Development of an immunosuppressed orthotopic hepatocellular carcinoma rat model for the evaluation of chemo- and radioembolization therapies.

Hepatocellular carcinoma (HCC) is widely known to be chemo-resistant and presents with significant liver disease resulting in low tolerability to systemic chemotherapy. As a counter measure, more targeted therapies such as trans-arterial chemoembolization (TACE) and trans-arterial radioembolization (TARE) have been developed. To further optimize these therapies, animal models are critical in elucidating the molecular events in disease progression and test new treatment options. The present study focuses on the development of a hepatoma bearing rat model. N1S1 rat hepatoma cells were transfected by a lentiviral method and injected into the liver of Sprague Dawley (SD) and Rowett Nude (RNU) rats. Longitudinal tumor growth was observed by bioluminescence imaging (BLI) and liver/tumor histology. In both models, tumors were visible within 4 days post cell inoculation. Tumor take rates were 52 % and 73 % for male and female SD rats, respectively, and 100 % for male RNU rats. By day 12 and 15 post inoculation, we recorded complete tumor regression in male and female SD rats. Liver histology showed advanced fibrosis in the tumor regressed SD rats, whilst RNU rats exhibited the characteristic sheet pattern of Novikoff tumor with mild liver fibrosis. Increased CD3 and TUNEL staining observed in SD rat livers may be key factors for tumor regression. Our data reveal that the immunocompetent SD rats are not recommended as a model for therapeutic investigations. The immunosuppressed RNU rats, however, are characterized by consistent and reliable tumor growth and thus a desirable model for future therapeutic investigations.

Kaempferide exhibits an anticancer effect against hepatocellular carcinoma in vitro and in vivo.

CONTEXT: Phytochemicals have been promising candidates for cancer therapy, affecting various cancer initiation and progression stages. Kaempferide is a mono methoxy flavone that shows potent anticancer effects on multiple cancers both in vitro and in vivo. MATERIALS AND METHODS: We evaluated the anticancer activity of kaempferide against HCC using an MTT ((3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. HepG2, Huh7, and N1S1 were used for preliminary in vitro studies. This is followed by an apoptosis analysis assessed by caspase-3 and 9. The in vivo effects of the compound were studied in the N1S1 orthotopically injected SD (Sprague Dawley) rat model, where the animal was given kaempferide (25 mg/kg thrice a week) and vehicle (Cremophor:ethanol) iv. The expression of caspase-9 and a critical tumor marker, transforming growth factor beta 1 (TGF-ß 1), were assessed in both control and treatment tumor samples. RESULTS: Kaempferide-induced dose-dependent cytotoxicity in three HCC cell lines (HepG2: IC50 = 27.94 ± 2.199 µM; Huh7: IC50 = 25.65 ± 0.956 µM; and N1S1: IC50 = 15.18 ± 3.68 µM). Furthermore, caspase-dependent apoptosis was confirmed in vitro. Kaempferide showed a significant reduction in tumor size and tumor volume in vivo. Histopathological evaluation by hematoxylin and eosin (H&E) staining confirmed that altered cells were significantly demolished in the kaempferide-treated animals, which correlates with tumor reduction compared to the vehicle-treated group. Caspase-9 levels were also found to be increased in the treatment group. TGF-ß 1, a crucial marker in invasion and metastasis of liver cancer, was also downregulated in the treatment group (control = 207.8 ± 22.9 pg/mL and kaempferide-treated = 157.3 ± 13.8 pg/mL). CONCLUSION: We report for the first time the potential of kaempferide as a promising alternative against HCC, which further warrants its clinical validation.

Comparison of Biomarkers Between Hepatic Tumors in Rat Models and a Dog.

BACKGROUND/AIM: N1S1 rat models are commonly used in human medicine to study hepatocellular carcinoma (HCC). However, their use in veterinary medicine has not been reported. Thus, the aim of this study was to investigate whether the N1S1 rat models could be used to study canine HCC. MATERIALS AND METHODS: The animals were divided into four groups: normal rat, N1S1 rat, normal dog, and HCC dog. Liver tissues of all animals were evaluated for vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR)-α, PDGFR-ß, and c-kit by immunohistochemistry. Slides of each factor were scored according to the percentage of stained tumor cells and intensity of the staining. RESULTS: Scores of VEGF and c-kit were high both in the tumor groups (the N1S1 rat and HCC dog groups) and the normal groups of dogs and rats. PDGFR-α was lower in the N1S1 rat group than that in the normal rat group (p=0.0042). It was also lower in the HCC dog group compared to the normal dog group (p=0.0008). PDGFR-ß was higher in the HCC dog group than that in the normal dog group (p=0.0023) but was not detectable in the rat groups. EGFR was not detectable in any group. CONCLUSION: Based on immunochemistry results, PDGFR-α and PDGFR-ß can be used as biomarkers of canine HCC. Because PDGFR-α showed consistency between rats and dogs, it can be used for studying canine HCC.

