Identifying cancer driver genes in individual tumours

Cancer is a heterogeneous disease with a strong genetic component making it suitable for precision medicine approaches aimed at identifying the underlying molecular drivers within a tumour. Large scale population-level cancer sequencing consortia have identified many actionable mutations common across both cancer types and sub-types, resulting in an increasing number of successful precision medicine programs. Nonetheless, such approaches fail to consider the effects of mutations unique to an individual patient and may miss rare driver mutations, necessitating personalised approaches to driver-gene prioritisation. One approach is to quantify the functional importance of individual mutations in a single tumour based on how they affect the expression of genes in a gene interaction network (GIN). These GIN-based approaches can be broadly divided into those that utilise an existing reference GIN and those that construct de novo patient-specific GINs. These single-tumour approaches have several limitations that likely influence their results, such as use of reference cohort data, network choice, and approaches to mathematical approximation, and more research is required to evaluate the in vitro and in vivo applicability of their predictions. This review examines the current state of the art methods that identify driver genes in single tumours with a focus on GIN-based driver prioritisation.

Testing Cell Migration, Invasion, Proliferation, and Apoptosis in Hepatic Stellate Cells

The hepatic wound repair process involves cell types including healthy and injured hepatocytes, Kupffer and inflammatory cells, sinusoidal endothelial cells (SECs), and hepatic stellate cells (HSCs). Normally, in their quiescent state, HSCs are a reservoir for vitamin A, but in response to hepatic injury, they become activated myofibroblasts that play a key role in the hepatic fibrotic response. Activated HSCs express extracellular matrix (ECM) proteins, elicit anti-apoptotic responses, and proliferate, migrate, and invade hepatic tissues to protect hepatic lobules from damage. Extended liver injury can lead to fibrosis and cirrhosis, the deposition of ECM that is driven by HSCs. Here we describe in vitro assays that quantify activated HSC responses in the presence of inhibitors targeting hepatic fibrosis.

Recent advances in cancer fusion transcript detection

Extensive investigation of gene fusions in cancer has led to the discovery of novel biomarkers and therapeutic targets. To date, most studies have neglected chromosomal rearrangement-independent fusion transcripts and complex fusion structures such as double or triple-hop fusions, and fusion-circRNAs. In this review, we untangle fusion-related terminology and propose a classification system involving both gene and transcript fusions. We highlight the importance of RNA-level fusions and how long-read sequencing approaches can improve detection and characterization. Moreover, we discuss novel bioinformatic tools to identify fusions in long-read sequencing data and strategies to experimentally validate and functionally characterize fusion transcripts.

Immune checkpoint inhibitors in HCC: Cellular, molecular and systemic data

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer related deaths in the world, and for patients with advanced disease there are few therapeutic options available. The complex immunological microenvironment of HCC and the success of immunotherapy in several types of tumours, has raised the prospect of potential benefit for immune based therapies, such as immune checkpoint inhibitors (ICIs), in HCC. This has led to significant breakthrough research, numerous clinical trials and the rapid approval of multiple systemic drugs for HCC by regulatory bodies worldwide. Although some patients responded well to ICIs, many have failed to achieve significant benefit, while others showed unexpected and paradoxical deterioration. The aim of this review is to discuss the pathophysiology of HCC, the tumour microenvironment, key clinical trials evaluating ICIs in HCC, various resistance mechanisms to ICIs, and possible ways to overcome these impediments to improve patient outcomes.

Targeting the PI3K/Akt/mTOR Pathway in Hepatocellular Carcinoma

Despite advances in the treatment of cancers through surgical procedures and new pharmaceuticals, the treatment of hepatocellular carcinoma (HCC) remains challenging as reflected by low survival rates. The PI3K/Akt/mTOR pathway is an important signaling mechanism that regulates the cell cycle, proliferation, apoptosis, and metabolism. Importantly, deregulation of the PI3K/Akt/mTOR pathway leading to activation is common in HCC and is hence the subject of intense investigation and the focus of current therapeutics. In this review article, we consider the role of this pathway in the pathogenesis of HCC, focusing on its downstream effectors such as glycogen synthase kinase-3 (GSK-3), cAMP-response element-binding protein (CREB), forkhead box O protein (FOXO), murine double minute 2 (MDM2), p53, and nuclear factor-κB (NF-κB), and the cellular processes of lipogenesis and autophagy. In addition, we provide an update on the current ongoing clinical development of agents targeting this pathway for HCC treatments.

Cell adhesion an important determinant of myogenesis and satellite cell activity

Skeletal muscles represent a complex and highly organised tissue responsible for all voluntary body movements. Developed through an intricate and tightly controlled process known as myogenesis, muscles form early in development and are maintained throughout life. Due to the constant stresses that muscles are subjected to, skeletal muscles maintain a complex course of regeneration to both replace and repair damaged myofibers and to form new functional myofibers. This process, made possible by a pool of resident muscle stem cells, termed satellite cells, and controlled by an array of transcription factors, is additionally reliant on a diverse range of cell adhesion molecules and the numerous signaling cascades that they initiate. This article will review the literature surrounding adhesion molecules and their roles in skeletal muscle myogenesis and repair.

