Pro-tumorigenic roles of TGF-β signaling during the early stages of liver tumorigenesis through upregulation of Snail

Many studies have focused on the tumor suppressive role of TGF-β signaling during the early stages of tumorigenesis by activating the target genes involved in cytostasis and apoptosis. We investigated the effects of TGF-β inhibition on early tumorigenesis in the liver, by employing diverse inhibitory methods. Strikingly, TGF-β inhibition consistently suppressed hepatic tumorigenesis that was induced either by activated RAS plus p53 downregulation or by the co-activation of RAS and TAZ signaling; this demonstrates the requirements for canonical TGF-β signaling in tumorigenesis. Moreover, we found that Snail is the target gene of the TGF-β signaling pathway that promotes hepatic carcinogenesis. The knockdown of Snail suppressed the early tumorigenesis in the liver, as did the TGF-β inhibition, while the ectopic expression of Snail restored tumorigenesis that was suppressed by the TGF-β inhibition. Our findings establish the oncogenic TGF-β-Smad- Snail signaling axis during the early tumorigenesis in the liver. [BMB Reports 2017; 50(12): 599-600].

Drought Persistence Errors in Global Climate Models

The persistence of drought events largely determines the severity of socioeconomic and ecological impacts, but the capability of current global climate models (GCMs) to simulate such events is subject to large uncertainties. In this study, the representation of drought persistence in GCMs is assessed by comparing state-of-the-art GCM model simulations to observation-based data sets. For doing so, we consider dry-to-dry transition probabilities at monthly and annual scales as estimates for drought persistence, where a dry status is defined as negative precipitation anomaly. Though there is a substantial spread in the drought persistence bias, most of the simulations show systematic underestimation of drought persistence at global scale. Subsequently, we analyzed to which degree (i) inaccurate observations, (ii) differences among models, (iii) internal climate variability, and (iv) uncertainty of the employed statistical methods contribute to the spread in drought persistence errors using an analysis of variance approach. The results show that at monthly scale, model uncertainty and observational uncertainty dominate, while the contribution from internal variability is small in most cases. At annual scale, the spread of the drought persistence error is dominated by the statistical estimation error of drought persistence, indicating that the partitioning of the error is impaired by the limited number of considered time steps. These findings reveal systematic errors in the representation of drought persistence in current GCMs and suggest directions for further model improvement.

Barrier to autointegration factor 1, procollagen-lysine, 2-oxoglutarate 5-dioxygenase 3, and splicing factor 3b subunit 4 as early-stage cancer decision markers and drivers of hepatocellular carcinoma

An accurate tool enabling early diagnosis of hepatocellular carcinoma (HCC) is clinically important, given that early detection of HCC markedly improves survival. We aimed to investigate the molecular markers underlying early progression of HCC that can be detected in precancerous lesions. We designed a gene selection strategy to identify potential driver genes by integrative analysis of transcriptome and clinicopathological data of human multistage HCC tissues, including precancerous lesions, low- and high-grade dysplastic nodules. The gene selection process was guided by detecting the selected molecules in both HCC and precancerous lesion. Using various computational approaches, we selected 10 gene elements as a candidate and, through immunohistochemical staining, showed that barrier to autointegration factor 1 (BANF1), procollagen-lysine, 2-oxoglutarate 5-dioxygenase 3 (PLOD3), and splicing factor 3b subunit 4 (SF3B4) are HCC decision markers with superior capability to diagnose early-stage HCC in a large cohort of HCC patients, as compared to the currently popular trio of HCC diagnostic markers: glypican 3, glutamine synthetase, and heat-shock protein 70. Targeted inactivation of BANF1, PLOD3, and SF3B4 inhibits in vitro and in vivo liver tumorigenesis by selectively modulating epithelial-mesenchymal transition and cell-cycle proteins. Treatment of nanoparticles containing small-interfering RNAs of the three genes suppressed liver tumor incidence as well as tumor growth rates in a spontaneous mouse HCC model. We also demonstrated that SF3B4 overexpression triggers SF3b complex to splice tumor suppressor KLF4 transcript to nonfunctional skipped exon transcripts. This contributes to malignant transformation and growth of hepatocyte through transcriptional inactivation of p27^Kip1 and simultaneously activation of Slug genes.

