Overexpression of insulin receptor substrate-1 and hepatitis Bx genes causes premalignant alterations in the liver

Advances and challenges in molecular understanding, early detection, and targeted treatment of liver cancer

In this review, we explore the application of next-generation sequencing in liver cancer research, highlighting its potential in modern oncology. Liver cancer, particularly hepatocellular carcinoma, is driven by a complex interplay of genetic, epigenetic, and environmental factors. Key genetic alterations, such as mutations in TERT, TP53, and CTNNB1, alongside epigenetic modifications such as DNA methylation and histone remodeling, disrupt regulatory pathways and promote tumorigenesis. Environmental factors, including viral infections, alcohol consumption, and metabolic disorders such as nonalcoholic fatty liver disease, enhance hepatocarcinogenesis. The tumor microenvironment plays a pivotal role in liver cancer progression and therapy resistance, with immune cell infiltration, fibrosis, and angiogenesis supporting cancer cell survival. Advances in immune checkpoint inhibitors and chimeric antigen receptor T-cell therapies have shown potential, but the unique immunosuppressive milieu in liver cancer presents challenges. Dysregulation in pathways such as Wnt/β-catenin underscores the need for targeted therapeutic strategies. Next-generation sequencing is accelerating the identification of genetic and epigenetic alterations, enabling more precise diagnosis and personalized treatment plans. A deeper understanding of these molecular mechanisms is essential for advancing early detection and developing effective therapies against liver cancer.

Emerging trends in gastrointestinal cancers: Targeting developmental pathways in carcinogenesis and tumor progression

Gastrointestinal carcinomas are a group of cancers associated with the digestive system and its accessory organs. The most prevalent cancers related to the gastrointestinal tract are colorectal, gall bladder, gastric, hepatocellular, and esophageal cancers, respectively. Molecular aberrations in different signaling pathways, such as signal transduction systems or developmental pathways are the chief triggering mechanisms in different cancers Though a massive advancement in diagnostic and therapeutic interventions results in improved survival of patients with gastrointestinal cancer; the lower malignancy stages of these carcinomas are comparatively asymptomatic. Various gastrointestinal-related cancers are detected at advanced stages, leading to deplorable prognoses and increased rates of recurrence. Recent molecular studies have elucidated the imperative roles of several signaling pathways, namely Wnt, Hedgehog, and Notch signaling pathways, play in the progression, therapeutic responsiveness, and metastasis of gastrointestinal-related cancers. This book chapter gives an interesting update on recent findings on the involvement of developmental signaling pathways their mechanistic insight in gastrointestinalcancer. Subsequently, evidences supporting the exploration of gastrointestinal cancer related molecular mechanisms have also been discussed for developing novel therapeutic strategies against these debilitating carcinomas.

Hepatitis B virus X protein increases LASP1 SUMOylation to stabilize HER2 and facilitate hepatocarcinogenesis

The hepatitis B virus (HBV) X protein (HBX), a viral macromolecule, plays a vital role in the development of HBV-related hepatocellular carcinoma (HCC). Increased expression of HER2 is linked to HBV infection, and HBX is responsible for HER2 upregulation in HCC. Nevertheless, the underlying molecular mechanisms are not yet fully understood. In the study, we discovered that HBX promoted HER2 expression to facilitate the sensitization of the insulin signaling pathway and enhance the growth and migration of HCC cells. Mechanistically, the viral protein enhanced the stability of HER2 by preventing its ubiquitination-mediated proteasomal degradation through LASP1, which could bind to HER2. Furthermore, increased SUMOylation of LASP1 contributed to the upregulation of HER2 and the interaction of LASP1 with HER2. In addition, RANBP2 and RANGAP1 were found to interact with LASP1 and promote SUMOylation of LASP1 to upregulate HER2 expression in HBX-associated hepatoma cells. In summary, our work provides a novel insight into hepatocarcinogenesis mediated by HBX and estimates the detailed mechanisms related to the increase in HER2 regulated by the viral protein, which might help provide a theoretical basis for identifying novel targets for HBV-positive HCC treatment.

Revamping the innate or innate-like immune cell-based therapy for hepatocellular carcinoma: new mechanistic insights and advanced opportunities

A cancerous tumour termed hepatocellular carcinoma (HCC) is characterized by inflammation and subsequently followed by end-stage liver disease and necrosis of the liver. The liver's continuous exposure to microorganisms and toxic molecules affects the immune response because normal tissue requires some immune tolerance to be safeguarded from damage. Several innate immune cells are involved in this process of immune system activation which includes dendritic cells, macrophages, and natural killer cells. The liver is an immunologic organ with vast quantities of innate and innate-like immune cells subjected to several antigens (bacteria, fungal or viral) through the gut-liver axis. Tumour-induced immune system engagement may be encouraged or suppressed through innate immunological systems, which are recognized promoters of liver disease development in pre-HCC conditions such as fibrosis or cirrhosis, ultimately resulting in HCC. Immune-based treatments containing several classes of drugs have transformed the treatment of several types of cancers in recent times. The effectiveness of such immunotherapies relies on intricate interactions between lymphocytes, tumour cells, and neighbouring cells. Even though immunotherapy therapy has already reported to possess potential effect to treat HCC, a clear understanding of the crosstalk between innate and adaptive immune cell pathways still need to be clearly understood for better exploitation of the same. The identification of predictive biomarkers, understanding the progression of the disease, and the invention of more efficient combinational treatments are the major challenges in HCC immunotherapy. The functions and therapeutic significance of innate immune cells, which have been widely implicated in HCC, in addition to the interplay between innate and adaptive immune responses during the pathogenesis, have been explored in the current review.

The effects of sodium-glucose cotransporter 2 inhibitors on hepatocellular carcinoma: From molecular mechanisms to potential clinical implications

Hepatocellular carcinoma (HCC) occurs in the setting of prolonged liver inflammation, hepatocyte necrosis and regeneration in patients with cirrhosis. Despite the progress made in the medical management of the disorder during the past decades, the available pharmacological options remain limited, leading to poor survival rates and quality of life for patients with HCC. Sodium-glucose cotransporter 2 inhibitors (SGLT2) originally emerged as drugs for the treatment of hyperglycemia; however, they soon demonstrated important extra-glycemic properties, which led to their evaluation as potential treatments for a wide range of non-metabolic disorders. Evidence from animal studies suggests that SGLT2i have the potential to modulate molecular pathways that affect hallmarks of HCC, including inflammatory responses, cell proliferation, and oxidative stress. The impressive benefits of neurohormonal modulation observed with SGLT2i in congestive heart failure set the stage for human trials in cirrhotic ascites. However, future studies need to evaluate several aspects of the benefit to risk ratio of such a therapeutic strategy, including the co-administration with antineoplastic agents and diuretics, infections, use in hospitalized individuals, renal safety and hypovolemia. In this narrative review, we discuss the putative role of SGLT2i in the treatment of patients with HCC, starting with the mechanisms that could justify a possible benefit and ending with potential clinical implications and areas for future research.

Analysis of miR-143, miR-1, miR-210 and let-7e Expression in Colorectal Cancer in Relation to Histopathological Features

Background: MicroRNAs (miRNAs) are small RNA molecules involved in the control of the expression of many genes and are responsible for, among other things, cell death, differentiation and the control of their division. Changes in miRNA expression profiles have been observed in colorectal cancer. This discovery significantly enriches our knowledge of the pathogenesis of colorectal cancer and offers new goals in diagnostics and therapy. Aim: The aim of this study was to analyze the expression of four miRNA sequences—miR-143, miR-1, miR-210 and let-7e—and to investigate their significance in the risk of developing colorectal cancer. Materials and methods: miRNA sequences were investigated in formalin-fixed, paraffin-embedded (FFPE) tissue in colorectal cancer patients (n = 150) and in cancer-free controls (n = 150). The real-time PCR method was used. Results: This study revealed a lower expression of miR-143 in colorectal cancer patients than in the controls. miR-143 was positively correlated with the degree of tumor differentiation (grading). Three out of four analyzed miRNA (miR-1, miR-210 and let-7e) were found to be statistically insignificant in terms of colorectal carcinoma risk. Conclusions: miR-143 may be associated with the development of colorectal cancer.

