Hepatocellular Carcinoma In Male Mice Research Articles

Effect of protocatechuic acid-layered double hydroxide nanoparticles on diethylnitrosamine/phenobarbital-induced hepatocellular carcinoma in mice.

Researchers investigating cancer chemotherapy and management continue to search for agents that selectively kill malignant cells and leave healthy neighboring cells intact. Natural products provide relevant resources for anti-cancer drug discovery. However, the physicochemical properties of these compounds limit their efficient uptake and bioavailability. We introduced a nanocarrier system, namely, zinc-aluminum-layered double hydroxide (ZnAl-LDH) intercalated with protocatechuic acid. In this study, the efficacy and toxicity of protocatechuic acid intercalated in zinc aluminum-layered double hydroxide nanoparticles (PCA-ZnAl) against diethylnitrosamine/phenobarbital (DEN/PB)-induced hepatocellular carcinoma (HCC) in BALB/c mice was evaluated. HCC in male mice was induced by a single-dose intraperitoneal administration of DEN and was promoted by the introduction of PB via drinking water for 12 weeks. HCC induction was confirmed after the DEN/PB introduction period by measurement of the elevated level of serum α-feto protein (AFP). The results showed that the level of α-fetoprotein was significantly reduced in PCA-ZnAl (350±43.90 ng/mL), doxorubicin (DOX) (290±20.52 ng/mL) and ZnAl-LDH (390±19.65 ng/mL) treated animals compared to HCC mice treated with normal saline (580.4± 52.04 ng/mL). Superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels were significantly increased, whereas the level of lipid peroxidation was significantly decreased in HCC mice treated with DOX, PCA-ZnAl and ZnAl-LDH compared with those in HCC mice treated with saline. Restoration of hepatocyte morphology was observed following treatment that was comparable to that in the normal control group. Deterioration of hepatic cells and a significant increase of aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) were observed in the cancer-induced untreated group compared with that in the groups treated with nanoparticles. The histopathological features of the liver obtained from PCA-ZnAl-treated mice showed a uniform size with a similar distribution of the nuclear-cytoplasmic ratio and nucleus centrally located in the cytoplasm, similar to the normal liver cells. The results underscored the potential of PCA-ZnAl for the treatment of hepatocellular carcinoma.

Vacuolar Protein Sorting 33B Is a Tumor Suppressor in Hepatocarcinogenesis.

Polarity defects are frequently involved in liver diseases, such as chronic hepatitis and hepatocellular carcinoma (HCC). It was reported that vacuolar protein sorting 33B (Vps33b) plays critical roles in the maintenance of hepatocyte polarity; however, the functional roles and mechanisms of Vps33b in HCC occurrence and progression remain unknown. First of all, we showed that Vps33b is down-regulated in human and mouse liver cancer samples, and the low expression levels of Vps33b correlate with the poor prognosis of many HCC patients. Liver-specific Vps33b deficiency induces liver damage, progressive hepatitis, fibrosis, and HCC in male mice, indicating that Vps33b is a crucial contributory factor to hepatocarcinogenesis. Vps33b deficiency-caused liver damage was primarily due to the disorders of structural and functional hepatocyte polarity, which were reflected by the decreased protein levels of E-cadherin because of inaccurate location to lysosomes and polarity defects at both apical and lateral plasma membrane proteins. The results of a mechanism study revealed that Vps33b interacts with VPS33B-interacting protein, which is involved in polarity and apical protein restriction; vesicle-trafficking protein Sec22b; and Flotillin-1 in hepatocytes and is in charge of the normal distribution of polarity-determined proteins. Expression levels of Vps33b negatively correlated with the degree of inflammatory cell infiltration in livers from diethylnitrosamine-induced or transgenic HCC mouse models, and the inflammatory stimuli suppressed the expression of Vps33b in vitro. Conclusion: Down-regulation of Vps33b expression is a critical step for inflammation-driven HCC, and Vps33b serves as an important tumor suppressor in hepatocarcinogenesis.

Loss of 5α-reductase type 1 accelerates the development of hepatic steatosis but protects against hepatocellular carcinoma in male mice.