CONCLUSION

The findings suggest molecular markers of BANF1, PLOD3, and SF3B4 indicating early-stage HCC in precancerous lesion, and also suggest drivers for understanding the development of hepatocarcinogenesis. (Hepatology 2018;67:1360-1377).

Influence of compressing pressure on macro void formation of carbon monolith for methane adsorption

Carbon monoliths for adsorbed natural gas (ANG) storage were prepared from Mongolian anthracite-based activated carbons using carboxy-methyl cellulose as a binder under different compressing pressures. Nitrogen adsorption/desorption experiments were carried out to obtain the specific surface area, pore volume, and pore size distribution of the monoliths.  Methane adsorption experiments on the carbon monoliths were conducted at different temperatures and pressures up to around 3.5 MPa in a high pressure volumetric adsorption apparatus. As expected, adsorption results indicated that the methane adsorption capacity of the carbon monoliths increased with increasing specific surface area and packing density.  The maximum volumetric adsorption of methane was observed as 163 V/V at 293 K and 3.5 MPa on a carbon monolith sample, PMAC1/2-3-65, that does not have the highest specific surface area but relatively high packing density comparing with other monoliths, which implies that two physical properties contribute contradictorily to the methane adsorption capacity.  Based on experimental results, the carbon monoliths prepared from Mongolian anthracite-based activated carbons can be promising media for ANG storage application.

Transforming Growth Factor-β Promotes Liver Tumorigenesis in Mice via Up-regulation of Snail

BACKGROUND & AIMS

Transforming growth factor beta (TGF-β) suppresses early stages of tumorigenesis, but also contributes to migration and metastasis of cancer cells. A large number of human tumors contain mutations that inactivate its receptors, or downstream proteins such as Smad transcription factors, indicating that the TGF-β signaling pathway prevents tumor growth. We investigated the effects of TGF-β inhibition on liver tumorigenesis in mice.

METHODS

C57BL/6 mice received hydrodynamic tail-vein injections of transposons encoding HRAS^G12V and a short hairpin RNA (shRNA) to down-regulate p53, or those encoding HRAS^G12V and MYC, or those encoding HRAS^G12V and TAZ^S89A, to induce liver tumor formation; mice were also given injections of transposons encoding SMAD7 or shRNA against SMAD2, SMAD3, SMAD4, or SNAI1 (Snail), with or without ectopic expression of Snail. Survival times were compared, and livers were weighted and examined for tumors. Liver tumor tissues were analyzed by quantitative reverse-transcription PCR, RNA sequencing, immunoblots, and immunohistochemistry. We analyzed gene expression levels in human hepatocellular carcinoma samples deposited in The Cancer Genome Atlas. A cell proliferation assay was performed using human liver cancer cell lines (HepG2 and Huh7) stably expressing Snail or shRNA against Snail.

RESULTS

TGF-β inhibition via overexpression of SMAD7 (or knockdown of SMAD2, SMAD3, or SMAD4) consistently reduced formation and growth of liver tumors in mice that expressed activated RAS plus shRNA against p53, or in mice that expressed activated RAS and TAZ. TGF-β signaling activated transcription of the Snail gene in liver tumors induced by HRAS^G12V and shRNA against p53, and by activated RAS and TAZ. Knockdown of Snail reduced liver tumor formation in both tumor models. Ectopic expression of Snail restored liver tumorigenesis suppressed by disruption of TGF-β signaling. In human hepatocellular carcinoma, Snail expression correlated with TGF-β activation. Ectopic expression of Snail increased cellular proliferation, whereas Snail knockdown led to reduced proliferation in human hepatocellular carcinoma cells.