Natural Progression of Non-Alcoholic Steatohepatitis to Hepatocellular Carcinoma

Non-alcoholic steatohepatitis (NASH) is a chronic and progressive form of non-alcoholic fatty liver disease (NAFLD). Its global incidence is increasing which makes NASH an epidemic and a public health threat. Due to repeated insults to the liver, patients are at risk for developing hepatocellular carcinoma (HCC). The progression of NASH to HCC was initially defined according to a two-hit model which involved the development of steatosis, followed by lipid peroxidation and inflammation. However, current research defines a “multi-hit” or “multi-parallel hit” model which synthesizes several contributing pathways involved in progressive fibrosis and oncogenesis. This perspective considers the effects of cellular, genetic, immunologic, metabolic, and endocrine pathways leading up to HCC which underscores the complexity of this condition. This article will provide an updated review of the pathogenic mechanisms leading from NASH to HCC as well as an exploration of the role of biomarkers and screening.

WNT/β-catenin signaling in the development of liver cancers

The WNT/β-catenin signaling pathway is a highly conserved and tightly controlled molecular mechanism that regulates embryonic development, cellular proliferation and differentiation. Of note, accumulating evidence has shown that the aberrant of WNT/β-catenin signaling promotes the development and/or progression of liver cancer, including hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), the two most prevalent primary liver tumours in adults. There are two different WNT signaling pathways have been identified, which were termed non-canonical and canonical pathways, the latter involving the activation of β-catenin. β-catenin, acting as an intracellular signal transducer in the WNT signaling pathway, is encoded by CTNNB1 and plays a critical role in tumorigenesis. In the past research, most liver tumors have mutations in genes encoding key components of the WNT/β-catenin signaling pathway. In addition, several of other signaling pathways also can crosswalk with β-catenin. In this review, we discuss the most relevant molecular mechanisms of action and regulation of WNT/β-catenin signaling in the development and pathophysiology of liver cancers, as well as in the development of therapeutics.

Expression and Significance of Insulin Receptor Substrate 1 in Human Hepatocellular Carcinoma

Background

Insulin receptor substrate 1 (IRS-1) is an important molecule of the insulin signal transduction pathway and has been associated with the occurrence and development of many tumors, including hepatocellular carcinoma (HCC). Our study was designed to determine the expression and significance of IRS-1 in human HCC.

Methods

Two hundred and forty specimens were drawn from 140 patients, including 100 HCC tissues and 100 paracancerous (PC) tissues from 100 HCC patients, 20 liver cirrhosis (LC) tissues from 20 LC patients, and 20 chronic hepatitis (CH) tissues from 20 CH patients. Baseline and pathological characteristics were included, and the expression of IRS-1 was examined by immunohistochemical (IHC) staining. Binary logistic regression model calculation was used for multivariate analysis.

Results

The total positive rates of IRS-1 expression were 41.0%, 17.0%, 15.0%, and 10.0% in HCC, PC, LC and CH tissues, respectively. IRS-1-positive signals were brown in color and located in the nucleus and cytoplasm. Compared with PC, LC, and CH tissues, a significantly increased expression was observed in human HCC tissues (P < 0.001, P = 0.028, and P = 0.008). Eight of the total 240 specimens had the strong immunostaining of IRS-1 expression, and all of them were HCC tissues. After control of the age, gender, and HBV and HCV infection, IRS-1 expression was independently associated with the diagnosis of HCC (OR 6.60, 95% CI 2.243-19.425, P = 0.001).

Conclusions

Positive expression of IRS-1 in HCC was increased significantly and may play an important role in the occurrence and development of human HCC.

Blockade of insulin receptor substrate-1 inhibits biological behavior of choroidal endothelial cells

AIM

To investigate the effects of blockade of insulin receptor substrate-1 (IRS-1) on the bio-function of tube formation of human choroidal endothelial cells (HCECs).

METHODS

Quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were performed to determine the expression level of IRS-1 and phospho-IRS-1 in HCECs. Tube formation of HCECs was analyzed using three dimensional in vitro Matrigel assay with or without IRS-1 blockage via IRS-1 inhibitor (GS-101) and vascular endothelial growth factor receptor 2 (VEGFR2) inhibitor. In addition, cell counting kit (CCK)-8 and Transwell migration assay were exerted to analyze the effects of blockade of IRS-1 on the bio-function of proliferation and migration of HCECs, respectively. The apoptosis of HCECs was examined using flow cytometry (FCM).

RESULTS

RT-PCR and Western blot revealed that IRS-1 phospho-IRS-1 were expressed in HCECs and the expression level was enhanced by stimulation of VEGF-A. The number of tube formation was decreased significantly in GS-101 treated groups compared to phosphate buffered saline (PBS) treated control groups. Furthermore, both cell proliferation and migration of HCECs were decreased in the presence of GS-101. FCM analysis showed that the apoptosis of HCECs was enhanced when the cells were treated with GS-101. Western blot also showed that the expression level of cleaved-caspase 3 in GS-101 treated group was higher than that in control group.

CONCLUSION

Blockade of IRS-1 can inhibit tube formation of HCECs through reducing cell proliferation and migration and promoting cell apoptosis.

Molecular Mechanisms Driving Progression of Liver Cirrhosis towards Hepatocellular Carcinoma in Chronic Hepatitis B and C Infections: A Review

Almost all patients with hepatocellular carcinoma (HCC), a major type of primary liver cancer, also have liver cirrhosis, the severity of which hampers effective treatment for HCC despite recent progress in the efficacy of anticancer drugs for advanced stages of HCC. Here, we review recent knowledge concerning the molecular mechanisms of liver cirrhosis and its progression to HCC from genetic and epigenomic points of view. Because ~70% of patients with HCC have hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection, we focused on HBV- and HCV-associated HCC. The literature suggests that genetic and epigenetic factors, such as microRNAs, play a role in liver cirrhosis and its progression to HCC, and that HBV- and HCV-encoded proteins appear to be involved in hepatocarcinogenesis. Further studies are needed to elucidate the mechanisms, including immune checkpoints and molecular targets of kinase inhibitors, associated with liver cirrhosis and its progression to HCC.

Molecular Mechanisms Driving Progression of Liver Cirrhosis towards Hepatocellular Carcinoma in Chronic Hepatitis B and C Infections: A Review

Almost all patients with hepatocellular carcinoma (HCC), a major type of primary liver cancer, also have liver cirrhosis, the severity of which hampers effective treatment for HCC despite recent progress in the efficacy of anticancer drugs for advanced stages of HCC. Here, we review recent knowledge concerning the molecular mechanisms of liver cirrhosis and its progression to HCC from genetic and epigenomic points of view. Because ~70% of patients with HCC have hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection, we focused on HBV- and HCV-associated HCC. The literature suggests that genetic and epigenetic factors, such as microRNAs, play a role in liver cirrhosis and its progression to HCC, and that HBV- and HCV-encoded proteins appear to be involved in hepatocarcinogenesis. Further studies are needed to elucidate the mechanisms, including immune checkpoints and molecular targets of kinase inhibitors, associated with liver cirrhosis and its progression to HCC.

Type 2 diabetes mellitus increases the risk of hepatocellular carcinoma in subjects with chronic hepatitis B virus infection: a meta-analysis and systematic review

Background

Type 2 diabetes mellitus has been proved to be a risk factor of hepatocellular carcinoma, but how diabetes affects incidence of hepatocellular carcinoma among patients with chronic hepatitis B virus infection remains controversial.

Methods

A comprehensive search of Medline and Embase was performed. Incidence of hepatocellular carcinoma in chronic hepatitis B patients was the primary outcome. Pooled HRs and 95% CIs were calculated to assess the correlation between diabetes and incidence of hepatocellular carcinoma.

