Study on mechanical properties of interbedded rock masses with microcrack based on thermal-mechanical coupling.

The mechanical properties of deep rock masses are significantly influenced by temperature and other factors. The effect of temperature on the strength of deep rock masses will pose a serious challenge to deep resource exploitation and engineering construction. In this paper, the thermal-mechanical coupling calculation model is established by particle flow code (PFC2D) to study the uniaxial compression response of rock masses with microcracks after temperature load. The strength of failure, microcracks, and strain was analyzed. The results show that: (i) When the soft rock thickness ratio Hs/H < 0.5, the displacement caused by the applied temperature is concentrated at the structural plane, and the contact force is concentrated at the end of the initial microcrack. When Hs/H ≥ 0.5, the displacement caused by the applied temperature is concentrated on both sides of the initial microcrack, and the contact force is concentrated in the hard rock area. (ii) The number of microcracks decreases with the increase of soft rock thickness under different working conditions. When the soft rock thickness ratio Hs/H < 0.5, the relationship curve between the number of microcracks and the vertical strain shows two stages of change. When Hs/H ≥ 0.5, the relationship curve between the number of cracks and the vertical strain changes shows three stages of change. (iii) When the soft rock thickness ratio Hs/H < 0.5, the failure strength decreases with the increase of soft rock thickness ratio at T = 100°C and 200°C. When T = 300°C and 400°C, the failure strength decreased first and then increased. When Hs/H ≥ 0.5, the failure strength increases with the increase of soft rock thickness at T = 200°C, 300°C, and 400°C. At T = 100°C, the failure strength decreases with the increase of soft rock thickness.

[Expression of aquaporin 3 and aquaporin 9 is regulated by oleic acid through the PI3K/Akt and p38 MAPK signaling pathways].

OBJECTIVE: To study the effect of oleic acid (OA) on expression of aquaglyceroporin genes, AQP3 and AQP9, in hepatocyte steatosis and to investigate the underlying molecular mechanisms using an in vitro system. METHODS: HepG2 cells were treated with OA at different concentration to establish in vitro models of nonalcoholic hepatocyte steatosis. The corresponding extents of hepatic steatosis modeling were assessed by oil red O staining and optical density (OD) measurements of the intracellular fat content. The model lines were then treated with inhibitors of the PI3K/Akt and p38 MAPK signaling pathway factors and effects on AQP3/9 expression was measured by real time RT-PCR and western blotting. RESULTS: The fat concentration, indicative of hepatic steatosis, increased in conjunction with increased concentrations of OA (0 less than 250 less than 500 mumol/L). OA exposure also down-regulated AQP3 mRNA and up-regulated AQP9 mRNA levels in a concentration-dependent manner. The most robust changes in expression occurred in response to the 500 mumol/L concentration of OA for both AQP3 (0.47+/-0.18; t = 4.5450, P less than 0.05) and AQP9 (1.57+/-0.21; t = 3.0306, P less than 0.05). Treatment with OA + PI3K pathway inhibitor (LY294004) significantly decreased AQP9 mRNA expression (4.55+/-0.62) as compared to the control group (1.00+/-0.10; t = 9.7909, P less than 0.01), that 500 mumol/L OA group (2.43+/-0.53; t = 4.5018, P less than 0.05), and the LY294002 group (1.90+/-0.16; t = 7.1683, P less than 0.01). Treatment with p38 MAPK pathway inhibitor (SB230580) significantly increased the OA-suppressed level of AQP3 mRNA to the level detected in the control group (1.27+/-0.11; t = 5.7455, P less than 0.01) and decreased the OA-stimulated AQP9 mRNA (0.38+/-0.09; t = 6.5727, P less than 0.01). No significant changes in mRNA expression of AQP3/9 were observed with inhibition of the ERK1/2 and JNK signal transduction pathways. The OA-induced changes in protein expression levels of AQR3 and AQP9 followed a similar trend of the genes. Finally, OA suppressed the level of phosphorylated Akt (from 0.21+/-0.02 to 0.13+/-0.03; t = 3.8431, P less than 0.05) but elevated the level of phosphorylated p38 (from 0.58+/-0.06 to 1.02+/-0.10; t = 12.5289, P less than 0.01). Again, OA treatment produced no significant affect on ERK1/2 and JNK phosphorylation. CONCLUSION: OA down-regulates AQP3 expression by stimulating the p38 MAPK signaling pathway, and up-regulates the AQP9 by blocking the PI3K/Akt pathway and activating the p38 MAPK signaling pathway.

