Autocrine insulin-like growth factor-II stimulation of tumor cell migration is a progression step in human hepatocarcinogenesis

Targeting HSP90 with picropodophyllin suppresses gastric cancer tumorigenesis by disrupting the association of HSP90 and AKT

Gastric cancer (GC) is one of the most common malignant tumors worldwide. Thus, the development of safe and effective therapeutic compounds for GC treatment is urgently required. Here, we aimed to examine the role of picropodophyllin (PPP), a compound extracted from the rhizome of Dysosma versipellis (Hance) M. Cheng ex Ying, on the proliferation of GC cells. Our study revealed that PPP inhibits the proliferation of GC cells in a dose-dependent manner by inducing apoptosis. Moreover, our study elucidated that PPP suppresses the growth of GC tumor xenografts with no side effects of observable toxicity. Mechanistically, PPP exerts its effects by blocking the AKT/mammalian target of rapamycin (mTOR) signaling pathway; these effects are markedly abrogated by the overexpression of constitutively active AKT. Furthermore, drug affinity responsive target stability (DARTS) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) revealed that heat shock protein 90 (HSP90) may be a potential target of PPP. Surface plasmon resonance and immunoprecipitation assay validated that PPP directly targets HSP90 and disrupts the binding of HSP90 to AKT, thereby suppressing GC cell proliferation. Thus, our study revealed that PPP may be a promising therapeutic compound for GC treatment.

Hepatocellular carcinoma cell line-microenvironment induced cancer-associated phenotype, genotype and functionality in mesenchymal stem cells

Mesenchymal stromal cells (MSCs) have shown promise in liver cancer treatment. However, when MSCs are recruited to hepatic site of injury, they acquire cancerous promoting phenotype.

AIMS

To assess the influence of Hepatocellular carcinoma (HCC) microenvironment on human adipose MSCs (hA-MSCs) and predict hA-MSCs intracellular miRNAs role.

MATERIALS AND METHODS

After indirect co-culturing with Huh-7 cells, hA-MSCs were characterized via cell cycle profile, proliferation and migration potentials by MTT and scratch assays respectively. Functional enrichment analysis of deregulated proteins and miRNA targets was also analyzed.

KEY FINDINGS

Co-cultured hA-MSCs could acquire a cancer-associated phenotype as shown by upregulation of CAF, cancer markers, and downregulation of differentiation markers. Migration of these cancer-associated cells was increased concomitantly with upregulation of adhesion molecules, but not epithelial to mesenchymal transition markers. Co-cultured cells showed increased proliferation confirmed by downregulation in cell percentage in G0/G1, G2/M and upregulation in S phases of cell cycle. Upregulation of miR-17-5p and 615-5p in co-cultured hA-MSCs was also observed. Functional enrichment analysis of dysregulated proteins in co-cultured hA-MSCs, including our selected miRNAs targets, showed their involvement in development of cancer-associated characteristics.

SIGNIFICANCE

This study suggests an interaction between tumor cells and surrounding stromal components to generate cancer associated phenotype of some CAF-like characteristics, known to favor cancer progression. This sheds the light on the use of hA-MSCs in HCC therapy. hA-MSCs modulation may be partially achieved via dysregulation of intracellular miR17-5P and 615-5p expression, suggesting an important role for miRNAs in HCC pathogenesis, and as a possible therapeutic candidate.

The Curious Case of the HepG2 Cell Line: 40 Years of Expertise

Liver cancer is the third leading cause of cancer death worldwide. Representing such a dramatic impact on our lives, liver cancer is a significant public health concern. Sustainable and reliable methods for preventing and treating liver cancer require fundamental research on its molecular mechanisms. Cell lines are treated as in vitro equivalents of tumor tissues, making them a must-have for basic research on the nature of cancer. According to recent discoveries, certified cell lines retain most genetic properties of the original tumor and mimic its microenvironment. On the other hand, modern technologies allowing the deepest level of detail in omics landscapes have shown significant differences even between samples of the same cell line due to cross- and mycoplasma infection. This and other observations suggest that, in some cases, cell cultures are not suitable as cancer models, with limited predictive value for the effectiveness of new treatments. HepG2 is a popular hepatic cell line. It is used in a wide range of studies, from the oncogenesis to the cytotoxicity of substances on the liver. In this regard, we set out to collect up-to-date information on the HepG2 cell line to assess whether the level of heterogeneity of the cell line allows in vitro biomedical studies as a model with guaranteed production and quality.

The Curious Case of the HepG2 Cell Line: 40 Years of Expertise

Liver cancer is the third leading cause of cancer death worldwide. Representing such a dramatic impact on our lives, liver cancer is a significant public health concern. Sustainable and reliable methods for preventing and treating liver cancer require fundamental research on its molecular mechanisms. Cell lines are treated as in vitro equivalents of tumor tissues, making them a must-have for basic research on the nature of cancer. According to recent discoveries, certified cell lines retain most genetic properties of the original tumor and mimic its microenvironment. On the other hand, modern technologies allowing the deepest level of detail in omics landscapes have shown significant differences even between samples of the same cell line due to cross- and mycoplasma infection. This and other observations suggest that, in some cases, cell cultures are not suitable as cancer models, with limited predictive value for the effectiveness of new treatments. HepG2 is a popular hepatic cell line. It is used in a wide range of studies, from the oncogenesis to the cytotoxicity of substances on the liver. In this regard, we set out to collect up-to-date information on the HepG2 cell line to assess whether the level of heterogeneity of the cell line allows in vitro biomedical studies as a model with guaranteed production and quality.

The Curious Case of the HepG2 Cell Line: 40 Years of Expertise

Liver cancer is the third leading cause of cancer death worldwide. Representing such a dramatic impact on our lives, liver cancer is a significant public health concern. Sustainable and reliable methods for preventing and treating liver cancer require fundamental research on its molecular mechanisms. Cell lines are treated as in vitro equivalents of tumor tissues, making them a must-have for basic research on the nature of cancer. According to recent discoveries, certified cell lines retain most genetic properties of the original tumor and mimic its microenvironment. On the other hand, modern technologies allowing the deepest level of detail in omics landscapes have shown significant differences even between samples of the same cell line due to cross- and mycoplasma infection. This and other observations suggest that, in some cases, cell cultures are not suitable as cancer models, with limited predictive value for the effectiveness of new treatments. HepG2 is a popular hepatic cell line. It is used in a wide range of studies, from the oncogenesis to the cytotoxicity of substances on the liver. In this regard, we set out to collect up-to-date information on the HepG2 cell line to assess whether the level of heterogeneity of the cell line allows in vitro biomedical studies as a model with guaranteed production and quality.

Yes-associated protein (YAP) induces a secretome phenotype and transcriptionally regulates plasminogen activator Inhibitor-1 (PAI-1) expression in hepatocarcinogenesis

Background

Overexpression and nuclear enrichment of the oncogene yes-associated protein (YAP) cause tumor initiation and support tumor progression in human hepatocellular carcinoma (HCC) via cell autonomous mechanisms. However, how YAP expression in tumor cells affects intercellular communication within the tumor microenvironment is not well understood.

Methods

To investigate how tumor cell-derived YAP is changing the paracrine communication network between tumor cells and non-neoplastic cells in hepatocarcinogenesis, the expression and secretion of cytokines, growth factors and chemokines were analyzed in transgenic mice with liver-specific and inducible expression of constitutively active YAP (YAP^S127A). Transcriptomic and proteomic analyses were performed using primary isolated hepatocytes and blood plasma. In vitro, RNAinterference (RNAi), expression profiling, functional analyses and chromatin immunoprecipitation (ChIP) analyses of YAP and the transcription factor TEA domain transcription factor 4 (TEAD4) were performed using immortalized cell lines. Findings were confirmed in cohorts of HCC patients at the transcript and protein levels.

Results

YAP overexpression induced the expression and secretion of many paracrine-acting factors with potential impact on tumorous or non-neoplastic cells (e.g. plasminogen activator inhibitor-1 (PAI-1), C-X-C motif chemokine ligand 13 (CXCL13), CXCL16). Expression analyses of human HCC patients showed an overexpression of PAI-1 in human HCC tissues and a correlation with poor overall survival as well as early cancer recurrence. PAI-1 statistically correlated with genes typically induced by YAP, such as connective tissue growth factor (CTGF) and cysteine rich angiogenic inducer 61 (CYR61) or YAP-dependent gene signatures (CIN4/25). In vitro, YAP inhibition diminished the expression and secretion of PAI-1 in murine and human liver cancer cell lines. PAI-1 affected the expression of genes involved in cellular senescence and oncogene-induced senescence was confirmed in YAP^S127A transgenic mice. Silencing of TEAD4 as well as treatment with the YAP/TEAD interfering substance Verteporfin reduced PAI-1 expression. ChIP analyses confirmed the binding of YAP and TEAD4 to the gene promoter of PAI-1 (SERPINE1).

Conclusions

These results demonstrate that the oncogene YAP changes the secretome response of hepatocytes and hepatocyte-derived tumor cells. In this context, the secreted protein PAI-1 is transcriptionally regulated by YAP in hepatocarcinogenesis. Perturbation of these YAP-dependent communication hubs including PAI-1 may represent a promising pharmacological approach in tumors with YAP overexpression.

