Preventive Effect of Geraniol on Diethylnitrosamine-Induced Hepatocarcinogenesis in Rats

Background

Geraniol is a plant-derived phytochemical possessing anti-cancer action. The anti-carcinogenic effect of geraniol was investigated in the diethylnitrosamine (DEN)-induced hepatocarcinogenic rat model.

Methods

Male Wistar rats were intraperitoneally injected with 300 μL of phosphate-buffered saline (PBS) (G1; n = 4) or DEN (100 mg/kg body weight) dissolved in PBS (G2; n = 8) every 2 weeks on experimental weeks 2, 4 and 6. The rats were treated with a low concentration (0.07%) of geraniol (G3; n = 9) and high concentration (0.35%) of geraniol (G4; n = 7) for 12 weeks. To evaluate the effects of geraniol on the DEN-induced hepatocarcinogenesis, we compared the relative liver weight, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) levels and expression levels of proliferating cell nuclear antigen (PCNA) and glutathione S transferase-P (GST-P) by immunohistochemical analyses among each group.

Results

Relative liver weight was significantly higher in G2 than in G1 (P < 0.01). Both serum AST and ALT levels were significantly higher in G2 than in G3 and in G4 (P < 0.05). Serum ALP levels did not show a significant difference among each group. Percentages of both PCNA- and GST-P- positive area were significantly decreased in G3 and in G4 compared to in G2 (P < 0.001, respectively), suggesting anti-hepatocarcinogenic effects of geraniol.

Conclusion

Geraniol is a promising compound useful for suppression of hepatocellular carcinoma. The mechanisms of action are required to be clarified in the future intensive study.     

Endothelial Rho and Rho kinase regulate neutrophil migration via endothelial myosin light chain phosphorylation

The transendothelial migration of neutrophils is a critical step in acute inflammation, which we previously showed to be regulated by endothelial myosin light chain (MLC) kinase. Recent studies suggest that Rho and Rho kinase are also key mediators of MLC phosphorylation, but their roles in neutrophil migration have not been investigated. In the present study, a transwell chamber migration assay system incorporating endothelial monolayer was used to examine the numbers of migrating neutrophils, endothelial F-actin and myosin II rearrangement, and endothelial MLC phosphorylation at selected times during the neutrophil migration in vitro. The results showed that pretreating endothelial cells with C3 (Rho inhibitor) or Y-27632 (Rho kinase inhibitor) significantly diminished neutrophil migration, actin polymerization, myosin II filament formation, and MLC phosphorylation normally associated with the migration. These data suggest that endothelial Rho and Rho kinase regulate transendothelial neutrophil migration by modulating the cytoskeletal events that mediate such migration.     

Selective loss of gastrointestinal mast cells and impaired immunity in PI3K-deficient mice

Mice that lack the p85alpha regulatory subunit of phosphatidylinositol-3 kinase (PI3K) are deficient in gastrointestinal and peritoneal mast cells but have dermal mast cells. Accordingly, these mice show impaired bacterial clearance in response to acute septic peritonitis and are highly susceptible to infection by the intestinal nematode Strongyloides venezuelensis. Systemic anaphylactic shock responses, however, are intact. We found that although reconstitution of PI3Kminus sign/minus sign mice with bone marrow--derived mast cells (BMMCs) restored anti-bacterial immunity, only T helper type 2 (TH2)-conditioned BMMCs, not "standard" BMMCs, were able to restore anti-nematode immunity. This finding highlights the importance of the TH2 response in the control of nematode infection. Thus, PI3K likely plays an essential role in host immune responses by regulating both the development and induction of mast cells.     

Alpha-fetoprotein-producing lung carcinoma: report of three cases

Three cases of alpha-fetoprotein (AFP)-producing lung carcinoma were studied histologically and immunohistochemically. Samples were obtained from two men and one woman who ranged in age from 64 to 71 years. Serum AFP levels for the three samples were 9826, 74.4 and 24.3 ng/mL. One case was classified as stage IIIA and two as stage IIIB. Two cases were diagnosed as large cell neuroendocrine carcinoma, and AFP expression was detected immunohistochemically. One of these samples showed differentiation to a hepatoid carcinoma, while the other was combined with a squamous cell carcinoma. The remaining case was a squamous cell carcinoma, and AFP was detected in only some of the tumor cells. All patients died within 2 years. The Ki-67 labeling indices of the AFP-producing pulmonary carcinomas (30.2 +/- 4.6%) were significantly higher than those of AFP-negative pulmonary carcinomas (P < 0.05). The high proliferative activity, advanced stage at presentation, vascular endothelial growth factor expression and vascular invasion observed in these tumors may explain the poor prognosis of AFP-producing lung carcinomas.     

