Mouse Model Of Human Hepatocellular Carcinoma Research Articles

Thioredoxin-interacting protein-activated intracellular potassium deprivation mediates the anti-tumour effect of a novel histone acetylation inhibitor HL23, a fangchinoline derivative, in human hepatocellular carcinoma

IntroductionHyperactivated histone deacetylases (HDACs) act as epigenetic repressors on gene transcription and are frequently observed in human hepatocellular carcinoma (HCC). Although multiple pharmacological HDAC inhibitors (HDACis) have been developed, none is available in human HCC. ObjectivesTo investigate the pharmacological effects of a fangchinoline derivative HL23, as a novel HDACi and its molecular mechanisms through TXNIP-mediated potassium deprivation in HCC. MethodsBoth in vitro assays and orthotopic HCC mouse models were used to investigate the effects of HL23 in this study. The inhibitory activity of HL23 on HDACs was evaluated by in silico studies and cellular assays. Chromatin immunoprecipitation (ChIP) was conducted to confirm the regulation of HL23 on acetylation mark at TXNIP promoter. Genome-wide transcriptome analysis together with bioinformatic analysis were conducted to identify the regulatory mechanisms of HL23. The clinical significance of TXNIP and HDACs was evaluated by analysing publicly available database. ResultsHL23 exerted compatible HDACs inhibition potency as Vorinostat (SAHA) while had superior anti-HCC effects than SAHA and sorafenib. Both in vitro and in vivo studies showed HL23 significantly suppressed HCC progression and metastasis. HL23 significantly upregulated TXNIP expression via regulating acetylation mark (H3K9ac) at TXNIP promoter. TXNIP was responsible for anti-HCC activity of HL23 through mediating potassium channel activity. HDAC1 was predicted to be the target of HL23 and HDAC1lowTXNIPhigh could jointly predict promising survival outcome of patients with HCC. Combination treatment with HL23 and sorafenib could significantly enhance sorafenib efficacy. ConclusionOur study identified HL23 as a novel HDACi through enhancing acetylation at TXNIP promoter to trigger TXNIP-dependent potassium deprivation and enhance sorafenib efficacy in HCC treatment.

Transforming primary human hepatocytes into hepatocellular carcinoma with genetically defined factors.

Our understanding of human hepatocellular carcinoma (HCC) development and progression has been hampered by the lack of in vivo models. We performed a genetic screen of 10 oncogenes and genetic mutations in Fah-ablated immunodeficient mice in which primary human hepatocytes (PHHs) are used to reconstitute a functional human liver. We identified that MYC, TP53R249S , and KRASG12D are highly expressed in induced HCC (iHCC) samples. The overexpression of MYC and TP53R249S transform PHHs into iHCC in situ, though the addition of KRASG12D significantly increases the tumorigenic efficiency. iHCC, which recapitulate the histological architecture and gene expression characteristics of clinical HCC samples, reconstituted HCC after serial transplantations. Transcriptomic analysis of iHCC and PHHs showed that MUC1 and FAP are expressed in iHCC but not in normal livers. Chimeric antigen receptor (CAR) T cells against these two surface markers efficiently lyse iHCC cells. The properties of iHCC model provide a biological basis for several clinical hallmarks of HCC, and iHCC may serve as a model to study HCC initiation and to identify diagnostic biomarkers and targets for cellular immunotherapy.

Analysis and Validation of Human Targets and Treatments Using a Hepatocellular Carcinoma-Immune Humanized Mouse Model.