Can Prohibitin 1 be a Safeguard against liver disease?

Prohibitin (PHB) 1 is involved in multiple regulatory pathways in liver disease to protect hepatocytes, and its function is associated with subcellular localization. PHB1 located in the nucleus, cytoplasm and the mitochondrial inner membrane has anti-oxidative stress and anti-inflammatory effects in hepatitis and cirrhosis, which can protect liver cells from damage caused by inflammatory factors and reactive oxygen species (ROS) stimulation. The low expression of PHB1 located in the nucleus of liver cancer cells inhibits the proliferation and metastasis of liver cancer; thus, PHB1 exhibits the function of a tumor suppressor gene. Understanding the mechanisms of PHB1 in liver diseases may be useful for further research on the disease and may provide new ideas for the development of targeted therapeutic drugs in the future. Therefore, this review puts forward an overview of the role of PHB1 and its protective mechanism in liver diseases.

Long noncoding RNA 91H overexpression contributes to the growth and metastasis of HCC by epigenetically positively regulating IGF2 expression

BACKGROUND & AIMS

Long noncoding RNA 91H is transcribed from the H19/IGF2 locus and contributes to the development of breast and oesophagus cancers by regulating the expression of IGF2, but the regulation mechanism remains poorly characterized. Here, we explored the role of 91H in hepatocellular carcinoma (HCC) and the mechanism of IGF2 expression regulation by 91H.

METHODS

Firstly, the expression of 91H was analysed in HCC by quantitative RT-PCR, the association of 91H with survival was evaluated by the Kaplan-Meier method and the effect of 91H on the growth and invasion of HCC was investigated by the in vitro and in vivo studies. Then, the association of 91H with the expression of IGF2 was evaluated in HCC tissues, and the effect of 91H on the expression of IGF2 was investigated by 91H knockdown. Finally, the binding of RBBP5 to 91H and the binding of RBBP5, activating H3K4me3 mark and repressive H3K27me3 mark to the P3 and P4 promoters of IGF2 gene were studied by RIP and ChIP respectively.

RESULTS

The overexpression of 91H was found in HCC and in association with the growth, metastasis and shorter survival time of HCC. The knockdown of 91H down-regulated the IGF2 expression in HCC, and the mechanism was correlated with the decreased enrichment of RBBP5 and H3K4me3 and increased enrichment of H3K27me3 at the bivalent P3 and P4 promoters.

CONCLUSIONS

The overexpression of 91H promotes tumour growth and metastasis, and is associated with a poor prognosis of HCC at least partially by positively regulating the expression of IGF2 through bivalent histone modification changes characterized by H3K4me3 and H3K27me3 at the P3 and P4 promoters.

Identification of a novel EphB4 phosphodegron regulated by the autocrine IGFII/IRA axis in malignant mesothelioma

Malignant mesothelioma is a deadly disease with limited therapeutic options. EphB4 is an oncogenic tyrosine kinase receptor expressed in malignant mesothelioma as well as in a variety of cancers. It is involved in tumor microenvironment mediating angiogenesis and invasive cellular effects via both EphrinB2 ligand-dependent and independent mechanisms. The molecular network underlying EphB4 oncogenic effects is still unclear. Here we show that EphB4 expression in malignant mesothelioma cells is markedly decreased upon neutralization of cancer-secreted IGF-II. In particular, we demonstrate that EphB4 protein expression in malignant mesothelioma cells depend upon a degradation rescue mechanism controlled by the autocrine IGF-II-insulin receptor-A specific signaling axis. We show that the regulation of EphB4 expression is linked to a competing post-translational modification of its carboxy-terminal tail via phosphorylation of its tyrosine 987 by the Insulin receptor isoform-A kinase-associated activity in response to the autocrine IGF-II stimuli. Neutralization of this autocrine-induced EphB4-phosphorylation by IGF-II associates with the increased ubiquitination of EphB4 carboxy-terminal tail and with its rapid degradation. We also describe a novel Ubiquitin binding motif in the targeted region as part of the identified EphB4 phosphodegron and provide 3D modeling data supporting a possible model for the acute EphB4 PTM-driven regulation by IGF-II. Altogether, these findings disclose a novel molecular mechanism for the maintenance of EphB4-expression in malignant mesothelioma cells and other IGF-II-secreting cancers (IGF2omas).

miRNA‑30a‑3p inhibits metastasis and enhances radiosensitivity in esophageal carcinoma by targeting insulin‑like growth factor 1 receptor

It has been demonstrated that microRNAs (miRNAs) serve important roles in various biological processes, such as tumorigenesis. In the present study, the role of miR‑30a‑3p in the pathogenesis of esophageal carcinoma (EC) was investigated. Reverse transcription‑quantitative polymerase chain reaction was performed to determine the levels of miR‑30a‑3p expression in EC tissues and cell lines. Then, the effects of miR‑30a‑3p on the migration, invasion and radiosensitivity of EC cells were investigated using scratch‑wound, Transwell and radiosensitivity assays, respectively. A dual‑luciferase reporter assay was performed to determine potential interactions between miR‑30a‑3p and the 3'‑untranslated region (3'‑UTR) of insulin‑like growth factor 1 receptor (IGF‑1R). The results demonstrated that the levels of miR‑30a‑3p expression in EC tissues and cell lines were significantly decreased compared with those in paired healthy tissues and a human esophageal epithelial cell line. Upregulation of miR‑30a‑3p expression significantly suppressed migration, invasion and epithelial‑mesenchymal transition (EMT), and enhanced radiosensitivity in EC cells. Analysis of luciferase activity demonstrated that miR‑30a‑3p interacted with the 3'‑UTR of IGF‑1R, and knockdown of IGF‑1R induced similar effects on the migration, invasion, EMT and radiosensitivity of EC cells. The results indicated that miR‑30a‑3p suppressed metastasis and enhanced the radiosensitivity of EC cells via downregulation IGF‑1R, suggesting that miR‑30a‑3p may be a potential therapeutic target in the treatment of EC.

Methylation in MIRLET7A3 Gene Induces the Expression of IGF-II and Its mRNA Binding Proteins IGF2BP-2 and 3 in Hepatocellular Carcinoma

miR-let-7a is a tumor suppressor miRNA with reduced expression in most cancers. Methylation of MIRLET7A3 gene was reported to be the cause of this suppression in several cancers; however, it was not explicitly investigated in hepatocellular carcinoma (HCC). We aimed at investigating miR-let-7a expression and molecular mode in HCC, identifying drug-targetable networks, which might be affected by its abundance. Our results illustrated a significant repression of miR-let-7a, which correlated with hypermethylation of its gene of origin MIRLRT7A3. This was further supported by the induction of miR-let-7a expression upon treatment of HCC cells with a DNA-methyltransferase inhibitor. Using a computational approach, insulin-like growth factor (IGF)-II and IGF-2 mRNA binding proteins (IGF2BP)-2/-3 were identified as potential targets for miR-let-7a that was further confirmed experimentally. Indeed, miR-let-7a mimics diminished IGF-II as well as IGF2BP-2/-3 expression. Direct binding of miR-let-7a to each respective transcript was confirmed using a luciferase reporter assay. In conclusion, this study suggests that DNA hypermethylation leads to epigenetic repression of miR-let-7a in HCC cells, which induces the oncogenic IGF-signaling pathway.

Metformin Counteracts HCC Progression and Metastasis Enhancing KLF6/p21 Expression and Downregulating the IGF Axis

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is the common tumor of the liver. Unfortunately, most HCC seem to be resistant to conventional chemotherapy and radiotherapy. The poor efficacy of antitumor agents is also due, at least in part, to the inefficient drug delivery and metabolism exerted by the steatotic/cirrhotic liver that hosts the tumor. Thus, novel approaches in chemotherapy may be needed to improve the survival rate in patients with HCC. Metformin (METF) has been found to lower HCC risk; however, the mechanisms by which METF performs its anticancer activity are not completely elucidated. Previous studies have showed METF action on growth inhibition in the liver in a dose/time-dependent manner and its antitumor role by targeting multiple pathways. We investigated molecular effects of METF in an in vitro human hepatoma model (HepG2), studying cell cycle regulators, tumorigenesis markers, and insulin-like growth factor (IGF) axis regulation.

MATERIALS AND METHODS

HepG2 cells were treated with METF (400 μM) for 24, 48, and 72 hours. METF action on cell cycle progression and cellular pathways involved in metabolism regulation was evaluated by gene expression analysis, immunofluorescence, and Western blot assay.

RESULTS

By assessing HepG2 cell viability, METF significantly decreased growth cell capacity raising KLF6/p21 protein content. Moreover, METF ameliorated the cancer microenvironment reducing cellular lipid drop accumulation and promoting AMPK activity. The overexpression of IGF-II molecule and the IGF-I receptor that plays a main role in HCC progression was counteracted by METF. Furthermore, the protein content of HCC principal tumor markers, CK19 and OPN, linked to the metastasis process was significantly reduced by METF stimulus.