CONCLUSIONS

In analyses of transgenic mice, we found TGF-β signaling to be required for formation of liver tumors upon expression of activated RAS and shRNA down-regulating p53, and upon expression of activated RAS and TAZ. Snail is the TGF-β target that is required for hepatic tumorigenesis in these models.

Comparison of liver oncogenic potential among human RAS isoforms

Mutation in one of three RAS genes (i.e., HRAS, KRAS, and NRAS) leading to constitutive activation of RAS signaling pathways is considered a key oncogenic event in human carcinogenesis. Whether activated RAS isoforms possess different oncogenic potentials remains an unresolved question. Here, we compared oncogenic properties among RAS isoforms using liver-specific transgenesis in mice. Hydrodynamic transfection was performed using transposons expressing short hairpin RNA downregulating p53 and an activated RAS isoform, and livers were harvested at 23 days after gene delivery. No differences were found in the hepatocarcinogenic potential among RAS isoforms, as determined by both gross examination of livers and liver weight per body weight ratio (LW/BW) of mice expressing HRAS^Q61L, KRAS4B^G12V and NRAS^Q61K. However, the tumorigenic potential differed significantly between KRAS splicing variants. The LW/BW ratio in KRAS4A^G12V mice was significantly lower than in KRAS4B^G12V mice (p < 0.001), and KRAS4A^G12V mice lived significantly longer than KRRAS4B^G12V mice (p < 0.0001). Notably, tumors from KRAS4A^G12V mice displayed higher expression of the p16^INK4A tumor suppressor when compared with KRAS4B^G12V tumors. Forced overexpression of p16^INK4A significantly reduced tumor growth in KRAS4B^G12V mice, suggesting that upregulation of p16^INK4A by KRAS4A^G12V presumably delays tumor development driven by the latter oncogene.

Computational and Performance Aspects of PCA-Based Face-Recognition Algorithms

Algorithms based on principal component analysis (PCA) form the basis of numerous studies in the psychological and algorithmic face-recognition literature. PCA is a statistical technique and its incorporation into a face-recognition algorithm requires numerous design decisions. We explicitly state the design decisions by introducing a generic modular PCA-algorithm. This allows us to investigate these decisions, including those not documented in the literature. We experimented with different implementations of each module, and evaluated the different implementations using the September 1996 FERET evaluation protocol (the de facto standard for evaluating face-recognition algorithms). We experimented with (i) changing the illumination normalization procedure; (ii) studying effects on algorithm performance of compressing images with JPEG and wavelet compression algorithms; (iii) varying the number of eigenvectors in the representation; and (iv) changing the similarity measure in the classification process. We performed two experiments. In the first experiment, we obtained performance results on the standard September 1996 FERET large-gallery image sets. In the second experiment, we examined the variability in algorithm performance on different sets of facial images. The study was performed on 100 randomly generated image sets (galleries) of the same size. Our two most significant results are (i) changing the similarity measure produced the greatest change in performance, and (ii) that difference in performance of ±10% is needed to distinguish between algorithms.

Predictive models of cytotoxicity as mediated by exposure to chemicals or drugs

Predicting cytotoxicity is a challenging task because of the complex biological mechanisms behind it. Cytotoxicity due to toxin - biologically produced poison - is known to play a substantial role in a disease process. Two objectives in this research are to derive robust general predictive cytotoxicity models to minimize unnecessary toxicity. The first objective is to build accurate predictive statistical models for cytotoxicity data based on lymphoblastoid cell lines obtained from in vitro studies. This could be an important step for accomplishing a goal in biomedecial/biophamarceutical research, by obtaining the best medical outcomes by minimizing toxicity in regard to a person's genetic profile. The second objective is to build predictive models to predict population-level cytotoxicity for unknown compounds based on chemical structural features. These two objectives were accomplished by a proposed variable selection process, the random forests, and the least absolute shrinkage and selection operator method. We achieved an excellent prediction result with the random forests algorithm using SNP markers from the proposed approach, having the smallest root mean squared error among the teams which participated in the DREAM Toxicogenetics Challenge. Since chemical compounds for drugs have great influence on human health, the predictive statistical models for these objectives could be helpful to government agencies in relevant decision-making.

