Genomic modeling of tumor onset and progression in a mouse model of aggressive human liver cancer

The role of natural killer cell activity as a milestone in oncologic outcome after curative resection of pancreatic adenocarcinoma

BACKGROUND

The objective of this study was to investigate differences in oncologic outcomes of patients with pancreas cancer according to natural killer cell activity (NKA).

METHODS

A total of 118 patients who underwent curative resection for primary pancreas cancer in two hospitals were analyzed. NKA change pattern was analyzed. Difference in disease-free survival or overall survival was investigated by dividing subjects into two groups based on a normal NKA value for each period.

RESULTS

NKA value decreased after surgery compared to the value measured at admission. It recovered to normal levels at 5 weeks postoperatively. The low NKA (less than 250 pg/mL) group at admission, 5 weeks postoperatively, and before 1st chemotherapy had significantly poorer disease-free survival than the normal NKA group. In multivariate analysis, NKA values less than 250 pg/mL at admission (odds ratio = 2.267, p = 0.023) and N 1 or N2 category (odds ratio = 2.478, p = 0.023) were significant factors associated with recurrence after curative resection.

CONCLUSIONS

NKA in patients with pancreatic cancer demonstrated noticeable changes after surgery. Immunologically predisposed patients with a low NKA value had a high risk of early recurrence and a poor prognosis, although pancreatic cancer was surgically removed.

Risk-stratified approach by aMAP score for community population infected with hepatitis B and C to guide subsequent liver cancer screening practice: A cohort study with 10-year follow-up

The aim of this study was to determine whether the age-Male-ALBI-Platelet (aMAP) score is applicable in community settings and how to maximise its role in risk stratification. A total of thousand five hundred and three participants had an aMAP score calculated at baseline and were followed up for about 10 years to obtain information on liver cancer incidence and death. After assessing the ability of aMAP to predict liver cancer incidence and death in terms of differentiation and calibration, the optimal risk stratification threshold of the aMAP score was explored, based on absolute and relative risks. The aMAP score achieved higher area under curves (AUCs) (almost all above 0.8) within 10 years and exhibited a better calibration within 5 years. Regarding absolute risk, the risk of incidence of and death from liver cancer showed a rapid increase after an aMAP score of 55. The cumulative incidence (5-year: 8.3% vs. 1.3% and 10-year: 20.9% vs. 3.6%) and mortality (5-year: 6.7% vs. 1.1% and 10-year: 17.5% vs. 3.1%) of liver cancer in individuals with an aMAP score of ≥55 were significantly higher than in those with a score of <55 (Grey's test p  < .001). In terms of relative risk, the risk of death from liver cancer surpassed that from other causes after an aMAP score of ≥55 [HR = 1.38(1.02-1.87)]. Notably, the two types of death risk had opposite trends between the subpopulation with an aMAP score of ≥55 and < 55. To conclude, this study showed the value of the aMAP score in community settings and recommends using 55 as a new risk stratification threshold to guide subsequent liver cancer screening.

Non-coding RNAs in hepatocellular carcinoma: Insights into regulatory mechanisms, clinical significance, and therapeutic potential

Hepatocellular carcinoma (HCC) is a complex and heterogeneous malignancy with high incidence and poor prognosis. In addition, owing to the lack of diagnostic and prognostic markers, current multimodal treatment options fail to achieve satisfactory outcomes. Tumor immune microenvironment (TIME), angiogenesis, epithelial-mesenchymal transition (EMT), invasion, metastasis, metabolism, and drug resistance are important factors influencing tumor development and therapy. The intercellular communication of these important processes is mediated by a variety of bioactive molecules to regulate pathophysiological processes in recipient cells. Among these bioactive molecules, non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), account for a large part of the human transcriptome, and their dysregulation affects the progression of HCC. The purpose of this review is to evaluate the potential regulatory mechanisms of ncRNAs in HCC, summarize novel biomarkers from somatic fluids (plasma/serum/urine), and explore the potential of some small-molecule modulators as drugs. Thus, through this review, we aim to contribute to a deeper understanding of the regulatory mechanisms, early diagnosis, prognosis, and precise treatment of HCC.

NK cell immunometabolism as target for liver cancer therapy

Natural killer (NK) cells are being used effectively as a potential candidate in tumor immunotherapy. However, the migration and transport of NK cells to solid tumors is inadequate. NK cell dysfunction, tumor invasiveness, and metastasis are associated with altered metabolism of NK cells in the liver cancer microenvironment. However, in liver cancers, metabolic impairment of NK cells is still not understood fully. Evidence from various sources has shown that the interaction of NK cell's immune checkpoints with its metabolic checkpoints is responsible for the regulation of the development and function of these cells. How immune checkpoints contribute to metabolic programming is still not fully understood, and how this can be beneficial needs a better understanding, but they are emerging to be incredibly compelling to rebuilding the function of NK cells in the tumor. It is expected to represent a potential aim that focuses on improving the efficacy of therapies based on NK cells for treating liver cancer. Here, the recent advancements made to understand the NK cell's metabolic reprogramming in liver cancer have been summarized, along with the possible interplay between the immune and the metabolic checkpoints in NK cell function. Finally, an overview of some potential metabolic-related targets that can be used for liver cancer therapy treatment has been presented.

Defective DNAM-1 Dependent Cytotoxicity in Hepatocellular Carcinoma-Infiltrating NK Cells

Simple Summary

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer and the fourth leading cause of cancer-related deaths worldwide. Although therapeutic options have improved in the last few years, mortality remains disturbingly high. The key role of innate immunity, particularly of natural killer (NK) cells, in tumor surveillance and response is well established. The anti-tumor NK cell activity is modulated by interactions between NK cells activating or inhibiting receptors and their ligands, expressed or released by tumor cells. Alterations in these networks lead to inadequate NK cell responses and a lack of cancer control. In our study, we focus on NK cells activating receptor DNAM-1 and its ligand CD155, expressed in HCC cells. We provide evidence of impaired NK cytotoxic function as a result of altered receptor/ligand axis. We conclude that this may represent a tumor escape mechanism and a possible target for new immunotherapeutic approaches to HCC treatment.