CONCLUSION

Our data show that METF could suppress HepG2 proliferation, through induction of cell cycle arrest at the G0/G1 phase. In addition, METF effect on the cancer microenvironment and on the IGF axis leads to the development of new METF therapeutic use in HCC treatment.

Insulin-like growth factor 2 axis supports the serum-independent growth of malignant rhabdoid tumor and is activated by microenvironment stress

Malignant rhabdoid tumors (MRTs) are rare, lethal, pediatric tumors predominantly found in the kidney, brain and soft tissues. MRTs are driven by loss of tumor suppressor SNF5/INI1/SMARCB1/BAF47. The prognosis of MRT is poor using currently available treatments, so new treatment targets need to be identified to expand treatment options for patients experiencing chemotherapy resistance. The growth hormone insulin-like growth factor 2 (IGF2) signaling pathway is a promising target to overcome drug resistance in many cancers. Here, we evaluated the role of IGF2 axis in MRT cell proliferation. We showed that microenvironment stress, including starvation treatment and chemotherapy exposure, lead to elevated expression of IGF2 in the SNF5-deficient MRT cell line. The autocrine IGF2, in turn, activated insulin-like growth factor 1 receptor (IGF1R), insulin receptor (INSR), followed by PI3K/AKT pathway and RAS/ERK pathway to promote cancer cell proliferation and survival. We further demonstrated that impairment of IGF2 signaling by IGF2 neutralizing antibody, IGF1R inhibitor NVP-AEW541 or AKT inhibitor MK-2206 2HCl treatment prevented MRT cell growth in vitro. Taken together, our characterization of this axis defines a novel mechanism for MRT cell growth in the microenvironment of stress. Our results also demonstrated the necessity to test the treatment effect targeting this axis in future research.

IGF-II induced by hepatitis B virus X protein regulates EMT via SUMO mediated loss of E-cadherin in mice

Hepatocellular carcinoma (HCC) is one of the most common cancers and a leading cause of cancer mortality. Prognosis of this disease largely depends on its stage. An Enlarged liver, due to dysplasia, may be a critical point in the multi-step progression to HCC. The mechanism underlying hepatomegaly in human and mouse models are poorly understood. We previously reported we observed enlarged liver in hepatitis B virus X protein (HBx) expressing mice (HBx mice). Here we identify the critical role of HBx induced IGF-II in hepatomegaly in mice and abnormal cell growth in human hepatoma cells. We found that HBx induced IGF-II is essential to induce epithelial-mesenchymal transition (EMT) through loss of E-cadherin. In mouse liver, loss of E-cadherin was mediated by post-translational regulation, at least in part, by protease and SUMOylation not by transcriptional regulation. In contrast, in hepatoma cell line (HepG2 cells) Akt signal pathway controls the mRNA expression level of EMT-related transcription factors, especially Twist, in addition to post- translational modification through SUMOylation. Thus, IGF-II-mediated loss of E-cadherin is central in developing hepatomegaly in mice and abnormal cell growth in the hepatoma cell line. HBx induced IGF-II represents a potential biomarker, which is also a therapeutic target in HCC.

Inhibition of insulin-like growth factor II (IGF-II)-dependent cell growth by multidentate pentamannosyl 6-phosphate-based ligands targeting the mannose 6-phosphate/IGF-II receptor

The mannose 6-phosphate/insulin-like growth factor II receptor (M6P/IGF2R) binds M6P-capped ligands and IGF-II at different binding sites within the ectodomain and mediates ligand internalization and trafficking to the lysosome. Multivalent M6P-based ligands can cross-bridge the M6P/IGF2R, which increases the rate of receptor internalization, permitting IGF-II binding as a passenger ligand and subsequent trafficking to the lysosome, where the IGF-II is degraded. This unique feature of the receptor may be exploited to design novel therapeutic agents against IGF-II-dependent cancers that will lead to decreased bioavailable IGF-II within the tumor microenvironment. We have designed a panel of M6P-based ligands that bind to the M6P/IGF2R with high affinity in a bivalent manner and cause decreased cell viability. We present evidence that our ligands bind through the M6P-binding sites of the receptor and facilitate internalization and degradation of IGF-II from conditioned medium to mediate this cellular response. To our knowledge, this is the first panel of synthetic bivalent ligands for the M6P/IGF2R that can take advantage of the ligand-receptor interactions of the M6P/IGF2R to provide proof-of-principle evidence for the feasibility of novel chemotherapeutic agents that decrease IGF-II-dependent growth of cancer cells.

How does the tumor microenvironment play a role in hepatobiliary tumors?

The tumor microenvironment (TME) is defined as the structural and dynamic network of cellular and non-cellular interactions between malignant cells and the surrounding non-malignant matrix. Hepatocellular carcinoma (HCC) and pancreatic ductal adenocarcinoma (PDAC) are two of the most challenging gastrointestinal malignancies. Despite clinical advancements in understanding tumor biology and growth of the chemotherapeutic industry, there have been no corresponding improvements in prognosis and overall survival of HCC and PDAC. Both of these cancers have a very intimate relationship with their surrounding environment; the TME is thought to actively participate in initiating and sustaining these malignancies. Individual TME constituents play a vital role in chemoresistance and recurrence after surgery and have been established as independent prognostic factors. This review article will highlight the diverse structural components, key signaling pathways, and extracellular matrices of HCC and PDAC and discuss their crosstalk with tumor cells to promote growth and metastasis. The article will also summarize the latest laboratory and clinical research based on therapeutic targets identified within the TME of both HCC and PDAC.

Sulfatide interacts with and activates integrin αVβ3 in human hepatocellular carcinoma cells

Integrin αVβ3 is a malignant driver of anchorage-independence and tumor angiogenesis, but its dysregulation in hepatocellular carcinoma (HCC) remains unclear. In this study, we observed that sulfatide significantly promoted integrin αV(ITGAV) expression and wound closure in HCC. We also noted that elevated sulfatide profoundly stimulated integrin αVβ3 clustering and signaling. In the cells with integrin αVβ3 clustering induced by sulfatide, integrin β3 subunit was phosphorylated. Simultaneously, focal adhesion kinase (FAK), Src and paxillin were also phosphorylated. Treatment with FAK inhibitor resulted in robust suppression of FAK-Y397 and Src-Y416 phosphorylation stimulated by sulfatide, but not suppression of integrin β3 phosphorylation. Src inhibitors repressed Src-Y416 and FAK Y861 and Y925 phosphorylation, but not FAK-Y397 and integrin β3 phosphorylation. After mutation of integrin β3 (Y773F and Y785F), FAK or Src phosphorylation failed to be stimulated by sulfatide. Moreover, β3 Y773 and Y785 phosphorylation was suppressed by insulin-like growth factor receptor knockdown even in cells stimulated by sulfatide. In assays of immunoprecipitation and immunostaining with integrin αV or β3 antibody, labeled sulfatide was found in the complex and co-localized with integrin αVβ3. Taken together, this study demonstrated that elevated sulfatide bound to integrin αVβ3 and induced clustering and phosphorylation of αVβ3 instead of matrix ligand binding, triggering outside-in signaling.

Association of tRNA methyltransferase NSUN2/IGF-II molecular signature with ovarian cancer survival

AIM

To investigate the association between NSUN2/IGF-II signature and ovarian cancer survival.

METHODS

Using a publicly accessible dataset of RNA sequencing and clinical follow-up data, we performed Classification and Regression Tree and survival analyses.

RESULTS

Patients with NSUN2 ^high IGF-II ^low had significantly superior overall and disease progression-free survival, followed by NSUN2 ^low IGF-II ^low, NSUN2 ^high IGF-II ^high and NSUN2 ^low IGF-II ^high (p < 0.0001 for overall, p = 0.0024 for progression-free survival, respectively). The associations of NSUN2/IGF-II signature with the risks of death and relapse remained significant in multivariate Cox regression models. Random-effects meta-analyses show the upregulated NSUN2 and IGF-II expression in ovarian cancer versus normal tissues.

CONCLUSION

The NSUN2/IGF-II signature associates with heterogeneous outcome and may have clinical implications in managing ovarian cancer.

Pivotal roles of glycogen synthase-3 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world, and represents the second most frequently cancer and third most common cause of death from cancer worldwide. At advanced stage, HCC is a highly aggressive tumor with a poor prognosis and with very limited response to common therapies. Therefore, there is still the need for new effective and well-tolerated therapeutic strategies. Molecular-targeted therapies hold promise for HCC treatment. One promising molecular target is the multifunctional serine/threonine kinase glycogen synthase kinase 3 (GSK-3). The roles of GSK-3β in HCC remain controversial, several studies suggested a possible role of GSK-3β as a tumor suppressor gene in HCC, whereas, other studies indicate that GSK-3β is a potential therapeutic target for this neoplasia. In this review, we will focus on the different roles that GSK-3 plays in HCC and its interaction with signaling pathways implicated in the pathogenesis of HCC, such as Insulin-like Growth Factor (IGF), Notch, Wnt/β-catenin, Hedgehog (HH), and TGF-β pathways. In addition, the pivotal roles of GSK3 in epithelial-mesenchymal transition (EMT), invasion and metastasis will be also discussed.