Nonalcoholic fatty liver disease (NAFLD) has been associated with glucocorticoid excess and androgen deficiency, yet in the majority of patients with steatohepatitis, circulating cortisol and androgen levels are normal. The enzyme 5α-reductase (5αR) has a critical role in androgen and glucocorticoid action. We hypothesize that 5αR has an important role in the pathogenesis of steatohepatitis through regulation of intracrine/paracrine hormone availability. Human liver samples from patients with NAFLD and normal donor tissue were used for gene expression and immunohistochemical analysis. NAFLD samples were scored using the Kleiner classification. In addition, 5αR1−/−, 5αR2−/−, and wild-type (WT) mice were fed normal chow or American lifestyle-induced obesity syndrome (ALIOS) diet for 6 or 12 months. Liver histology was graded and staged. Hepatic and circulating free fatty acid and triglyceride levels were quantified, and gene and protein expression was measured by real-time PCR and immunohistochemistry. 5αR1 and -2 were highly expressed in human liver, and 5αR1 protein expression increased with severity of NAFLD. 5αR1−/− (but not 5αR2−/−) mice fed an ALIOS diet developed greater hepatic steatosis than WT mice, and hepatic mRNA expression of genes involved in insulin signaling was decreased. Furthermore, 60% of WT mice developed focal hepatocellular lesions consistent with hepatocellular carcinoma after 12 months of the ALIOS diet, compared with 20% of 5αR2−/− and 0% of 5αR1−/− mice (P < .05). 5αR1 deletion accelerates the development of hepatic steatosis but may protect against the development of NAFLD-related hepatocellular neoplasia and therefore has potential as a therapeutic target.

Liver‐gender mosaicism and not androgen signaling correlates with hepatocellular carcinoma in male mice

Liver‐gender mosaicism and not androgen signaling correlates with hepatocellular carcinoma in male mice

Health span and life span in transgenic mice with modulated DNA repair.

One way to better understand the contribution of DNA repair, DNA damage, and mutagenesis in aging would be to enhance DNA repair activity, lower DNA damage, and lower mutagenesis. Because the repair protein O6-methylguanine-DNA methyltransferase (MGMT) acts alone and stoichiometrically, the human MGMT (hMGMT) cDNA was selected to test the feasibility of enhancing DNA repair activity in transgenic mice. MGMT activity is largely responsible for ameliorating the deleterious effects of O6-methylguanine (O6mG) lesions in DNA in a direct reversal mechanism. A transgene was constructed consisting of a portion of the human transferrin (TF) promoter and hMGMT cDNA such that hMGMT is expressed in transgenic mouse brain and liver. Expression of hMGMT was associated with a significant reduction in the occurrence of an age-related hepatocellular carcinoma in male mice at 15 months of age. Longitudinal and cross-sectional studies were initiated to determine whether the reduced incidence of hepatocellular carcinoma would impact median or maximum life span. The cross-sectional study performed on 15-month-old male animals confirmed the reduced occurrence of spontaneous hepatocellular carcinoma. At 30 months of age, however, the occurrence of hepatocellular carcinoma in at least one transgenic line was similar to that for nontransgenic animals. The longitudinal study is ongoing; however, at present no significant differences in life span have been detected. Tissues expressing the MGMT transgene also displayed greater resistance to alkylation-induced tumor formation. These results suggest that transgenes can be used to direct enhanced DNA repair gene expression and that enhanced expression can protect animals from certain spontaneous and induced tumors.