Background and AimsRecent development of multiple treatments for human hepatocellular carcinoma (HCC) has allowed for the selection of combination therapy to enhance the effectiveness of monotherapy. Optimal selection of therapies is based on both HCC and its microenvironment. Therefore, it is critical to develop and validate preclinical animal models for testing clinical therapeutic solutions.Approach and ResultsWe established cell line–based or patient‐derived xenograft–based humanized‐immune‐system mouse models with subcutaneous and orthotopic HCC. Mice were injected with human‐specific antibodies (Abs) to deplete human immune cells. We analyzed the transcription profiles of HCC cells and human immune cells by using real‐time PCR and RNA sequencing. The protein level of HCC tumor cells/tissues or human immune cells was determined by using flow cytometry, western blotting, and immunohistochemistry. The HCC tumor size was measured after single, dual‐combination, and triple‐combination treatment using N‐(1ʹ,2‐Dihydroxy‐1,2ʹ‐binaphthalen‐4ʹ‐yl)‐4‐methoxybenzenesulfonamide (C188‐9), bevacizumab, and pembrolizumab. In this study, human immune cells in the tumor microenvironment were strongly selected and modulated by HCC, which promoted the activation of the IL‐6/Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in tumor cells and led to augmented HCC proliferation and angiogenesis by releasing angiogenic cytokines in humanized‐immune‐system mice with HCC. In particular, intratumor human cluster of differentiation–positive (hCD14+) cells could produce IL‐33 through damage‐associated molecular pattern/Toll‐like receptor 4/activator protein 1, which up‐regulated IL‐6 in other intratumor immune cells and activated the JAK2/STAT3 pathway in HCC. Specific knockdown of the CD14 gene in human monocytes could impair IL‐33 production induced by cell lysates. Subsequently, we evaluated the in vivo anti‐HCC effect of C188‐9, bevacizumab, and pembrolizumab. The results showed that the anti‐HCC effect of triple‐combination therapy was superior to that of single or dual treatments.ConclusionsHumanized‐immune‐system HCC mouse models are suitable for identifying targets from cancer and immune components and for testing combinational therapies.

The DEN and CCl4 -Induced Mouse Model of Fibrosis and Inflammation-Associated Hepatocellular Carcinoma.

Human hepatocellular carcinoma (HCC) develops most often as a complication of fibrosis or cirrhosis. Although most human studies of HCC provide crucial insights into the molecular signatures of HCC, they seldom address its etiology. Mouse models provide essential tools for investigating the pathogenesis of HCC, but the majority of rodent cancer models do not feature liver fibrosis. Detailed here is a protocol for an experimental mouse model of HCC that arises in association with advanced liver fibrosis. The disease model is induced by a single injection of N-nitrosodiethylamine (DEN) at 2 weeks of age followed by repeated administration of carbon tetrachloride (CCl4 ) from 8 weeks of age for up to 14 consecutive weeks. A dramatic potentiation of liver tumor incidence is observed following administration of DEN and CCl4 , with 100% of mice developing liver tumors at 5 months of age. This model has been employed for studying the molecular mechanisms of fibrogenesis and HCC development, as well as for cancer hazard/chemotherapy testing of drug candidates. © 2021 Wiley Periodicals LLC. Basic Protocol: The DEN and CCl4 -induced mouse model of fibrosis and inflammation-associated hepatocellular carcinoma.

The lncRNA H19-Derived MicroRNA-675 Promotes Liver Necroptosis by Targeting FADD.

Simple SummaryLiver cancer develops mostly in a chronically inflamed liver. The inflammation process can enhance or suppress the development of liver cancer. H19 is a noncoding RNA that is upregulated in inflamed livers. The role of H19 in liver cancer was intensely investigated, but the reported findings are conflicting. Some reported that H19 is a tumor suppressor and others that it has oncogenic properties. To understand the contribution of H19 to liver cancer development, we investigated miR-675, which is generated from the first exon of the H19 RNA message. Interestingly, we found that miR-675 suppresses liver cancer cell growth by inducing cell death. Following our investigation of the mechanism of this killing effect, we established that miR-675 represses the protein called Fas-associated protein with death domain (FADD) and that this repression leads to the development of a specific type of necrosis named necroptosis. These findings can have future therapeutic implications.The H19-derived microRNA-675 (miR-675) has been implicated as both tumor promoter and tumor suppressor and also plays a role in liver inflammation. We found that miR-675 promotes cell death in human hepatocellular carcinoma (HCC) cell lines. We show that Fas-associated protein with death domain (FADD), a mediator of apoptotic cell death signaling, is downregulated by miR-675 and a negative correlation exists between miR-675 and FADD expression in mouse models of HCC (p = 0.014) as well as in human samples (p = 0.017). We demonstrate in a mouse model of liver inflammation that overexpression of miR-675 promotes necroptosis, which can be inhibited by the necroptosis-specific inhibitor Nec-1/Nec-1s. miR-675 induces the level of both p-MLKL (Mixed Lineage Kinase Domain-Like Pseudokinase) and RIP3 (receptor-interacting protein 3), which are key signaling molecules in necroptosis, and enhances MLKL binding to RIP3. miR-675 also inhibits the levels of cleaved caspases 8 and 3, suggesting that miR-675 induces a shift from apoptosis to a necroptotic cellular pathway. In conclusion, downregulation of FADD by miR-675 promotes liver necroptosis in response to inflammatory signals. We propose that this regulation cascade can stimulate and enhance the inflammatory response in the liver, making miR-675 an important regulator in liver inflammation and potentially also in HCC.