Association Between Hepatocellular Carcinoma and Type 2 Diabetes Mellitus in Chinese Hepatitis B Virus Cirrhosis Patients: A Case-Control Study

BACKGROUND Whether the presence of type 2 diabetes mellitus (T2DM) increases the risk of hepatocellular carcinoma (HCC) in hepatitis B virus (HBV) cirrhosis patients is controversial. We conducted a retrospective case-control study to evaluate this issue. MATERIAL AND METHODS We considered all patients diagnosed with HBV-related liver cirrhosis at our hospital from July 2011 to June 2014. The case (n=91) and control (n=91) groups were HBV cirrhosis patients with and without T2DM, respectively. They were matched at a ratio of 1: 1 according to the individual age (±2 years) and same sex and Child-Pugh score. RESULTS None of the baseline data were significantly different between the 2 groups. The percentage of HCC was similar between the 2 groups (case versus control group: 34.1% versus 46.2%, P=0.13). In the case group, sex (P=0.002), alkaline phosphatase (P<0.001), g-glutamine transferase (P=0.001), and sodium (P=0.003) were associated with the risk of HCC. In the control group, platelet (P=0.041), alanine aminotransferase (P=0.034), aspartate aminotransferase (P=0.026), alkaline phosphatase (P<0.001), and γ-glutamine transferase (P<0.001) were associated with the risk of HCC. CONCLUSIONS T2DM may not be a risk factor for the presence of HCC in HBV cirrhosis.

MicroRNAs 125a and 125b inhibit ovarian cancer cells through post-transcriptional inactivation of EIF4EBP1

The aim of the present study was to identify the specific miRNAs involved in regulation of EIF4EBP1 expression in ovarian cancer and to define their biological function. miRNA mimics and miRNA inhibitors were used in quantitative PCR, western blotting, and luciferase reporter assays to assess cell migration, invasiveness, and viability. miR-125a and miR-125b were downregulated in ovarian cancer tissue and cell lines relative to healthy controls. Increased expression of miR-125a and miR-125b inhibited invasion and migration of SKOV3 and OVCAR-429 ovarian cancer cells and was associated with a decrease in EIF4EBP1 expression. The inverse relationship between miR-125a and miR-125b was corroborated by cotransfection of a luciferase reporter plasmid. Furthermore, miR-125a and miR-125b caused apoptosis and decreased cell viability and migration in an apparently EIF4EBP1-directed manner. Collectively, these results indicate that miR-125a and miR-125b are important posttranscriptional regulators of EIF4EBP1 expression, providing rationale for new therapeutic approaches to suppress tumour invasion and migration using miR-125a, miR-125b, or their mimics for the treatment of ovarian cancer.

Silencing IGF-II impairs C-myc and N-ras expressions of SMMC-7721 cells via suppressing FAK/PI3K/Akt signaling pathway

Emerging evidence confirms that insulin-like growth factor -II (IGF-II), oncogenes C-myc and N-ras are an essential regulator for development and growth in hepatocellular carcinoma (HCC). Although our previous study also indicated that IGF-II might upregulate levels of oncogenes C-myc and N-ras in hepatoma carcinoma cells, the molecular mechanism had not been fully elucidated. Herein, we successfully silenced IGF-II expression in SMCC-7721 cells by small RNA interference. Functional analysis showed that knockdown of IGF-II significantly suppressed growth and proliferation of SMMC-7721 cells and decreased C-myc and N-ras mRNA and protein levels. And this function was mediated by the FAK/PI3K/Akt signaling pathway. Taken together, IGF-II siRNA inactivates the FAK/PI3K/Akt signaling pathway, and further reduces cell proliferation, N-ras and C-myc levels in SMMC-7721 cells. Especially, understanding the relationship between IGF-II and oncogenes N-ras and C-myc in cancer cells will provide novel clues for clinic HCC treatment in the future.

Prohibitin 1 Regulates the H19-Igf2 Axis and Proliferation in Hepatocytes

Prohibitin 1 (PHB1) is a mitochondrial chaperone that regulates cell growth. Phb1 knock-out mice exhibit liver injury and hepatocellular carcinoma (HCC). Phb1 knock-out livers show induction of tumor growth-associated genes, H19 and insulin-like growth factor 2 (Igf2). These genes are controlled by the imprinting control region (ICR) containing CCCTC-binding transcription factor (CTCF)-binding sites. Because Phb1 knock-out mice exhibited induction of H19 and Igf2, we hypothesized that PHB1-mediated regulation of the H19-Igf2 axis might control cell proliferation in normal hepatocytes. H19 and Igf2 were induced (8-20-fold) in 3-week-old Phb1 knock-out livers, in Phb1 siRNA-treated AML12 hepatocytes (2-fold), and HCC cell lines when compared with control. Phb1 knockdown lowered CTCF protein in AML12 by ∼30% when compared with control. CTCF overexpression lowered basal H19 and Igf2 expression by 30% and suppressed Phb1 knockdown-mediated induction of these genes. CTCF and PHB1 co-immunoprecipitated and co-localized on the ICR element, and Phb1 knockdown lowered CTCF ICR binding activity. The results suggest that PHB1 and CTCF cooperation may control the H19-Igf2 axis. Human HCC tissues with high levels of H19 and IGF2 exhibited a 40-50% reduction in PHB1 and CTCF expression and their ICR binding activity. Silencing Phb1 or overexpressing H19 in the mouse HCC cell line, SAMe-D, induced cell growth. Blocking H19 induction prevented Phb1 knockdown-mediated growth, whereas H19 overexpression had the reverse effect. Interestingly H19 silencing induced PHB1 expression. Taken together, our results demonstrate that the H19-Igf2 axis is negatively regulated by CTCF-PHB1 cooperation and that H19 is involved in modulating the growth-suppressive effect of PHB1 in the liver.

Interplay between microRNA-17-5p, insulin-like growth factor-II through binding protein-3 in hepatocellular carcinoma

AIM

To investigate the effect of microRNA on insulin-like growth factor binding protein-3 (IGFBP-3) and hence on insulin-like growth factor-II (IGF-II) bioavailability in hepatocellular carcinoma (HCC).

METHODS

Bioinformatic analysis was performed using microrna.org, DIANA lab and Segal lab softwares. Total RNA was extracted from 23 HCC and 10 healthy liver tissues using mirVana miRNA Isolation Kit. microRNA-17-5p (miR-17-5p) expression was mimicked and antagonized in HuH-7 cell lines using HiPerFect Transfection Reagent, then total RNA was extracted using Biozol reagent then reverse transcribed into cDNA followed by quantification of miR-17-5p and IGFBP-3 expression using TaqMan real-time quantitative PCR. Luciferase reporter assay was performed to validate the binding of miR-17-5p to the 3'UTR of IGFBP-3. Free IGF-II protein was measured in transfected HuH-7 cells using IGF-II ELISA kit.

RESULTS

Bioinformatic analysis revealed IGFBP-3 as a potential target for miR-17-5p. Screening of miR-17-5p and IGFBP-3 revealed a moderate negative correlation in HCC patients, where miR-17-5p was extensively underexpressed in HCC tissues (P = 0.0012), while IGFBP-3 showed significant upregulation in the same set of patients (P = 0.0041) compared to healthy donors. Forcing miR-17-5p expression in HuH-7 cell lines showed a significant downregulation of IGFBP-3 mRNA expression (P = 0.0267) and a significant increase in free IGF-II protein (P = 0.0339) compared to mock untransfected cells using unpaired t-test. Luciferase assay validated IGFBP-3 as a direct target of miR-17-5p; luciferase activity was inhibited by 27.5% in cells co-transfected with miR-17-5p mimics and the construct harboring the wild-type binding region 2 of IGFBP-3 compared to cells transfected with this construct alone (P = 0.0474).

CONCLUSION

These data suggest that regulating IGF-II bioavailability and hence HCC progression can be achieved through targeting IGFBP-3 via manipulating the expression of miRNAs.

Relevance of microRNA-18a and microRNA-199a-5p to hepatocellular carcinoma recurrence after living donor liver transplantation

There are few reports about recurrence-related microRNAs (miRNAs) after liver transplantation (LT) for hepatocellular carcinoma (HCC). The purpose of this study was to identify novel recurrence-related miRNAs after living donor liver transplantation (LDLT) for HCC. First, we performed microarray analyses of samples from a liver with primary HCC, a liver that was noncancerous, and a liver that had recurrence-metastasis from 3 patients with posttransplant recurrence. Then we selected miRNAs with consistently altered expression in both primary HCC and recurrence as potential candidates of recurrence-related miRNAs. Expression of the miRNAs in HCC and noncancerous livers was assessed in 70 HCC patients who underwent LDLT. The target genes regulated by the recurrence-related miRNAs were identified. MicroRNA-18a (miR-18a) expression was increased, and microRNA-199a-5p (miR-199a-5p) expression was decreased in both primary HCC and recurrence. Increased miR-18a expression correlated with high levels of tumor markers, large tumor size, and a high recurrence rate. Decreased miR-199a-5p expression correlated with high levels of tumor markers, portal venous invasion, and a high recurrence rate. In HCC cells, miR-18a regulated the expression of tumor necrosis factor alpha-induced protein 3 (TNFAIP3), and miR-199a-5p regulated the expression of hypoxia-inducible factor 1 alpha (HIF1A), vascular endothelial growth factor A (VEGFA), insulin-like growth factor 1 receptor, and insulin-like growth factor 2. In conclusion, increased miR-18a levels and decreased miR-199a-5p levels are relevant to HCC recurrence after LDLT. MiR-18a and miR-199a-5p could be novel therapeutic targets of recurrent HCC after LDLT. Liver Transplantation 22 665-676 2016 AASLD.