Results

Five cohort studies and two case–control studies were identified, with a total of 21,842 chronic hepatitis B patients. The diabetes mellitus cohort was found to have increased incidence of hepatocellular carcinoma (pooled HR 1.77, 95% CI 1.28–2.47; fixed effect) and worse overall mortality (pooled RR 1.93, 95% CI 1.64–2.27; fixed effect) in comparison with those without diabetes. In case–control studies, hepatocellular carcinoma cases were found to have an insignificantly elevated diabetes mellitus rate in comparison with the control group.

Conclusion

Type 2 diabetes mellitus is significantly associated with increased risk of hepatocellular carcinoma among patients with chronic hepatitis B virus infection, and aggressive management of diabetes mellitus is strongly suggested.

Diabetes and hepatocellular carcinoma: A pathophysiological link and pharmacological management

Both diabetes mellitus (DM) and cancer are multifarious, dissimilar, and long-lasting, fatal diseases with a remarkable influence on health worldwide. DM is not only related to cardiovascular diseases, neuropathy, nephropathy, and retinopathy, but also related to a number of liver diseases such as nonalcoholic fatty liver disease, steatohepatitis, and liver cirrhosis. Recently, it is hypothesized that DM has a greater risk for many forms of cancer, such as breast, colorectal, endometrial, pancreatic, gallbladder, renal, and liver cancer including hepatocellular carcinoma (HCC). Both DM and cancer have many common risk factors, but the association between these two is poorly stated. Several epidemiologic studies have revealed the association between pathogenic and prognostic characteristics of DM and a higher incidence of HCC, thus representing DM as an independent risk factor for HCC development. The etiological and pathophysiological relationship between DM and HCC has been presented in this review by linking hyperglycemia, hyperinsulinemia, insulin resistance, and activation of insulin-like growth factor signaling pathways and pharmacological management of HCC associated with DM.

Identification of the β-catenin/JNK/prothymosin-alpha axis as a novel target of sorafenib in hepatocellular carcinoma cells

Sorafenib is a kinase inhibitor used as anticancer drug against various human tumors, including advanced hepatocellular carcinoma (HCC). β-Catenin and prothymosin alpha (PTMA) are overexpressed in HCC and other tumors. Previous studies have shown that PTMA expression modulates the response of HCC cells to sorafenib. However, the underlying mechanism of PTMA activity in this context remains unclear. We show here that sorafenib inhibits both β-catenin and PTMA in a dose-dependent manner. Silencing β-catenin reduces PTMA level and sensitizes HCC cells to sorafenib. In contrast, ectopic expression of β-catenin induces PTMA expression and cell resistance to the drug. Sorafenib inhibits PTMA expression at the transcriptional level by inhibiting the β-catenin pathway. Nucleotide deletion analysis of the PTMA gene promoter reveals that a DNA segment lying 1,500–1,600 bp upstream of the PTMA transcription start site represents an AP-1-binding site that is critical for β-catenin modulation of gene transcription in response to sorafenib. In addition, chemical inhibitors that target JNK abrogate β-catenin/AP-1 binding to the endogenous PTMA gene and reduces PTMA transcription and protein expression. Silencing of β-catenin or c-Fos induces similar effects on gene regulation and these are reversed by ectopic expression of β-catenin. Mutations in the PTMA promoter at the predicted β-catenin/AP-1 binding site partly abrogate sorafenib's effects on PTMA transcription. These results indicate that PTMA is induced by the oncoprotein β-catenin and protects HCC cells against sorafenib-induced cell death. The β-catenin/JNK/PTMA axis may thus represent a novel target for chemotherapy against HCC.

LPIN1 promotes epithelial cell transformation and mammary tumourigenesis via enhancing insulin receptor substrate 1 stability

LPIN1 is a protein that exhibits dual functions as a phosphatidic acid phosphatase enzyme in regulation of triglyceride and glycerophospholipid metabolism and a transcriptional coregulator. Through unknown tumour-promoting mechanism, LPIN1 frequently observed in various human cancer cell lines controls main cellular processes involved in cancer progression. Here, we demonstrate that LPIN1 enhances the tumour-promoting function of insulin receptor substrate 1 (IRS1) by controlling IRS1 stability. LPIN1 interacts with IRS1 in an insulin growth factor-1-dependent signalling pathway and inhibits its serine phosphorylation, and thereby eliminating ubiquitin-dependent degradation of IRS1 via proteasomal and lysosomal pathways. Consequently, LPIN1 overexpression increases IRS1 abundance and enhances IRS1's ability to induce epithelial cell proliferation and mammary tumourigenesis. By contrast, depletion or inhibition of LPIN1 in breast cancer cells leads to a decreased IRS1 level, which subsequently inhibits the RAF1-mediated signalling pathway and AP-1 activity. In the syngeneic 4T1 breast cancer model, LPIN1 overexpression increased tumour development, whereas inhibition of LPIN1 and IRS1 suppressed it. Consistent with these observations, LPIN1 levels were positively correlated with IRS1 expression in human breast cancer. Thus, our results indicate a mechanism by which IRS1 expression is increased in breast cancer, and LPIN1 may be a promising drug target for anticancer therapy.

Tobacco Smoke Exposure Impairs Brain Insulin/IGF Signaling: Potential Co-Factor Role in Neurodegeneration

BACKGROUND

Human studies suggest tobacco smoking is a risk factor for cognitive impairment and neurodegeneration, including Alzheimer's disease (AD). However, experimental data linking tobacco smoke exposures to underlying mediators of neurodegeneration, including impairments in brain insulin and insulin-like growth factor (IGF) signaling in AD are lacking.

OBJECTIVE

This study tests the hypothesis that cigarette smoke (CS) exposures can impair brain insulin/IGF signaling and alter expression of AD-associated proteins.

METHODS

Adult male A/J mice were exposed to air for 8 weeks (A8), CS for 4 or 8 weeks (CS4, CS8), or CS8 followed by 2 weeks recovery (CS8+R). Gene expression was measured by qRT-PCR analysis and proteins were measured by multiplex bead-based or direct binding duplex ELISAs.

RESULTS

CS exposure effects on insulin/IGF and insulin receptor substrate (IRS) proteins and phosphorylated proteins were striking compared with the mRNA. The main consequences of CS4 or CS8 exposures were to significantly reduce insulin R, IGF-1R, IRS-1, and tyrosine phosphorylated insulin R and IGF-1R proteins. Paradoxically, these effects were even greater in the CS8+R group. In addition, relative levels of S312-IRS-1, which inhibits downstream signaling, were increased in the CS4, CS8, and CS8+R groups. Correspondingly, CS and CS8+R exposures inhibited expression of proteins and phosphoproteins required for signaling through Akt, PRAS40, and/or p70S6K, increased AβPP-Aβ, and reduced ASPH protein, which is a target of insulin/IGF-1 signaling.

CONCLUSION

Secondhand CS exposures caused molecular and biochemical abnormalities in brain that overlap with the findings in AD, and many of these effects were sustained or worsened despite short-term CS withdrawal.

Type 2 diabetes and gender differences in liver cancer by considering different confounding factors: a meta-analysis of cohort studies

PURPOSE

Questions remain uncertainty regarding the gender differences in the relationship between type 2 diabetes (T2DM) and liver cancer risk. By considering several confounding factors, we aimed to identify this issue according to a meta-analysis of cohort studies.

METHODS

We searched EMBASE and MEDLINE for studies on the association between T2DM and risk of liver cancer up to November 30, 2014. A random-effects model was performed to calculate summary relative risks (SRRs) with corresponding 95% confidence intervals (CIs).

RESULTS

A total of 24 cohort studies (including more than 20,000 liver cancer cases) were recruited. T2DM was associated with an elevated liver cancer incidence in both men (SRR = 2.16; 95% CI, 1.74-2.69) and women (SRR = 1.85; 95% CI, 1.40-2.44). Stratified analyses showed that the risk associations were significantly stronger in non-Asian than those in Asian for both men and women. Both tobacco smoking and body mass index were significant confounding factors for the T2DM-liver cancer association in men, whereas alcohol use was not the case. The SRR estimates of liver cancer mortality with T2DM were statistically significant in both men and women (men: SRR = 2.26; 95% CI, 1.60-3.19 and women: SRR = 2.01; 95% CI, 1.45-2.74).