The transmembrane semaphorin Sema6A controls cerebellar granule cell migration

The transmembrane semaphorin protein Sema6A is broadly expressed in the developing nervous system. Sema6A repels several classes of developing axons in vitro and contributes to thalamocortical axon guidance in vivo. Here we show that during cerebellum development, Sema6A is selectively expressed by postmitotic granule cells during their tangential migration in the deep external granule cell layer, but not during their radial migration. In Sema6A-deficient mice, many granule cells remain ectopic in the molecular layer where they differentiate and are contacted by mossy fibers. The analysis of ectopic granule cell morphology in Sema6a-/- mice, and of granule cell migration and neurite outgrowth in cerebellar explants, suggests that Sema6A controls the initiation of granule cell radial migration, probably through a modulation of nuclear and/or soma translocation. Finally, the analysis of mouse chimeras suggests that this function of Sema6A is primarily non-cell-autonomous.     

Significance of switching of the nucleos(t)ide analog used to treat Japanese patients with chronic hepatitis B virus infection from entecavir to tenofovir alafenamide fumarate

The significance of switching of the nucleos(t)ide analog used to treat patients with hepatitis B virus (HBV) from entecavir (ETV) to tenofovir alafenamide fumarate (TAF) is uncertain. The subjects of this study were 159 patients with HBV who received treatment with ETV followed by TAF. Among these patients, serial changes in the HBV marker levels were monitored in 92 patients in whom the serum HBsAg levels were ≥100 IU/mL during the 48-week period immediately before and after the switching. A questionnaire survey for medication compliance was performed in 127 patients. The serum HBsAg levels (log IU/mL) decreased by 0.041 during the ETV treatment period and by 0.068 during the TAF administration period. The degree of reduction was higher during the TAF administration period than during the ETV administration period in patients without cirrhosis (P = .030), patients with genotype B HBV (P = .014), and patients with undetectable serum HBcrAg (P = .038). Multivariate analysis revealed the HBV genotype (B vs C; odds ratio, 3.400; P = .025) and serum aspartate aminotransferase level (every 1+; 1.111; P = .015) at the time of switching as factors influencing the treatment efficacy. Thirty-six patients (28%) responded that the number of days that they forgot to take the drug decreased after the drug switching, and 77 patients (61%) reported feeling satisfied with the drug switching. Switching of the nucleos(t)ide analog used from ETV to TAF may be useful in the treatment of patients with HBV infection, as it is associated with both a decrease in the serum HBsAg level and improvement of the medication compliance.     

Experimental autoimmune thyroiditis in nonobese diabetic mice lacking interferon regulatory factor-1

Interferon regulatory factor-1 (IRF-1) is pivotal in the regulation of interferon (IFN)-mediated immune reactions, and studies suggest that IRF-1 is involved in the development of autoimmune diseases. IRF-1+/+, +/-, and -/- nonobese diabetic (NOD) mice were immunized with mouse thyroglobulin (mTg) to determine whether IRF-1 is required in experimental autoimmune thyroiditis (EAT), a murine model for Hashimoto's thyroiditis (HT). IRF-1-deficient mice developed EAT and anti-mTg antibodies comparable to IRF-1+/+ and +/- mice. Whereas both CD4+ and CD8+ T cells were found in thyroids of IRF-1+/+ mice, the latter was not in IRF-1-/- mice. Major histocompatibility complex class II antigen was comparably expressed in thyroids of IRF-1+/+ and -/- mice. Lack of IRF-1 resulted in decreased CD8+ T cell number in the spleen and reduced IFNgamma production by splenocytes. Our results suggest that IRF-1 is not pivotal in EAT in NOD mice.     

Identification of ligand recognition sites in heat-stable enterotoxin receptor, membrane-associated guanylyl cyclase C by site-directed mutational analysis.

Guanylyl cyclase C (STaR), a receptor protein for heat-stable enterotoxin (STa) elaborated by Escherichia coli, is associated with and spans the plasma membrane of mammalian intestinal cells. The extracellular domain functions in the binding of STa and the association of each domain to an oligomeric form. Two amino acid residues, Arg-136 and Asp-347, were identified as the residues binding to STa in the extracellular domain of pig STaR by site-directed mutagenesis and analysis of expression on 293T cells. Replacement of these residues by other amino acid residues resulted in the loss of binding of pig STaR to STa, and as a result, STa-induced guanylyl cyclase activity was eliminated. Furthermore, mutation in a region (from Asp-347 to Val-401) which is close to the transmembrane domain caused a significant reduction in both STa-binding activity and guanylyl cyclase catalytic activity. These results suggest that the region adjacent to the transmembrane domain plays an important role in facilitating a favorable conformation of STaR for STa binding.