An aptamer-based drug delivery agent (CD133-apt-Dox) selectively and effectively kills liver cancer stem-like cells

Liver cancer has no effective therapies, hence a poor survival. Cancer stem-like cells not only contribute to cancer initiation and progression, but also to drug resistance, cancer metastasis, and eventually treatment failure. Hence, any approaches that can effectively kill cancer stem-like cells hold a great potential for cancer treatment. CD133 is a robust marker for liver cancer stem-like cells. We developed a specific aptamer against CD133 (CD133-apt), and then loaded this aptamer with an anticancer drug doxorubicin (CD133-apt-Dox). The efficacy of CD133-apt-Dox in targeting liver cancer stem-like cells and its overall effect in treating liver cancer were investigated using multiple in vitro and in vivo studies including in patients-derived liver cancer organoids. We have observed that CD133-apt could preferably delivered doxorubicin to CD133-expressing cells with efficient drug accumulation and retention. CD133-apt-Dox impaired the self-renewal capacity of liver cancer stem-like cells and attenuated their stem-ness phenotypes in vitro or in vivo. CD133-apt-Dox significantly inhibited the growth of liver cancer cells and patients-derived organoids and reduced the growth of xenograft tumours in nude mice inhibited the growth of DEN-induced liver cancer in immunocompetent mice. Hence, aptamer-mediated targeting of CD133 is a highly promising approach for liver cancer therapy.

The role of DNA damage and repair in liver cancer

Hepatocellular carcinoma is rapidly becoming a major cause of global mortality due to the ever-increasing prevalence of obesity. DNA damage is known to play an important role in cancer initiation, however DNA repair systems are also vital for the survival of cancer cells. Given the function of the liver and its exposure to the gut, it is likely that DNA damage and repair would be of particular importance in hepatocellular carcinoma. However, many contemporary reports have neglected the role of individual pathways of DNA damage and repair in their hypotheses. This review, therefore, aims to provide a concise overview for researchers in the field of liver cancer to understand the pathways of DNA damage and repair and their individual roles in hepatocellular carcinoma.

The effects of fructose and metabolic inhibition on hepatocellular carcinoma

Hepatocellular carcinoma is rapidly becoming one of the leading causes of cancer-related deaths, largely due to the increasing incidence of non-alcoholic fatty liver disease. This in part may be attributed to Westernised diets high in fructose sugar. While many studies have shown the effects of fructose on inducing metabolic-related liver diseases, little research has investigated the effects of fructose sugar on liver cancer metabolism. The present study aimed to examine the metabolic effects of fructose on hepatocellular carcinoma growth in vitro and in vivo. Fructose sugar was found to reduce cell growth in vitro, and caused alterations in the expression of enzymes involved in the serine-glycine synthesis and pentose phosphate pathways. These biosynthesis pathways are highly active in cancer cells and they utilise glycolytic by-products to produce energy and nucleotides for growth. Hence, the study further investigated the efficacy of two novel drugs that inhibit these pathways, namely NCT-503 and Physcion. The study is the first to show that the combination treatment of NCT-503 and Physcion substantially inhibited hepatocellular carcinoma growth in vitro and in vivo. The combination of fructose diet and metabolism-inhibiting drugs may provide a unique metabolic environment that warrants further investigation in targeting hepatocellular carcinoma.

A Sweet Connection? Fructose's Role in Hepatocellular Carcinoma

Hepatocellular carcinoma is one of few cancer types that continues to grow in incidence and mortality worldwide. With the alarming increase in diabetes and obesity rates, the higher rates of hepatocellular carcinoma are a result of underlying non-alcoholic fatty liver disease. Many have attributed disease progression to an excess consumption of fructose sugar. Fructose has known toxic effects on the liver, including increased fatty acid production, increased oxidative stress, and insulin resistance. These effects have been linked to non-alcoholic fatty liver (NAFLD) disease and a progression to non-alcoholic steatohepatitis (NASH). While the literature suggests fructose may enhance liver cancer progression, the precise mechanisms in which fructose induces tumor formation remains largely unclear. In this review, we summarize the current understanding of fructose metabolism in liver disease and liver tumor development. Furthermore, we consider the latest knowledge of cancer cell metabolism and speculate on additional mechanisms of fructose metabolism in hepatocellular carcinoma.

Targeting mTOR and Src restricts hepatocellular carcinoma growth in a novel murine liver cancer model

Liver cancer is a poor prognosis cancer with limited treatment options. To develop a new therapeutic approach, we derived HCC cells from a known model of murine hepatocellular carcinoma (HCC). We treated adiponectin (APN) knock-out mice with the carcinogen diethylnitrosamine, and the resulting tumors were 7-fold larger than wild-type controls. Tumors were disassociated from both genotypes and their growth characteristics evaluated. A52 cells from APN KO mice had the most robust growth in vitro and in vivo, and presented with pathology similar to the parental tumor. All primary tumors and cell lines exhibited activity of the mammalian target of Rapamycin (mTOR) and Src pathways. Subsequent combinatorial treatment, with the mTOR inhibitor Rapamycin and the Src inhibitor Dasatinib reduced A52 HCC growth 29-fold in vivo. Through protein and histological analyzes we observed activation of these pathways in human HCC, suggesting that targeting both mTOR and Src may be a novel approach for the treatment of HCC.