Peroxisomal trans-2-enoyl-CoA inhibits proliferation, migration and invasion of hepatocellular carcinoma cells.

OBJECTIVES: Peroxisomal trans-2-enoyl-CoA reductase (PECR) encodes proteins related to fatty acid metabolism and synthesis. It has been confirmed that PECR has decreased expression in colon cancer and breast cancer, while the role of PECR in liver cancer is unknown. We aimed to study the role and mechanism of PECR in the genesis and development of liver cancer. METHODS: In this study, the expression of PECR was queried in the Cancer Genome Atlas Database and Western Blotting and RT-PCR experiments were carried out in paired liver cancer tissues to detect the expression of PECR. Functional tests were evaluated by cell count kit-8 (CCK-8), Flow cytometry, wound healing assay, Transwell, migration. In vivo study, we constructed a nude mouse tumorigenic model to observe the effect of PECR on the proliferation of liver cancer. And the tumor body of the mouse was taken out for histochemistry (IHC). Multiple Cox regression was used to analyze the correlation between PECR and Clinicopathology. RESULTS: We confirmed that the overexpression of PECR inhibited the proliferation, migration and invasion of hepatocellular carcinoma and promoted the apoptosis of hepatocellular carcinoma. The low expression group of PECR promoted the proliferation and metastasis of liver cancer. In vivo, overexpression of PECR inhibits the proliferation of mouse tumors. In addition, the mechanism study shows that PECR may indirectly affect the proliferation of hepatocellular carcinoma cells through ERK pathway. CONCLUSION: In general, PECR may be a new diagnostic marker and a potential therapeutic target for hepatocellular carcinoma.

Transcriptomic profiling of peroxisome-related genes reveals a novel prognostic signature in hepatocellular carcinoma.

Emerging evidence suggests that peroxisomes play a role in the regulation of tumorigenesis and cancer progression. However, the prognostic value of peroxisome-related genes has been rarely investigated. This study aimed to establish a peroxisome-related gene signature for overall survival (OS) prediction in patients with hepatocellular carcinoma (HCC). First, univariate Cox regression analysis was employed to identify prognostic peroxisome-related genes in The Cancer Genome Atlas liver cancer cohort, and least absolute shrinkage and selection operator Cox regression analysis was used to construct a 10-gene signature. The risk score based on the signature was positively correlated with poor prognosis (HR = 4.501, 95% CI = 3.021-6.705, P = 1.39e-13). Second, multivariate Cox regression incorporating additional characteristics revealed that the signature was an independent predictor. Time-dependent ROC curves demonstrated good performance of the signature in predicting the OS of HCC patients. The prognostic performance was validated using International Cancer Genome Consortium HCC cohort data. Gene set enrichment analysis revealed that the signature-related alterations in biological processes mainly involved peroxisomal functions. Finally, we developed a nomogram model based on the gene signature and TNM stage, which showed a superior prognostic power (C-index = 0.702). Thus, our study revealed a novel peroxisome-related gene signature that may help improve personalized OS prediction in HCC patients.

Study on blasting characteristics of rock mass with weak interlayer based on energy field.