Transcriptional activation of the IGF-II/IGF-1R axis and inhibition of IGFBP-3 by miR-155 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is characterized by the aberrant expression of a number of genes that govern crucial signaling pathways. The insulin-like growth factor (IGF) axis is important in this context, and the precise regulation of expression of members of this axis is known to be lost in HCC. miR-155 is a well-established oncogene in numerous types of cancer. However, to the best of our knowledge, its effect on the regulation of the IGF axis has not been investigated to date. The present study aimed to elucidate the interactions between miR-155 and key components of the IGF axis, in addition to examining its effect on HCC development. Reverse transcription-quantitative polymerase chain reaction was used to measure the expression of miR-155 in HCC and cirrhotic tissues, in addition to HCC cell lines. Furthermore, the effect of the induction of miR-155 expression on the expression of three members of the IGF axis [IGF II, IGF type-1 receptor (IGF-1R) and IGF-binding protein 3 (IGFBP-3)], was analyzed. Finally, the effect of miR-155 on HCC cell proliferation, migration and clonogenicity was also examined. Quantification of the expression of miR-155 demonstrated that it is upregulated in HCC. Induction of the expression of miR-155 in HCC cell lines led to the upregulation of IGF-II and IGF-IR, and the downregulation of IGFBP-3. In addition, the proliferation, migration and clonogenicity of HCC was increased following induction of miR-155 expression. miR-155 is an oncomiR, which upregulates the oncogenes, IGF-II and IGF-IR, and downregulates the tumor suppressor, IGFBP-3, thereby resulting in increased HCC cell carcinogenicity. Therefore, miR-155 may be a therapeutic target in HCC.

A pleiotropic effect of the single clustered hepatic metastamiRs miR-96-5p and miR-182-5p on insulin-like growth factor II, insulin-like growth factor-1 receptor and insulin-like growth factor-binding protein-3 in hepatocellular carcinoma

MicroRNAs (miRs) have a major role in the pathogenesis of hepatocellular carcinoma (HCC). As the insulin-like growth factor (IGF) axis is a highly tumorigenic pathway in HCC, the present study attempted to target it with miRs. Potential targeting of crucial members of the IGF axis by miRNAs at the 3'-untranslated region (3'-UTR) was predicted using bioinformatic tools, such as microrna.org, Diana lab and Targetscan, while 5'-UTR targeting was predicted using bibiserv software. Expression profiling of obtained miRNAs was performed using quantitative polymerase chain reaction (qPCR) in 22 non-metastatic HCC biopsy samples and 10 healthy tissues. To investigate the impact of miRNAs on their potential downstream targets, transfection of miRNAs was performed in HuH-7 cells and the targets' expression was quantified using qPCR. Transcripts of insulin-like growth factor-1 receptor (IGF-1R), insulin-like growth factor binding protein-3 (IGFBP-3) and IGF-II were found to be potentially targeted at the 5'-UTR and 3'-UTR regions by the single clustered hepatic metastamiRs miR-96-5p and miR-182-5p. The two miRNAs showed a similar expression pattern in HCC tissues compared to those in healthy tissues. Forced expression of miR-96-5p and miR-182-5p in the HCC cell line HuH-7 had inducing effects on IGFBP-3 and IGF-II transcripts. Of note, the two miRs had differential effects on IGF-1R, where miR-96-5p induced IGF-1R mRNA expression and miR-182-5p inhibited its expression. The present study revealed the pleiotropic impact of the single clustered hepatic metastamiRs miR-96-5p and miR-182-5p on IGF-1R, and an inducing effect on IGF-II and IGFBP-3 in hepatocellular carcinoma.

Picropodophyllin causes mitotic arrest and catastrophe by depolymerizing microtubules via insulin-like growth factor-1 receptor-independent mechanism

Picropodophyllin (PPP) is an anticancer drug undergoing clinical development in NSCLC. PPP has been shown to suppress IGF-1R signaling and to induce a G2/M cell cycle phase arrest but the exact mechanisms remain to be elucidated. The present study identified an IGF-1-independent mechanism of PPP leading to pro-metaphase arrest. The mitotic block was induced in human cancer cell lines and in an A549 xenograft mouse but did not occur in normal hepatocytes/mouse tissues. Cell cycle arrest by PPP occurred in vitro and in vivo accompanied by prominent CDK1 activation, and was IGF-1R-independent since it occurred also in IGF-1R-depleted and null cells. The tumor cells were not arrested in G2/M but in mitosis. Centrosome separation was prevented during mitotic entry, resulting in a monopolar mitotic spindle with subsequent prometaphase-arrest, independent of Plk1/Aurora A or Eg5, and leading to cell features of mitotic catastrophe. PPP also increased soluble tubulin and decreased spindle-associated tubulin within minutes, indicating that it interfered with microtubule dynamics. These results provide a novel IGF-1R-independent mechanism of antitumor effects of PPP.

Hepatitis B virus X protein promotes P3 transcript expression of the insulin-like growth factor 2 gene via inducing hypomethylation of P3 promoter in hepatocellular carcinoma

BACKGROUND & AIMS

Hepatitis B virus (HBV) X protein (HBx) contributes to hepatocarcinogenesis. The overexpression of transcripts from P3 and P4 promoters of the insulin-like growth factor 2 (IGF2) gene is observed in hepatocellular carcinoma (HCC). Here, we aimed to explore the involvement of HBx in P3-driven mRNA overexpression and underlying epigenetic mechanism.

METHODS

P3 mRNA, P3 methylation status, HBx mRNA and HBx protein were analysed in human HCC samples with and without HBV infection using quantitative RT-PCR, bisulphite sequencing and Western blotting. The effects of HBx on P3 mRNA expression, and P3 transcriptional activity and methylation were further evaluated in HCC cell lines.

RESULTS

P3 mRNA level was higher and P3 methylation level was lower in HBV-positive HCC specimens compared with those of HBV-negative HCC specimens. P3 transcript abundance was positively correlated with HBx expression and negatively correlated with P3 methylation in HCC specimens. The stable expression of HBx upregulated P3 mRNA expression and reduced P3 methylation level in HepG2-HBx cells. The transient expression of HBx stimulated P3 promoter activity and decreased P3 methylation level of P3 promoter-luciferase construct in a dose-dependent manner in HepG2 and Huh-7 cells. Furthermore, HBx mRNA expression was found to be independent predictive factors for both shorter disease-free survival time and shorter overall survival time of HCC patients.

CONCLUSION

HBx may promote IGF2-P3 transcript expression by inducing hypomethylation of P3 promoter and may be associated with an inferior clinical outcome of HBV-related HCC patients. This study provides useful information for understanding the mechanism of HBx-mediated HCC.

The dichotomy of the Insulin-like growth factor 1 receptor: RTK and GPCR: friend or foe for cancer treatment?

The prime position of the insulin-like growth factor 1 receptor (IGF-1R), at the head of the principle mitogenic and anti-apoptotic signalling cascades, along with the resilience to transformation of IGF-1R deficient cells fuelled great excitement for its anti-cancer targeting. Yet its potential has not been fulfilled, as clinical trial results fell far short of expectations. Advancements in understanding of other receptors' function have now begun to shed light on this incongruity, with the now apparent parallels highlighting the immaturity of our understanding of IGF-1R biology, with the model used for drug development now recognised as having been too simplistic. Gathering together the many advancements of the field of IGF-1R research over the past decade, alongside those in the GPCR field, advocates for a major paradigm shift in our appreciation of the subtle workings of this receptor. This review will emphasise the updating of the IGF-1R's classification from an RTK, to an RTK/GPCR functional hybrid, which integrates both canonical kinase signalling with many functions characteristic of a GPCR. Recognition of the shortcomings of IGF-1R inhibitor drug development programs and the models used not only allows us to reignite the initial interest in the IGF-1R as an anti-cancer therapeutic target, but also points to the possibility of biased ligand therapeutics, which together may hold a very powerful key to unlocking the true potential of IGF-1R modulation.