Gamma-secretase complex-dependent intramembrane proteolysis of CD147 regulates the Notch1 signaling pathway in hepatocellular carcinoma.

The γ-secretase complex is a presenilin-dependent aspartyl protease involved in the intramembranous cleavage of various type I transmembrane proteins. As a type I transmembrane protein, CD147 is highly expressed in hepatoma cells and promotes cell proliferation, migration, and invasion. However, the direct underlying mechanism of how CD147 promotes cancer cell proliferation is unknown. Here, we demonstrated that CD147 undergoes an intramembranous cleavage by the γ-secretase at lysine 231 to release its intracellular domains (ICDs). The nuclear translocation of the CD147ICD regulated Notch1 expression by directly binding to the NOTCH1 promoter and promoted the activation of the Notch signaling pathway. Simultaneously, overexpression of CD147ICD promoted cancer cell proliferation via Notch1 signaling. In 102 cases of human hepatocellular carcinoma (HCC) tissues, patients with a high positive rate of nuclear CD147ICD expression had a significantly poor overall survival compared with patients with a low positive rate of nuclear CD147ICD expression. We confirmed that nuclear CD147ICD predicted a poor prognosis in human HCC. The combined therapy of the γ-secretase complex inhibitor and CD147-directed antibody showed better efficacy than monotherapy in orthotopic transplantation HCC mouse models. In conclusion, CD147 is cleaved by the γ-secretase and releases CD147ICD to the cell nucleus, promoting Notch1 expression via direct binding to the NOTCH1 promoter. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Characterization of HCC Mouse Models: Towards an Etiology-Oriented Subtyping Approach.

Murine liver tumors often fail to recapitulate the complexity of human hepatocellular carcinoma (HCC), which might explain the difficulty to translate preclinical mouse studies into clinical science. The aim of this study was to evaluate a subtyping approach for murine liver cancer models with regard to etiology-defined categories of human HCC, comparing genomic changes, histomorphology, and IHC profiles. Sequencing and analysis of gene copy-number changes [by comparative genomic hybridization (CGH)] in comparison with etiology-dependent subsets of HCC patients of The Cancer Genome Atlas (TCGA) database were conducted using specimens (75 tumors) of five different HCC mouse models: diethylnitrosamine (DEN) treated wild-type C57BL/6 mice, c-Myc and AlbLTαβ transgenic mice as well as TAK1LPC-KO and Mcl-1Δhep mice. Digital microscopy was used for the assessment of morphology and IHC of liver cell markers (A6-CK7/19, glutamine synthetase) in mouse and n = 61 human liver tumors. Tumor CGH profiles of DEN-treated mice and c-Myc transgenic mice matched alcohol-induced HCC, including morphologic findings (abundant inclusion bodies, fatty change) in the DEN model. Tumors from AlbLTαβ transgenic mice and TAK1LPC-KO models revealed the highest overlap with NASH-HCC CGH profiles. Concordant morphology (steatosis, lymphocyte infiltration, intratumor heterogeneity) was found in AlbLTαβ murine livers. CGH profiles from the Mcl-1Δhep model displayed similarities with hepatitis-induced HCC and characteristic human-like phenotypes (fatty change, intertumor and intratumor heterogeneity). IMPLICATIONS: Our findings demonstrate that stratifying preclinical mouse models along etiology-oriented genotypes and human-like phenotypes is feasible. This closer resemblance of preclinical models is expected to better recapitulate HCC subgroups and thus increase their informative value.