Abstract

Background: Natural killer (NK) cells play a key role in immune surveillance and response to tumors, their function regulated by NK cell receptors and their ligands. The DNAM-1 activating receptor recognizes the CD155 molecule expressed in several tumor cells, such as hepatocellular carcinoma (HCC). This study aims to investigate the role of the DNAM-1/CD155 axis in mediating the NK cell response in patients with HCC. Methods: Soluble CD155 was measured by ELISA. CD155 expression was sought in HCC cells by immunohistochemistry, qPCR, and flow cytometry. DNAM-1 modulation in NK cells was evaluated in transwell experiments and by a siRNA-mediated knockdown. NK cell functions were examined by direct DNAM-1 triggering. Results: sCD155 was increased in sera from HCC patients and correlated with the parameters of an advanced disease. The expression of CD155 in HCC showed a positive trend toward better overall survival. DNAM-1 downmodulation was induced by CD155-expressing HCC cells, in agreement with lower DNAM-1 expressions in tumor-infiltrating NK (NK-TIL) cells. DNAM-1-mediated cytotoxicity was defective both in circulating NK cells and in NK-TIL of HCC patients. Conclusions: We provide evidence of alterations in the DNAM-1/CD155 axis in HCC, suggesting a possible mechanism of tumor resistance to innate immune surveillance.

Identification of chromatin organization-related gene signature for hepatocellular carcinoma prognosis and predicting immunotherapy response

BACKGROUND

Chromatin organization is associated with tumorigenesis; however, information on its role in hepatocellular carcinoma (HCC) is limited. Moreover, although immune checkpoint inhibitors (ICIs) have proven effective against HCC, the optimal index remains unknown. In this study, we aimed to construct a chromatin organization-related gene signature (CORGS) for prognosis and predicting response to ICIs in HCC.

METHODS

HCC-related data were obtained from The Cancer Genome Atlas (TCGA) and International Cancer Genome Construction (ICGC). Chromatin organization-related genes (CORGs) were retrieved from Gene Set Enrichment Analysis. Differentially expressed genes (DEGs) and prognostic genes were then applied to select candidate genes using advanced statistical methods, including learning vector quantization, random forest, and lasso regression. Subsequently, the CORGS was established based on chromatin organization-related hub genes using multivariate Cox regression analysis, evaluated with Kaplan-Meier survival curves, and verified in 64 samples of HCC patients from Fujian Provincial Hospital (FPH) via quantitative PCR. Subsequently, functional enrichment analysis, tumor somatic mutation analysis, and tumor immune analysis were performed to evaluate the potential value of the CORGS.

RESULTS

Three hundred and thirty-nine CORGs were identified as DEGs, and 186 were associated with HCC prognosis (all P < 0.05). Four intersection genes were selected to establish the CORGS using TCGA cohort, which was found to serve as an independent risk factor for HCC patients. CORGS was then validated in an ICGC cohort. In addition, CORGS reliability was verified in 64 samples from HCC patients and 26 adjacent non-tumorous tissues, collected from the FPH. The CORGS was also associated with tumor immune microenvironment characteristics and ICI response. Moreover, data from "IMvigor 210" revealed that more patients in the low CORGS group responded to atezolizumab compared to high CORGS patients (P < 0.05). Finally, a nomogram of tumor characteristics and the CORGS was established, exhibiting superior discrimination and calibration compared to the current staging system and published models.

CONCLUSIONS

CORGS may serve as an effective predictive biomarker for HCC as well as a potential index of the tumor immune microenvironment and ICI response.

Construction and Comprehensive Analysis of ceRNA Networks and Tumor-Infiltrating Immune Cells in Hepatocellular Carcinoma With Vascular Invasion

Background: Hepatocellular carcinoma (HCC) is a common malignant cancer. Metastasis plays a critical role in tumor progression, and vascular invasion is considered one of the most crucial factors for HCC metastasis. However, comprehensive analysis focusing on competitive endogenous RNA (ceRNA) and immune infiltration in the vascular invasion of HCC is lacking.

Methods: The gene expression profiles of 321 samples, including 210 primary HCC cases and 111 HCC cases with vascular invasion, were downloaded from The Cancer Genome Atlas-Liver Hepatocellular Carcinoma project, and used in identifying significant differentially expressed lncRNAs (DElncRNAs), miRNAs (DEmiRNAs), and mRNAs (DEmRNAs). The RNAs associated with vascular invasion were used in constructing a ceRNA network. A multigene-based risk signature was constructed using the least absolute shrinkage and selection operator algorithm. We detected the fractions of 28 immune cell types in HCC through single-sample gene set enrichment analysis (ssGSEA). Finally, the relationship between the ceRNA network and immune cells was determined through correlation analysis and used in clarifying the potential mechanism involved in vascular invasion.

Results: Overall, 413 DElncRNAs, 27 DEmiRNAs, and 397 DEmRNAs were recognized in HCC. A specific ceRNA network based on the interaction among 3 lncRNA–miRNA pairs and 24 miRNA–mRNA pairs were established. A ceRNA-based prognostic signature was constructed and used in dividing samples into high- and low-risk subgroups. The signature showed significant efficacy; its 3- and 5-year areas under the receiver operating characteristic curves were 0.712 and 0.653, respectively. ceRNA and ssGSEA integration analysis demonstrated that PART1 (p = 0, R = −0.33) and CDK5R2 (p = 0.01, R = −0.15) were negatively correlated to natural killer cells.

Conclusion: This study demonstrated that vascular invasion in HCC might be related to PART1, and its role in regulating CDK5R2 and NK cells. A nomogram was developed to predict the prognosis of patients with HCC and demonstrated the value of the ceRNA network and tumor-infiltrating immune cells value in improving personalized management.

Down-regulation of PR/SET domain 10 underlies natural killer cell dysfunction in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the world's leading cause of tumor-related mortalities. Natural killer (NK) cells play a critical role at the first immunological defense line against HCC initiation and progression. NK cell dysfunction is therefore an important mechanism for immune evasion of HCC cells. In the present study using a murine HCC model, we revealed the down-regulation of PR/SET Domain 10 (PRDM10) in hepatic NK cells that were phenotypically and functionally exhausted. PRDM10 silencing diminished the expression of natural killer group 2 member D (NKG2D) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), augmented T cell immunoglobulin and ITIM domain (TIGIT) expression, and decreased the expression of interferon (IFN)-γ, perforin and granzyme B in normal hepatic NK cells in vitro. Consistently, PRDM10-deficient NK cells exhibited impaired cytotoxicity on target cells. In contrast, PRDM10 over-expression promoted NKG2D and Fas ligand (FasL) expression, reduced CD96 expression and enhanced transcripts of IFN-γ, perforin and granzyme B in NK cells in vivo. Moreover, PRDM10 silencing and PRDM10 over-expression down-regulated and up-regulated Eomesodermin (Eomes) expression, respectively. In summary, this study reveals PRDM10 down-regulation as a novel mechanism underlying NK cell dysfunction and identifies PRDM10 as a supporting factor of NK cell function.