Evaluation of antiglypican-3 therapy as a promising target for amelioration of hepatic tissue damage in hepatocellular carcinoma

In Egypt, hepatocellular carcinoma (HCC) was predicted to continue to rise over the next few decades causing a national problem. Meanwhile, glypican-3 (GPC3), a highly expressed glypican, has emerged as a potential target for HCC immunotherapy. Therefore, we aimed to identify the impact of blocking GPC3 on liver damage in HCC as well as a possible mechanism. Fifty four HCC patients, 20 cirrhotic patients and 10 healthy subjects were recruited. Serum levels of GPC3, sulfatase-2 (SULF-2), heparan sulfate proteoglycan (HSPG), insulin-like growth factor-II (IGF-II) were measured by ELISA. In parallel, HCC was induced in 40 male Sprague-Dawley rats in presence/absence of antiGPC-3. Liver impairment was detected by investigating liver sections stained with hematoxylin/eosin and serum α-fetoprotein (AFP). Liver homogenates of GPC3, SULF-2, and HSPG were measured by ELISA. Gene expression of caspase-3 and IGF-II were assayed by RT-PCR. HCC patients showed significant elevated serum levels of GPC3, IGF-II and SULF-2 accompanied by decreased HSPG. However, treatment of HCC rats with antiGPC-3 significantly reduced serum AFP and showed nearly normal hepatocytes. In addition, antiGPC-3 significantly reduced elevated liver homogenates protein levels of GPC3 and SULF-2 and gene expression of IGF-II and caspase-3. antiGPC-3 restored the reduced hepatic HSPG. antiGPC-3 showed anti-tumor activity as well as hepatoprotective effects. antiGPC-3-chemoprotective effect can be explained by forced reduction of IGF-II expression, restoration of HSPGs, deactivation of SULF-2 and reduction of gene expression of caspase-3. Targeting GPC3 is a promising therapeutic approach for HCC.

Activation of IL6/IGFIR confers poor prognosis of HBV-related hepatocellular carcinoma through induction of OCT4/NANOG expression

PURPOSE

To unravel the role of interleukin (IL)-6 and insulin-like growth factor (IGF)-I receptor (IGFIR) in expressing stemness-related properties and to evaluate the prognostic values of pluripotent transcription factor OCT4/NANOG, and IGFIR in hepatocellular carcinoma (HCC).

EXPERIMENTAL DESIGN

Serum levels of IL6 were detected using ELISA assays (n = 120). The effects of IL6/IGFI on stemness expression in HCC were examined using OCT4/NANOG promoter luciferase reporter, RNA interference, secondary sphere formation, side population, and xenograft animal models. The OCT4/NANOG protein and phospho-IGFI receptor (p-IGFIR) in tissues were detected by Western blotting (n = 8) and immunohistochemical staining (n = 85). OCT4, NANOG, and IGFIR expression levels in tissues (n = 191) were analyzed by real-time qRT-PCR and was correlated with early tumor recurrence using the Kaplan-Meier survival analysis.

RESULTS

A high positive correlation between the expression levels of OCT4/NANOG and IGFIR/p-IGFIR in human HCC tissues was observed. The concurrent expression of OCT4/NANOG/IGFIR was mostly confined to hepatitis B virus (HBV)-related HCC (HBV-HCC) and was significantly correlated with early tumor recurrence. High serum levels of IL6 were significantly correlated with high OCT4/NANOG expression. IL6 stimulated an autocrine IGFI/IGFIR expression STAT3 dependently, which stimulated stemness-related properties in both the cell lines and the xenografted mouse tumors. The inhibition of IGFIR activation by either RNA interference or by treatment with the inhibitor picropodophyllin (PPP) significantly suppressed the IL6-induced stemness-related properties both in vitro and in vivo.

CONCLUSIONS

The expression of pluripotency-related genes is associated with early tumor recurrence and is regulated by IL6-induced IGF/IGFIR activation, particularly in HBV-HCC.

Paternal breed effects on expression of IGF-II, BAK1 and BCL2-L1 in bovine preimplantation embryos

The effects of the paternal breed on early embryo and later pre- and postnatal development are well documented. Several recent studies have suggested that such paternal effects may be mediated by the paternally induced epigenetic modifications during early embryogenesis. The objective of this study was to investigate the effects of the paternal breed on the early embryonic development and relative expression of the maternally imprinted gene, IGF-II, and the apoptosis-related genes BAK1 and BCL2-L1 in in vitro produced (IVP) bovine embryos derived from two unrelated paternal breeds (Holstein and Brown Swiss). The degree of correlation of IGF-II expression pattern with embryo developmental competence and apoptosis-related genes was also investigated. The relative abundance of IGF-II, BCL2-L1 and BAK1 transcripts in day 8 embryos was measured by quantitative reverse-transcription polymerase chain reaction using the comparative Cp method. Our data revealed that the paternal breed did not influence cleavage rate, blastocyst rate and relative abundance of IGF-II, BAK1 and BCL2-L1 in day 8 blastocysts (P > 0.05). Nevertheless, IGF-II expression levels were highly correlated with embryonic developmental competence (r = 0.66, P < 0.1), relative expression of BCL2-L1 (r = 0.72, P < 0.05) and ratio of BCL2-L1/BAK1 (r = 0.78, P < 0.05). In conclusion, our data show that IGF-II, BCL2-L1 and BAK1 expression is not related to the chosen combination of paternal breed, but that IGF-II expression is correlated with embryonic viability and apoptosis-related gene expression.

The GH-IGF-SST system in hepatocellular carcinoma: biological and molecular pathogenetic mechanisms and therapeutic targets

Hepatocellular carcinoma (HCC) is the sixth most common malignancy worldwide. Different signalling pathways have been identified to be implicated in the pathogenesis of HCC; among these, GH, IGF and somatostatin (SST) pathways have emerged as some of the major pathways implicated in the development of HCC. Physiologically, GH-IGF-SST system plays a crucial role in liver growth and development since GH induces IGF1 and IGF2 secretion and the expression of their receptors, involved in hepatocytes cell proliferation, differentiation and metabolism. On the other hand, somatostatin receptors (SSTRs) are exclusively present on the biliary tract. Importantly, the GH-IGF-SST system components have been indicated as regulators of hepatocarcinogenesis. Reduction of GH binding affinity to GH receptor, decreased serum IGF1 and increased serum IGF2 production, overexpression of IGF1 receptor, loss of function of IGF2 receptor and appearance of SSTRs are frequently observed in human HCC. In particular, recently, many studies have evaluated the correlation between increased levels of IGF1 receptors and liver diseases and the oncogenic role of IGF2 and its involvement in angiogenesis, migration and, consequently, in tumour progression. SST directly or indirectly influences tumour growth and development through the inhibition of cell proliferation and secretion and induction of apoptosis, even though SST role in hepatocarcinogenesis is still opened to argument. This review addresses the present evidences suggesting a role of the GH-IGF-SST system in the development and progression of HCC, and describes the therapeutic perspectives, based on the targeting of GH-IGF-SST system, which have been hypothesised and experimented in HCC.

Expression levels of insulin-like growth factors and receptors in hepatocellular carcinoma: a retrospective study

Background

The insulin-like growth factor (IGF) pathway is implicated in the pathogenesis of hepatocellular carcinoma (HCC) and may be important in nonalcoholic fatty liver disease (NAFLD). The aim of this study is to determine expression levels of IGFs and receptors in NAFLD-associated HCC.

Methods

Tissue microarrays were constructed from patients who underwent hepatectomy for HCC. Immunohistochemistry was performed using antibodies for IGF ligands and receptors. Immunostain results were scored by a pathologist blinded to clinical data.

Results

Among 27 patients with HCC, the most common underlying liver diseases included NAFLD, hepatitis C, and alcoholic hepatitis. Expression levels of IGFs and receptors were not associated with patients’ underlying liver disease. In all patients, IGF-2 expression was upregulated in tumor and adjacent non-neoplastic liver. Expression of IGF-1 was low in adjacent liver in 6 of 10 patients with cirrhosis, compared with 2 of 17 patients without cirrhosis (P = 0.025). Higher IGF-1 expression in liver adjacent to tumor was associated with poorer median survival of 22 months, compared with 72 months with equal or lower IGF-1 expression in adjacent liver relative to tumor (P = 0.006).

Conclusions

Our preliminary results demonstrate significant associations between IGF-1 expression and liver cirrhosis and survival after resection in patients with HCC, independent of their underlying liver disease.

Exploration of liver cancer genomes

Liver cancer is the third leading cause of cancer-related death worldwide. Advances in sequencing technologies have enabled the examination of liver cancer genomes at high resolution; somatic mutations, structural alterations, HBV integration, RNA editing and retrotransposon changes have been comprehensively identified. Furthermore, integrated analyses of trans-omics data (genome, transcriptome and methylome data) have identified multiple critical genes and pathways implicated in hepatocarcinogenesis. These analyses have uncovered potential therapeutic targets, including growth factor signalling, WNT signalling, the NFE2L2-mediated oxidative pathway and chromatin modifying factors, and paved the way for new molecular classifications for clinical application. The aetiological factors associated with liver cancer are well understood; however, their effects on the accumulation of somatic changes and the influence of ethnic variation in risk factors still remain unknown. The international collaborations of cancer genome sequencing projects are expected to contribute to an improved understanding of risk evaluation, diagnosis and therapy for this cancer.

Overexpression of insulin-like growth factor-I receptor as a pertinent biomarker for hepatocytes malignant transformation

AIM

To investigate the dynamic features of insulin-like growth factor-I receptor (IGF-IR) expression in rat hepatocarcinogenesis, and the relationship between IGF-IR and hepatocytes malignant transformation at mRNA or protein level.