Establishment of animal models with orthotopic hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most serious health problems worldwide. Many researchers have investigated HCC at the level of genes, ribonucleic acid, proteins, cells, and animals. The resultant development of animal models and monitoring methods has improved the effectiveness of guidelines provided to researchers working with preclinical HCC models. HCC in animal models and clinical patients is monitored by various current imaging modalities such as ultrasound (US) imaging, computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), positron emission tomography (PET) and bioluminescence imaging (BLI). These techniques are currently used for both preclinical and clinical assessment, and provide valuable diagnostic information. In this article, we have mainly reviewed the established animal models and the assessment of orthotopic HCC using imaging modalities. Additionally, we have introduced a method of orthotopic HCC rat model developed in our laboratory. We have furthermore evaluated the occurrence of tumor mass using molecular imaging techniques.

LY2456302 is a novel, potent, orally-bioavailable small molecule kappa-selective antagonist with activity in animal models predictive of efficacy in mood and addictive disorders.

Kappa opioid receptors and their endogenous neuropeptide ligand, dynorphin A, are densely localized in limbic and cortical areas comprising the brain reward system, and appear to play a key role in modulating stress and mood. Growing literature indicates that kappa receptor antagonists may be beneficial in the treatment of mood and addictive disorders. However, existing literature on kappa receptor antagonists has used extensively JDTic and nor-BNI which exhibit long-lasting pharmacokinetic properties that complicate experimental design and interpretation of results. Herein, we report for the first time the in vitro and in vivo pharmacological profile of a novel, potent kappa opioid receptor antagonist with excellent selectivity over other receptors and markedly improved drug-like properties over existing research tools. LY2456302 exhibits canonical pharmacokinetic properties that are favorable for clinical development, with rapid absorption (t(max): 1-2 h) and good oral bioavailability (F = 25%). Oral LY2456302 administration selectively and potently occupied central kappa opioid receptors in vivo (ED50 = 0.33 mg/kg), without evidence of mu or delta receptor occupancy at doses up to 30 mg/kg. LY2456302 potently blocked kappa-agonist-mediated analgesia and disruption of prepulse inhibition, without affecting mu-agonist-mediated effects at doses >30-fold higher. Importantly, LY2456302 did not block kappa-agonist-induced analgesia one week after administration, indicating lack of long-lasting pharmacodynamic effects. In contrast to the nonselective opioid antagonist naltrexone, LY2456302 produced antidepressant-like effects in the mouse forced swim test and enhanced the effects of imipramine and citalopram. LY2456302 reduced ethanol self-administration in alcohol-preferring (P) rats and, unlike naltrexone, did not exhibit significant tolerance upon 4 days of repeated dosing. LY2456302 is a centrally-penetrant, potent, kappa-selective antagonist with pharmacokinetic properties favorable for clinical development and activity in animal models predictive of efficacy in mood and addictive disorders.

In vitro demonstration of synergy/additivity between (188)rhenium and sorafenib on hepatoma lines: preliminary results.

BACKGROUND: Hepatocellular carcinoma is generally diagnosed at advanced stages, for which only palliative treatments are possible by intra-arterial route or by targeted therapies. Among these treatments, metabolic radiotherapy using (90)-yttrium or (188)Re and sorafenib are two options adopted in monotherapy. MATERIALS AND METHODS: We address the question of a possible synergy arising from the combination of these two treatments. Two primary malignant hepatoma cell lines, N1S1 (murine HCC) and HepG2 (human hepatoblastoma) were treated in media containing increasing concentrations of sorafenib with/without (188)Re to assess the cellular toxicities of each treatment alone and in combination. The combination index method was used to look for synergy or additivity. RESULTS: A synergistic advantage of a treatment combining (188)Re and sorafenib is shown in vitro on hepatoma cell lines. CONCLUSION: This combined approach is promising and now needs to be confirmed by more complex in vitro models integrating the tumoral stroma, as well as by in vivo studies.

Effects of benzo(a)pyrene on the expression of heat shock proteins, pro-inflammatory cytokines and antioxidant enzymes in hepatic tumors induced by rat hepatoma N1-S1 cells.

Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) that is easily introduced to humans via consumption of grilled or smoked meat. BaP causes harmful oxidative effects on cell development, growth and survival through an increase in membrane lipid peroxidation, oxidative DNA damage and mutagenesis. Therefore, the present study was conducted to evaluate the synergistic effects of BaP on oxidative stress in hepatic tumors. In this study, we established a hepatic tumor model by injecting rat hepatoma N1-S1 cells into healthy rats. Changes in the abundance of heat shock proteins (HSPs), antioxidant enzymes and pro-inflammatory cytokines were then investigated by western blot analysis. In addition, we examined changes in oxidative stress levels. Injection of N1-S1 cells or concomitant injection of BaP and N1-S1 cells resulted in the formation of hepatic tumors at the injection site. Evaluation of rat plasma reveals that hepatic tumors induced by BaP and N1-S1 cells expresses higher levels of Hsp27, superoxide dismutase (SOD), and tumor necrosis factor-α (TNF-α) when compared to those induced by N1-S1 cells only. The collective results of this study suggest that BaP exerts synergistic effects on the expression of HSP, cytokines and antioxidant enzymes in hepatic tumors induced by rat hepatoma N1-S1 cells.

Effects of Benzo(a)pyrene on the Expression of Heat Shock Proteins, Pro-inflammatory Cytokines and Antioxidant Enzymes in Hepatic Tumors Induced by Rat Hepatoma N1-S1 Cells

Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) that is easily introduced to humans via consumption of grilled or smoked meat. BaP causes harmful oxidative effects on cell development, growth and survival through an increase in membrane lipid peroxidation, oxidative DNA damage and mutagenesis. Therefore, the present study was conducted to evaluate the synergistic effects of BaP on oxidative stress in hepatic tumors. In this study, we established a hepatic tumor model by injecting rat hepatoma N1-S1 cells into healthy rats. Changes in the abundance of heat shock proteins (HSPs), antioxidant enzymes and pro-inflammatory cytokines were then investigated by western blot analysis. In addition, we examined changes in oxidative stress levels. Injection of N1-S1 cells or concomitant injection of BaP and N1-S1 cells resulted in the formation of hepatic tumors at the injection site. Evaluation of rat plasma reveals that hepatic tumors induced by BaP and N1-S1 cells expresses higher levels of Hsp27, superoxide dismutase (SOD), and tumor necrosis factor-alpha (TNF-alpha) when compared to those induced by N1-S1 cells only. The collective results of this study suggest that BaP exerts synergistic effects on the expression of HSP, cytokines and antioxidant enzymes in hepatic tumors induced by rat hepatoma N1-S1 cells.

Highly malignant intra-hepatic metastatic hepatocellular carcinoma in rats.

UNLABELLED: Intra-hepatic metastasis is one of the major modalities that lead to the recurrence of advanced HCC. Research efforts to investigate HCC metastasis/recurrence and therapy response will require appropriate models. For our study, the main purpose was to compare two different rodent syngenic orthotopic HCC models using MRI and pathologic evidence; we specifically sought to investigate the intra-hepatic metastatic properties of HCC in Buffalo rats. METHODS: 12 female Buffalo rats and 16 male Sprague Dawley (SD) rats were used in these studies. Subcapsular implantation of 1×10(6) McA-RH7777 and 1×10(6) N1-S1 rat hepatoma cells into the left hepatic lobe was carried out in Buffalo and SD rats, respectively. Buffalo hepatoma rats (n=5/6) and SD hepatoma rats (n=6/8) were imaged using MRI at 6-8 days after implantation. Then, another group of Buffalo HCC rats (n=6/6) and SD HCC (n=6/8) rats were scanned at 21-25 days interval post-implantation. After image acquisition, tumor sections were evaluated with H&E and CD34 staining. RESULTS: Tumor induction rate for Buffalo rats was 92% (11/12) compared to 75% (12/16) for SD rats. The mean tumor size of McA-RH7777 hepatoma rats at 6-8 day interval was 1.32±0.56cm, but progressed to multiple intra-hepatic metastasis at 21-25 day interval in 6/6 rats (100%). In contrast, the mean tumor size of N1-S1 rats at early interval was 1.06±0.32cm, these progressed to only a single solid mass of 2.35±0.69cm at later interval without obvious intra-hepatic metastasis. H&E staining showed that McA-RH7777 cell induced Morris hepatoma exhibited typical trabecular growth pattern, better representative of human HCC compared to the sheet pattern of N1-S1 cell induced Novikoff hepatoma. CONCLUSION: The McA-Rh7777 rat hepatoma model was demonstrated to be a highly malignant intra-hepatic metastasis model of potential utility for HCC research.