A Novel Orthotopic Liver Cancer Model for Creating a Human-like Tumor Microenvironment

Simple Summary

Hepatocellular carcinoma is the most common form of liver cancer. The lack of models that resemble actual tumor development in patients, limits the research to improve the diagnosis rate and develop new treatments. This study describes a novel mouse model that involves organoid formation and an implantation technique. This mouse model shares human genetic profiles and factors around the tumor, resembling the actual tumor development in patients. We demonstrate the roles of different cell types around the tumor, in promoting tumor growth, using this model. This model will be useful to understand the tumor developmental process, drug testing, diagnosis, prognosis, and treatment development.

Abstract

Hepatocellular carcinoma (HCC) is the most common form of liver cancer. This study aims to develop a new method to generate an HCC mouse model with a human tumor, and imitates the tumor microenvironment (TME) of clinical patients. Here, we have generated functional, three-dimensional sheet-like human HCC organoids in vitro, using luciferase-expressing Huh7 cells, human iPSC-derived endothelial cells (iPSC-EC), and human iPSC-derived mesenchymal cells (iPSC-MC). The HCC organoid, capped by ultra-purified alginate gel, was implanted into the disrupted liver using an ultrasonic homogenizer in the immune-deficient mouse, which improved the survival and engraftment rate. We successfully introduced different types of controllable TME into the model and studied the roles of TME in HCC tumor growth. The results showed the role of the iPSC-EC and iPSC-MC combination, especially the iPSC-MC, in promoting HCC growth. We also demonstrated that liver fibrosis could promote HCC tumor growth. However, it is not affected by non-alcoholic fatty liver disease. Furthermore, the implantation of HCC organoids to humanized mice demonstrated that the immune response is important in slowing down tumor growth at an early stage. In conclusion, we have created an HCC model that is useful for studying HCC development and developing new treatment options in the future.

Natural killer cell activity is a risk factor for the recurrence risk after curative treatment of hepatocellular carcinoma

Background

Natural killer (NK) cells have been known to contribute to surveillance and control of hepatocellular carcinoma (HCC). However, the association of NK cell activity with stage and recurrence risk of HCC have not been fully evaluated.

Methods

Untreated patients with newly diagnosed HCC were prospectively enrolled. Peripheral blood mononuclear cells were isolated at the time of diagnosis. Patients who had undergone surgery or radiofrequency ablation were classified as the curative treatment group, and their blood samples were collected again at 1 month after treatment.

Results

A total of 80 patients with HCC were enrolled. The mean age was 62.5 years. At baseline, interferon (IFN)-γ producing NK cell proportion was significantly lower in patients with Barcelona clinic liver cancer (BCLC) stage B, C, or D than in those with BCLC stage 0 (42.9% vs. 56.8%, P = 0.045). Among all patients, 56 patients had undergone curative treatment, and 42 patients re-visited at 1 month after curative treatment. There was no significant change in total NK cell and IFN-γ producing NK cell proportion from baseline to 1 month after treatment (all P > 0.05). During a median follow-up of 12.4 months, HCC recurred in 14 patients (33.3%). When patients were classified according to the IFN-γ producing NK cell proportion (group 1, ≥ 45%; and group 2, < 45%), HCC recurrence rate did not differ according to the IFN-γ producing NK cell proportion at baseline (log-rank test, P = 0.835). However, patients with < 45% IFN-γ producing NK cell proportion at 1 month after treatment had a significantly higher HCC recurrence rate than patients with that of ≥ 45% (log-rank test, P < 0.001). Multivariate analysis revealed that BCLC stage B (hazard ratio [HR] = 3.412, P = 0.045) and < 45% IFN-γ producing NK cell proportion at 1 month after treatment (HR = 6.934, P = 0.001) independently predicted an increased risk of HCC recurrence.

Conclusions

Decreased NK cell activity is significantly associated with the advanced stage of HCC, and the increased recurrence risk of HCC after curative treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01833-2.

Combination of NK-based immunotherapy and sorafenib against hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most frequent malignancy of the liver, which is considered the fourth leading cause of cancer-related death in the United States. Liver transplant and surgical resection are curative treatments for HCC, but only 10-15% of HCC patients are eligible candidates. The FDA-approved sorafenib is a multi-kinase inhibitor systemic therapy for advanced HCC that extends the overall survival by over 3 months when compared with placebo. Adoptive transfer of Natural Killer (NK) cells holds great promise for clinical cancer treatment. However, only limited clinical benefit has been achieved in cancer patients. Therefore, there is currently considerable interest in development of the combination of sorafenib and NK cells for the treatment of HCC patients. However, the mechanism of how sorafenib affects the function of NK cells remains to be comprehensively clarified. In this paper, we will discuss NK cell-based immunotherapies that are currently under preclinical and clinical investigation and its potential combination with sorafenib for improving the survival of HCC patients.

Immunological Mechanisms for Hepatocellular Carcinoma Risk after Direct-Acting Antiviral Treatment of Hepatitis C Virus Infection

Direct-acting antiviral agents (DAAs) that allow for rapid clearance of hepatitis C virus (HCV) may evoke immunological changes. Some cases of rapid de novo hepatocellular carcinoma (HCC) development or early recurrence of HCC after DAA treatment have been reported. During chronic HCV infection, natural killer (NK) cells exhibited a deviant functional phenotype with decreased production of antiviral cytokines and increased cytotoxicity; however, DAA treatment rapidly decreased their cytotoxic function. Effective DAA therapy also suppressed the intrahepatic activation of macrophages/monocytes. This was followed by a decrease in mucosal-associated invariant T (MAIT) cell cytotoxicity without normalization of cytokine production. Rapid changes in the phenotypes of NK and MAIT cells after DAA treatment may attenuate the cytotoxicity of these cells against cancer cells. Moreover, DAA treatment did not normalize the increased frequencies of regulatory T cells even after clearance of HCV infection. Thus, the persistently increased frequency of regulatory T cells may contribute to a local immunosuppressive milieu and hamper the clearance of cancer cells. This review will focus on recent studies describing the changes in innate and adaptive immune responses after DAA treatment in patients with chronic HCV infection in the context of de novo occurrence or recurrence of HCC.