Hepatic expression of Sonic Hedgehog induces liver fibrosis and promotes hepatocarcinogenesis in a transgenic mouse model

BACKGROUND & AIMS

Liver fibrosis is an increasing health concern worldwide and a major risk factor for hepatocellular carcinoma (HCC). Although the involvement of Hedgehog signaling in hepatic fibrosis has been known for some time, the causative role of activated Hedgehog signaling in liver fibrosis has not been verified in vivo.

METHODS

Using hydrodynamics-based transfection, a transgenic mouse model has been developed that expresses Sonic Hedgehog (SHH), a ligand for Hedgehog signaling, in the liver. Levels of hepatic fibrosis and fibrosis-related gene expression were assessed in the model. Hepatic expression of SHH was induced in a murine model for hepatocellular adenoma (HCA) and tumor development was subsequently investigated.

RESULTS

The transgenic mice revealed SHH expression in 2-5% of hepatocytes. Secreted SHH activated Hedgehog signaling in numerous cells of various types in the tissues. Hepatic expression of SHH led to fibrosis, activation of hepatic stellate cells, and an upregulation of various fibrogenic genes. Liver injury and hepatocyte apoptosis were observed in SHH mice. Persistent expression of SHH for up to 13months failed to induce tumors in the liver; however, it promoted liver tumor development induced by other oncogenes. By employing a HCA model induced by P53(R172H) and KRAS(G12D), we found that the SHH expression promoted the transition from HCA to HCC.

CONCLUSIONS

SHH expression in the liver induces liver fibrosis with concurrent activation of hepatic stellate cells and fibrogenic genes. It can also enhance hepatocarcinogenesis induced by other oncogenes.

Development of a transgenic mouse model of hepatocellular carcinoma with a liver fibrosis background

Background

Liver fibrosis and its end-stage disease, cirrhosis, are major risk factors for hepatocellular carcinoma (HCC) and present in 80 to 90 % of patients with HCC. Current genetically engineered mouse models for HCC, however, generally do not feature liver fibrosis, which is a critical discrepancy between human HCC and murine models thereof. In this study, we developed a simple transgenic mouse model of HCC within the context of a fibrotic liver.

Methods

Employing hydrodynamic transfection (HT), coupled with the Sleeping Beauty (SB) transposon system, liver was stably transfected with transposons expressing cMyc and a short hairpin RNA down-regulating p53 (shp53). A chronic liver injury model, induced by hepatotoxic carbon tetrachloride (CCl₄), was applied to the transgenic mice, allowing cells expressing cMyc plus shp53 to become malignant in the background of liver fibrosis.

Results

Livers harvested about 3 months after HT had excessive collagen deposition and activated hepatic stellate cells surrounding the tumors. Hepatocarcinogenesis was significantly accelerated in the fibrotic livers compared to those of the control, significantly decreasing the life span of the mice. The tumor incidence and average number of tumors per mouse were significantly higher in the group treated with CCl₄ compared to the vehicle-treated control mice, following HT (p < 0.01).

Conclusions

Considering the simplicity and efficiency in generating HCC for fibrotic livers, the transgenic HCC model has the potential to be effectively used in preclinical testing of HCC anticancer therapy and in studies of hepatocarcinogenesis in fibrotic livers.

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-016-0423-6) contains supplementary material, which is available to authorized users.

Morphological characteristics and clinical manifestations of orbital emphysema caused by isolated medial orbital wall fractures

PURPOSE

To investigate the morphological characteristics and clinical manifestations of orbital emphysema in patients with isolated medial orbital wall fractures.