CONCLUSIONS

Results of this meta-analysis indicate that the T2DM-liver cancer correlation is confounded by smoking and body mass index in both men and women. Results also suggest a significantly stronger T2DM-liver cancer correlation in non-Asian than that in Asian for both men and women.

Tobacco Nitrosamine Exposures Contribute to Fetal Alcohol Spectrum Disorder Associated Cerebellar Dysgenesis

Variability in the phenotypic features and severity of fetal alcohol spectrum disorder (FASD) is not fully linked to alcohol dose. We hypothesize that FASD-type neurodevelopmental abnormalities may be caused by exposures to the tobacco-specific nitrosamine, NNK, since a high percentage of pregnant women who drink also smoke. In vitro experiments using PNET2 human cerebellar neuronal cultures examined ethanol and NNK effects on viability and mitochondrial function. Early postnatal rat cerebellar slice cultures were used to examine effects of ethanol and NNK on cerebellar histology and neuroglial and stress protein expression. Ethanol (50 mM) decreased viability and ATP content and increased mitochondrial mass, while NNK (100 μM or higher) selectively inhibited mitochondrial function. The slice culture studies demonstrated striking adverse effects of ethanol, NNK and ethanol+NNK exposures manifested by architectural disorganization of the cortex with relative reductions of internal granule cells, increases in external granule cells, and loss of Purkinje cells. Ethanol, NNK, and ethanol+NNK inhibited expression of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE), and increased levels of 4-hydroxynonenal (HNE). In addition, ethanol increased activated Caspase 3, NNK decreased tau and phospho-tau, and ethanol+NNK inhibited expression of Aspartyl-β-hydroxylase (ASPH), which mediates neuronal migration. In conclusion, ethanol and NNK were shown to exert independent but overlapping adverse effects on cerebellar cortical development, neuronal viability, function, and neuroglial protein expression. These findings support our hypothesis that NNK exposures via tobacco smoking in pregnancy can contribute to FASD-associated neurodevelopmental abnormalities.

Potential Co-Factor Role of Tobacco Specific Nitrosamine Exposures in the Pathogenesis of Fetal Alcohol Spectrum Disorder

BACKGROUND

Cerebellar developmental abnormalities in Fetal Alcohol Spectrum Disorder (FASD) are linked to impairments in insulin signaling. However, co-morbid alcohol and tobacco abuses during pregnancy are common. Since smoking leads to tobacco specific Nitrosamine (NNK) exposures which have been shown to cause brain insulin resistance, we hypothesized that neurodevelopmental abnormalities in FASD could be mediated by ethanol and/or NNK.

METHODS

Long Evans rat pups were intraperitoneal (IP) administered ethanol (2 g/kg) on postnatal days (P) 2, 4, 6 and/or NNK (2 mg/kg) on P3, P5, and P7 to simulate third trimester human exposures. The Cerebellar function, histology, insulin and Insulin-like Growth Factor (IGF) signaling, and neuroglial protein expression were assessed.

RESULTS

Ethanol, NNK and ethanol+NNK groups had significant impairments in motor function (rotarod tests), abnormalities in cerebellar structure (Purkinje cell loss, simplification and irregularity of folia, and altered white matter), signaling through the insulin and IGF-1 receptors, IRS-1, Akt and GSK-3β, and reduced expression of several important neuroglial proteins. Despite similar functional effects, the mechanisms and severity of NNK and ethanol+NNK induced alterations in cerebellar protein expression differed from those of ethanol.

CONCLUSIONS

Ethanol and NNK exert independent but overlapping adverse effects on cerebellar development, function, insulin signaling through cell survival, plasticity, metabolic pathways, and neuroglial protein expression. The results support the hypothesis that tobacco smoke exposure can serve as a co-factor mediating long-term effects on brain structure and function in FASD.

Differential Effects of 3rd Trimester-Equivalent Binge Ethanol and Tobacco-Specific Nitrosamine Ketone Exposures on Brain Insulin Signaling in Adolescence

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is associated with impairments in insulin and insulin-like growth factor (IGF) signaling through Akt pathways and altered expression of neuro-glial proteins needed for structural and functional integrity of the brain. However, alcohol abuse correlates with smoking, and tobacco smoke contains 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which like other nitrosamines, impairs insulin and IGF signaling.

HYPOTHESIS

NNK exposure can serve as a co-factor in mediating long-term neuro-developmental abnormalities associated with FASD.

DESIGN

Long Evans rat pups were IP administered ethanol (2 g/kg) on postnatal days (P) 2, 4, 6 and/or NNK (2 mg/kg) on P3, P5, and P7, simulating third trimester human exposures. Temporal lobes from P30 rats (young adolescent) were used to measure signaling through the insulin/IGF-1/Akt pathways by multiplex ELISAs, and expression of neuroglial proteins by duplex ELISAs.

RESULTS

Ethanol, NNK, and ethanol + NNK exposures significantly inhibited insulin receptor tyrosine phosphorylation, and IRS-1 and myelin-associated glycoprotein expression. However, the major long-term adverse effects on Akt pathway downstream signaling and its targeted proteins including choline acetyltransferase, Tau, pTau, ubiquitin, and aspartate-β-hydroxylase were due to NNK rather than ethanol.

CONCLUSION

Alcohol and tobacco exposures can both contribute to long-term brain abnormalities currently regarded fetal ethanol effects. However, the findings suggest that many of the adverse effects on brain function are attributable to smoking, including impairments in signaling through survival and metabolic pathways, and altered expression of genes that regulate myelin synthesis, maturation and integrity and synaptic plasticity. Therefore, public health measures should address both substances of abuse to prevent "FASD".

The evolving roles of canonical WNT signaling in stem cells and tumorigenesis: implications in targeted cancer therapies

The canonical WNT/β-catenin signaling pathway governs a myriad of biological processes underlying the development and maintenance of adult tissue homeostasis, including regulation of stem cell self-renewal, cell proliferation, differentiation, and apoptosis. WNTs are secreted lipid-modified glycoproteins that act as short-range ligands to activate receptor-mediated signaling pathways. The hallmark of the canonical pathway is the activation of β-catenin-mediated transcriptional activity. Canonical WNTs control the β-catenin dynamics as the cytoplasmic level of β-catenin is tightly regulated via phosphorylation by the 'destruction complex', consisting of glycogen synthase kinase 3β (GSK3β), casein kinase 1α (CK1α), the scaffold protein AXIN, and the tumor suppressor adenomatous polyposis coli (APC). Aberrant regulation of this signaling cascade is associated with varieties of human diseases, especially cancers. Over the past decade, significant progress has been made in understanding the mechanisms of canonical WNT signaling. In this review, we focus on the current understanding of WNT signaling at the extracellular, cytoplasmic membrane, and intracellular/nuclear levels, including the emerging knowledge of cross-talk with other pathways. Recent progresses in developing novel WNT pathway-targeted therapies will also be reviewed. Thus, this review is intended to serve as a refresher of the current understanding about the physiologic and pathogenic roles of WNT/β-catenin signaling pathway, and to outline potential therapeutic opportunities by targeting the canonical WNT pathway.

HBV-related chronic liver disease and insulin resistance

The liver is the major organ regulating glucose metabolism. When liver injury occurs, glucose metabolism disturbance and insulin resistance (IR) may develop, which can even cause the development of hepatogenic diabetes. The correlation between viral hepatitis, liver cirrhosis and diabetes has become a hot research topic in recent years. This paper reviews the progress in research of hepatitis B virus (HBV) infection and early predictors of diabetes. We give a brief introduction to the concept of IR and its causes, and discuss the relationship of HBV infection, HBV and HCV coinfection, and hepatitis associated cirrhosis with IR. We also describe the possible mechanisms for IR in HBV infected people. Besides, we discuss the impact of IR on prognosis of HBV related chronic liver diseases, mainly fatty, liver fibrosis, and liver cancer. The clinical treatment of patients with HBV infection and IR is also discussed.