An Anti-MICA/B Antibody and IL-15 Rescue Altered NKG2D-Dependent NK Cell Responses in Hepatocellular Carcinoma

Natural killer (NK) cells play a pivotal role in cancer immune surveillance, and activating the receptor/ligand interaction may contribute to control the development and evolution of hepatocellular carcinoma (HCC). We investigated the role of the natural killer group 2 member D (NKG2D) activating receptor and its ligand, the major histocompatibility complex class I chain-related protein A and B (MICA/B) in patients with cirrhosis and HCC subjected to surgical resection, patients with cirrhosis and no HCC, and healthy donors (HD). The NKG2D-mediated function was determined in peripheral blood (PB), in tumor-infiltrating lymphocytes (NK-TIL), and in matched surrounding liver tissue (NK-LIL). A group of patients treated with sorafenib because of clinically advanced HCC was also studied. A humanized anti-MICA/B monoclonal antibody (mAb) was used in in vitro experiments to examine NK cell-mediated antibody-dependent cellular cytotoxicity. Serum concentrations of soluble MICA/B were evaluated by ELISA. IL-15 stimulation increased NKG2D-dependent activity which, however, remained dysfunctional in PB NK cells from HCC patients, in line with the reduced NKG2D expression on NK cells. NK-TIL showed a lower degranulation ability than NK-LIL, which was restored by IL-15 stimulation. Moreover, in vitro IL-15 stimulation enhanced degranulation and interferon-γ production by PB NK from patients at month one of treatment with sorafenib. Anti-MICA/B mAb associated with IL-15 was able to induce PB NK cytotoxicity for primary HCC cells in HD and patients with HCC, who also showed NK-TIL degranulation for autologous primary HCC cells. Our findings highlight the key role of the NKG2D-MICA/B axis in the regulation of NK cell responses in HCC and provide evidence in support of a potentially important role of anti-MICA/B mAb and IL-15 stimulation in HCC immunotherapy.

Comparative study of alterations in phospholipid profiles upon liver cancer in humans and mice

Comparative studies of molecular alterations upon cancer between mice and humans are of great importance in order to determine the relevance of research involving mouse cancer models to the development of diagnostic and therapeutic approaches in clinical practice as well as for the mechanistic studies of pathology in humans. Herein, using molecular fingerprinting by internal extractive electrospray ionization mass spectrometry (iEESI-MS), we identified 50 differential signals in mouse liver tissue and 62 differential signals in human liver tissue that undergo significant intensity alterations (variable importance in the project (VIP) >1.0) upon liver cancer, out of which only 27 were common in both mouse and human tissues. Out of the 27 common differential signals, six types of phospholipids were also identified to undergo significant alterations in human serum upon liver cancer, including PC(34:2), PC(36:4), PC(38:6), PC(36:2), PC(38:4) and PC(42:9). Statistical analysis of the relative intensity distribution of these six identified phospholipids in serum allowed confident determination of liver cancer in humans (sensitivity 91.0%, specificity 88.0%, and accuracy 90.0%). Our results indicate that, despite the significant difference in the overall alterations of phospholipid profiles upon liver cancer between humans and mice, the six identified 'core' differential phospholipids of liver cancer found in the liver tissues of both humans and mice as well as in human serum show high potential as a minimal panel for the rapid targeted diagnosis of liver cancer with high accuracy, sensitivity and specificity using direct mass spectrometry (MS) analysis.

Natural Killer Cell Responses in Hepatocellular Carcinoma: Implications for Novel Immunotherapeutic Approaches

Hepatocellular carcinoma (HCC) still represents a significant complication of chronic liver disease, particularly when cirrhosis ensues. Current treatment options include surgery, loco-regional procedures and chemotherapy, according to specific clinical practice guidelines. Immunotherapy with check-point inhibitors, aimed at rescuing T-cells from exhaustion, has been applied as second-line therapy with limited and variable success. Natural killer (NK) cells are an essential component of innate immunity against cancer and changes in phenotype and function have been described in patients with HCC, who also show perturbations of NK activating receptor/ligand axes. Here we discuss the current status of NK cell treatment of HCC on the basis of existing evidence and ongoing clinical trials on adoptive transfer of autologous or allogeneic NK cells ex vivo or after activation with cytokines such as IL-15 and use of antibodies to target cell-expressed molecules to promote antibody-dependent cellular cytotoxicity (ADCC). To this end, bi-, tri- and tetra-specific killer cell engagers are being devised to improve NK cell recognition of tumor cells, circumventing tumor immune escape and efficiently targeting NK cells to tumors. Moreover, the exciting technique of chimeric antigen receptor (CAR)-engineered NK cells offers unique opportunities to create CAR-NK with multiple specificities along the experience gained with CAR-T cells with potentially less adverse effects.

Animal Models of Hepatocellular Carcinoma: The Role of Immune System and Tumor Microenvironment

Hepatocellular carcinoma (HCC) is the most common type of liver cancer in adults and has one of the highest mortality rates of solid cancers. Ninety percent of HCCs are associated with liver fibrosis or cirrhosis developed from chronic liver injuries. The immune system of the liver contributes to the severity of the necrotic-inflammatory tissue damage, the establishment of fibrosis and cirrhosis, and the disease progression towards HCC. Immunotherapies have emerged as an exciting strategy for HCC treatment, but their effect is limited, and an extensive translation research is urgently needed to enhance anti-tumor efficacy and clinical success. Establishing HCC animal models that are analogous to human disease settings, i.e., mimicking the tumor microenvironment of HCC, is extremely challenging. Hence, this review discusses different animal models of HCC by summarizing their advantages and their limits with a specific focus on the role of the immune system and tumor microenvironment.

Expression of long non-coding RNA ANRIL predicts a poor prognosis in intrahepatic cholangiocarcinoma

BACKGROUND

Intrahepatic cholangiocarcinoma (iCCA) is a deadly cancer worldwide associated with an increased incidence, limited therapeutic options and absence of reliable prognostic biomarkers. Long non-coding RNAs (lncRNA) emerge as relevant biomarkers in cancer being associated with tumor progression. However, lncRNA have been poorly investigated in iCCA.

AIM

To identify lncRNA significantly associated with the survival of patients with iCCA after tumor resection for curative intent.

METHODS

Gene expression profiling and Q-RT-PCR were performed from a cohort of 39 clinically well-annotated iCCA. Univariate Cox proportional hazards model with Wald Statistic was used to identify lncRNA significantly associated with overall (OS) and/or disease-free (DFS) survival.

RESULTS

A signature made of 9 lncRNA was identified to be significantly (P < 0.05) associated with OS and DFS, including 4 lncRNA (lnc-CDK9-1, XLOC_l2_009441, CDKN2B-AS1, HOXC13-AS) highly expressed in poor prognosis iCCA and 5 lncRNA (lnc-CCHCR1-1, lnc-AF131215.3.1, lnc-CBLB-5, COL18A1-AS2, lnc-RELL2-1) highly expressed in better prognosis iCCA. We further validated CDKN2B-AS1 (ANRIL) as a poor prognosis biomarker, not only in iCCA, but also in hepatocellular carcinoma, kidney renal clear cell carcinoma and uterine corpus endometrial carcinoma.

