remarkably suppressed stemness properties, migration and invasion in HCC cells. Mechanistically, ACLY could regulate the canonical Wnt pathway by affecting the stability of β-catenin, and Lys49 acetylation of β-catenin might mediate ACLY-regulated β-catenin level in HCC cells. Conclusions: ACLY is a potent regulator of Wnt/β-catenin signaling in modulating LTICs stemness and metastasis in HCC. ACLY may serve as a new target for the diagnosis and treatment of HCC.     

The Wnt/β-catenin signaling pathway in liver biology and disease

The Wnt signaling pathway is an evolutionarily conserved, highly complex signaling pathway that is critical for development, differentiation and cellular homeostasis. The protein β-catenin is the central player in one major arm of the Wnt pathway called the canonical Wnt pathway. As in other organs, the Wnt/β-catenin pathway is critical for liver development. However, recent research suggests that the pathway is also important in liver regeneration, liver metabolism and maintenance of normal function in the adult liver. Aberrant activation of β-catenin has also been implicated in the pathogenesis of hepatobiliary neoplasia, ranging from benign lesions to liver cancer. The explosion of research into the many roles of the Wnt/β-catenin pathway promises to change our fundamental understanding of normal liver biology and the aberrations that lead to disease and cancer.     

Lysophosphatidylcholine acyltransferase 1 promotes epithelial-mesenchymal transition of hepatocellular carcinoma via the Wnt/β-catenin signaling pathway

Introduction and objectivesHepatocellular carcinoma (HCC) is one of the most malignant digestive tumors, and its insidious onset and rapid progression are the main reasons for the difficulty in effective treatment. Lysophosphatidylcholine acyltransferase 1 (LPCAT1) is a key enzyme that regulates phospholipid metabolism of the cell membrane. However, the mechanism by which LPCAT1 regulates HCC metastasis remains unknown. This study aimed to explore its biological function and potential mechanisms concerning migration and invasion in HCC.Materials and methodsLPCAT1 expression in HCC tissues and its association with clinical outcomes were investigated by western blotting and bioinformatic methods, respectively. The role of LPCAT1 in migration and invasion was assessed via Transwell assays. The expression pattern of epithelial-mesenchymal transition (EMT) markers was quantified by western blotting. The biological behaviors of LPCAT1 in vivo were evaluated using xenograft tumor models and caudal vein metastatic models. Signaling pathways related to LPCAT1 were predicted using gene set enrichment analysis (GSEA) and further confirmed by western blotting.ResultsLPCAT1 expression was significantly upregulated in HCC tissues and indicated a poor prognosis of HCC patients. Several EMT-related markers were found to be regulated by LPCAT1. HCC cells overexpressing LPCAT1 exhibited remarkably high migration and invasion capacities, upregulated expression of mesenchymal markers and reduced E-cadherin expression. In vivo, LPCAT1 promoted HCC pulmonary metastasis. Furthermore, the Wnt/β-catenin signaling pathway was confirmed to be activated by LPCAT1.ConclusionsLPCAT1 could serve as a promising biomarker of HCC and as a novel therapeutic target for the treatment of metastatic HCC.     

The research progress of Wnt/β-catenin signaling pathway in colorectal cancer

The Wnt/β-catenin signaling pathway is highly conservative. β-catenin is the key molecule in this pathway. The β-catenin target genes regulate cell proliferation and apoptosis. Since Wnt pathway proteins are distributed on the cell membrane, cytoplasm, and nucleus, inhibiting or activating these pathway proteins presents a novel target for cancer treatment via the Wnt signaling pathway. Studies have found that this pathway plays a significant role in the formation and progression of cancers, particularly colorectal cancer. We summarised the activation and inhibition of the Wnt signaling pathway in tumors, its relationship with the microenvironment and crosstalk with other pathways, and the effect of targeting abnormal Wnt signaling in the treatment of colorectal cancer. Here is to review future targeted therapeutics in colorectal cancer research and implementation.     