Matrine suppresses lung metastasis of human hepatocellular carcinoma by directly targeting matrix metalloproteinase-9

Matrine is a natural compound derived from Radix Sophora flavescens which is a commonly used Chinese herb. Herein, we report that matrine may inhibit lung metastasis in liver cancer in mice. Invasion chamber assay, scratch-wound assay and orthotopic liver tumor implantation mice were introduced to investigate the potential pharmacological effects of matrine on human hepatocellular carcinoma (HCC). Our results showed that matrine at non-toxic dose could significantly suppress PLC/PRF/5 and MHCC97L cells migration and invasion. Furthermore, matrine treatment (5 mg/kg/day) significantly decreased lung metastasis in orthotopic HCC mouse models. Quantitative polymerase chain reaction, gelatin zymography and immunoblotting assay indicated that matrine could inhibit the activity of matrix metalloproteinase-9 without down-regulating its protein expression in HCC. The docking approach, site-directed mutagenesis, and surface plasmon resonance were applied to identify residues involved in matrine binding in matrix metalloproteinase-9. The biophysical and cell-based assays showed that Pro415, Arg424 residue might contribute to the binding affinity of matrine on matrix metalloproteinase-9 activity. In conclusion, matrine might be a promising anti-cancer agent for inhibiting HCC metastasis.

04:12 PM Abstract No. 226 Glypican-3 optical molecular imaging enables in vivo detection and monitoring of response to adoptive immunotherapy

We have previously described synthesis of a bispecific fusion protein for catheter-directed targeting of glypican-3 (GPC3) expressed on hepatocellular carcinoma (HCC) tumors and CD3 T-cell receptors (GPC3-CD3-bsAb) (1). We hypothesized that in vivo optical fluorescent imaging of GPC3 in mouse models of human HCC would enable effective monitoring of adoptive immunotherapy mediated by GPC3-CD3-bsAb. A modified GPC3 specific small peptide was labeled with Hylite488 or Cylyte5 fluorescent dyes (GPC3-FL) and used for in-vitro and in vivo imaging, respectively. In-vitro competitive binding assay was performed to assess specific probe binding to GPC3 on human HCC tumor cells (HepG2 (GPC3+) and SNU449 (GPC3-)). For in vivo imaging, HCC mouse xenograft models were created through implantation of HepG2 and SNU449 cells in the flanks of nude mice (n=5 each group). Optical imaging was performed after tail-vein injection of 6.25μg of GPC3-FL on IVIS Spectrum in vivo imaging system. Mice were imaged at baseline, followed by GPC3 blockage using higher concentrations of non-labeled GPC3 specific peptide and after adoptive immunotherapy with concurrent injection of GPC3-CD3-bsAb and activated human T-cells. In-vitro assays confirmed dose dependent blockage of GPC3-FL binding to GPC3+ HepG2 cells by GPC3 specific antibodies. Optical imaging of HepG2 and SNU449 tumor bearing mice demonstrated a significantly higher target to background ratio (TBR) for GPC3+ HepG2 tumors compared to GPC3- SNU449 tumors (2.99±0.36 vs 1.16±1.15, p=0.01). Concurrent injection of non-labeled GPC3 specific peptide and GPC-FL showed a marked decrease in tumor TBRs in GPC3+ HepG2 tumors (1.45±0.18 vs. 2.99±0.36, p=0.004). Following an adoptive immunotherapy treatment course, fluorescent signal in treated tumors markedly decreased in the treatment group compared to controls (4.36±0.9 before treatment vs 1.8±0.4, p=0.049). Optical imaging using GPC3-FL is feasible for in vivo detection of GPC3 positive HCC cells and allows non-invasive monitoring of tumor response to adoptive immunobtherapy, which cannot be achieved using available morphological methods of imaging.

Endoscopic Cerenkov luminescence imaging and image-guided tumor resection on hepatocellular carcinoma-bearing mouse models

Detecting deep tumors inside living subject is still challenging for Cerenkov luminescence imaging (CLI). In this study, a high-sensitivity endoscopic CLI (ECLI) system was developed with a dual-mode deep cooling approach to improve the imaging sensitivity. System was characterized through a series of ex vivo studies. Furthermore, subcutaneous and orthotropic human hepatocellular carcinoma (HCC) mouse models were established for ECLI guided tumor resection in vivo. The results showed that the ECLI system had spatial resolution (62.5 μm) and imaging sensitivity (6.29 × 10−2 kBq/μl 18F-FDG). The in vivo experimental data from the HCC mouse models demonstrated that the system was effective to intraoperatively guide the surgery of deep tumors such as liver cancer. Overall, the developed system exhibits promising potential for the applications of tumor precise resection and novel nanoprobe based optical imaging.