CONCLUSIONS

We report a prognosis lncRNA signature in iCCA and the clinical relevance of CDKN2B-AS1 (ANRIL) overexpression in several cancers.

Hepatic Natural Killer Cells: Organ-Specific Sentinels of Liver Immune Homeostasis and Physiopathology

The liver is considered a preferential tissue for NK cells residency. In humans, almost 50% of all intrahepatic lymphocytes are NK cells that are strongly imprinted in a liver-specific manner and show a broad spectrum of cellular heterogeneity. Hepatic NK (he-NK) cells play key roles in tuning liver immune response in both physiological and pathological conditions. Therefore, there is a pressing need to comprehensively characterize human he-NK cells to better understand the related mechanisms regulating their effector-functions within the dynamic balance between immune-tolerance and immune-surveillance. This is of particular relevance in the liver that is the only solid organ whose parenchyma is constantly challenged on daily basis by millions of foreign antigens drained from the gut. Therefore, the present review summarizes our current knowledge on he-NK cells in the light of the latest discoveries in the field of NK cell biology and clinical relevance.

Activity of IL-12/15/18 primed natural killer cells against hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is common, but remains difficult to treat. Natural killer (NK) cells are cells of the innate immune system that have potent anti-cancer activity. Recent work has shown that stimulation with IL-12/15/18 leads to the generation of NK cells with enhanced functional and putative "memory" properties. We have investigated the activity of these NK cells against HCC cell lines in vitro and in a mouse model.

METHODS

NK cells from healthy donors or individuals with HCC were activated with IL-12/15/18 in vitro and tested for cytotoxic activity against a panel of human HCC cell lines. IL-12/15/18 primed murine NK cells were then infused into a murine model of spontaneously arising HCC to test for anti-tumor activity.

RESULTS

NK cells from patients and healthy controls had similar expression levels of activating and inhibitory NK cell receptors. However, proliferation of NK cells from HCC patients was weaker than healthy controls in response to IL-12/15/18 and IL-2 (p < 0.001 at day 9). In vitro, NK cells from both groups of individuals killed HCC targets to similar levels and this was unrelated to NKG2D expression. In a spontaneous model of HCC, IL-12/15/18 activated NK cells trafficked to the liver and resulted in lower levels of spontaneous HCC formation (p < 0.01).

CONCLUSION

Cytokine-primed NK cells from patients with HCC have similar levels of activity against HCC cell lines as those from healthy controls. This type of activated NK cell has immunotherapeutic potential against hepatocellular carcinoma.

Integrative proteomic analysis reveals potential high-frequency alternative open reading frame-encoded peptides in human colorectal cancer

Identification of alternative open reading frame-encoded peptides (AEPs) for the diagnosis of colorectal cancer at the proteome level is largely unexplored because of a lack of comprehensive proteomics data. Here, we performed a comprehensive integrative analysis of mass spectral data published by Clinical Proteomic Tumor Analysis Consortium and characterized 93 high-confident AEPs encoded within 75 genes. There are four cancer-related genes appeared to have AEPs identified frequently in >20 out of 95 colorectal cancer samples, including ABCF2, AR, RBM10 and NRG1. Further network analysis of the identified AEPs found the enrichment of novel AEPs within hormone androgen receptor and a highly-modularised network with 42 genes associated with patient survival. Our results not only suggested a mechanistic view of how AEPs work in cancer progression, but also shed light on somatic amino acid mutations in AEPs, which might be overlooked previously because of their low frequencies. In particular, potential high-frequency mutations in 77 samples associated with EDARADD may contribute to the discovery of new biomarkers and the development of innovative therapeutic approaches.

Natural Killer Cell Dysfunction in Hepatocellular Carcinoma: Pathogenesis and Clinical Implications

Hepatocellular carcinoma (HCC) is currently the third leading cause of malignancy-related mortalities worldwide. Natural killer (NK) cells are involved in the critical role of first line immunological defense against cancer development. Defects in NK cell functions are recognized as important mechanisms for immune evasion of tumor cells. NK cell function appears to be attenuated in HCC, and many previous reports suggested that NK cells play a critical role in controlling HCC, suggesting that boosting the activity of dysfunctional NK cells can enhance tumor cell killing. However, the detailed mechanisms of NK cell dysfunction in tumor microenvironment of HCC remain largely unknown. A better understanding of the mechanisms of NK cell dysfunction in HCC will help in the NK cell-mediated eradication of cancer cells and prolong patient survival. In this review, we describe the various mechanisms underlying human NK cell dysfunction in HCC. Further, we summarize current advances in the approaches to enhance endogenous NK cell function and in adoptive NK cell therapies, to cure this difficult-to-treat cancer.

Treatment of advanced hepatocellular carcinoma: immunotherapy from checkpoint blockade to potential of cellular treatment

The absence of potent therapeutic option accounts for the dismal prognosis of advanced hepatocellular carcinoma (HCC) with high mortality and recurrence rate. For a decade, sorafenib is the only approved systemic drug in the first-line setting and warrants as the standard-of-care for HCC in the advanced stage. Given the common failures of chemotherapies and targeted therapies in the field of HCC treatment, promising breakthroughs were eagerly needed and until recently, immunotherapies have opened a new era of anticancer treatment. The liver organ is perceived as "immunotolerant" owing to its functional role, and the hepatic immune balance is found to be deregulated during chronic liver inflammation and HCC tumorigenesis. Restoring a competent immunity by mitigation of immunosuppression signals is a contemporary approach. In this regard, novel immune checkpoint inhibitors have revolutionized cancer pharmacological treatment options with remarkable clinical outcomes in hematologic malignancy and multiple solid tumors including advanced HCC. Nivolumab, an immunotherapeutic agent to block programmed cell death protein 1 (PD-1), showed high efficacy potential for patients progressed with sorafenib and granted accelerated approval by the US Food and Drug Administration (FDA) recently. The development of this class of immunotherapeutic drug is currently based on myriad studies established on the role of T-cell mediated immunosuppression through immune checkpoints. Heterogeneous results have led to further explorations to the profile of oncogenic processes and signaling pathways associated with PD1/PD-L1 axis. Emerging evidence from preclinical studies implicate natural killer (NK) cells as a mediator to the PD-1 checkpoint signaling immunoevasion. The strategy of adopting immunomodulating ability of NK cells by immune checkpoints inhibitors is potential to additive effects in stimulating anticancer immunity. This idea is not entirely newfound but has recently gained prominence because of advances in defining phenotypic heterogeneity of NK cell populations. The physiological significance and synergistic value of NK cells await further investigation in clinical trials. In this review, an overview of the treatment paradigm shift of HCC management is presented. Current knowledge concerning immunological mechanisms of immune checkpoints attributed to T cell is further discussed and relevant ongoing clinical trials are summarized. We proposed that NK cells should be viewed as part of the network of checkpoint immunoevasion and delineate current evidence of translational clinical research in this area. It is conceivable that immune checkpoint inhibitors in combination with NK cell-based therapeutic strategies will be great promise for treatment of advanced HCC.