The role of obesity in inflammatory bowel disease

In just over a generation overweight and obesity has become a worldwide health concern. The ramifications for this on future health care costs and longevity are consequent, whilst increased adiposity is a harbinger for diabetes, kidney and bone failure, and cancer. An area of intense interest where the role of adiposity is avidly discussed is in inflammatory bowel disease (IBD), which presents mainly as Crohn's disease (CD) and ulcerative colitis (UC). Studies in patients associating IBD with a western diet are divergent. Nevertheless, elegant studies have found gene polymorphisms in humans that in murine models parallel the inflammatory and gut microbiome changes seen in IBD patients. However, an area not to be ignored are the alterations in adipocyte function with ensuing adiposity, in particular and a focus of this review, the dysregulation of the levels of adipocytokines such as leptin and adiponectin. Herein, we present and discuss the known influences of a western diet on IBD in patients and rodent models and how adipocytokines could influence the IBD disease process.

Aptamers as targeting ligands and therapeutic molecules for overcoming drug resistance in cancers

Traditional anticancer therapies are often unable to completely eradicate the tumor bulk due to multi-drug resistance (MDR) of cancers. A number of mechanisms such as micro-environmental stress and overexpression of drug efflux pumps are involved in the MDR process. Hence, therapeutic strategies for overcoming MDR are urgently needed to improve cancer treatment efficacy. Aptamers are short single-stranded oligonucleotides or peptides exhibiting unique three-dimensional structures and possess several unique advantages over conventional antibodies such as low immunogenicity and stronger tissue-penetration capacity. Aptamers targeting cancer-associated receptors have been explored to selectively deliver a therapeutic cargo (anticancer drugs, siRNAs, miRNAs and drug-carriers) to the intratumoral compartment where they can exert better tumor-killing effects. In this review, we summarize current knowledge of the multiple regulatory mechanisms of MDR, with a particular emphasis on aptamer-mediated novel therapeutic agents and strategies that seek to reversing MDR. The challenges associated with aptamer-based agents and approaches are also discussed.

Aptamers: A promising chemical antibody for cancer therapy

Aptamers, also known as chemical antibodies, are single-stranded nucleic acid oligonucleotides which bind to their targets with high specificity and affinity. They are typically selected by repetitive in vitro process termed systematic evolution of ligands by exponential enrichment (SELEX). Owing to their excellent properties compared to conventional antibodies, notably their smaller physical size and lower immunogenicity and toxicity, aptamers have recently emerged as a new class of agents to deliver therapeutic drugs to cancer cells by targeting specific cancer-associated hallmarks. Aptamers can also be structurally modified to make them more flexible in order to conjugate other agents such as nano-materials and therapeutic RNA agents, thus extending their applications for cancer therapy. This review presents the current knowledge on the practical applications of aptamers in the treatment of a variety of cancers.

Dysregulated long noncoding RNAs (lncRNAs) in hepatocellular carcinoma: implications for tumorigenesis, disease progression, and liver cancer stem cells

Hepatocellular carcinoma (HCC) is one of the most common malignant tumours with a poor prognosis worldwide. While early stage tumours can be treated with curative approaches such as liver transplantation or surgical resection, these are only suitable for a minority of patients. Those with advanced stage disease are only suitable for supportive approaches and most are resistant to the conventional chemotherapy or radiotherapy. Liver cancer stem cells (LCSCs) are a small subset of cancer cells with unlimited differentiation ability and tumour forming potential. In order to develop novel therapeutic approaches for HCC, we need to understand how the cancer develops and why treatment resistance occurs. Using high-throughput sequencing techniques, a large number of dysregulated long noncoding RNAs (lncRNAs) have been identified, and some of which are closely linked to key aspects of liver cancer pathology, progression, outcomes and for the maintenance of cancer stem cell-like properties. In addition, some lncRNAs are potential biomarkers for HCC diagnosis and may serve as the therapeutic targets. This review summarizes data recently reported lncRNAs that might be critical for the maintenance of the biological properties of LCSCs.

Aptamer-Based Therapeutic Approaches to Target Cancer Stem Cells

Cancer stem cells (CSCs) are believed to be a principal cellular source for tumour progression and therapeutic drug resistance as they are capable of self-renewal and can differentiate into cancer cells. Importantly, CSCs acquire the ability to evade the killing effects of cytotoxic agents through changes at the genetic, epigenetic and micro-environment levels. Therefore, therapeutic strategies targeting CSCs hold great potential as an avenue for cancer treatment. Aptamers or "chemical antibodies" are a group of single-stranded nucleic acid (DNA or RNA) oligonucleotides with distinctive properties such as smaller size, lower toxicity and less immunogenicity compared to conventional antibodies. They have been frequently used to deliver therapeutic payloads to cancer cells and have achieved encouraging anti-tumour effects. This review discusses progress in CSC evolution theory and the role of aptamers to target CSCs for cancer treatment. Challenges of aptamer-mediated CSC targeting approaches are also discussed.