In order to explore the influence of weak interlayer on blasting characteristics in natural rock mass, by using the particle flow code (PFC2D), a single hole blasting numerical model of hard rock with soft interlayer is established. The blasting experiments at different positions and thicknesses of weak interlayer are carried out. Then an in-depth analysis from the perspectives of crack effect, stress field and energy field is made. Results showed that: (i) When the explosion is initiated outside the weak interlayer, if the interlayer is located within about twice the radius of the crushing area, the closer the interlayer is to the blast hole, the higher the damage degree of the rock mass around the blast hole. And the number of cracks will increase by about 1-2% when the distance between the weak interlayer and the blast hole decreases by 0.5 m. (ii) When detonating outside the weak interlayer, if the interlayer is within about 4 times radius of the crushing area, the hard rock on both sides of the weak interlayer will in a high stress state. Under the same case, the peak kinetic energy and peak friction energy will increase by about 23 and 13%, respectively, and the peak strain energy will increase by about 218 kJ for every 0.1 m increase in the thickness of the weak interlayer.

Identification and validation of EPHX2 as a prognostic biomarker in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common types of cancer, which is associated with a poor prognosis. It is necessary to identify novel prognostic biomarkers and therapeutic targets to improve the survival of patients with HCC. In the present study, a seven­gene signature associated with HCC progression was identified using weighted gene co­expression network analysis and least absolute shrinkage and selection operator, and its prognostic prediction value was confirmed in The Cancer Genome Atlas­liver HCC and International Cancer Genome Consortium liver cancer­RIKEN, Japan cohorts. Subsequently, a rarely reported gene, epoxide hydrolase 2 (EPHX2), was selected for further validation. Downregulation of EPHX2 in HCC was revealed using multiple expression datasets. Furthermore, reduced expression of EPHX2 was confirmed in HCC tissue samples and cell lines using reverse transcription­quantitative polymerase chain reaction and western blotting. Additionally, Kaplan­Meier survival curves indicated that patients with higher EPHX2 expression exhibited better prognosis, and clinicopathological analysis also revealed elevated EPHX2 levels in patients with early­stage HCC. Notably, EPHX2 was identified as an independent prognostic biomarker for overall survival of patients with HCC. Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes analysis and gene set enrichment analysis were performed to elucidate the functions of EPHX2. The results suggested that EPHX2 expression was closely associated with metabolic reprogramming. Finally, the prognostic value of EPHX2 was evaluated using HCC tissue microarrays. In conclusion, downregulation of EPHX2 was significantly associated with the development of HCC; therefore, EPHX2 may be considered a putative therapeutic candidate for the targeted treatment of HCC.

Hypoxia-Induced Aquaporin-3 Changes Hepatocellular Carcinoma Cell Sensitivity to Sorafenib by Activating the PI3K/Akt Signaling Pathway.

PURPOSE: Hypoxia-induced changes are primarily activated in patients with hepatocellular carcinoma (HCC) and long-term sorafenib exposure, thereby reducing the sensitivity to the drug. Aquaporin-3 (AQP3), a member of the aquaporin family, is a hypoxia-induced substance that affects the chemosensitivity of non-hepatocellular tumors. However, its expression and role in the sensitivity of hypoxic HCC cells to sorafenib-induced apoptosis remain unclear. The purpose of this study was to detect changes in AQP3 expression in hypoxic HCC cells and to determine whether these changes alter the sensitivity of these cells to sorafenib. MATERIALS AND METHODS: Huh7 and HepG2 hypoxic cell models were established and AQP3 expression was detected using quantitative real-time polymerase chain reaction (qPCR) and Western blotting. Furthermore, the role of AQP3 in cell sensitivity to sorafenib was evaluated via flow cytometry, Western blotting, and a CCK-8 assay. RESULTS: The results of qPCR and Western blotting showed that AQP3 was overexpressed in the Huh7 and HepG2 hypoxic cell models. Furthermore, AQP3 protein levels were positively correlated with hypoxia-inducible factor-1α (HIF-1α) levels. Compared with cells transfected with lentivirus-GFP (Lv-GFP), hypoxic cells transfected with lentivirus-AQP3 (Lv-AQP3) were less sensitive to sorafenib-induced apoptosis. However, the sensitivity to the drug increased in cells transfected with lentivirus-AQP3RNAi (Lv-AQP3RNAi). Akt and Erk phosphorylation was enhanced in Lv-AQP3-transfected cells. Compared with UO126 (a Mek1/2 inhibitor), LY294002 (a PI3K inhibitor) attenuated the AQP3-induced insensitivity to sorafenib observed in hypoxic cells transfected with Lv-AQP3. Combined with LY294002-treated cells, hypoxic cells transfected with Lv-AQP3RNAi were more sensitive to sorafenib. CONCLUSION: The study results show that AQP3 is a potential therapeutic target for improving the sensitivity of hypoxic HCC cells to sorafenib.