A Herpes Simplex Virus Thymidine Kinase-Induced Mouse Model of Hepatocellular Carcinoma Associated with Up-Regulated Immune-Inflammatory-Related Signals

Inflammation and fibrosis in human liver are often precursors to hepatocellular carcinoma (HCC), yet none of them is easily modeled in animals. We previously generated transgenic mice with hepatocyte-specific expressed herpes simplex virus thymidine kinase (HSV-tk). These mice would develop hepatitis with the administration of ganciclovir (GCV)(Zhang, 2005 #1). However, our HSV-tk transgenic mice developed hepatitis and HCC tumor as early as six months of age even without GCV administration. We analyzed the transcriptome of the HSV-tk HCC tumor and hepatitis tissue using microarray analysis to investigate the possible causes of HCC. Gene Ontology (GO) enrichment analysis showed that the up-regulated genes in the HCC tissue mainly include the immune-inflammatory and cell cycle genes. The down-regulated genes in HCC tumors are mainly concentrated in the regions related to lipid metabolism. Gene set enrichment analysis (GSEA) showed that immune-inflammatory-related signals in the HSV-tk mice are up-regulated compared to those in Notch mice. Our study suggests that the immune system and inflammation play an important role in HCC development in HSV-tk mice. Specifically, increased expression of immune-inflammatory-related genes is characteristic of HSV-tk mice and that inflammation-induced cell cycle activation maybe a precursory step to cancer. The HSV-tk mouse provides a suitable model for the study of the relationship between immune-inflammation and HCC, and their underlying mechanism for the development of therapeutic application in the future.

Role of altered immune cells in liver diseases: a review

Immune cells play an important role in controlling liver tumorigenesis, viral hepatitis, liver fibrosis and contribute to pathogenesis of liver inflammation and injury. Accumulating evidence suggests the effectiveness of natural killer (NK) cells and Kupffer cells (KCs) against viral hepatitis, hepatocellular damage, liver fibrosis, and carcinogenesis. Activation of natural killer cells provides a novel therapeutic strategy to cure liver related diseases. This review discusses the emerging roles of immune cells in liver disorders and it will provide baseline data to scientists to design better therapies for treatment.

The Dual Roles of NRF2 in Cancer

NRF2 has been traditionally considered as a tumor suppressor because its cytoprotective functions are deemed to be the main cellular defense mechanism against exogenous and endogenous insults, including xenobiotics and oxidative stress. However, several recent studies demonstrate that hyperactivation of the NRF2 pathway creates an environment that favors the survival of normal as well as malignant cells, protecting them against oxidative stress, chemotherapeutic agents, and radiotherapy. In a rapidly advancing field, this review summarizes some of the known mechanisms by which NRF2 can exert its oncogenic functions, and describes the current status of NRF2 inhibitors, providing a clear rationale for the consideration of NRF2 as a powerful putative therapeutic target in cancer treatment.

microRNA-129-5p, a c-Myc negative target, affects hepatocellular carcinoma progression by blocking the Warburg effect

Deregulation of microRNAs (miRNAs) and c-Myc (Myc) contributes to hepatocellular carcinoma (HCC) progression, but how miRNAs and Myc regulate each other in hepatocarcinogenesis is still poorly understood. Using a functional screen, we identified miR-129-5p as a miRNA that inhibits HCC cell growth. miR-129-5p targets the mitochondrial matrix protein pyruvate dehydrogenase kinase 4 (PDK4), which leads to decreased phosphorylation of the E1α subunit of pyruvate dehyrogenase (PDH) complex, inhibition of glycolysis, retarded tumor growth, and impaired lung colonization. Enforced expression of PDK4 refractory to inhibition by miR-129-5p rescued all of these phenotypes. Targeting PDK4 by shRNA recapitulated the effects caused by miR-129-5p. miR-129-5p is transcriptionally repressed by a complex comprised of Myc, histone deacetylase 3 (HDAC3), and enhancer of zeste 2 polycomb repressive complex 2 (EZH2). Levels of miR-129-5p negatively correlated with clinical stages in human HCC. Restoring miR-129-5p expression suppressed the diethylnitrosamine (DEN)-induced hepatocarcinogenesis in mice. Thus, we concluded that miR-129-5p, which is a negative target of Myc, blocks glycolysis to retard hepatocarcinogenesis via targeting PDK4. The critical link between miR-129-5p and PDK4 in the progression of HCC suggests potential points of therapeutic intervention for this disease.

Nrf2, but not β-catenin, mutation represents an early event in rat hepatocarcinogenesis

Hepatocellular carcinoma (HCC) develops through a multistage process, but the nature of the molecular changes associated with the different steps, the very early ones in particular, is largely unknown. Recently, dysregulation of the NRF2/KEAP1 pathway and mutations of these genes have been observed in experimental and human tumors, suggesting their possible role in cancer development. To assess whether Nrf2/Keap1 mutations are early or late events in HCC development, we investigated their frequency in the rat Resistant Hepatocyte model, consisting of the administration of diethylnitrosamine followed by a brief exposure to 2-acetylaminofluorene. This model enables the dissection of all stages of hepatocarcinogenesis. We found that Nrf2/Keap1 mutations were present in 71% of early preneoplastic lesions and in 78.6% and 59.3% of early and advanced HCCs, respectively. Mutations of Nrf2 were more frequent, missense, and located in the Nrf2-Keap1 binding region. Mutations of Keap1 occurred at a much lower frequency in both preneoplastic lesions and HCCs and were mutually exclusive with those of Nrf2. Functional in vitro and in vivo studies showed that Nrf2 silencing inhibited the ability of tumorigenic rat cells to grow in soft agar and to form tumors. Unlike Nrf2 mutations, those of Ctnnb1, which are frequent in human HCC, were a later event as they appeared only in fully advanced HCCs (18.5%).

CONCLUSION

In the Resistant Hepatocyte model of hepatocarcinogenesis the onset of Nrf2 mutations is a very early event, likely essential for the clonal expansion of preneoplastic hepatocytes to HCC, while Ctnnb1 mutations occur only at very late stages. Moreover, functional experiments demonstrate that Nrf2 is an oncogene critical for HCC progression and development.