Activation of signal transduction pathways during hepatic oncogenesis

BACKGROUND AND AIMS

Understanding the molecular pathogenesis of hepatocellular carcinoma (HCC) is essential to identify therapeutic targets. A hepatitis B virus (HBV) related double transgenic murine model was developed.

METHODS

Liver specific expression of HBV X protein (HBx) and insulin receptor substrate 1 (IRS1) was achieved and transgenic mice were followed from birth to age 21 months. Liver and tumor tissue were assessed for histologic changes as well as activation of signal transduction pathways by qRT-PCR and multiplex ELISA protein assays.

RESULTS

Overexpression of HBx and IRS1 stimulates liver cell proliferation in the double transgenic mice. Only the male mice developed HCC starting at age 15-18 months. The IN/IGF1/IRS1/MAPK/ERK and IN/IGF1/IRS1/PI3K/AKT/GSK3β cascades were activated early (6-9 months) in the liver followed by WNT/β-catenin and Notch signaling. Aspartate β-hydroxylase (ASPH) was found to link these upstream growth factor signaling pathways to downstream Notch activation in tumor tissues.

CONCLUSIONS

Sustained overexpression of HBx and IRS1 led to constitutive activation of a tripartite growth factor signal transduction cascade in the liver and was necessary and sufficient to promote HCC development and progression.

Hyperinsulinaemia and insulin signalling in the pathogenesis and the clinical course of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most prevalent cancer and is one of the leading causes of cancer-related death. The risk factors for HCC include cirrhosis, chronic viral hepatitis, heavy alcohol intake and metabolic diseases such as obesity, type 2 diabetes and metabolic syndrome. Insulin resistance is a common denominator of all of these conditions and is tethered to hyperinsulinaemia. Here, we give an overview of the recent advances linking hyperinsulinaemia to HCC development and progression. In particular, we summarise the underlying causes of hyperinsulinaemia in the setting of chronic liver diseases. We present epidemiological evidence linking metabolic diseases to HCC risk and HCC-related mortality, as well as the pathogenic cellular and molecular mechanisms explaining this relation. A better understanding of the mechanisms by which insulin participates in HCC biology might ultimately provide novel opportunities for prevention and treatment.

Implications of miR cluster 143/145 as universal anti-oncomiRs and their dysregulation during tumorigenesis

Tumorigenesis is a multistep process, de-regulated due to the imbalance of oncogenes as well as anti-oncogenes, resulting in disruption of tissue homeostasis. In many cases the effect of oncogenes and anti-oncogenes are mediated by various other molecules such as microRNAs. microRNAs are small non-coding RNAs established to post-transcriptionally regulate more than half of the protein coding genes. miR cluster 143/145 is one such cancer-related microRNA cluster which is down-regulated in most of the cancers and is able to hinder tumorigenesis by targeting tumor-associated genes. The fact that they could sensitize drug-resistant cancer cells by targeting multidrug resistant genes makes them potent tools to target cancer cells. Their low levels precede events which lead to cancer progression and therefore could be considered also as biomarkers to stage the disease. Interestingly, evidence suggests the existence of several in vivo mechanisms by which this cluster is differentially regulated at the molecular level to keep their levels low in cancer. In this review, we summarize the roles of miR cluster 143/145 in cancer, their potential prognostic applications and also their regulation during tumorigenesis.

microRNA regulation of Wnt signaling pathways in development and disease

Wnt signaling pathways and microRNAs (miRNAs) are critical regulators of development. Aberrant Wnt signaling pathways and miRNA levels lead to developmental defects and diverse human pathologies including but not limited to cancer. Wnt signaling pathways regulate a plethora of cellular processes during embryonic development and maintain homeostasis of adult tissues. A majority of Wnt signaling components are regulated by miRNAs which are small noncoding RNAs that are expressed in both animals and plants. In animal cells, miRNAs fine tune gene expression by pairing primarily to the 3'untranslated region of protein coding mRNAs to repress target mRNA translation and/or induce target degradation. miRNA-mediated regulation of signaling transduction pathways is important in modulating dose-sensitive response of cells to signaling molecules. This review discusses components of the Wnt signaling pathways that are regulated by miRNAs in the context of development and diseases. A fundamental understanding of miRNA functions in Wnt signaling transduction pathways may yield new insight into crosstalks of regulatory mechanisms essential for development and disease pathophysiology leading to novel therapeutics.

Hepatocellular carcinoma

The hepatitis B virus (HBV) is a widespread human pathogen that causes liver inflammation, cirrhosis, and hepatocellular carcinoma (HCC). Recent sequencing technologies have refined our knowledge of the genomic landscape and pathogenesis of HCC, but the mechanisms by which HBV exerts its oncogenic role remain controversial. In a prevailing view, inflammation, liver damage, and regeneration may foster the accumulation of genetic and epigenetic defects leading to cancer onset. However, a more direct and specific contribution of the virus is supported by clinical and biological observations. Among genetically heterogeneous HCCs, HBV-related tumors display high genomic instability, which may be attributed to the ability of HBV to integrate its DNA into the host cell genome, provoking chromosomal alterations and insertional mutagenesis of cancer genes. The viral transactivator HBx may also participate in transformation by deregulating diverse cellular machineries. A better understanding of the complex mechanisms linking HBV to HCC will improve prevention and treatment strategies.

The Novel Functions of High-Molecular-Mass Complexes Containing Insulin Receptor Substrates in Mediation and Modulation of Insulin-Like Activities: Emerging Concept of Diverse Functions by IRS-Associated Proteins

Insulin-like peptides, such as insulin-like growth factors (IGFs) and insulin, induce a variety of bioactivities, such as growth, differentiation, survival, increased anabolism, and decreased catabolism in many cell types and in vivo. In general, IGFs or insulin bind to IGF-I receptor (IGF-IR) or insulin receptor (IR), activating the receptor tyrosine kinase. Insulin receptor substrates (IRSs) are known to be major substrates of receptor kinases, mediating IGF/insulin signals to direct bioactivities. Recently, we discovered that IRSs form high-molecular-mass complexes (referred to here as IRSomes) even without IGF/insulin stimulation. These complexes contain proteins (referred to here as IRSAPs; IRS-associated proteins), which modulate tyrosine phosphorylation of IRSs by receptor kinases, control IRS stability, and determine intracellular localization of IRSs. In addition, in these complexes, we found not only proteins that are involved in RNA metabolism but also RNAs themselves. Thus, IRSAPs possibly contribute to modulation of IGF/insulin bioactivities. Since it is established that disorder of modulation of insulin-like activities causes various age-related diseases including cancer, we could propose that the IRSome is an important target for treatment of these diseases.

A cell-surface β-hydroxylase is a biomarker and therapeutic target for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has a poor prognosis as a result of widespread intra- and extrahepatic metastases. There is an urgent need to understand signaling cascades that promote disease progression. Aspartyl-(asparaginyl)-β-hydroxylase (ASPH) is a cell-surface enzyme that generates enhanced cell motility, migration, invasion, and metastatic spread in HCC. We hypothesize that inhibition of its enzymatic activity could have antitumor effects. Small molecule inhibitors (SMIs) were developed based on the crystal structure of the ASPH catalytic site followed by computer-assisted drug design. Candidate compounds were tested for inhibition of β-hydroxylase activity and selected for their capability to modulate cell proliferation, migration, invasion, and colony formation in vitro and to inhibit HCC tumor growth in vivo using orthotopic and subcutaneous murine models. The biological effects of SMIs on the Notch signaling cascade were evaluated. The SMI inhibitor, MO-I-1100, was selected because it reduced ASPH enzymatic activity by 80% and suppressed HCC cell migration, invasion, and anchorage-independent growth. Furthermore, substantial inhibition of HCC tumor growth and progression was observed in both animal models. The mechanism(s) for this antitumor effect was associated with reduced activation of Notch signaling both in vitro and in vivo.

