MiR-21 Upregulation Induced by Promoter Zone Histone Acetylation is Associated with Chemoresistance to Gemcitabine and Enhanced Malignancy of Pancreatic Cancer Cells

Song, Wei-Feng,Wang, Lei,Huang, Wei-Yi,Cai, Xun,Cui, Jiu-Jie,Wang, Li-Wei Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Background and Aims: MicroRNA-21 (miR-21) is reported to be overexpressed and to contribute to proliferation, apoptosis and gemcitabine resistance in pancreatic ductal adenocarcinomas (PDACs). The aims of this study were to explore regulation of miR-21 expression by epigenetic change and its impact on chemoresistance and malignant properties of of pancreatic cancer. Materials and methods: We retrospectively collected 41 cases of advanced pancreatic cancer patients who were sensitive or resistant to gemcitabine and assessed levels of serum circulating miR-21 for correlation with cytotoxic activity. Histone acetylation in the miR-21 promoter was also studied in gemcitabine-sensitive and gemcitabine-resistant PDAC cells. Gemcitabine-resistant HPAC and PANC-1 cells were transfected with pre-miR-21 precursors (pre-miR-21) and antisense oligonucleotides (anti-miR-21), and were treated with TSA. Finally, invasion and metastasis assays were performed and alteration in mir-21, PTEN, AKT and pAKT level was evaluated in these cells. Results: Serum miR-21 levels were increased in gemcitabine-resistant PDAC patients compared with gemcitabine-sensitive subjects. The miR-21 levels were increased in 6 PDAC cells treated with gemcitabine significantly, associated with 50% inhibitory concentrations ($IC_{50}s$). Histone acetylation levels at miR-21 promoter were increased in PDAC cells after treatment with gemcitabine. Enhanced invasion and metastasis, increased miR-21 expression, decreased PTEN, elevated pAKT level were demonstrated in gemcitabine-resistant HPAC and PANC-1 cells. Pre-miR-21 transfection or TSA treatment further increased invasion and metastasis ability, decreased PTEN, and elevated pAKT levels in these two lines. In contrast, anti-miR-21 transfection could reverse invasion and metastasis, and PTEN and pAKT expressions induced by gemcitabine. Conclusions: MiR-21 upregulation induced by histone acetylation in the promoter zone is associated with chemoresistance to gemcitabine and enhanced malignant potential in pancreatic cancer cells.

Knockdown of a Proliferation-inducing Ligand (PRIL) Suppresses the Proliferation of Gastric Cancer Cells

Cui, Jiu-Wei,Li, Yan,Wang, Chang,Yao, Cheng,Li, Wei Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2

Purpose: PRIL (proliferation-inducing ligand) is a newly identified member of the tumor necrosis factor (TNF) family and modulates death ligand-induced apoptosis. Here, we investigated the effect of PRIL on cellular characteristics relating to tumor progression in human gastric cancer. Method: Recombinant lentivirus containing PRIL siRNA was constructed and then infected MGC803 and SGC7901 gastric cancer cells. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] colony formation and cell cycle analysis were used to study the effect of PRIL knockdown on gastric cancer cell proliferation. Results: PRIL expression in lentivirus infected cells was significantly reduced as evidenced by quantitative real-time PCR. Cell viability and colony formation of MGC803 and SGC7901 cells were significantly hampered in PRIL knock-down cells. Moreover, the cell cycle was arrested at G2/M phase, elucidating the mechanism underlying the inhibitory effect of siRNA on cell proliferation. Conclusions: Our study indicated that PRIL functions in promoting cell growth, and lentivirus-mediated PRIL gene knockdown might be a promising strategy in the treatment of gastric cancer.