Immunology of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is primarily a malignancy of the liver, advancing from a damaged, cirrhotic liver to HCC. Globally, HCC is the sixth most prevalent cancer and the third-most prevalent reason for neoplastic disease-related deaths. A diverse array of infiltrating immunocytes regulates the development and progression of HCC, as is the case in many other cancers. An understanding of the various immune components during HCC becomes necessary so that novel therapeutic strategies can be designed to combat the disease. A dysregulated immune system (including changes in the number and/or function of immune cells, cytokine levels, and the expression of inhibitory receptors or their ligands) plays a key role in the development of HCC. Alterations in either the innate or adaptive arm of the immune system and cross-talk between them make the immune system tolerant to tumors, leading to disease progression. In this review, we have discussed the status and roles of various immune effector cells (e.g., dendritic cells, natural killer cells, macrophages, and T cells), their cytokine profile, and the chemokine-receptor axis in promoting or impeding HCC.

MicroRNA/gene profiling unveils early molecular changes and nuclear factor erythroid related factor 2 (NRF2) activation in a rat model recapitulating human hepatocellular carcinoma (HCC)

Studies on gene and/or microRNA (miRNA) dysregulation in the early stages of hepatocarcinogenesis are hampered by the difficulty of diagnosing early lesions in humans. Experimental models recapitulating human hepatocellular carcinoma (HCC) are then used to perform this analysis. We performed miRNA and gene expression profiling to characterize the molecular events involved in the multistep process of hepatocarcinogenesis in the resistant-hepatocyte rat model. A high percentage of dysregulated miRNAs/genes in HCC were similarly altered in early preneoplastic lesions positive for the stem/progenitor cell marker cytokeratin-19, indicating that several HCC-associated alterations occur from the very beginning of the carcinogenic process. Our analysis also identified miRNA/gene-target networks aberrantly activated at the initial stage of hepatocarcinogenesis. Activation of the nuclear factor erythroid related factor 2 (NRF2) pathway and up-regulation of the miR-200 family were among the most prominent changes. The relevance of these alterations in the development of HCC was confirmed by the observation that NRF2 silencing impaired while miR-200a overexpression promoted HCC cell proliferation in vitro. Moreover, T3-induced in vivo inhibition of the NRF2 pathway accompanied the regression of cytokeratin-19-positive nodules, suggesting that activation of this transcription factor contributes to the onset and progression of preneoplastic lesions towards malignancy. The finding that 78% of genes and 57% of dysregulated miRNAs in rat HCC have been previously associated with human HCC as well underlines the translational value of our results.

CONCLUSION

This study indicates that most of the molecular changes found in HCC occur in the very early stages of hepatocarcinogenesis. Among these, the NRF2 pathway plays a relevant role and may represent a new therapeutic target.

Hepatic fibrosis and the microenvironment: fertile soil for hepatocellular carcinoma development

Hepatocellular carcinoma is an emerging worldwide health threat that has few curative treatment options and poor overall survival. Progressive hepatic fibrosis is a common pathway for all forms of chronic liver disease and is closely linked epidemiologically to hepatocellular carcinoma risk. However, the molecular events that predispose a fibrotic liver to cancer development remain elusive. Nonetheless, a permissive hepatic microenvironment provides fertile soil for transition of damaged hepatocytes into hepatocellular carcinoma. Key predisposing features include alterations in the extracellular matrix, bidirectional signaling pathways between parenchymal and nonparenchymal cells, and immune dysfunction. Emerging research into the contributions of autophagy, tumor-associated fibroblasts, and hepatocellular carcinoma progenitor cells to this dangerous milieu also provides new mechanistic underpinnings to explain the contribution of fibrosis to cancer. As effective antifibrotic therapies are developed, these approaches could attenuate the rising surge of hepatocellular carcinoma associated with chronic liver disease.

β-ionone inhibits persistent preneoplastic lesions during the early promotion phase of rat hepatocarcinogenesis: TGF-α, NF-κB, and p53 as cellular targets

Dietary isoprenic derivatives such as β-ionone (βI) are a promising class of chemopreventive agents. In this study, cellular aspects of βI protective activities during early hepatocarcinogenesis were evaluated. Male Wistar rats were submitted to "resistant hepatocyte" model and then received daily 16 mg/100 g body weight (b.w.) of βI (βI group) or only 0.25 mL/100 g b.w. of corn oil (vehicle, control group [CO]) during 4 wk, specifically during early promotion phase. Compared to controls, βI inhibited (P < 0.05) the development of persistent preneoplastic lesions (pPNL), considered to be potential hepatocellular carcinoma (HCC) progression sites, and increased remodeling PNL (rPNL) (P < 0.05) that tend to regress to a normal phenotype. Increased βI hepatic levels (P < 0.05), in the βI group, were associated with its chemopreventive actions. Compared to control rats, βI reduced the frequency of both pPNL and rPNL positive for tumor growth factor (TGF)-α (P < 0.05), reduced the frequency of pPNL stained for p65 (nuclear factor-kappaB; NF-κB) (P < 0.05), and reduced the frequency of pPNL positive for cytoplasmic p53 (P < 0.05). Our data demonstrated that βI targets TGF-α, NF-κB, and p53 in initial phases of hepatocarcinogenesis and specifically inhibits PNL with increased probability to progress to HCC. This isoprenoid may represent a chemopreventive agent of choice for HCC control.

NAFLD, NASH and liver cancer

NAFLD affects a large proportion of the US population and its incidence and prevalence are increasing to epidemic proportions around the world. As with other liver diseases that cause cirrhosis, NAFLD increases the risk of liver cancer, a disease with poor outcomes and limited therapeutic options. The incidences of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma are also rising, and HCC is now the leading cause of obesity-related cancer deaths in middle-aged men in the USA. In this Review, we summarize the correlations between liver cancer and NAFLD-related cirrhosis, and the role of the metabolic syndrome in the development of liver cancer from diverse aetiologies, including HCV-mediated cirrhosis. Recent advances in understanding the progression of NAFLD to HCC from preclinical models will also be discussed. Targeted genetic manipulation of certain metabolic or stress-response pathways, including one-carbon metabolism, NF-κB, PTEN and microRNAs, has been valuable in elucidating the pathways that regulate carcinogenesis in NAFLD. Although tremendous advances have occurred in the identification of diagnostic and therapeutic opportunities to reduce the progression of NAFLD, considerable gaps in our knowledge remain with regard to the mechanisms by which NAFLD and its risk factors promote liver cancer.