Phenformin-Induced Mitochondrial Dysfunction Sensitizes Hepatocellular Carcinoma for Dual Inhibition of mTOR

Purpose: Hepatocellular carcinoma (HCC) ranks second in cancer mortality and has limited therapeutic options. We recently described the synergistic effect of allosteric and ATP-site competitive inhibitors against the mTOR for the treatment of HCC. However, such inhibitors induce hyperglycemia and increase mitochondrial efficiency. Here we determined whether the mitochondrial complex I inhibitor phenformin could reverse both side effects, impose an energetic stress on cancer cells, and suppress the growth of HCC.Experimental Design: Human HCC cell lines were used in vitro to access the signaling and energetic impact of mTOR inhibitors and phenformin, either alone or in combination. Next, the therapeutic utility of these drugs alone or in combination was investigated preclinically in human orthotopic tumors implanted in mice, by analyzing their impact on the tumor burden and overall survival.Results: We found phenformin caused mitochondrial dysfunction and fragmentation, inducing a compensatory shift to glycolysis. In contrast, dual inhibition of mTOR impaired cell growth and glycolysis, while increasing mitochondrial fusion and efficiency. In a mouse model of human HCC, dual inhibition of mTOR, together with phenformin, was highly efficacious in controlling tumor burden. However, more strikingly, pretreatment with phenformin sensitized tumors to dual inhibition of mTOR, leading to a dramatic improvement in survival.Conclusions: Treatment of HCC cells in vitro with the biguanide phenformin causes a metabolic shift to glycolysis, mitochondrial dysfunction and fragmentation, and dramatically sensitizes orthotopic liver tumors to dual inhibition of mTOR. We therefore propose this therapeutic approach should be tested clinically in HCC. Clin Cancer Res; 24(15); 3767-80. ©2018 AACR.

P-324 - Phenformin-induced mitochondrial dysfunction sensitizes hepatocellular carcinoma for dual inhibition of mTOR

Purpose: Hepatocellular carcinoma (HCC) ranks second in cancer mortality and has limited therapeutic options. We recently described the synergistic effect of allosteric and ATP-site competitive inhibitors against the mTOR for the treatment of HCC. However, such inhibitors induce hyperglycemia and increase mitochondrial efficiency. Here we determined whether the mitochondrial complex I inhibitor phenformin could reverse both side effects, impose an energetic stress on cancer cells, and suppress the growth of HCC. Experimental Design: Human HCC cell lines were used in vitro to access the signaling and energetic impact of mTOR inhibitors and phenformin, either alone or in combination. Next, the therapeutic utility of these drugs alone or in combination was investigated preclinically in human orthotopic tumors implanted in mice, by analyzing their impact on the tumor burden and overall survival. Results: We found phenformin caused mitochondrial dysfunction and fragmentation, inducing a compensatory shift to glycolysis. In contrast, dual inhibition of mTOR impaired cell growth and glycolysis, while increasing mitochondrial fusion and efficiency. In a mouse model of human HCC, dual inhibition of mTOR, together with phenformin, was highly efficacious in controlling tumor burden. However, more strikingly, pretreatment with phenformin sensitized tumors to dual inhibition of mTOR, leading to a dramatic improvement in survival. Conclusions: Treatment of HCC cells in vitro with the biguanide phenformin causes a metabolic shift to glycolysis, mitochondrial dysfunction and fragmentation, and dramatically sensitizes orthotopic liver tumors to dual inhibition of mTOR. We therefore propose this therapeutic approach should be tested clinically in HCC. Clin Cancer Res; 24(15); 3767–80. ©2018 AACR.