CONCLUSIONS

These studies suggest that the enzymatic activity of ASPH is important for hepatic oncogenesis. Reduced β-hydroxylase activity generated by the SMI MO-I-1100 leads to antitumor effects through inhibiting Notch signaling cascade in HCC. ASPH promotes the generation of an HCC malignant phenotype and represents an attractive molecular target for therapy of this fatal disease.

Potential mechanisms of hepatitis B virus induced liver injury

Chronic active hepatitis (CAH) is acknowledged as an imperative risk factor for the development of liver injury and hepatocellular carcinoma. The histological end points of CAH are chronic inflammation, fibrosis and cirrhosis which are coupled with increased DNA synthesis in cirrhotic vs healthy normal livers. The potential mechanism involved in CAH includes a combination of processes leading to liver cell necrosis, inflammation and cytokine production and liver scaring (fibrosis). The severity of liver damage is regulated by Hepatitis B virus genotypes and viral components. The viral and cellular factors that contribute to liver injury are discussed in this article. Liver injury caused by the viral infection affects many cellular processes such as cell signaling, apoptosis, transcription, DNA repair which in turn induce radical effects on cell survival, growth, transformation and maintenance. The consequence of such perturbations is resulted in the alteration of bile secretion, gluconeogenesis, glycolysis, detoxification and metabolism of carbohydrates, proteins, fat and balance of nutrients. The identification and elucidation of the molecular pathways perturbed by the viral proteins are important in order to design effective strategy to minimize and/or restore the hepatocytes injury.

Wnt signaling pathway and hepatic carcinogenesis

The disturbance of signal transduction often occurs in tumor, and the Wnt signaling pathway is one of the most studied signaling pathways in tumorigenesis. Some studies have shown that the Wnt signaling pathway is related to the occurrence and development of hepatocellular carcinoma (HCC). Elucidation of the interactions between factors in the Wnt signaling pathway is important for understanding the pathogenesis of HCC, which can provide a theoretical basis for more effective diagnosis and treatment of this malignancy.

Synergistic function of Kras mutation and HBx in initiation and progression of hepatocellular carcinoma in mice

Although the activation of Ras pathway is frequently observed in human hepatocellular carcinoma (HCC), the in vivo role of Ras activation in HCC initiation and progression is underdetermined. To test the consequence of Kras activation in hepatocyte, we generated a hepatocyte-specific Kras(G12D) transgenic mouse strain and observed spontaneous development of HCC in these mice. Remarkably, HBV X protein (HBx) expression significantly promotes the formation and malignant progression of Kras(G12D)-driven HCC as shown with the accelerated tumor onset, the increased tumor burden and the more poorly differentiated lesions. At the cellular level, concomitant expression of Kras(G12D) and HBx results in a robust increase in hepatocellular proliferation. We reveal that the Akt, MAPK, p53 and TGF-β pathways are deregulated in the Kras(G12D)-driven HCCs. Also, the dysregulation is more pronounced in the HCCs developed in Kras(G12D) and HBx double transgenic mice. In addition, the altered expressions of β-catenin, CD44 and E-cadherin are only observed in the Kras(G12D) and HBx double transgenic mice. These results demonstrate a crucial role of Ras activation in hepatocellular carcinogenesis and the functional synergy between Kras(G12D) and HBx in HCC initiation and progression. The novel genetic mouse models that closely recapitulate the histopathologic progression and molecular alterations of human HCC may potentially facilitate the future therapeutic studies.

Loss of exon 4 in a human T-cell factor-4 isoform promotes hepatic tumourigenicity

BACKGROUND

T-cell factor (TCF) proteins represent key transcription factors that activate Wnt/β-catenin signalling. We have reported that a pair of TCF-4 isoforms (TCF-4C and TCF-4D) exhibit differential TCF transcriptional activity in hepatocellular carcinoma (HCC) cells, although their structure differs by only the presence (TCF-4D) or absence (TCF-4C) of exon 4.

AIM

To demonstrate a regulatory role of exon 4 in HCC development.

METHODS

TCF-4C and TCF-4D expression profiles were examined in 27 pairs of human HCC and adjacent liver tissues. The functional role of the TCF-4 isoforms was evaluated in OUMS-29 (an immortalized hepatocyte-derived) and HAK-1A (a well-differentiated HCC) cell lines using stable clones overexpressing the TCF-4 isoforms.

RESULTS

TCF-4C was significantly upregulated in HCC tissues compared with corresponding peritumour and normal liver tissues; in contrast, there was no difference in TCF-4D expression. TCF-4C clones derived from both cell lines exhibited increased TCF activity, Wnt-responsive target genes, cell proliferation, cell cycle progression and resistance to chemotherapeutic drugs compared with TCF-4D clones. Capability of cell migration and colony formation was significantly higher in TCF-4C than TCF-4D clones. In a nude mice xenograft model, the HAK-1A-derived TCF-4C clone rapidly developed tumours compared with the TCF-4D clone. TCF-4C clone-derived tumours exhibited upregulation of Wnt-responsive target genes compared with the slow developing and small TCF-4D-derived tumours.

CONCLUSION

These results demonstrate that the TCF-4C isoform lacking exon 4 is associated with a malignant phenotype compared with the exon 4-harbouring TCF-4D isoform, indicating that exon 4 of TCF-4 plays a prominent role in HCC development.

Wnt signaling and hepatocarcinogenesis: molecular targets for the development of innovative anticancer drugs

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer death worldwide. HCC can be cured by radical therapies if early diagnosis is done while the tumor has remained of small size. Unfortunately, diagnosis is commonly late when the tumor has grown and spread. Thus, palliative approaches are usually applied such as transarterial intrahepatic chemoembolization and sorafenib, an anti-angiogenic agent and MAP kinase inhibitor. This latter is the only targeted therapy that has shown significant, although moderate, efficiency in some individuals with advanced HCC. This highlights the need to develop other targeted therapies, and to this goal, to identify more and more pathways as potential targets. The Wnt pathway is a key component of a physiological process involved in embryonic development and tissue homeostasis. Activation of this pathway occurs when a Wnt ligand binds to a Frizzled (FZD) receptor at the cell membrane. Two different Wnt signaling cascades have been identified, called non-canonical and canonical pathways, the latter involving the β-catenin protein. Deregulation of the Wnt pathway is an early event in hepatocarcinogenesis and has been associated with an aggressive HCC phenotype, since it is implicated both in cell survival, proliferation, migration and invasion. Thus, component proteins identified in this pathway are potential candidates of pharmacological intervention. This review focuses on the characteristics and functions of the molecular targets of the Wnt signaling cascade and how they may be manipulated to achieve anti-tumor effects.

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.

Distinctive microRNA signature associated of neoplasms with the Wnt/β-catenin signaling pathway

As the crucial biological regulators, microRNAs that act by suppressing their target genes are involved in a variety of pathophysiological processes. It is generally accepted that microRNAs are often dysregulated in many types of neoplasm and other human diseases. In neoplasm, microRNAs may function as oncogenes or tumor suppressors. As constitutive activation of the Wnt signaling pathway is a common feature of neoplasm and contributes to its development, progression and metastasis in various cancers, numerous studies have revealed that microRNA-mediated gene regulation are interconnected with the Wnt/β-catenin signaling pathway, forming a Wnt/β-catenin-microRNA regulatory network, which is critical to successful targeting of the Wnt/β-catenin pathway for oncotherapy. In this review, we aim to accumulate recent advances on microRNAs that work in tandem with Wnt/β-catenin signaling in tumorigenesis, with particular focus on how microRNAs affect Wnt/β-catenin activity as well as how microRNAs are regulated through the Wnt/β-catenin pathway.