Role of lymphocytes in liver cancer

Hepatocellular carcinoma (HCC) typically occurs in patients with chronic inflammatory liver diseases, such as viral hepatitis or (non-)alcoholic steatohepatitis. Inflammation appears indeed as a crucial factor in hepatocarcinogenesis. Nevertheless, sophisticated animal models and studies of human samples revealed that the HCC also elicits antitumor immune responses. Patrolling and infiltrating lymphocytes (e.g., NKT and T cells, respectively) can exert decisive functions in the transition from chronic hepatic inflammation to cancer as well as in antitumor immune responses. An improved understanding of the cellular and molecular mechanisms whereby inflammation promotes or restricts hepatocarcinogenesis will open new avenues for therapeutic approaches to liver cancer.

HBV induced HCC: major risk factors from genetic to molecular level

Hepatocellular carcinoma (HCC) is a deadly and emerging disease leading to death in Asian countries. High hepatitis B virus (HBV) load and chronic hepatitis B (CHB) infection increase the risk of developing HCC. HBV is a DNA virus that can integrate DNA into host genome thereby increase the yield of transactivator protein HBxAg that may deregulate many pathways involving in metabolism of cells. Several monogenic and polygenic risk factors are also involved in HCC development. This review summarizes the mechanism involved in HCC development and discusses some promising therapies to make HCC curative.

A c-Myc-MicroRNA functional feedback loop affects hepatocarcinogenesis

c-Myc (Myc) plays an important role in normal liver development and tumorigenesis. We show here that Myc is pathologically activated in and essential for promoting human hepatocellular carcinoma (HCC). Myc induces HCC through a novel, microRNA (miRNA)-mediated feedback loop comprised of miR-148a-5p, miR-363-3p, and ubiquitin-specific protease 28 (USP28). Myc directly binds to conserved regions in the promoters of the two miRNAs and represses their expression. miR-148a-5p directly targets and inhibits Myc, whereas miR-363-3p destabilizes Myc by directly targeting and inhibiting USP28. Inhibition of miR-148a-5p or miR-363-3p induces hepatocellular tumorigenesis by promoting G1 to S phase progression, whereas activation of them has the opposite effects. The Myc-miRNA feedback loop is dysregulated in human HCC.

CONCLUSION

These results define miR-148a-5p and miR-363-3p as negative regulators of Myc, thus revealing their heretofore unappreciated roles in hepatocarcinogenesis. (HEPATOLOGY 2013;57:2378-2389).

Natural killer cells in liver disease

Natural killer (NK) cells are enriched in lymphocytes within the liver and have unique phenotypic features and functional properties, including tumor necrosis factor-related apoptosis-inducing ligand-dependent cytotoxicity and specific cytokine profiles. As a key component of innate immunity in the liver, NK cells perform critical roles in host defense against pathogens and tumors through their natural cytotoxicity and cytokine production, and they also act as regulatory cells by engaging in reciprocal interactions with other types of liver cells through cell-to-cell contact and the production of cytokines. Accumulating evidence from the last decade suggests that NK cells play an important role in controlling viral hepatitis, liver fibrosis, and liver tumorigenesis, but also contribute to the pathogenesis of liver injury and inflammation. The characterization of intrahepatic NK cell functions has not only helped us to better understand the pathogenesis of liver disease, but has also revealed new therapeutic targets for managing this disease.

Chronic inflammation, immune escape, and oncogenesis in the liver: a unique neighborhood for novel intersections

Sustained hepatic inflammation, driven by alcohol consumption, nonalcoholic fatty liver disease, and/or chronic viral hepatitis (hepatitis B and C), results in damage to parenchyma, oxidative stress, and compensatory regeneration/proliferation. There is substantial evidence linking these inflammation-associated events with the increased incidence of hepatocellular carcinogenesis. Although acute liver inflammation can play a vital and beneficial role in response to liver damage or acute infection, the effects of chronic liver inflammation, including liver fibrosis and cirrhosis, are sufficient in a fraction of individuals to initiate the process of transformation and the development of hepatocellular carcinoma. This review highlights immune-dependent mechanisms that may be associated with hepatocellular oncogenesis, including critical transformative events/pathways in the context of chronic inflammation and subverted tolerogenesis.

Hepatocyte-stellate cell cross-talk in the liver engenders a permissive inflammatory microenvironment that drives progression in hepatocellular carcinoma

Many solid malignant tumors arise on a background of inflamed and/or fibrotic tissues, features that are found in more than 80% hepatocellular carcinomas (HCC). Activated hepatic stellate cells (HSC) play a critical role in fibrogenesis associated with HCC onset and progression, yet their functional impact on hepatocyte fate remains largely unexplored. Here, we used a coculture model to investigate the cross-talk between hepatocytes (human hepatoma cells) and activated human HSCs. Unsupervised genome-wide expression profiling showed that hepatocyte-HSC cross-talk is bidirectional and results in the deregulation of functionally relevant gene networks. Notably, coculturing increased the expression of proinflammatory cytokines and modified the phenotype of hepatocytes toward motile cells. Hepatocyte-HSC cross-talk also generated a permissive proangiogenic microenvironment, particularly by inducing VEGFA and matrix metalloproteinase (MMP)9 expression in HSCs. An integrative genomic analysis revealed that the expression of genes associated with hepatocyte-HSC cross-talk correlated with HCC progression in mice and was predictive of a poor prognosis and metastasis propensity in human HCCs. Interestingly, the effects of cross-talk on migration and angiogenesis were reversed by the histone deacetylase inhibitor trichostatin A. Our findings, therefore, indicate that the cross-talk between hepatoma cells and activated HSCs is an important feature of HCC progression, which may be targeted by epigenetic modulation.

An integrative model links multiple inputs and signaling pathways to the onset of DNA synthesis in hepatocytes

During liver regeneration, quiescent hepatocytes re-enter the cell cycle to proliferate and compensate for lost tissue. Multiple signals including hepatocyte growth factor, epidermal growth factor, tumor necrosis factor α, interleukin-6, insulin and transforming growth factor β orchestrate these responses and are integrated during the G₁ phase of the cell cycle. To investigate how these inputs influence DNA synthesis as a measure for proliferation, we established a large-scale integrated logical model connecting multiple signaling pathways and the cell cycle. We constructed our model based upon established literature knowledge, and successively improved and validated its structure using hepatocyte-specific literature as well as experimental DNA synthesis data. Model analyses showed that activation of the mitogen-activated protein kinase and phosphatidylinositol 3-kinase pathways was sufficient and necessary for triggering DNA synthesis. In addition, we identified key species in these pathways that mediate DNA replication. Our model predicted oncogenic mutations that were compared with the COSMIC database, and proposed intervention targets to block hepatocyte growth factor-induced DNA synthesis, which we validated experimentally. Our integrative approach demonstrates that, despite the complexity and size of the underlying interlaced network, logical modeling enables an integrative understanding of signaling-controlled proliferation at the cellular level, and thus can provide intervention strategies for distinct perturbation scenarios at various regulatory levels.