Down-regulation of the microRNAs miR-34a, miR-127, and miR-200b in rat liver during hepatocarcinogenesis induced by a methyl-deficient diet

Altered expression of microRNAs (miRNAs) has been reported in diverse human cancers; however, the down-regulation or up-regulation of any particular miRNAs in cancer is not sufficient to address the role of these changes in carcinogenesis. In this study, using the rat model of liver carcinogenesis induced by a methyl-deficient diet, which is relevant to the hepatocarcinogenesis in humans associated with viral hepatitis C and B infections, alcohol exposure and metabolic liver diseases, we showed that the development of hepatocellular carcinoma (HCC) is characterized by prominent early changes in expression of miRNA genes, specifically by inhibition of expression of microRNAs miR-34a, miR-127, miR-200b, and miR-16a involved in the regulation of apoptosis, cell proliferation, cell-to-cell connection, and epithelial-mesenchymal transition. The mechanistic link between these alterations in miRNAs expression and the development of HCC was confirmed by the corresponding changes in the levels of E2F3, NOTCH1, BCL6, ZFHX1B, and BCL2 proteins targeted by these miRNAs. The significance of miRNAs expression dysregulation in respect to hepatocarcinogenesis was confirmed by the persistence of these miRNAs alterations in the livers of methyl-deficient rats re-fed a methyl-adequate diet. Altogether, the early occurrence of alterations in miRNAs expression and their persistence during the entire process of hepatocarcinogenesis indicate that the dysregulation of microRNAs expression may be an important contributing factor in the development of HCC.     

In vivo bystander effect: cranial X-irradiation leads to elevated DNA damage, altered cellular proliferation and apoptosis, and increased p53 levels in shielded spleen

PURPOSE: It is well accepted that irradiated cells may "forward" genome instability to nonirradiated neighboring cells, giving rise to the "bystander effect" phenomenon. Although bystander effects were well studied by using cell cultures, data for somatic bystander effects in vivo are relatively scarce. METHODS AND MATERIALS: We set out to analyze the existence and molecular nature of bystander effects in a radiation target-organ spleen by using a mouse model. The animal's head was exposed to X-rays while the remainder of the body was completely protected by a medical-grade shield. Using immunohistochemistry, we addressed levels of DNA damage, cellular proliferation, apoptosis, and p53 protein in the spleen of control animals and completely exposed and head-exposed/body bystander animals. RESULTS: We found that localized head radiation exposure led to the induction of bystander effects in the lead-shielded distant spleen tissue. Namely, cranial irradiation led to increased levels of DNA damage and p53 expression and also altered levels of cellular proliferation and apoptosis in bystander spleen tissue. The observed bystander changes were not caused by radiation scattering and were observed in two different mouse strains; C57BL/6 and BALB/c. CONCLUSION: Our study proves that bystander effects occur in the distant somatic organs on localized exposures. Additional studies are required to characterize the nature of an enigmatic bystander signal and analyze the long-term persistence of these effects and possible contribution of radiation-induced bystander effects to secondary radiation carcinogenesis.     

Genetic and epigenetic changes in rat preneoplastic liver tissue induced by 2-acetylaminofluorene

Genotoxic carcinogens, including 2-acetylaminofluorene (2-AAF), in addition to exerting their genotoxic effects, often cause a variety of non-genotoxic alterations in cells. It is believed that these non-genotoxic effects may be indispensable events in tumorigenesis; however, there is insufficient knowledge to clarify the role of carcinogens in both the genetic and epigenetic changes in premalignant tissues and a lack of conclusive information on the link between epigenetic alterations and carcinogenic exposure. In the current study, we investigated whether or not the mechanism of 2-AAF-induced hepatocarcinogenesis consists of both genotoxic (genetic) and non-genotoxic (epigenetic) alterations. Male and female Sprague-Dawley rats were fed NIH-31 diet containing 0.02% of 2-AAF for 6, 12, 18 or 24 weeks. The levels of DNA adducts obtained from 2-AAF in liver and kidney tissues were assessed by high-performance liquid chromatography combined with electrospray tandem mass spectrometry (HPLC-ES-MS/MS). N-(Deoxyguanosine-8-yl)-2-aminofluorene was the major adduct detected at all time points in both tissues. Global DNA methylation in the livers and kidneys, as determined by an HpaII-based cytosine extension assay and by HPLC-ES-MS/MS, did not change over the 24-week period. In the livers of male rats, there was a progressive decrease of global and long interspersed nucleotide element-1-associated histone H4 lysine 20 trimethylation, as well as hypermethylation of the p16(INK4A) gene. These epigenetic changes were not observed in the livers of female rats or the kidneys of both sexes. Importantly, morphological evidence of formation and progression of neoplastic process was observed in the liver of male rats only. In conclusion, we have demonstrated that exposure of rats to genotoxic hepatocarcinogen 2-AAF, in addition to formation of 2-AAF-specific DNA lesions, resulted in substantial alterations in cellular epigenetic status.     