Adiponectin confers protection from acute colitis and restricts a B cell immune response

Adiponectin demonstrates beneficial effects in various metabolic diseases, including diabetes, and in bowel cancer. Recent data also suggest a protective role in colitis. However, the precise molecular mechanisms by which adiponectin and its receptors modulate colitis and the nature of the adaptive immune response in murine models are yet to be elucidated. Adiponectin knock-out mice were orally administered dextran sulfate sodium for 7 days and were compared with wild-type mice. The severity of disease was analyzed histopathologically and through cytokine profiling. HCT116 colonic epithelial cells were employed to analyze the in vitro effects of adiponectin and AdipoR1 interactions in colonic injury following dextran sulfate sodium treatment. Adiponectin knock-out mice receiving dextran sulfate sodium exhibited severe colitis, had greater inflammatory cell infiltration, and an increased presence of activated B cells compared with controls. This was accompanied by an exaggerated proinflammatory cytokine profile and increased STAT3 signaling. Adiponectin knock-out mouse colons had markedly reduced proliferation and increased epithelial apoptosis and cellular stress. In vitro, adiponectin reduced apoptotic, anti-proliferative, and stress signals and restored STAT3 signaling. Following the abrogation of AdipoR1 in vitro, these protective effects of adiponectin were abolished. In summary, adiponectin maintains intestinal homeostasis and protects against murine colitis through interactions with its receptor AdipoR1 and by modulating adaptive immunity.

Overcoming treatment resistance in cancer: Current understanding and tactics

Chemotherapy is the standard treatment for many, if not all, metastatic cancers. While chemotherapy is often capable of inducing cell death in tumors leading to shrinkage of the tumor bulk, many patients suffer from recurrence and ultimately death due to resistance. During the last decade, treatment resistance has attracted great attention followed by some seminal discoveries, including sequential mutations, cancer stem cells, and bidirectional inter-conversion of stem and non-stem cancer cell populations. Nevertheless, the successful treatment of cancer will require a considerable refinement of our knowledge concerning treatment resistance. In doing so, we expect that a more informed and refined approach to treat cancer will be developed and this may improve prognosis of cancer patients. In this review, we will discuss the current knowledge concerning the failure of cancer treatments and the potential approaches to overcome therapeutic resistance.

Hepatocellular carcinoma and non-alcoholic steatohepatitis: The state of play

Hepatocellular carcinoma (HCC) is now the fifth cancer of greatest frequency and the second leading cause of cancer related deaths worldwide. Chief amongst the risks of HCC are hepatitis B and C infection, aflatoxin B1 ingestion, alcoholism and obesity. The latter can promote non-alcoholic fatty liver disease (NAFLD), that can lead to the inflammatory form non-alcoholic steatohepatitis (NASH), and can in turn promote HCC. The mechanisms by which NASH promotes HCC are only beginning to be characterized. Here in this review, we give a summary of the recent findings that describe and associate NAFLD and NASH with the subsequent HCC progression. We will focus our discussion on clinical and genomic associations that describe new risks for NAFLD and NASH promoted HCC. In addition, we will consider novel murine models that clarify some of the mechanisms that drive NASH HCC formation.

The role of fructose in metabolism and cancer

Fructose consumption has dramatically increased in the last 30 years. The principal form has been in the form of high-fructose corn syrup found in soft drinks and processed food. The effect of excessive fructose consumption on human health is only beginning to be understood. Fructose has been confirmed to induce several obesity-related complications associated with the metabolic syndrome. Here we present an overview of fructose metabolism and how it contrasts with that of glucose. In addition, we examine how excessive fructose consumption can affect de novo lipogenesis, insulin resistance, inflammation, and reactive oxygen species production. Fructose can also induce a change in the gut permeability and promote the release of inflammatory factors to the liver, which has potential implications in increasing hepatic inflammation. Moreover, fructose has been associated with colon, pancreas, and liver cancers, and we shall discuss the evidence for these observations. Taken together, data suggest that sustained fructose consumption should be curtailed as it is detrimental to long-term human health.

Oct4 is a reliable marker of liver tumor propagating cells in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the 6th most common cancer worldwide and the 2nd most common cause of cancer related mortality. The poor prognosis is largely due to the difficulty in early diagnoses and eradication of stem-like cells within HCC, which are termed liver tumor propagating cells (LTPCs). These LTPCs are involved in all stages of tumorigenesis including tumor initiation, progression, and treatment failure. The greatest challenge in understanding these LTPCs is finding effective ways in isolating and characterizing these cells with current methods showing large inter-tumor variability in isolating these cells. Oct4 is a stem cell gene associated with LTPCs and has been shown to be involved in regulating a range of functions in HCC cells associated with LTPC features. In this study we determined the efficacy and reliability in utilizing Oct4 to isolate and characterize LTPCs. We have shown that Oct4 is ubiquitously expressed in all HCC tumors tested whereas other traditional LTPC markers had high intratumor variability in their expression. We then utilized a human Oct4 promoter driving an enhanced green fluorescent protein (EGFP) reporter which showed that Oct4+ cells had all the classic features of LTPCs including increased sphere formation in vitro, tumor forming potential in immunocompromised mice, expression of stemness associated genes, and resistance to Sorafenib which is the major drug used to treat advanced HCC. Based on our findings we have identified Oct4 as a reliable marker of LTPCs and discovered a novel way to isolate and characterize LTPCs.