Upregulation of T-cell factor-4 isoform-responsive target genes in hepatocellular carcinoma

BACKGROUND

The Wnt/β-catenin signalling pathway regulates genes involved in cell proliferation, survival, migration and invasion through regulation by T-cell factor (TCF)-4 transcription factor proteins. However, the role of TCF-4 isoforms generated by alternative splicing events in hepatocellular carcinoma (HCC) is unknown.

AIM

Here, we investigated TCF-4 isoforms (TCF-4J and K)-responsive target genes that are important in hepatic oncogenesis and tumour development.

METHODS

Gene expression microarray was performed on HCC cells overexpressing TCF-4J and K isoforms. Expression level of selected target genes was evaluated and correlations were made between their expression level and that of TCF-4 isoform in 47 pairs of human HCC tumours.

RESULTS

Comparison by gene expression microarray revealed that 447 genes were upregulated and 343 downregulated more than 2.0-fold in TCF-4J compared with TCF-4K expressing cells. We validated expression of 18 selected target genes involved in Wnt/β-catenin, insulin/IGF-1/IRS1 and Notch signalling pathways in 47 pairs of human HCCs and adjacent uninvolved liver tissues. It was observed that 13 genes (CLDN2, STK17B, SPP1, AXIN2, WISP2, MMP7, IRS1, ANXA1, CAMK2N1, ASPH, GPR56, CD24 and JAG1) activated by TCF-4J isoform in HCC cells, were also upregulated in HCC tumours compared with adjacent peritumour tissue; more importantly, 10 genes exhibited a significant correlation with the TCF-4J expression level in tumour.

CONCLUSION

TCF-4 isoforms (TCF-4J and K) activated different downstream target genes in HCC. The biological consequence of TCF-4J isoform expression was upregulation of genes associated with tripartite Wnt/β-catenin, insulin/IGF-1/IRS1 and Notch signal transduction pathway activation, which contribute to the pathogenesis of HCC.

Obesity, an independent risk factor for hepatocellular carcinoma (HCC) in NAFLD non-cirrhotic patients

Hepatocellular carcinoma (HCC) is one of the most common malignancies with increasing incidence in developed countries. Epidemiological studies show that the cause of new discovered HCC cases remains unclear in 15%-50% of cases. Obesity and the subsequent/ underlying nonalcoholic fatty liver disease (NAFLD) can be responsible for most of these cases. The aim of our study was to estimate the risk of HCC in obese patients diagnosed with NAFLD, without clinical or imagistic features of liver cirrhosis, in order to see if HCC can develop in fatty liver in the absence of cirrhosis. Patients with regular/daily alcohol consumption or diagnosed with liver viral infections were excluded. We studied 214 obese patients with NAFLD over a period of 5 years. We evaluated all patients using abdominal ultrasound and serum alpha-fetoprotein every 6 month, in order to detect the HCC occurrence. Kaplan-Meier analysis estimated the cumulative incidence of HCC. Univariate and multivariate Cox regression analysis were used to assess associations between HCC and obesity. The median follow-up was 4.3 years. During the study period, 16 from 118 cirrhotic NFLAD patients (13.5%) and 12 from 96 non-cirrhotic NAFLD patients (12.5 %) developed HCC (p = 0.07, ns). The cumulative incidence of HCC was found to be 2.9% in obese patients with NAFLD-cirrhosis, compared with 2.2% in obese patients without cirrhosis (p = 0.09, ns). Multivariate regression analysis revealed that older age (p = 0.04) was independent variable associated with development of HCC in patients with/without NAFLDcirrhosis. Obesity seems to be an independent risk factor for HCC occurrence, regardless the presence of mild or advanced liver fibrosis in NAFLD patients.

Multi-target lentivirus specific to hepatocellular carcinoma: in vitro and in vivo studies

BACKGROUND & AIMS

We aimed at investigating the effects of the targeted transduction of the Wtp53-pPRIME-miR30-shRNA gene into liver cancer cells, under the mediation of anti-alpha fetoprotein scFv-directed lentivirus, and the inhibitory effect of this system on liver cancer cells.

METHODS

The result of infection was observed by fluorescence microscopy. Polymerase chain reaction and Western blotting were used to demonstrate the successful transduction and transcription of the Wtp53-pPRIME-miR30-shRNA-IGF1R gene. Cell growth was observed via the Cell-Counting Kit-8 Method, and cell apoptosis was detected by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling. To observe further the effects of AFP-Wtp53-pPRIME-miR30-shRNA-IGF1R therapy in animals, models of BALB-C nude mice bearing subcutaneous human hepatocellular carcinoma were established. The influence of the growth of subcutaneously transplanted tumor, expression of Wtp53 protein, apoptosis, and microvessel formation on the overall level of AFP-Wtp53 pPRIME-miR30-shRNA-IGF1R were also evaluated.

RESULTS

Recombinant lentivirus was successfully constructed, and its functional plaque-forming unit titer was determined as 4.58 × 10(9)plaque-forming units/ml. A positive strand was detected by polymerase chain reaction and Western blotting. Lentiviral construction worked effectively in AFP-positive liver cancer cells. In vitro and in vivo experiments showed that the recombinant lentivirus was more efficacious in inhibiting the proliferation of Hep3B cells.

CONCLUSIONS

The Wtp53-pPRIME-miR30-shRNA gene can be subjected to targeted transduction into liver cancer cells under the mediation of anti-alpha fetoprotein scFv-directed lentivirus. The Wtp53-pPRIME-miR30-shRNA system has targeting ability and lethal effects on liver cancer cells.

Functional consequences of WNT3/Frizzled7-mediated signaling in non-transformed hepatic cells

We have previously demonstrated that WNT3 and Frizzled7 (FZD7) expression levelswere upregulated in hepatocellular carcinoma (HCC) and that they directly interact to activate the canonical Wnt/β–catenin pathway in HCC cell lines. In this study, we investigated the functional consequences of WNT3 and FZD7 expression levels in non-transformed hepatic cells to address the question of whether WNT3/FZD7-mediated signal transduction could be involved in cellular transformation. After stable transfection of WNT3 and FZD7, the activation of the Wnt/β–catenin pathway was confirmed by western blot, immunostaining and quantitative real-time reverse transcriptase–PCR (qRT–PCR) analysis in two non-transformed hepatocyte-derived cell lines. In vitro characteristics of the malignant phenotype were measured, including cell proliferation, migration, invasion and anchorage-independent growth in soft agar. Stable expression of WNT3 and FZD7 in the two cell lines led to cellular accumulation of β-catenin and expression of downstream target genes activated by this pathway. In the stable WNT3/FZD7-expressing clones, hepatic cell proliferation, migration, invasion as well as soft agar colony formation were enhanced compared with the non-transformed control cells. The epithelial–mesenchymal transition (EMT) factors, Twist, Snail and Vimentin, were increased in cells expressing WNT3 and FZD7. However, the WNT3/FZD7-expressing cells did not form tumors in vivo. We conclude that activation of the WNT3/FZD7 canonical pathway has a role in the early stages of hepatocarcinogenesis by promoting the acquisition of a malignant phenotype with features of EMT.

Body mass index and risk of primary liver cancer: a meta-analysis of prospective studies

BACKGROUND

Questions remain about the dose-response relationship between body mass index (BMI) and primary liver cancer (PLC) risk, possible confounding by hepatitis virus infection, and differences by gender or geographic location. We performed a meta-analysis of prospective studies to explore these issues.

METHODS

We searched PubMed and Embase for studies of BMI and risk of PLC through November 30, 2011. Summary relative risks with their corresponding 95% confidence intervals (CIs) were calculated using a random effects model.

RESULTS

A total of 21 prospective studies (including 17,624 PLC cases) were included in our analysis. The summary relative risk for a 5-unit increment in BMI (in kg/m(2)) was 1.39 (95% CI: 1.25-1.55), with high heterogeneity. These positive results were robust when stratified by sex, geographic location, ascertainment of exposure and outcome, the number of cases, duration of follow-up, sample source, and cofounders. There was evidence of a nonlinear association between BMI and PLC risk, with the most pronounced increase in risk among persons with a BMI >32 kg/m(2). Patients with hepatitis C virus or cirrhosis (but not patients with hepatitis B virus) with excess weight had a higher risk of PLC development than general populations with excess weight.