Oncogenicity Testing of 2-Ethylhexanol in Fischer 344 Rats and B6C3F1 Mice

2-Ethylhexanol (2EH) is a weak nongenotoxic hepatic peroxisome proliferator in the rat. It is a high-volume chemical intermediate in the preparation of the plasticizers bis-(2-ethylhexyl) adipate (DEHA), bis-(2-ethylhexyl) phthalate (DEHP), and tris-(2-ethylhexyl) phosphate (TEHP), which are weak hepatocellular tumorigens in female mice. In consequence, the oncogenic potential of 2EH was evaluated in male (M) and female (F) rats and mice (50 animals/sex/group). Oral gavage doses of 2EH in 0.005% aqueous Cremophor EL (polyoxyl-35 castor oil) were given five times a week to rats: 0 (water), 0 (vehicle), 50, 150, and 500 mg/kg for 24 months, and to mice: 0 (water), 0 (vehicle), 50, 200, and 750 mg/kg for 18 months. Statistical comparisons of data were made between vehicle controls and treatment groups. There were no differences of biological significance between data from vehicle and water control groups. In rats, there were no dose-related changes at 50 mg/kg. There was reduced body weight gain at 150 mg/kg (M, 16; F, 12%) and 500 mg/kg (M, 33; F, 31%) and an increased incidence of lethargy and unkemptness. There were dose-related increases in relative liver, stomach, brain, kidney, and testis weights at sacrifice. Female rat mortality was markedly increased at 500 mg/kg. There was marked aspiration-induced bronchopneumonia in rats at 500 mg/kg; hematologic, gross, and microscopic changes, including tumors, were otherwise comparable among all rat groups. In mice at 50 and 200 mg/kg there were no dose-related changes and essentially no time-dependent or time-independent adverse trends in liver tumor incidence at the 5% significance level. At 750 mg/kg mouse body weight gain was reduced (M, 26; F, 24%), and mortality increased (M and F, 30%) versus vehicle controls. At 750 mg/kg there was a slight increase in nonneoplastic focal hyperplasia in the forestomach of mice (M 5/50, F 4/50) versus vehicle controls (M 1/50, F 1/50). There were increases in mouse relative liver (F, 21%) and stomach (M, 13%; F, 19%) weights at 750 mg/kg. There was a 12% incidence of hepatic basophilic foci and an 18% incidence of hepatocellular carcinomas in male mice at 750 mg/kg, not statistically significant compared with either control by Fisher's exact test. There was a 12% incidence of hepatic basophilic foci and a 10% incidence of hepatocellular carcinomas in female mice at 750 mg/kg, statistically significant (p< 0.05) compared with vehicle but not with water controls by Fisher's exact test. There were no metastases. Time-dependent and -independent statistical analyses showed an adverse trend in the incidence of hepatocellular carcinomas in male and female mice, correlated with toxicity (expressed as mortality) at 750 mg/kg. The time-adjusted incidence of hepatocellular carcinomas in male mice (18.8%) was within the historical normal range at the testing facility (0–22%), but that in females (13.1%) lay outside the normal range (0–2%). Under the conditions of these studies 2EH was not oncogenic in rats, but there were weak adverse trends in hepatocellular carcinoma incidence in mice at high dose levels which may have been associated with toxicity. The major effects of chronic dosing were mortality in female rats at 500 mg/kg and in male and female mice at 750 mg/kg, accompanied by reductions in body weight gain in rats at 150 and 500 mg/kg and in mice at 750 mg/kg. Direct comparison of any tumorogenic effects of 2EH given alone to female mice with those due to 2EH formedin vivofrom DEHA, DEHP, or TEHP is limited by the high mortality caused by 2EH in female mice at equivalent doses of 2EH. While 2EH may be a contributing factor in the hepatocellular carcinogenesis in female mice associated with the chronic administration of DEHA and DEHP, it is unlikely to be the entire proximate carcinogen.

Carcinogenicity studies on halogenated hydrocarbons.

A series of halogenated compounds was tested by oral intubation in 200 Osborne-Mendel rats and 200 B6C3F1 mice of both sexes. Carbon tetrachloride, used as a positive control, induced liver and adrenal tumors in mice and neoplastic nodules in the livers of rats. 1,2-Dibromoethane and 1,2-dibromo-3-chloropropane caused stomach tumors with many metastases in both rats and mice. Chloroform, known to cause hepatocellular carcinomas in mice, led in addition to kidney tumors in male rats. 1,2-Dichloroethane was much weaker than the analog, 1,2-dibromoethane, and induced only a few stomach tumors in rats. It increased liver and lung tumors in mice. Most of the compounds, namely, trichloroethylene, 1,1-dichloroethane, 1,1,2-trichloroethane, hexachloroethane, and tetrachloroethylene, increased hepatocellular carcinomas in mice but had little or no action in rats. Iodoform tended to increase thyroid tumors in male rats and hepatocellular carcinomas in male mice. The action of 3-chloropropene was questionable. No tumors could be attributed to 1,1,1-trichloroethane (methyl-chloroform).