Adiponectin reduces hepatic stellate cell migration by promoting tissue inhibitor of metalloproteinase-1 (TIMP-1) secretion

Hepatic stellate cells (HSC) are central players in liver fibrosis that when activated, proliferate, migrate to sites of liver injury, and secrete extracellular matrix. Obesity, a known risk factor for liver fibrosis is associated with reduced levels of adiponectin, a protein that inhibits liver fibrosis in vivo and limits HSC proliferation and migration in vitro. Adiponectin-mediated activation of adenosine monophosphate-activated kinase (AMPK) inhibits HSC proliferation, but the mechanism by which it limits HSC migration to sites of injury is unknown. Here we sought to elucidate how adiponectin regulates HSC motility. Primary rat HSCs were isolated and treated with adiponectin in migration assays. The in vivo actions of adiponectin were examined by treating mice with carbon tetrachloride for 12 weeks and then injecting them with adiponectin. Cell and tissue samples were collected and analyzed for gene expression, signaling, and histology. Serum from patients with liver fibrosis was examined for adiponectin and tissue inhibitor of metalloproteinase-1 (TIMP-1) protein. Adiponectin administration into mice increased TIMP-1 gene and protein expression. In cultured HSCs, adiponectin promoted TIMP-1 expression and through binding of TIMP-1 to the CD63/β1-integrin complex reduced phosphorylation of focal adhesion kinase to limit HSC migration. In mice with liver fibrosis, adiponectin had similar effects and limited focal adhesion kinase phosphorylation. Finally, in patients with advanced fibrosis, there was a positive correlation between serum adiponectin and TIMP-1 levels. In sum, these data show that adiponectin stimulates TIMP-1 secretion by HSCs to retard their migration and contributes to the anti-fibrotic effects of adiponectin.

Non alcoholic steatohepatitis a precursor for hepatocellular carcinoma development

Hepatocellular carcinoma (HCC) is increasing in prevalence and is one of the most common cancers in the world. Chief amongst the risks of attaining HCC are hepatitis B and C infection, aflatoxin B1 ingestion, alcoholism and obesity. The later has been shown to promote non alcoholic fatty liver disease, which can lead to the inflammatory form non alcoholic steatohepatitis (NASH). NASH is a complex metabolic disorder that can impact greatly on hepatic function. The mechanisms by which NASH promotes HCC are only beginning to be characterized. Here in this review, we give an overview of the recent novel mechanisms published that have been associated with NASH and subsequent HCC progression. We will focus our discussion on inflammation and gut derived inflammation and how they contribute to NASH driven HCC.

Non-alcoholic steatohepatitis weakens the acute phase response to endotoxin in rats

BACKGROUND & AIMS

Patients with non-alcoholic steatohepatitis (NASH) have increased mortality, including from infections. We, therefore, tested in a rodent model of steatohepatitis whether the hepatic acute phase response is intact.

METHODS

Steatohepatitis was induced in rats by feeding a high-fat, high-cholesterol diet for 4 (early) and 16 weeks (advanced NASH). 2 h after low-dose LPS (0.5 mg/kg i.p.), we measured the serum concentrations of tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6). We also measured liver mRNA's and the serum concentrations of acute phase proteins 24 h after LPS.

RESULTS

Non-alcoholic steatohepatitis in itself increased the liver mRNA levels of TNF-α and IL-6 and also the liver mRNA and serum levels of the acute phase proteins. The exposure to LPS increased serum TNF-α in both early and advanced NASH and more so than in the control rats. However, the increases in acute phase protein genes in liver tissue and proteins in the blood were lower than in the control rats.

CONCLUSION

In rats with early or advanced experimental NASH, LPS despite an increased interleukin release resulted in a blunted acute phase protein response. This tachyphylaxis may be part of the mechanism for the increased infection susceptibility of patients with NASH. We speculate that the steatosis-related interleukin release desensitises the signalling pathway leading to acute phase protein synthesis.

Experimental nonalcoholic steatohepatitis compromises ureagenesis, an essential hepatic metabolic function