METHODS

Hepatoma models were made by inducing with 2-fluorenylacetamide (2-FAA) on male Sprague-Dawley rats. Morphological changes of hepatocytes were observed by pathological Hematoxylin and eosin staining, the dynamic expressions of liver and serum IGF-IR were quantitatively analyzed by an enzyme-linked immunosorbent assay. The distribution of hepatic IGF-IR was located by immunohistochemistry. The fragments of IGF-IR gene were amplified by reverse transcription-polymerase chain reaction, and confirmed by sequencing.

RESULTS

Rat hepatocytes after induced by 2-FAA were changed dynamically from granule-like degeneration, precancerous to hepatoma formation with the progressing increasing of hepatic mRNA or IGF-IR expression. The incidences of liver IGF-IR, IGF-IR mRNA, specific IGF-IR concentration (ng/mg wet liver), and serum IGF-IR level (ng/mL) were 0.0%, 0.0%, 0.63 ± 0.17, and 1.33 ± 0.47 in the control; 50.0%, 61.1%, 0.65 ± 0.2, and 1.51 ± 0.46 in the degeneration; 88.9%, 100%, 0.66 ± 0.14, and 1.92 ± 0.29 in the precancerosis; and 100%, 100%, 0.96 ± 0.09, and 2.43 ± 0.57 in the cancerous group, respectively. IGF-IR expression in the cancerous group was significantly higher (P < 0.01) than that in any of other groups at mRNA or protein level. The closely positive IGF-IR relationship was found between livers and sera (r = 0.91, t = 14.222, P < 0.01), respectively.

CONCLUSION

IGF-IR expression may participate in rat hepatocarcinogenesis and its abnormality should be an early marker for hepatocytes malignant transformation.

Abnormal expression of insulin-like growth factor-I receptor in hepatoma tissue and its inhibition to promote apoptosis of tumor cells

Abnormal signaling of insulin-like growth factor I receptor (IGF-IR) is associated with hepatocellular carcinoma, but the underlying molecular mechanisms remain largely unknown. The objective of this study was to investigate IGF-IR's role as a signaling molecule, its pathological alteration in hepatoma tissues, and its effect on hepatoma cell proliferation when inhibited. As measured by immunohistochemical analysis, the incidence of hepatic IGF-IR expression in cancerous tissue was 80.0 % (24 of 30), which was significantly higher (P < 0.05) than 43.3 % (13 of 30) occurrence in the surrounding tissue and the nondetectable (0 of 30) frequency in the distal cancerous tissue. Hepatoma IGF-IR expression was correlated to the differentiation degree and not to the number or size of tumors, HBV infection, and AFP level. The in vitro IGF-IR expression in hepatoma cells was down-regulated significantly by picropodophyllin, a specific kinase inhibitor, in a time- and dose-dependent manner. Cell proliferation was inhibited through typical mechanisms of promoting apoptosis and cell cycle arrest (G2/M phase). Up-regulation of IGF-IR in hepatocarcinogenesis suggests that the down-regulation of IGF-IR expression could be a specific molecular target for hepatoma cell proliferation.

Something old, something new and something borrowed: emerging paradigm of insulin-like growth factor type 1 receptor (IGF-1R) signaling regulation

The insulin-like growth factor type 1 receptor (IGF-1R) plays a key role in the development and progression of cancer; however, therapeutics targeting it have had disappointing results in the clinic. As a receptor tyrosine kinase (RTK), IGF-1R is traditionally described as an ON/OFF system, with ligand stabilizing the ON state and exclusive kinase-dependent signaling activation. Newly added to the traditional model, ubiquitin-mediated receptor downregulation and degradation was originally described as a response to ligand/receptor interaction and thus inseparable from kinase signaling activation. Yet, the classical model has proven over-simplified and insufficient to explain experimental evidence accumulated over the last decade, including kinase-independent signaling, unbalanced signaling, or dissociation between signaling and receptor downregulation. Based on the recent findings that IGF-1R “borrows” components of G-protein coupled receptor (GPCR) signaling, including β-arrestins and G-protein-related kinases, we discuss the emerging paradigm for the IGF-1R as a functional RTK/GPCR hybrid, which integrates the kinase signaling with the IGF-1R canonical GPCR characteristics. The contradictions to the classical IGF-1R signaling concept as well as the design of anti-IGF-1R therapeutics treatment are considered in the light of this paradigm shift and we advocate recognition of IGF-1R as a valid target for cancer treatment.

Overexpression of insulin-like growth factor-I receptor as a pertinent biomarker for hepatocytes malignant transformation

AIM

To investigate the dynamic features of insulin-like growth factor-I receptor (IGF-IR) expression in rat hepatocarcinogenesis, and the relationship between IGF-IR and hepatocytes malignant transformation at mRNA or protein level.

METHODS

Hepatoma models were made by inducing with 2-fluorenylacetamide (2-FAA) on male Sprague-Dawley rats. Morphological changes of hepatocytes were observed by pathological Hematoxylin and eosin staining, the dynamic expressions of liver and serum IGF-IR were quantitatively analyzed by an enzyme-linked immunosorbent assay. The distribution of hepatic IGF-IR was located by immunohistochemistry. The fragments of IGF-IR gene were amplified by reverse transcription-polymerase chain reaction, and confirmed by sequencing.

RESULTS

Rat hepatocytes after induced by 2-FAA were changed dynamically from granule-like degeneration, precancerous to hepatoma formation with the progressing increasing of hepatic mRNA or IGF-IR expression. The incidences of liver IGF-IR, IGF-IR mRNA, specific IGF-IR concentration (ng/mg wet liver), and serum IGF-IR level (ng/mL) were 0.0%, 0.0%, 0.63 ± 0.17, and 1.33 ± 0.47 in the control; 50.0%, 61.1%, 0.65 ± 0.2, and 1.51 ± 0.46 in the degeneration; 88.9%, 100%, 0.66 ± 0.14, and 1.92 ± 0.29 in the precancerosis; and 100%, 100%, 0.96 ± 0.09, and 2.43 ± 0.57 in the cancerous group, respectively. IGF-IR expression in the cancerous group was significantly higher (P < 0.01) than that in any of other groups at mRNA or protein level. The closely positive IGF-IR relationship was found between livers and sera (r = 0.91, t = 14.222, P < 0.01), respectively.

CONCLUSION

IGF-IR expression may participate in rat hepatocarcinogenesis and its abnormality should be an early marker for hepatocytes malignant transformation.

Progress in understanding role of diabetes mellitus in the development of hepatitis virus-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. Hepatitis B or hepatitis C virus infection has been considered the most important etiologic factor for human HCC. Recently, it has been suggested that diabetes mellitus is a risk factor for HCC, and that insulin resistance as a critical component of diabetes mellitus pathogenesis may be involved in the occurrence of hepatitis virus-related HCC. Since IRS-1-Ser312 is a molecule that is involved in the pathogenesis of both hepatitis C virus and diabetes mellitus, IRS-1 or ROS may play a role in the development of HCC associated with diabetes mellitus and hepatitis B virus. Hence, diabetes mellitus and hepatitis virus not only are independent risk factors for HCC but also interact with each other to contribute to the development of this malignancy.

Potentiating the efficacy of molecular targeted therapy for hepatocellular carcinoma by inhibiting the insulin-like growth factor pathway

Insulin-like growth factor (IGF) signaling pathway is an important regulatory mechanism of tumorigenesis and drug resistance in many cancers. The present study explored the potential synergistic effects between IGF receptor (IGFR) inhibition and other molecular targeted agents (MTA) in HCC cells. HCC cell lines (Hep3B, PLC5, and SK-Hep1) and HUVECs were tested. The MTA tested included sorafenib, sunitinib, and the IGFR kinase inhibitor NVP-AEW541. The potential synergistic antitumor effects were tested by median dose effect analysis and apoptosis assay in vitro and by xenograft models in vivo. The activity and functional significance of pertinent signaling pathways and expression of apoptosis-related proteins were measured by RNA interference and Western blotting. We found that IGF can activate IGFR and downstream AKT signaling activities in all the HCC cells tested, but the growth-stimulating effect of IGF was most prominent in Hep3B cells. NVP-AEW541 can abrogate IGF-induced activation of IGFR and AKT signaling in HCC cells. IGF can increase the resistance of HCC cells to sunitinib. The apoptosis-inducing effects of sunitinib, but not sorafenib, were enhanced when IGFR signaling activity was inhibited by NVP-AEW541 or IGFR knockdown. Chk2 kinase activation was found contributory to the synergistic anti-tumor effects between sunitinib and IGFR inhibition. Our data indicate that the apoptosis-potentiating effects of IGFR inhibition for HCC may be drug-specific. Combination therapy of IGFR inhibitors with other MTA may improve the therapeutic efficacy in HCC.

Should visceral fat, strictly linked to hepatic steatosis, be depleted to improve survival?

Numerous epidemiologic studies have implicated abdominal obesity as a major risk factor for insulin resistance, type 2 diabetes mellitus, cardiovascular disease, stroke, metabolic syndrome and its further expression, i.e., nonalcoholic fatty liver disease and death. Using novel models of visceral obesity, several studies have demonstrated that the relationship between visceral fat and longevity is causal, while the accrual of subcutaneous fat does not appear to play an important role in the etiology of disease risk. The need of reducing the visceral fat to improve survival, mainly taking into account the strict link between nonalcoholic fatty liver disease and the coronary artery disease is discussed.