Efficacy of combining ING4 and TRAIL genes in cancer-targeting gene virotherapy strategy: first evidence in preclinical hepatocellular carcinoma

Current treatments of hepatocellular carcinoma (HCC) are ineffective and unsatisfactory in many aspects. Cancer-targeting gene virotherapy using oncolytic adenoviruses (OAds) armed with anticancer genes has shown efficacy and safety in clinical trials. Nowadays, both inhibitor of growth 4 (ING4), as a multimodal tumor suppressor gene, and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), as a potent apoptosis-inducing gene, are experiencing a renaissance in cancer gene therapy. Herein we investigated the antitumor activity and safety of mono- and combined therapy with OAds armed with ING4 (Ad-ΔB/ING4) and TRAIL (Ad-ΔB/TRAIL) gene, respectively, on preclinical models of human HCC. OAd-mediated expression of ING4 or TRAIL transgene was confirmed. Ad-ΔB/TRAIL and/or Ad-ΔB/ING4 exhibited potent killing effect on human HCC cells (HuH7 and Hep3B) but not on normal liver cells. Most importantly, systemic therapy with Ad-ΔB/ING4 plus Ad-ΔB/TRAIL elicited more eradicative effect on an orthotopic mouse model of human HCC than their monotherapy, without causing obvious overlapping toxicity. Mechanistically, Ad-ΔB/ING4 and Ad-ΔB/TRAIL were remarkably cooperated to induce antitumor apoptosis and immune response, and to repress tumor angiogenesis. This is the first study showing that concomitant therapy with Ad-ΔB/ING4 and Ad-ΔB/TRAIL may provide a potential strategy for HCC therapy and merits further investigations to realize its possible clinical translation.

TNFSF9 exerts an inhibitory effect on hepatocellular carcinoma.

Tumor necrosis factor superfamily member 9 (TNFSF9), also known as 4-1BBL and CD137L, has been implicated in cancer immunotherapy due to its function as a T-cell co-stimulator. We aimed to investigate the role of TNFSF9 in the cancer pathogenesis in hepatocellular carcinoma (HCC). TNFSF9 expression was examined by immunohistochemistry in 106 pairs of HCC and adjacent non-tumorous tissues, and by quantitative polymerase chain reaction and Western blot in HCC cell lines. The impact of TNFSF9 on the proliferation, migration and invasion of HCC cells was determined using the 3-(4,5-diethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) and transwell assays in vitro. We also assessed the influence of TNFSF9 on the growth and metastasis of HCC tumors in an orthotopic mouse model of human HCC. TNFSF9 expression was downregulated in approximately 70% of HCC tissues. A decreased expression of TNFSF9 was also consistently observed in all the four HCC cell lines. Either the overexpression of TNFSF9 or treatment with recombinant TNFSF9 protein could significantly inhibit the proliferation, migration and invasion of Huh7 and SMMC-7721 HCC cells in vitro. The inhibitory effect of TNFSF9 on HCC was further confirmed in vivo. Mice orthotopically transplanted with TNFSF9-overexpressing Huh7 cells developed significantly smaller tumors with less intrahepatic metastasis and distant metastasis compared with the control group. TNFSF9 may be a tumor suppressor in HCC. Based on its immune stimulatory aspect and the tumor inhibition property, TNFSF9 may be a promising therapeutic target for HCC.

Longitudinal metabolic imaging of hepatocellular carcinoma in transgenic mouse models identifies acylcarnitine as a potential biomarker for early detection.

The cumulative effects of hepatic injury due to hepatitis B virus (HBV) infections and aflatoxin-B1 (AFB1) exposure are the major risk factors of HCC. Understanding early metabolic changes involving these risk factors in an animal model closely resembling human hepatocellular carcinoma (HCC) is critical for biomarker discovery and disease therapeutics. We have used the hepatitis B surface antigen (HBsAg) transgenic mouse model that mimics HBV carriers with and without AFB1 treatment. We investigated early metabolic changes from preneoplastic state to HCC by non-invasive longitudinal imaging in three HCC groups of mice: HBsAg + AFB1(Gp-I), AFB1 alone (Gp-II), HBsAg alone (Gp-III) and a control group (wild-type untreated; Gp-IV). For the first time, we have identified acylcarnitine signals in vivo in the liver prior to the histological manifestation of the tumors in all three groups. Acylcarnitine concentration increased with increase in tumor growth in all HCC mouse models, indicating elevated metabolic activity and increased cell turnover. This was confirmed in a pilot study using human serum from HCC patients, which revealed a higher concentration of acylcarnitine compared with normal subjects. Translational clinical studies can be designed to detect acylcarnitine in patients with high risk factors for HCC.