Nonalcoholic steatohepatitis (NASH) is increasing in prevalence, yet its consequences for liver function are unknown. We studied ureagenesis, an essential metabolic liver function of importance for whole body nitrogen homeostasis, in a rodent model of diet-induced NASH. Rats were fed a high-fat, high-cholesterol diet for 4 and 16 wk, resulting in early and advanced experimental NASH, respectively. We examined the urea cycle enzyme mRNAs in liver tissue, the hepatocyte urea cycle enzyme proteins, and the in vivo capacity of urea-nitrogen synthesis (CUNS). Early NASH decreased all of the urea cycle mRNAs to an average of 60% and the ornithine transcarbamylase protein to 10%, whereas the CUNS remained unchanged. Advanced NASH further decreased the carbamoyl phosphate synthetase protein to 63% and, in addition, decreased the CUNS by 20% [from 5.65 ± 0.23 to 4.58 ± 0.30 μmol × (min × 100 g)(-1); P = 0.01]. Early NASH compromised the genes and enzyme proteins involved in ureagenesis, whereas advanced NASH resulted in a functional reduction in the capacity for ureagenesis. The pattern of urea cycle perturbations suggests a prevailing mitochondrial impairment by NASH. The decrease in CUNS has consequences for the ability of the body to adjust to changes in the requirements for nitrogen homeostasis e.g., at stressful events. NASH, thus, in terms of metabolic consequences, is not an innocuous lesion, and the manifestations of the damage seem to be a continuum with increasing disease severity.

Synergistic effects of IAP inhibitor LCL161 and paclitaxel on hepatocellular carcinoma cells

Inhibitor of Apoptosis Proteins (IAPs) are key regulators of apoptosis in hepatocellular carcinoma (HCC) and their expression is negatively correlated with patient survival. LCL161 is a small molecule inhibitor of IAPs that has potent antitumour activity in a range of solid tumours. In HCC, response to LCL161 therapy has shown to be mediated by Bcl-2 expression. In this study, we aim to determine whether LCL161 has any therapeutic potential in HCC. Protein expression was determined by Western blot. Cell proliferation was determined by Cell Proliferation ELISA and BrdU colorimetric assays. Apoptosis was determined by Annexin V assay. Cell cycle analysis was performed by staining cells with propidium iodide and analysed in a FACScan. Automated Cell Counter and phase contrast microscopy were used to determine the cell viability. We have found that LCL161 targets (cIAP1, cIAP2 and XIAP) were up-regulated in HCC tumours. Both high Bcl-2 expressing HuH7 cells and low Bcl-2 expressing SNU423 cells showed strong resistance to LCL161 therapy with significant effects on both apoptosis and cell viability only evident at LCL161 concentrations of ⩾100μM. At these doses there was significant inhibition of IAP targets, however there was also significant inhibition of off-target proteins including pERK and pJNK suggesting apoptosis caused by drug toxicity. However, when used in combination with paclitaxel in HuH7 and SNU423 cells, LCL161 had significant antiproliferative effects at doses as low as 2μM and this was independent of Bcl-2 expression. Thus, LCL161 may be a useful agent in combination with paclitaxel to treat liver tumours.

Classical and innovative insulin sensitizing drugs for the prevention and treatment of NAFLD

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disorder worldwide, comprises a spectrum of conditions ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) and cirrhosis. NASH is associated with an increased risk of hepatocellular carcinoma (HCC) and cardiometabolic disease. Insulin resistance (IR) is the underlying pathogenic mechanism for NAFLD, the presence of which in turn, is a strong predictor for the development of metabolic disorders. Hence, therapy of NAFLD with insulin-sensitizing drugs (ISDs) should ideally improve the key hepatic histological changes (steatosis, inflammation and fibrosis), but should also reduce cardiometabolic and cancer risk.

OBJECTIVES

In this review, the rationale for the use of ISDs and the evidence for their efficacy are detailed. In particular, the mechanism of action, potential for use, limitations and untoward effects of metformin and thiazolidinediones are systematically reviewed. Further, we discuss novel ISDs that may have potential clinical utility in NAFLD.

RESULTS AND CONCLUSION

Despite the theoretical prediction that ISDs might have beneficial effects on disease outcomes, evidence that ISDs are able to alter the natural history of NAFLD are presently not available. The exploration of novel strategies exploiting "nonconventional" ISDs is encouraged.

Multifaceted roles of adiponectin in cancer

Obesity is linked to increased cancer risk. Pathological expansion of adipose tissue impacts adipocyte function and secretion of hormonal factors regulating tissue homeostasis and metabolism. Adiponectin is an adipocyte-secreted, circulating hormone with pleiotropic functions in lipid and glucose metabolism, and beneficial roles in cardiovascular functions and inflammation. In obesity, decreased Adiponectin plasma levels correlate with tumor development and progression. The association of Adiponectin with potential tumor-limiting functions has raised significant interest in exploring this adipokine as a target for cancer-diagnostic and therapeutic applications. Recent studies, however, also implicate Adiponectin in supporting malignancy. This review highlights the evidence that links Adiponectin signaling to either cancer-protective or cancer-supporting functions. In this context, we discuss Adiponectin interactions with its receptors and associated signaling pathways. Despite significant advances in understanding Adiponectin functions and signaling mechanisms, its role in cancer remains multifaceted and subject to controversy.