Yes-associated protein up-regulates Jagged-1 and activates the Notch pathway in human hepatocellular carcinoma

BACKGROUND & AIMS

Cancer cells often lose contact inhibition to undergo anchorage-independent proliferation and become resistant to apoptosis by inactivating the Hippo signaling pathway, resulting in activation of the transcriptional co-activator yes-associated protein (YAP). However, the oncogenic mechanisms of YAP activity are unclear.

METHODS

By using cross-species analysis of expression data, the Notch ligand Jagged-1 (Jag-1) was identified as a downstream target of YAP in hepatocytes and hepatocellular carcinoma (HCC) cells. We analyzed the functions of YAP in HCC cells via overexpression and RNA silencing experiments. We used transgenic mice that overexpressed a constitutively activated form of YAP (YAP(S127A)), and measured protein levels in HCC, colorectal and pancreatic tumor samples from patients.

RESULTS

Human HCC cell lines and mouse hepatocytes that overexpress YAP(S127A) up-regulated Jag-1, leading to activation of the Notch pathway and increased proliferation. Induction of Jag-1, activation of Notch, and cell proliferation required binding of YAP to its transcriptional partner TEA domain family member 4 (TEAD4); TEAD4 binding required the Mst1/2 but not β-catenin signaling. Levels of YAP correlated with Jag-1 expression and Notch signaling in human tumor samples and correlated with shorter survival times of patients with HCC or colorectal cancer.

CONCLUSIONS

The transcriptional regulator YAP up-regulates Jag-1 to activate Notch signaling in HCC cells and mouse hepatocytes. YAP-dependent activity of Jag-1 and Notch correlate in human HCC and colorectal tumor samples with patient survival times, suggesting the use of YAP and Notch inhibitors as therapeutics for gastrointestinal cancer. Transcript profiling: microarray information was deposited at the Gene Expression Omnibus database (http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?token=jxepvsumwosqkve&acc=GSE35004).

Repression of miR-17-5p with elevated expression of E2F-1 and c-MYC in non-metastatic hepatocellular carcinoma and enhancement of cell growth upon reversing this expression pattern

E2F-1, c-MYC, and miR-17-5p is a triad of two regulatory loops: a negative and a positive loop, where c-MYC induces the expression of E2F-1 that induces the expression of miR-17-5p which in turn reverses the expression of E2F-1 to close the loop. In this study, we investigated this triad for the first time in hepatocellular carcinoma (HCC), where miR-17-5p showed a significant down-regulation in 23 non-metastatic HCC biopsies compared to 10 healthy tissues; however, E2F-1 and c-MYC transcripts were markedly elevated. Forced over-expression of miR-17-5p in HuH-7 cells resulted in enhanced cell proliferation, growth, migration and clonogenicity with concomitant inhibition of E2F-1 and c-MYC transcripts expressions, while antagomirs of miR-17-5p reversed these events. In conclusion, this study revealed a unique pattern of expression for miR-17-5p in non-metastatic HCC patients in contrast to metastatic HCC patients. In addition we show that miR-17-5p is the key player among the triad that tumor growth and spread.

microRNA-125a-3p reduces cell proliferation and migration by targeting Fyn

Fyn, a member of the Src family kinases (SFKs), has a pivotal role in cell adhesion, proliferation, migration and survival, and its overexpression is associated with several types of cancer. MicroRNAs (miRNAs) play a major role in post-transcriptional repression of protein expression. In light of the significant functions of Fyn, together with studies demonstrating miR-125a as a tumor-suppressing miRNA that is downregulated in several cancer cell types and on our bioinformatics studies presented here, we chose to examine the post-transcription regulation of Fyn by miR-125a-3p in the HEK 293T cell line. We show that Fyn expression can be dramatically reduced by elevated levels of miR-125a-3p. Following this reduction, the activity of proteins downstream of Fyn, such as FAK, paxillin and Akt (proteins known to be overexpressed in various tumors), is also reduced. On a broader level, we show that miR-125a-3p causes an arrest of the cell cycle at the G2/M stage and decreases cell viability and migration, probably in a Fyn-directed manner. The results are reinforced by control experiments conducted using Fyn siRNA and anti-miR-125a-3p, as well as by the fact that numerous cancer cell lines show a significant downregulation of Fyn after mir-125a-3p overexpression. Collectively, we conclude that miR-125a-3p has an important role in the regulation of Fyn expression and of its signaling pathway, which implies that it has a therapeutic potential in overexpressed Fyn-related diseases.

The evolving landscape of therapeutic drug development for hepatocellular carcinoma

Currently, only one drug, sorafenib, is FDA approved for the treatment of advanced hepatocellular carcinoma (HCC), achieving modest objective response rates while still conferring an overall survival benefit. Unlike other solid tumors, no oncogenic addiction loops have been validated as clinically actionable targets in HCC. Outcomes of HCC could potentially be improved if critical molecular subclasses with distinct therapeutic vulnerabilities can be identified, biomarkers that predict recurrence or progression early can be determined and key epigenetic, genetic or microenvironment drivers that determine best response to a specific targeting treatment can be uncovered. Our group and others have examined the molecular heterogeneity of hepatocellular carcinoma. We have developed a panel of patient derived xenograft models to enable focused pre-clinical drug development of rationally designed therapies in specific molecular subgroups. We observed unique patterns, including synergies, of drug activity across our molecularly diverse HCC xenografts, pointing to specific therapeutic vulnerabilities for individual tumors. These efforts inform clinical trial designs and catalyze therapeutic development. It also argues for efficient strategic allocation of patients into appropriate enriched clinical trials. Here, we will discuss some of the recent important therapeutic studies in advanced HCC and also some of the potential strategies to optimize clinical therapeutic development moving forward.

Changes of Serum Trace Elements, AFP, CEA, SF, T3, T4 and IGF-II in Different Periods of Rat Liver Cancer

OBJECTIVE

Based on liver cancer model built in SD rats, the contents of trace elements (Cu, Fe, Zn, Ca and Mg), AFP, CEA, SF, TH and IGF-II in serum were measured at different stages to explore the molecular changes during the rat liver cancer development.

METHODS

The SD rat liver cancer model was built by using diethylnitrosamine (DENA) as the mutagen. During 16 weeks of DENA gavage, blood samples were taken in the 14th, 28th, 56th, 77th, 105th and 112th days respectively after the first day of gavage with DENA, then the contents of five trace elements (Cu, Fe, Zn, Ca and Mg), T3, T4, IGF-II, AFP, CEA and SF in serum were determined.

RESULTS

During the development of the rat liver cancer, in the test group, the Cu content significantly increased in serum, while the contents of Fe, Zn and Ca significantly decreased. The content of Mg showed no significant change. AFP and CEA of the test group showed same expression level with the control group; while the content of SF was lower than that of the control group when cancerization appeared. T3 and T4 increased at the first stage and then went down, and the content of IGF-II was always high.

CONCLUSION

Cu, Fe, Zn, Ca, T3, T4, SF and IGF-II are closely related to the development of liver cancer. The changes of their contents in the development of cancer could enlighten the researches on cancer pathogenesis and prevention.

Klotho endows hepatoma cells with resistance to anoikis via VEGFR2/PAK1 activation in hepatocellular carcinoma

Klotho was originally characterized as an aging suppressor gene that predisposed Klotho-deficient mice to premature aging-like syndrome. Although Klotho was recently reported to exhibit tumor suppressive properties during various malignant transformations, the functional role and molecular mechanism of Klotho in hepatocarcinogenesis remains poorly understood. In our present study, immunohistochemical Klotho staining levels in a clinical follow-up of 52 hepatoma patients were significantly associated with liver cirrhosis, tumor multiplicity and venous invasion. The overall survival rate of hepatoma patients with high Klotho expression was significantly lower than those patients with low Klotho expression. Moreover, Klotho overexpression increased cellular migration, anchorage-independent growth, and anoikis resistance in hepatoma cells. Klotho overexpression elevated p21-activated kinase 1 (PAK1) expression and shRNA-mediated PAK1 knockdown and kinase activity inhibition with kinase dead mutant PAK1 K299R coexpression or allosteric inhibitor IPA3 treatment reversed anoikis resistance in Klotho-overexpressed hepatoma cells. More importantly, the pivotal significance of upregulated VEGFR2 protein levels mediated by Klotho expression was confirmed by VEGFR2 inhibitor Axitinib and blocking antibody treatment in hepatoma cells. Axitinib treatment sensitized anoikis was reversed by constitutive active mutant PAK1 T423E coexpression in Klotho-overexpressed hepatoma cells. Conversely, knockdown of Klotho reduced VEGFR2/PAK1 dependent anoikis resistance, which could be reversed by PAK1 T423E. These results revealed a novel oncogenic function of Klotho in promoting anoikis resistance via activating VEGFR2/PAK1 signaling, thus facilitating tumor migration and invasion during hepatoma progression, which could provide a putative molecular mechanism for tumor metastasis.