Aquaporin 9 inhibits hepatocellular carcinoma through up-regulating FOXO1 expression.

Aquaporin 9 (AQP9) is the main aquaglyceroporin in the liver. Few studies have been performed regarding the role of AQP9 in liver cancer. Here we report AQP9 expression and function in liver cancer. We found that AQP9 mRNA and protein levels were reduced in human hepatocellular cancer compared to the para-tumor normal liver tissues. Human hepatoma cell line SMMC7721 expressed low basal levels of AQP9. When AQP9 was overexpressed in SMMC7721 cell line, cell proliferation was inhibited due to cell cycle arrest at G1 phase and increased apoptosis. At the molecular level, AQP9 overexpression decreased the protein levels of phosphatidylinositol-3-kinase (PI3K), leading to reduced phosphorylation of Akt. Subsequently, the protein levels of forkhead box protein O1 (FOXO1) were increased, resulting in down-regulation of proliferating cell nuclear antigen (PCNA) expression and up-regulation of caspase-3 expression. AQP9 overexpression inhibited growth of subcutaneously xenografted liver tumors in nude mice. These findings suggest that AQP9 expression is down-regulated in liver cancer compared to the normal liver tissue and restoration of AQP9 expression can inhibit development of liver cancer.

FOXO1-mediated epigenetic modifications are involved in the insulin-mediated repression of hepatocyte aquaporin 9 expression.

Aquaporin (AQP) 9 transports glycerol and water, and belongs to the aquaglyceroporin subfamily. Insulin acts as a negative regulator of AQP9, and FOXO1 has the ability to mediate the regulatory effects of insulin on target gene expression. The aim of the present study was to determine whether insulin­induced repression of AQP9 involved an epigenetic mechanism. HepG2 human hepatocyte cells were treated with 500 µM insulin for different durations. AQP9 mRNA expression levels were determined by quantitative polymerase chain reaction (qPCR), and histone H3 acetylation, phosphorylation and methylation at the insulin responsive element (IRE) of the AQP9 promoter was assessed using chromatin immunoprecipitation coupled with qPCR. The effects of lentiviral FOXO1 overexpression on AQP9 expression levels and H3 modifications at the AQP9 promoter were also determined. The insulin treatment resulted in a significant and time­dependent reduction in AQP9 mRNA expression levels in HepG2 cells, as compared with untreated cells (P<0.05). In the insulin­treated cells, the levels of H3 acetylation and phosphorylation were significantly reduced (P<0.05), but the level of H3 methylation was increased. Enforced expression of FOXO1 increased AQP9 mRNA and protein expression levels in HepG2 cells. Furthermore, FOXO1 overexpression promoted H3 acetylation and phosphorylation, and reduced H3 methylation at the IRE locus of the AQP9 promoter. These data provide, to the best of our knowledge, the first evidence that insulin­induced transcriptional suppression of AQP9 expression in hepatocytes involves FOXO1­mediated H3 modifications at the IRE locus in the promoter.