MicroRNA-194 inhibits cell invasion and migration in hepatocellular carcinoma through PRC1-mediated inhibition of Wnt/β-catenin signaling pathway

BackgroundHepatocellular carcinoma (HCC) is a commonly occurring malignancy accompanied by significant mortality rates. More recently, extensive investigations into microRNA (miRNA) expression profiles have been conducted to identify their ability to inhibit tumors. Thus, this study explored the role of miR-194 in epithelial-mesenchymal transition (EMT), cell invasion and migration through Wnt/β-catenin signaling pathway by binding to protein regulator of cytokinesis 1 (PRC1) in HCC.MethodsInitially, HCC related microarray data were retrieved and analyzed, and regulatory miRNAs of PRC1 were predicted accordingly. Next, the roles of miR-194, PRC1, and Wnt/β-catenin signaling pathway in HCC were determined, with relationship between PRC1 and miR-194 being verified subsequently. The role of miR-194 in cell EMT, migration, proliferation and invasion was evaluated through gain- and loss- function studies. Finally, tumor xenograft in nude mice was induced to assess tumor growth of HCC.ResultsmiR-194 affected HCC development in Wnt/β-catenin signaling pathway with putative binding sites to PRC1. MiR-194 could target PRC1. MiR-194 was downregulated while PRC1 was upregulated in HCC tissues. Additionally, miR-194 elevation and PRC1 silencing could suppress EMT, growth, proliferation, invasion, and migration in HCC cells by inactivating Wnt/β-catenin signaling pathway.ConclusionTaken together, this study demonstrated that miR-194 inhibited EMT, cell invasion and migration through inactivation of PRC1-dependent Wnt/β-catenin signaling pathway.     

Nerve growth factor/nuclear factor-κB pathway as a therapeutic target in breast cancer

Introduction  Nuclear factor-κB pathway (NF-κB) is activated in many breast cancers. NF-кB has interactions with other pathways such as the nerve growth factor (NGF) pathway, which is involved in the survival and proliferation of breast cancer cells. NGF treatment of breast cancer cells activates NF-κB resulting in the inhibition of ceramide-induced apoptosis. NGF effects on apoptosis and cell proliferation are mediated through p75NTR and p140TrkA receptors, respectively. In this study we investigate the NGF/NF-κB pathway as a therapeutic target in breast cancer. Results  We demonstrate that p75NTR inhibitor Pep5, p140TrkA inhibitor K-252a, and NF-κB inhibitor BAY11-7085 have pro-apoptotic and anti-proliferation activities in breast cancer cells. We also show a synergy in combining the NGF receptor inhibitors with the conventional breast cancer treatments tamoxifen and taxol. Conclusion   These data suggest that NGF/NF-κB pathway is a potential therapeutic target in breast cancer.     

Expression of β-catenin in hepatocellular carcinoma

AIM: The β-catenin has been recognized as a critical member of the Wnt signaling pathway and plays an important role in the generation/differentiation of many tissues. Inappropriate activation of this pathway has been implicated in carcinogenesis. The mechanism underlying the development as well as its prognosis of hepatocellular carcinoma (HCC) has remained unclear. The purpose of this study is to analyze the expression of β-catenin in HCC in relation to histological grades and viral hepatitis backgrounds. METHODS: Thirty-two sections were selected at random from autopsy and surgical cases of HCC. Immuohistologically, the location and positivity of β-catenin expression in HCC was examined. RESULTS: Normal hepatocytes did not express β-catenin. In 78% of HCC β-catenin was expressed at the membrane of the cells, with or without cytoplasmic and/or nuclear expression. The tumor cells with well- and moderately-differentiated grades expressed frequently at the membrane and cytoplasm compared with poorly-differentiated type. Nuclear expression of β-catenin was prone to occur in the tumor cells of poorly-differentiated grade. There were 15% of hepatitis C virus (HCV) backgrounds with nuclear expression. In contrast, there was 38% with nuclear expression in hepatitis B virus (HBV) backgrounds. In nonBnonC hepatitis, no case expressed nuclear β-catenin. CONCLUSION: The β-catenin expression in HCC cells was heterogenous among types of hepatitis viral infection. Wnt signaling pathway might be deeply involved in less-differentiated HCC and HBV background.     