MicroRNA let-7c Inhibits Cell Proliferation and Induces Cell Cycle Arrest by Targeting CDC25A in Human Hepatocellular Carcinoma.

Down-regulation of the microRNA let-7c plays an important role in the pathogenesis of human hepatocellular carcinoma (HCC). The aim of the present study was to determine whether the cell cycle regulator CDC25A is involved in the antitumor effect of let-7c in HCC. The expression levels of let-7c in HCC cell lines were examined by quantitative real-time PCR, and a let-7c agomir was transfected into HCC cells to overexpress let-7c. The effects of let-7c on HCC proliferation, apoptosis and cell cycle were analyzed. The in vivo tumor-inhibitory efficacy of let-7c was evaluated in a xenograft mouse model of HCC. Luciferase reporter assays and western blotting were conducted to identify the targets of let-7c and to determine the effects of let-7c on CDC25A, CyclinD1, CDK6, pRb and E2F2 expression. The results showed that the expression levels of let-7c were significantly decreased in HCC cell lines. Overexpression of let-7c repressed cell growth, induced cell apoptosis, led to G1 cell cycle arrest in vitro, and suppressed tumor growth in a HepG2 xenograft model in vivo. The luciferase reporter assay showed that CDC25A was a direct target of let-7c, and that let-7c inhibited the expression of CDC25A protein by directly targeting its 3ʹ UTR. Restoration of CDC25A induced a let-7c-mediated G1-to-S phase transition. Western blot analysis demonstrated that overexpression of let-7c decreased CyclinD1, CDK6, pRb and E2F2 protein levels. In conclusion, this study indicates that let-7c suppresses HCC progression, possibly by directly targeting the cell cycle regulator CDC25A and indirectly affecting its downstream target molecules. Let-7c may therefore be an effective therapeutic target for HCC.

Nitidine chloride induces apoptosis in human hepatocellular carcinoma cells through a pathway involving p53, p21, Bax and Bcl-2.

Nitidine chloride (NC), a novel benzo[c]phenanthridine alkaloid, induces the growth inhibition of cancer cells. Previously it was demonstrated that SMMC-7721 human hepatocellular carcinoma (HCC) cells are highly susceptible to the antiproliferative effects of NC. However, the specific mechanisms remained unclear. In the present study the pathways of growth inhibition induced by NC in SMMC-7721 cells were investigated. The effects of NC on SMMC-7721 cell proliferation were characterized by MTT and colony formation assays. Additionally, BALB/c nude mice were transplanted with SMMC-7721 cells to verify the inhibition of HCC by NC in vivo. The results showed that NC inhibited the proliferation of SMMC-7721 cells in vitro in a time- and dose-dependent manner and identified efficacy in vivo in a mouse model of HCC. Acridine orange (AO) staining, transmission electron microscopy, Annexin V/PI staining, TUNEL assay and caspase-3 activation assays were used to investigate apoptosis and the cell cycle distribution. Inhibition was mediated in part by cell cycle arrest in G2/M, leading to chromatin condensation, DNA fragmentation and the formation of apoptotic bodies. Apoptosis was also verified by Annexin V/PI staining, TUNEL assay and caspase-3 activation. To assess the levels of the cell cycle and apoptotic regulators, immunohistochemical staining, ELISA, real-time PCR and RNA interference (RNAi) were employed. The apoptotic process triggered by NC involved the upregulation of p53, p21 and Bax, and the downregulation of Bcl-2. These data elucidate a pathway of apoptosis in SMMC‑7721 cells that involves G2/M arrest, upregulation of p53, Bax, caspase-3 and p21, and downregulation of Bcl-2.

The DEN and CCl4 -Induced Mouse Model of Fibrosis and Inflammation-Associated Hepatocellular Carcinoma.