CONCLUSION

Excess weight increases PLC risk. For people with HCV infection or cirrhosis, risk increases are greater than for general population.

Tumor progression-related transmembrane protein aspartate-β-hydroxylase is a target for immunotherapy of hepatocellular carcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) has a poor survival rate due to recurrent intrahepatic metastases and lack of effective adjuvant therapy. Aspartate-β-hydroxylase (ASPH) is an attractive cellular target since it is a highly conserved transmembrane protein overexpressed in both murine and human HCC tumors, and promotes a malignant phenotype as characterized by enhanced tumor cell migration and invasion.

METHODS

Dendritic cells (DCs), expanded and isolated from the spleen, were incubated with a cytokine cocktail to optimize IL-12 secretion and co-stimulatory molecule expression, then subsequently loaded with ASPH protein for immunization. Mice were injected with syngeneic BNL HCC tumor cells followed by subcutaneous inoculation with 5-10×10(5) ASPH loaded DCs using a prophylactic and therapeutic experimental approach. Tumor infiltrating lymphocytes (TILs) were characterized, and their role in producing anti-tumor effects determined. The immunogenicity of ASPH protein with respect to activating antigen specific CD4+ T cells derived from human peripheral blood mononuclear cells (PBMCs) was also explored.

RESULTS

We found that immunotherapy with ASPH-loaded DCs suppressed and delayed established HCC and tumor growth when administered prophylactically. Ex-vivo re-stimulation experiments and in vivo depletion studies demonstrated that both CD4+ and CD8+ cells contributed to anti-tumor effects. Using PBMCs derived from healthy volunteers and HCC patients, we showed that ASPH stimulation led to significant development of antigen-specific CD4+ T-cells.

CONCLUSIONS

Immunization with ASPH-loaded DCs has substantial anti-tumor effects which could reduce the risk of HCC recurrence.

Association of total energy intake and macronutrient consumption with colorectal cancer risk: results from a large population-based case-control study in Newfoundland and Labrador and Ontario, Canada

Background

Diet is regarded as one of the most important environmental factors associated with colorectal cancer (CRC) risk. A recent report comprehensively concluded that total energy intake does not have a simple relationship with CRC risk, and that the data were inconsistent for carbohydrate, cholesterol and protein. The objective of this study was to identify the associations of CRC risk with dietary intakes of total energy, protein, fat, carbohydrate, fiber, and alcohol using data from a large case-control study conducted in Newfoundland and Labrador (NL) and Ontario (ON), Canada.

Methods

Incident colorectal cancer cases (n = 1760) were identified from population-based cancer registries in the provinces of ON (1997-2000) and NL (1999-2003). Controls (n = 2481) were a random sample of residents in each province, aged 20-74 years. Family history questionnaire (FHQ), personal history questionnaire (PHQ), and food frequency questionnaire (FFQ) were used to collect study data. Logistic regression was used to evaluate the association of intakes of total energy, macronutrients and alcohol with CRC risk.

Results

Total energy intake was associated with higher risk of CRC (OR: 1.56; 95% CI: 1.21-2.01, p-trend = 0.02, 5^th versus 1^st quintile), whereas inverse associations emerged for intakes of protein (OR: 0.85, 95%CI: 0.69-1.00, p-trend = 0.06, 5^th versus 1^st quintile), carbohydrate (OR: 0.81, 95%CI: 0.63-1.00, p-trend = 0.05, 5^th versus 1^st quintile) and total dietary fiber (OR: 0.84, 95% CI:0.67-0.99, p-trend = 0.04, 5^th versus 1^st quintile). Total fat, alcohol, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, and cholesterol were not associated with CRC risk.

Conclusion

This study provides further evidence that high energy intake may increase risk of incident CRC, whereas diets high in protein, fiber, and carbohydrate may reduce the risk of the disease.

Excess body weight and the risk of primary liver cancer: an updated meta-analysis of prospective studies

AIMS

To provide a quantitative assessment of the association between excess body weight (EBW) and the risk of primary liver cancer (PLC), we performed an updated meta-analysis of prospective observational studies.

METHODS

We searched PUBMED and EMBASE for studies of body mass index and the risk of PLC published through 15 th September 2011. Summary relative risks (SRRs) with their corresponding 95% confidence intervals (CIs) were calculated using a random-effects model. The meta-regression and stratified methods were used to examine heterogeneity across studies.

RESULTS

A total of 26 prospective studies, including 25,337 PLC cases, were included in this analysis. Overall, excess body weight (EBW: body mass index (BMI) ≥ 25 kg/m2) and obesity (BMI ≥ 30 kg/m2) were associated with an increased risk of PLC, with significant heterogeneity (EBW: SRRs 1.48, 95% CIs 1.31-1.67, P(h)<0.001, I2=83.6%; Obesity: SRRs 1.83, 95% CIs 1.59-2.11, P(h)<0.001, I2=75.0%). Subgroup analyses revealed that the positive associations were independent of geographic locations, alcohol consumption, history of diabetes or infections with hepatitis B (HBV) and/or hepatitis C virus (HCV). Obese males had a higher risk of PLC than obese females did (P=0.027). A stronger risk of PLC with EBW was observed for patients with HCV (but not HBV) infection or cirrhosis compared with the general population.

CONCLUSIONS

Findings from this meta-analysis strongly support that EBW or obesity is associated with an increased risk of PLC in both males and females.

MiR-145 modulates multiple components of the insulin-like growth factor pathway in hepatocellular carcinoma

Profiling of microRNA expression in human cancers has highlighted downregulation of miR-145 as a common event in epithelial malignancies. Here, we describe recurrent underexpression of miR-145 in hepatocellular carcinoma (HCC) and the identification of a biological pathway by which miR-145 exerts its functional effects in liver tumorigenesis. In a cohort of 80 HCC patients, quantitative reverse transcription polymerase chain reaction corroborated reduced miR-145 expression in 50% of tumors, which also correlated with a shorter disease-free survival of patients. One HCC tumor analyzed with low endogenous miR-145 was propagated as cell line. This in vitro model HKCI-C2 maintained low miR-145 level and upon restoration of miR-145 expression, a consistent inhibitory effect on cell viability and proliferation was readily found. Flow cytometric analysis indicated that miR-145 re-expression could induce G(2)-M cell cycle arrest and apoptosis. Multiple in silico algorithms predicted that miR-145 could target a number of genes along the insulin-like growth factor (IGF) signaling, including insulin receptor substrate (IRS1)-1, IRS2 and insulin-like growth factor 1 receptor. We found protein expression of these putative targets was concordantly downregulated in the presence of miR-145. Luciferase reporter assay further verified direct target association of miR-145 to specific sites of the IRS1 and IRS2 3'-untranslated regions. Subsequent analysis also affirmed miR-145 modulation on the IGF signaling cascade by reducing its downstream mediator, namely the active β-catenin level. Taken together, our study shows for the first time the pleiotropic effect of miR-145 in targeting multiple components of the oncogenic IGF signaling pathway in HCC.

The role of oncogenic viruses in the pathogenesis of hepatocellular carcinoma

HBV and HCV have major roles in hepatocarcinogenesis. More than 500 million people are infected with hepatitis viruses and, therefore, HCC is highly prevalent, especially in those countries endemic for HBV and HCV. Viral and host factors contribute to the development of HCC. The main viral factors include the circulating load of HBV DNA or HCV RNA and specific genotypes. Various mechanisms are involved in the host-viral interactions that lead to HCC development, among which are genetic instability, self-sufficiency in growth signals, insensitivity to antigrowth signals, evasion of apoptosis, limitless replicative potential, sustained angiogenesis, and tissue invasiveness. Prevention of HBV by vaccination, as well as antiviral therapy against HBV and for HCV seem able to inhibit the development of HCC.