Expression of β-catenin in hepatocellular carcinoma

AIM: The p-catenin has been recognized as a critical member of the Wnt signaling pathway and plays an important role in the generation/differentiation of many tissues. Inappropriate activation of this pathway has been implicated in carcinogenesis. The mechanism underlying the development as well as its prognosis of hepatocellular carcinoma (HCC) has remained unclear. The purpose of this study is to analyze the expression of p-catenin in HCC in relation to histological grades and viral hepatitis backgrounds. METHODS: Thirty-two sections were selected at random from autopsy and surgical cases of HCC. Immuohistologically, the location and positivity of p-catenin expression in HCC was examined. RESULTS: Normal hepatocytes did not express p-catenin. In 78% of HCC p-catenin was expressed at the membrane of the cells, with or without cytoplasmic and/or nuclear expression. The tumor cells with well- and moderately-differentiated grades expressed frequently at the membrane and cytoplasm compared with poorly-differentiated type. Nuclear expression of p-catenin was prone to occur in the tumor cells of poorly-differentiated grade. There were 15% of hepatitis C virus (HCV) backgrounds with nuclear expression. In contrast, there was 38% with nuclear expression in hepatitis B virus (HBV) backgrounds. In nonB-nonC hepatitis, no case expressed nuclear p-catenin. CONCLUSION: The β-catenin expression in HCC cells was heterogenous among types of hepatitis viral infection. Wnt signaling pathway might be deeply involved in less-differentiated HCC and HBV background.     

Reactivation of the insulin-like growth factor-Ⅱ signaling pathway in human hepatocellular carcinoma

Constitutive activation of the insulin-like growth factor （IGF）-signaling axis is frequently observed in human hepatocellular carcinoma （HCC）. Especially the overexpression of the fetal growth factor IGF-Ⅱ, IGF-Ⅰ receptor （IGF-IR）, and cytoplasmic downstream effectors such as insulin-receptor substrates （IRS） contribute to proliferation, anti-apoptosis, and invasive behavior. This review focuses on the relevant alterations in this signaling pathway and independent in vivo models that support the central role IGF-Ⅱ signaling during HCC development and progression. Since this pathway has become the center of interest as a target for potential anti-cancer therapy in many types of malignancies, various experimental strategies have been developed, including neutralizing antibodies and selective receptor kinase inhibitors, with respect to the specific and efficient reduction of oncogenic IGF- Ⅱ/IGF-IR-signaling.     

Wnt/β-catenin signaling regulates MAPK and Akt1 expression and growth of hepatocellular carcinoma cells

In hepatocellular carcinoma (HCC), Wnt/β-catenin, Ras/MAPK and PI3K/AKT signaling pathways form a complex network and play important roles during HCC genesis and development. To study their relationship and the influence on cell growth, the siRNA directed against β-catenin was transfected into HCC HepG2 cells. β-catenin mRNA and protein levels were measured respectively at various times by RT-PCR and Western blot. Furthermore, HCC cell growth was measured by MTT assay. Finally, MAPK family and Akt1 protein levels were also measured by Western blot. After the transfection, β-catenin mRNA levels were markedly inhibited at 24 h and increased gradually at 48, 72 and 96 h; β-catenin protein levels decreased gradually at 24, 48 and 72 h and slightly increased at 96 h. HCC cell growth was inhibited from 24-72 h, but this inhibition decreased at 96 h. ERK1/2 (p42/p44 MAPK), JNK/SAPK, p38 MAPK, and Akt1 protein levels showed no change following transfection, while their phosphorylated protein levels showed changes. Thus, siRNA directed against β-catenin markedly decreased β-catenin gene expression and inhibited cell growth. Wnt/β-catenin signaling pathway might regulate Ras/MAPK and PI3K/Akt signaling pathways through regulation of the phosphorylation state of ERK1/2, JNK/SAPK and Akt1 protein in HCC HepG2 cells. These pathways might compensate for the inhibitory effect of β-catenin, thereby affecting tumor cell growth and others downstream factors.     