METHODS

This was a retrospective observational case series of 348 orbits of 348 patients with isolated medial orbital wall fractures. Medical charts were reviewed, and computed tomographic (CT) images were examined to determine the morphological characteristics of orbital emphysema.

RESULTS

Orbital emphysema was detected in 70 orbits (20.1%). Large and communited type fracture was related with the presence of orbital emphysema (P<0.05). Orbital air pockets were detected in medial or superior extraconal orbital segment in all cases with orbital emphysema. Swollen eyelid with crepitus (90.0%) and supraduction limitation (31.4%) were developed with orbital emphysema. All cases with supraduction limitation accompanied with superior extraconal orbital emphysema and superior rectus muscle deviation, and these eyes were fully recovered with conservative management without surgery.

CONCLUSIONS

Orbital emphysema can be a cause of ocular motility restriction following orbital wall fracture. If supraduction limitation is noted with isolated medial wall fracture and superior orbital emphysema with superior rectus muscle deviation is detected by CT scan, conservative management can be a good choice for spontaneous recovery delaying the surgery.

Analysis of miRNA expression patterns in human and mouse hepatocellular carcinoma cells

AIM

Hepatocellular carcinoma (HCC), one of the most common malignancies in adults displays aberrant miRNA expression during its pathogenesis. We assessed expression of miRNA in surgically resected human HCC of an early stage and murine HCC with a high malignancy in order to find miRNA overexpressed in HCC regardless of tumor stage and underlying etiology. Further, the role of the deregulated miRNA in HCC pathogenesis was investigated.

METHODS

miRNA were isolated from HCC tissues and surrounding non-tumorous tissues from HCC patients and a murine transgenic model of HCC. A quantitative reverse transcription polymerase chain reaction was performed to determine expression levels of miRNA. Human HCC cell lines stably expressing individual miRNA were generated to investigate the biological function of overexpressed miRNA.

RESULTS

We found that levels of miR-221, -181b-1, -155-5p, -25 and -17-5p were significantly upregulated in both human and murine HCC regardless of tumor stage, underlying etiology or the presence of fibrosis. Using HCC cell lines stably expressing respective miRNA, we found that miR-221 increased the proliferation of hepatoma cells, while miR-17-5p induced cell migration.

CONCLUSION

We identified miRNA that are consistently upregulated in HCC. The overexpressed miRNA could potentially be used as a bona fide biomarker for HCC.

Bactericidal effects of triclosan in soap both in vitro and in vivo

OBJECTIVES

On December 2013, the US FDA proposed a rule stating that manufacturers must provide data to demonstrate that antibacterial soap is more effective than plain soap or water. The objective of the present study was to examine the in vitro and in vivo bactericidal effect of triclosan (the most widely used antiseptic agent in soap) in soap.

METHODS

Twenty bacterial strains (proposed by the FDA) were exposed to plain and antibacterial soaps (the same formulation as plain soap, but containing 0.3% triclosan) for 20 s at 22°C (room temperature) and 40°C (warm temperature). The temperature and time were selected to simulate the hand washing conditions and procedures used by consumers. The triclosan concentration of 0.3% is the maximum allowed by law. The decontamination efficacy of plain soap and antibacterial soap was also examined in vivo: the hands of volunteers were artificially inoculated with Serratia marcescens.

RESULTS

There was no significant difference (P > 0.05) in bactericidal activity between plain soap and antibacterial soap at either test temperature. However, antibacterial soap showed significantly greater bactericidal effects after 9 h. These results suggest that although triclosan-containing soap does have antibacterial activity, the effects are not apparent during the short time required for hand washing.

CONCLUSIONS

Antibacterial soap containing triclosan (0.3%) was no more effective than plain soap at reducing bacterial contamination when used under 'real-life' conditions. The present study provides practical information that may prove useful for both industry and governments.