Tumoricidal effects of the JAK inhibitor Ruxolitinib (INC424) on hepatocellular carcinoma in vitro

Hepatocellular carcinoma (HCC) is an aggressive tumour with limited treatment options. The Janus kinase/signal transducers and activators of transcription (JAK/STAT) signalling pathway plays a key role in promoting tumorigenesis in HCC. Recently a new JAK inhibitor Ruxolitinib (INC424) has been developed by Novartis Pharmaceuticals and it shows high affinity for JAK signalling with very low affinity for non-JAK targets. Clinical trials have demonstrated that Ruxolitinib has good therapeutic efficacy for the treatment of myelofibrosis and is currently FDA approved for the treatment of advanced stages of this disease. Our study tested the effects of Ruxolitinib on HCC tumorigenesis in vitro. Ruxolitinib effectively inhibited JAK/STAT signalling in HCC cells with a significant reduction in the expression of JAK downstream targets pSTAT1 and pSTAT3. Ruxolitinib also caused a marked reduction in the proliferation and colony formation of HCC cells. The antiproliferative effect of Ruxolitinib on HCC cells is unlikely due to off-target effects with no inhibition of key regulators of other cell proliferative pathways. To our knowledge this study is the first to report on the effect of Ruxolitinib on liver cancer cells.

ROCK1 inhibition promotes the self-renewal of a novel mouse mammary cancer stem cell

The differentiation of stem-like tumor cells may contribute to the cellular heterogeneity of breast cancers. We report the propagation of highly enriched mouse mammary cancer stem cells that retain the potential to differentiate both in vivo and in culture and their use to identify chemical compounds that influence both self-renewal and differentiation. We identify epithelial tumor-initiating cells (ETICs) that express lineage markers of both basal and luminal mammary cell lineages and retain the potential, from even single cells, to generate heterogeneous tumors similar to the tumor of origin. ETICs can progress through a Rho-associated coiled-coil containing protein kinase 1 dependent, epithelial to mesenchymal transition to generate mesenchymal tumor-initiating cells capable of initiating tumors of limited heterogeneity. The propagation of ETICs may allow for the identification of new therapeutic compounds that may inhibit or prevent progression of some types of breast cancer.

Hepatic fat loss in advanced nonalcoholic steatohepatitis: are alterations in serum adiponectin the cause?

Advanced liver fibrosis in nonalcoholic steatohepatitis (NASH) is often accompanied by a reduction in hepatic fat to the point of complete fat loss (burnt-out NASH), but the mechanisms behind this phenomenon have not been elucidated. Adiponectin is raised in cirrhosis of any cause and has potent antisteatotic activity. In this study we examined 65 patients with advanced biopsy-proven NASH (fibrosis stage 3-4) and 54 with mild disease (fibrosis stage 0-1) to determine if disappearance of steatosis correlated with changes in serum adiponectin. All patents had fasting blood tests and anthropometric measures at the time of liver biopsy. Liver fat was accurately quantitated by morphometry. Serum adiponectin was measured by immunoassay. When compared to those with early disease, patients with advanced NASH were more insulin-resistant, viscerally obese, and older, but there was no difference in liver fat content or adiponectin levels. Adiponectin had a significant negative correlation with liver fat percentage in the whole cohort (r = -0.28, P < 0.01), driven by patients with advanced NASH (r = -0.40, P < 0.01). In advanced NASH, for each 4 μg/L increase in adiponectin there was an odds ratio OR of 2.0 (95% confidence interval [CI]: 1.3-3.0, P < 0.01) for a 5% reduction in hepatic fat. Adiponectin was highly and significantly associated with almost complete hepatic fat loss or burnt-out NASH (12.1 versus 7.4 μg/L, P = 0.001) on multivariate analysis. A relationship between adiponectin, bile acids, and adipocyte fexaramine activation was demonstrated in vivo and in vitro, suggestive of hepatocyte-adipocyte crosstalk.

CONCLUSION

Serum adiponectin levels in advanced NASH are independently associated with hepatic fat loss. Adiponectin may in part be responsible for the paradox of burnt-out NASH. (HEPATOLOGY 2012).

Role of adiponectin and its receptors in cancer

Adiponectin (APN), a novel hormone/cytokine derived from adipocyte tissue, is involved in various physiological functions. Genetics, nutrition, and adiposity are factors contributing to circulating plasma concentrations of APN. Clinical correlation studies have shown that lower levels of serum APN are associated with increased malignancy of various cancers, such as breast and colon cancers, suggesting that APN has a role in tumorigenesis. APN affects insulin resistance, thus further influencing cancer development. Tumor cells may express receptors for APN. Cellular signaling is the mechanism by which APN exerts its host-protective responses. These factors suggest that serum APN levels and downstream signaling targets of APN may serve as potential diagnostic markers for malignancies. Further research is necessary to clarify the exact role of APN in cancer diagnosis and therapy.

Animal models of nonalcoholic fatty liver disease

In 1980, Ludwig and colleagues described a series of patients with liver histology characterized by the accumulation of fat and the presence of hepatic necroinflammation in the absence of a history of excessive alcohol consumption. They coined the term nonalcoholic steatohepatitis (NASH), which today is regarded as one of the most common causes of liver disease in affluent countries. NASH is a subset of a larger spectrum of diseases termed fatty liver disease (including alcoholic and nonalcoholic fatty liver disease; AFLD and NAFLD, respectively). NAFLD and NASH are linked to visceral adiposity, insulin resistance, dyslipidemia and type 2 diabetes, and are increasing due to the prevalence of the metabolic syndrome. In this context, research has been undertaken using animals to model human steatosis and NAFLD to NASH disease progression. This Review discusses the prevalent dietary and inflammation-based genetic animal models described in recent years.