一叶萩的化学成分

目的：对一叶萩枝叶的化学成分进行研究。方法：应用各种色谱技术从一叶萩总碱部位中分离化合物，根据理化常数和波谱（NMR及MS等）分析方法对化合物的结构进行鉴定。结果：自一叶萩枝叶的总碱部位中分离得到11个化合物。分别鉴定为：（-）-15β-ethoxy-14，15-dihvdroviroallosecurinine（1），一叶萩碱（securinine，2），二氢一叶萩碱（14，15-dihydrosecurinine，3），4-epiph），llanthine（4），securitinine（5），右旋别一叶萩碱（viroallosecurinine，6），一叶萩醇A（securinol A，7），secu’amamineA（8），ent-phyllanthidine（9），（＋）-aquilegiohde（10）和（＋）-menisdaurilide（11）。结论：1为新化合物，4，8，10和11为首次从一叶萩中分离得到。     

No association between maternal psychological symptoms and infant outcome after pregnancy complicated by early-onset hypertensive disorders

Aim: The aim of this work was to study the effect of maternal psychological symptoms on infant development 1 year after early-onset hypertensive disorders of pregnancy.
Methods: All mothers were enrolled in the Pre-eclampsia, Eclampsia TRial Amsterdam. Mothers were asked to complete the 90-item Symptom Check List (SCL-90) at the corrected ages of their infants of 0, 3 and 12 months. The total sum score of these three checklists was calculated. Infants were examined at the corrected age of 12 months using the Bayley Scales of Infant Development (Mental Developmental Index [MDI] and Psychomotor Developmental Index [PDI] subscales). The Bayley scores were compared between infants of mothers with SCL-90 sum scores in the highest 25% and lowest 75%.
Results: For 141 mother–infant pairs (80%) all three SCL-90 checklists and Bayley scores were available. Mean gestational age was 32 weeks and 90% of the infants were growth restricted. The mean MDI was 87 in the highest 25% and 89 in the lowest 75% group. This was 79 versus 80 for the PDI.
Conclusion: In this population of high-risk growth-restricted infants born after a pregnancy complicated by early-onset hypertensive disorders, there is no additional impact of negative maternal psychological symptoms on infant development after 1 year.     

Opportunities to integrate new approaches in genetic toxicology: An ILSI‐HESI workshop report

Genetic toxicity tests currently used to identify and characterize potential human mutagens and carcinogens rely on measurements of primary DNA damage, gene mutation, and chromosome damage in vitro and in rodents. The International Life Sciences Institute Health and Environmental Sciences Institute (ILSI‐HESI) Committee on the Relevance and Follow‐up of Positive Results in In Vitro Genetic Toxicity Testing held an April 2012 Workshop in Washington, DC, to consider the impact of new understanding of biology and new technologies on the identification and characterization of genotoxic substances, and to identify new approaches to inform more accurate human risk assessment for genetic and carcinogenic effects. Workshop organizers and speakers were from industry, academe, and government. The Workshop focused on biological effects and technologies that would potentially yield the most useful information for evaluating human risk of genetic damage. Also addressed was the impact that improved understanding of biology and availability of new techniques might have on genetic toxicology practices. Workshop topics included (1) alternative experimental models to improve genetic toxicity testing, (2) Biomarkers of epigenetic changes and their applicability to genetic toxicology, and (3) new technologies and approaches. The ability of these new tests and technologies to be developed into tests to identify and characterize genotoxic agents; to serve as a bridge between in vitro and in vivo rodent, or preferably human, data; or to be used to provide dose response information for quantitative risk assessment was also addressed. A summary of the workshop and links to the scientific presentations are provided. Environ. Mol. Mutagen. 56:277–285, 2015. © 2014 Wiley Periodicals, Inc.     

The Role of Parasympathetic Modulation of the Reentrant Arrhythmic Substrate in the Genesis of Sustained Ventricular Tachycardia

The influence of parasympathetic activity on the reentrant arrhythmic substrate in the genesis of sustained ventricular tachycardia remains unclear. To assess this influence, we studied the heart rate variability in 59 patients referred for invasive electrophysiological testing. In addition, the presence of late potentials and high grade ventricular ectopy, and the left ventricular ejection fraction was determined. The 28 patients with inducible sustained ventricular tachycardia were found to have lower heart rate variability by time- and frequency-domain measurements over 24 hours when compared to the 31 subjects who were noninducible. PNN50 was 4% in the inducible patients, whereas it was 9% in the subjects who were noninducible (P = 0.03). Similarly, HFP24H was 9 and 14 msec, respectively (P = 0.02). MAXHFP1H also differed (20 vs 27 msec [P = 0.04]) but not MINHFP1H (5 vs 6 msec). There was no association between heart rate variability and late potentials, degree of ventricular ectopy, or left ventricular ejection fraction. Thus, vagal tone does not appear to correlate with the presence of late potentials, ventricular ectopy, or left ventricular dysfunction. Low mean as well as maximal vagal tone, in contrast to minimal vagal tone, predicts inducibility of sustained ventricular tachycardia. Our data suggest that the inability to modulate parasympathetic tone appears to be an important determinant in the genesis of reentrant sustained ventricular tachycardia.     

Chemotherapy for advanced (stage IIIB and stage IV) non-small cell lung cancer: The Hong Kong perspective

Abstract Non-small cell lung cancer (NSCLC) accounts for about 80% of all primary lung cancers, and 60% of cases present as advanced stages IIIB and IV disease. Traditionally, treatment of stages IIIB and IV disease was only symptomatic (including radiotherapy) and supportive care, and cytotoxic chemotherapy was relatively ineffective. Our initial clinical trials, using MACC, FuAM, FAM, Hi-FAM and cisplatin-VP16, gave response rates of 5–20% and a stabilization rate of 7–25%, with no impact on median survival. Our most recent chemotherapy regimen MIP (mitomycin-C, ifosfamide and cisplatin) proved to be more effective with a 44% response rate and a 28% stabilzation rate, and produced a significantly longer median survival (32 weeks) than best supportive care alone (19.5 weeks, P < 0.05). The response rate further increased to 62.5% with dose intensification and GM-CSF support. Chemotherapy can now be recommended to motivated, well-informed patients with good performance status in institutions with experience in cancer chemotherapy on a protocol basis. The most recent addition of new effective cytotoxic agents such as paclitaxel, docetaxel, gemitabine and vinorelbine gave promising results in NSCLC, and optimal combinations and dose schedules are being defined by multicentred studies.