Human hepatocellular carcinoma (HCC) develops most often as a complication of fibrosis or cirrhosis. While most human studies of HCC provide crucial insights into the molecular signatures of HCC, seldom do they address the etiology of HCC. Mouse models are essential tools for investigating the pathogenesis of HCC; however, the overwhelming majority of cancer models in rodents do not feature liver fibrosis. Detailed in this unit is a protocol for an experimental mouse model of HCC that arises in association with advanced liver fibrosis. The disease model is induced by a single injection of N-nitrosodiethylamine (DEN) followed by repeated administration of carbon tetrachloride (CCl4 ). A dramatic potentiation of liver tumor incidence is observed following administration of DEN and CCl4 , with 100% of mice developing liver tumors at 5 months of age. This model can be employed for studying the molecular mechanisms of fibrogenesis and HCC development, and in cancer hazard/chemotherapy testing of drug candidates.

Evaluation of tumor microvascular response to brivanib by dynamic contrast-enhanced 7-T MRI in an orthotopic xenograft model of hepatocellular carcinoma.

The purpose of this article is to evaluate the antiangiogenic effects of brivanib using dynamic contrast-enhanced MRI (DCE-MRI) in an orthotopic mouse model of human hepatocellular carcinoma (HCC). With human HCC (HepG2 cell line) orthotopic nude mouse xenografts, brivanib was administered orally to the treatment group, and the vehicle was administered to the control group for 14 days. DCE-MRI was performed before the start of the therapy and 7 and 14 days after the start of therapy. Treatment-induced changes in tumor volume and microvessel density (MVD) assessed by CD31 immunohistochemistry were analyzed. Perfusion parameters, including volume transfer constant between blood plasma and extravascular extracellular space (K(trans)), fractional extravascular extracellular space per unit volume of tissue (ve), and rate constant between extravascular extracellular space and blood plasma (Kep), were calculated using the two-compartment model. Brivanib shows potent antitumor activity in tumor volume. The mean (± SD) MVD of the tumors was statistically significantly lower in the brivanib-treated group (40.8 ± 17.3 vessels/field) than in the control group (55.2 ± 9.05 vessels/field) (p < 0.05). In the control group, the K(trans) value increased statistically significantly between the baseline and 14 days after treatment (p = 0.048). In the brivanib-treated group, the K(trans) and ve values decreased statistically significantly between baseline and 7 days after treatment (p = 0.024 and p = 0.031, respectively) and between baseline and 14 days after treatment (p = 0.043 and p = 0.018, respectively). The difference between the K(trans) and ve values between baseline and 14 days after treatment showed a statistically significant difference between the two groups (p = 0.004 and p = 0.034, respectively). DCE-MRI is feasible in the orthotopic mouse model of human HCC, and it can noninvasively monitor brivanib-induced changes in tumor microvasculature.

Effects of Angiotensin II Type 2 Receptor Overexpression on the Growth of Hepatocellular Carcinoma Cells In Vitro and In Vivo

Increasing evidence suggests that the renin-angiotensin system (RAS) plays an important role in tumorigenesis. The interaction between Angiotensin II (AngII) and angiotensin type 1 receptor (AT1R) may have a pivotal role in hepatocellular carcinoma (HCC) and therefore, AT1R blocker and angiotensin I-converting enzyme (ACE) inhibitors may have therapeutic potential in the treatment of hepatic cancer. Although the involvement of AT1R has been well explored, the role of the angiotensin II Type 2 receptor (AT2R) in HCC progression remains poorly understood. Thus, the aim of this study was to explore the effects of AT2R overexpression on HCC cells in vitro and in mouse models of human HCC. An AT2R recombinant adenoviral vector (Ad-G-AT2R-EGFP) was transduced into HCC cell lines and orthotopic tumor grafts. The results indicate that the high dose of Ad-G-AT2R-EGFP–induced overexpression of AT2R in transduced HCC cell lines produced apoptosis. AT2R overexpression in SMMC7721 cells inhibited cell proliferation with a significant reduction of S-phase cells and an enrichment of G1-phase cells through changing expression of CDK4 and cyclinD1. The data also indicate that overexpression of AT2R led to apoptosis via cell death signaling pathway that is dependent on activation of p38 MAPK, pJNK, caspase-8 and caspase-3 and inactivation of pp42/44 MAPK (Erk1/2). Finally, we demonstrated that moderately increasing AT2R expression could increase the growth of HCC tumors and the proliferation of HCC cells in vivo. Our findings suggest that AT2R overexpression regulates proliferation of hepatocellular carcinoma cells in vitro and in vivo, and the precise mechanisms of this phenomenon are yet to be fully determined.