Abstract 4217: Contrasting mouse mammary cancer stem cells before and after EMT

We isolated mouse mammary cancer stem cells from a Wnt1-driven tumor model of aggressive breast cancer. These tumorigenic progenitor cells show expression of marker of both luminal (keratin 8) and myoepithelial (keratin 14) cells, express CD24, CD29 and CD49f surface markers. The K8+, K14+ double positive cells can be greatly enriched from less than 5% of the tumor to greater than 60% of the cultured cells in a 3D-culture system under hypoxic conditions. Transplantation of these cultured cells generated tumors with the differentiated morphology of the tumor of origin from a few as a single cell. In a 2D culture setting under normoxic conditions, double positive cells generate single positive differentiated derivates. Serial transplantation of the tumor generated from the cultured cells resulted in increasing growth rate reflected by reduced generation time from 52 days to 21 days after four passages. The fast-growing tumors were strongly positive for vimentin, negative for K14 and few cells expressed K8. Analysis of the cells in 2D revealed a fibroblast-like growth pattern. When grown in 3D, the cells do not form spheroids but rather grow in an invasive pattern in Matrigel. This tumor line has undergone an epithelial to mesenchymal transition (EMT). These cells also generate tumors from single cell transplants but do not generate heterogeneous tumors.

In summary, we have succeeded in cultivating a mammary cancer stem cell, demonstrated its self renewal capacity and potential for differentiation both in vivo and in culture. Furthermore, we have isolated an EMT derivative that is tumorgenic but appears to have lost the potential for self limiting differentiation. This demonstrates that tumorigenic cells with severely restricted capacity for differentiation can be derived from a cancer stem cell. Potential therapies based on the potential of cancer stem cells to differentiate may need to be applied at very early stages of the development of breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4217.

Angiogenic acceleration of Neu induced mammary tumor progression and metastasis

The Neu (ErbB2, HER2) member of the epidermal growth factor receptor family is implicated in many human breast cancers. We have tested the importance of increased angiogenic signaling in the NeuYD [mouse mammary tumor virus (MMTV)-Neu(ndl)-YD5] mammary tumor model. Transgenic mice expressing vascular endothelial growth factor (VEGF)(164) from the MMTV promoter were generated. These mice expressed VEGF(164) RNA and protein at 20- to 40-fold higher levels throughout mammary gland development but exhibited normal mammary gland development and function. However, in combination with the NeuYD oncogene, VEGF(164) expression resulted in increased vascularization of hyperplastic mammary epithelium and dramatic acceleration of tumor appearance from 111 to 51 days. Gene expression profiling also indicated that the VEGF-accelerated tumors were substantially more vascularized and less hypoxic. The preferential vascularization of early hyperplastic portions of mammary epithelia in NeuYD;MMTV-VEGF animals was associated with NeuYD RNA expression, disorganization of the tight junctions, and overlapping transgenic VEGF expression. NeuYD;MMTV-VEGF(164) bigenic, tumor-bearing animals resulted in an average of 10 tumor cell colonies/lung lodged within vascular spaces. No similar lung colonies were found in control NeuYD mice with similar tumor burdens. Overall, these results demonstrate the angiogenic restriction of early hyperplastic mammary lesions. They also reinforce in vivo the importance of activated Neu in causing disorganization of mammary luminal epithelial cell junctions and provide support for an invasion-independent mechanism of metastasis.

CD44 expression and regulation during mammary gland development and function

The CD44v6 epitope has been widely reported to be expressed in human mammary carcinomas, yet its prognostic significance is controversial and its function in mammary tumors and mammary glands is unknown. To begin to resolve these issues, we analysed in detail the normal postnatal expression patterns and regulation of the CD44v6 epitope in murine mammary glands. We demonstrate that significant CD44v6 epitope expression is first seen during puberty, and that after puberty CD44v6 epitope expression follows the estrous cycle. CD44v6 epitope expression is observed in the myoepithelium and also less widely in luminal epithelial cells. During lactation, CD44v6 epitope expression is turned off and reappears during involution. The CD44 variant isoform bearing the v6 epitope is CD44v1-v10. Using HC11, a mammary epithelial cell line with stem cell characteristics, and facilitated by the cloning of the murine CD44 promoter, we show that growth factors and hormones which regulate ductal growth and differentiation modulate CD44 transcription. Together our data suggest that the CD44v6 epitope is expressed in mammary epithelial stems cells and in lineages derived from these cells, and that CD44v6 expression is regulated in part by hormones and growth factors such as IGF-1 and EGF which regulate the growth and differentiation of the mammary epithelium. The function of these same growth factors and hormones is often perturbed in mammary carcinomas, and we suggest that CD44v6 expression in tumors reflects this perturbation. We conclude that the expression of the CD44v6 epitope observed in some mammary tumors reflects the stem cell origin of breast tumors, and that whether or not the CD44v6 epitope is expressed in a mammary tumor is determined by the differentiation status of the tumor cells.