Parathyroid hormone induces endothelialto-adipocyte transition in endothelial cells by Wnt/β-catenin pathway

<正>Objective To investigate whether elevated parathyroid hormone (PTH) levels could induce endothelial-tomesenchymal transition (End MT) and adipocyte transition in endothelial cells (ECs),and to determine the possible underlying mechanism. Methods (1) A rat model of secondary hyperparathyroidism and chronic kid-     

Tumor suppressor function of ezrin-radixin-moesin-binding phosphoprotein-50 through β-catenin/E-cadher in pathway in human hepatocellular cancer

AIM:To determine the effect and molecular mechanism of ezrin-radixin-moesin-binding phosphoprotein-50(EBP50) in hepatocellular carcinoma(HCC).METHODS:Three human HCC cell lines,i.e.,SMMC7721,HepG2 and Hep3B,were used.We transfected the Pbk-CMV-HA-EBP50 plasmid into SMMC7721 cells with Lipofectamine 2000 to overexpress EBP50.Western blotting were performed to determine the effects of the plasmid on EBP50 expression and to detect the expression of β-catenin and E-cadherin before and after the transfection of the plasmid into SMMC7721 cells.In vitro cell proliferation was assessed with a Cell Counting Kit-8(CCK-8) assay.Cell cycle distribution was assessed with flow cytometry.Invasion and migration ability of before and after the transfection were determined with a transwell assay.Cell apoptosis was demonstrated with Annexin V-FITC.The effect of EBP50 overexpressing on tumor growth in vivo was performed with a xenograft tumor model in nude mice.RESULTS:The transfection efficiency was confirmed with Western blotting(1.36 ± 0.07 vs 0.81 ± 0.09,P < 0.01).The CCK8 assay demonstrated that the growth of cells overexpressing EBP50 was significantly lower than control cells(P < 0.01).Cell cycle distribution showed there was a G0/G1 cell cycle arrest in cells overexpressing EBP50(61.3% ± 3.1% vs 54.0% ± 2.4%,P < 0.05).The transwell assay showed that cell invasion and migration were significantly inhibited in cells overexpressing EBP50 compared with control cells(5.8 ± 0.8 vs 21.6 ± 1.3,P < 0.01).Annexin V-FITC revealed that apoptosis was significantly increased in cells overexpressing EBP50 compared with control cells(14.8% ± 2.7% vs 3.4% ± 1.3%,P < 0.05).The expression of β-catenin was downregulated and E-cadherin was upregulated in cells overexpressing EBP50 compared with control cells(0.28 ± 0.07 vs 0.56 ± 0.12,P < 0.05;0.55 ± 0.08 vs 0.39 ± 0.07,P < 0.05).In vivo tumor growth assay confirmed that up-regulation of EBP50 could obviously slow the growth of HCC derived from SMMC7721 cells(     

Is human hepatocellular carcinoma a hormone-responsive tumor？

Before the positive results recently obtained with multitarget tyrosine kinase inhibitor sorafenib, there was no standard systemic treatment for patients with advanced hepatocellular carcinoma （HCC）. Sex hormones receptors are expressed in a significant proportion of HCC samples. Following preclinical and epidemiological studies supporting a relationship between sex hormones and HCC tumorigenesis, several randomized controlled trials （RCTs） tested the efficacy of the anti-estrogen tamoxifen as systemic treatment. Largest among these trials showed no survival advantage from the administration of tamoxifen, and the recent Cochrane systematic review produced a completely negative result. This questions the relevance of estrogen receptor-mediated pathways in HCC. However, a possible explanation for these disappointing results is the lack of proper patients selection according to sex hormones receptors expression, but unfortunately the interaction between this expression and efficacy of tamoxifen has not been studied adequately. It has been also proposed that negative results might be explained if tamoxifen acts in HCC via an estrogen receptor-independent pathway, that requires higher doses than those usually administered, but an Asian RCT conducted to assess dose-response effect was completely negative. Interesting, preliminary results have been obtained when hormonal treatment （tamoxifen or megestrol） has been selected according to the presence of wild-type or variant estrogen receptors respectively, but no large RCTs are available to support this strategy. Negative results have been obtained also with anti-androgen therapy. In conclusion, there is no robust evidence to consider HCC a hormone-responsive tumor. Hormonal treatments should not be part of the current management of HCC.