Silencing of the COPS3 Gene by siRNA Reduces Proliferation of Lung Cancer Cells Most Likely via induction of Cell Cycle Arrest and Apoptosis

Wang, Xue-Mei,Cui, Jiu-Wei,Li, Wei,Cai, Lu,Song, Wei,Wang, Guan-Jun Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.3

The COPS3 gene has stimulating effect on cell proliferation and progression of osteosarcomas and related cells. However, the features of COPS3 and its potential application as a therapeutic target in other cancers has not yet been studied. In this study, therefore, the effect of COPS3 silencing via COPS3 siRNA on lung cancer cell proliferation was examined. Expression levels of COPS3 gene in COPS3 siRNA infected cells and control siRNA infected cells were compared with real time PCR and Western blot analysis. Cell proliferation levels were comprehensively analyzed by MTT, BrdU incorporationy, and colony formation assays. For mechanistic assessment the effects of COPS3 silencing on cell cycle and apoptosis were analyzed using flow cytometry. Results showed that successful silencing of the COPS3 gene at both translational and transcriptional levels significantly reduced the proliferation and colony formation by lung cancer cells (p<0.01). Flow cytometry showed cell cycle arrest in the G0/G1 phase after COPS3 silencing, and more importantly, apoptosis was induced as a result of COPS3 knockdown, which negatively affected cell survival. Therefore, these results provide another piece of important evidence that the COPS3 gene expressed in lung cancer cells may play a critical role in stimulating proliferation. Down-regulation of COPS3 could significantly inhibit lung cancer cell growth, which was most likely mediated via induction of cell cycle arrest in G0/G1 phase and apoptosis.

Experimental and numerical investigation on post-earthquake fire behaviour of the circular concrete-filled steel tube columns

Yu-Hang Wang,Qi Tang,Mei-Ni Su,Ji-Ke Tan,Wei-Yong Wang,Yong-Sen Lan,Xiao-Wei Deng,Yong-Tao Bai,Wei Luo,Xiao-Hua Li,Jiu-Lin Bai 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.1

Post-earthquake fire is a common disaster which causes serious safety issues to infrastructures. This study aims to investigate the residual loading capacities of circular concrete-filled steel tube (CFST) columns under post-earthquake fire experimentally and numerically. The experimental programme contains two loading steps - pre-damage cyclic loading at room temperature and transient state tests with constant compression loads. Three finite element models are developed and validated against the test results. Upon validation, a total of 48 numerical results were generated in the parametric study to investigate the effects of thickness and strengths of steel tube, axial compression ratio and damage degree on the fire resistance of circular CFST columns. Based on the analysis on experimental and numerical results, the loading mechanism of circular CFST columns is discussed. A design method is proposed for the prediction of fire resistance time under different seismic pre-damage and compression loads. The predictions by the new method is compared with the newly generated experimental and numerical results and is found to be accurate and consistent with the mean value close to the unity and a coefficient of variation around 1%.

Inhibition of Tumor Growth in Vitro by a Combination of Extracts from Rosa Roxburghii Tratt and Fagopyrum Cymosum

Liu, Wei,Li, Su-Yi,Huang, Xin-En,Cui, Jiu-Jie,Zhao, Ting,Zhang, Hua Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Objective: Traditional Chinese herbal medicines have a very long history. Rosa roxburghii Tratt and Fagopyrum cymosum are two examples of plants which are reputed to have benefits in improving immune responses, enhancing digestive ability and demonstrating anti-aging effects. Some evidence indicates that herbal medicine soups containing extracts from the two in combination have efficacy in treating malignant tumors. However, the underlying mechanisms are far from well understood. The present study was therefore undertaken to evaluate anticancer effects and explore molecular mechanisms in vitro. Methods: Proliferation and apoptosis were assessed with three carcinoma cell lines (human esophageal squamous carcinoma CaEs-17, human gastric carcinoma SGC-7901 and pulmonary carcinoma A549) by MTT assay and flow cytometry, respectively, after exposure to extract from Rosa roxburghii Tratt (CL) and extract from Fagopyrum cymosum (FR). $IC_{30}$ of CL and FR were obtained by MTT assay. Tumor cells were divided into four groups : control with no exposure to CL or FR; CL with $IC_{30}$ CL; FR with $IC_{30}$ FR; CL+FR group with 1/2 ($IC_{30}$ CL + $IC_{30}$ FR). RT-PCR and Western blot analysis were used to detect the expression of Ki-67, Bax and Bcl-2 at mRNA and protein levels. Results: Compared with the CL or FR groups, the combination of CL+FR showed significant inhibition of cell growth and increase in apoptosis; the mRNA and protein expression levels of Ki-67 and Bcl-2 in CL+FR group were all greatly decreased, while the expression of Bax was markedly increased. Conclusions: These results indicate that the synergistic antitumor effects of combination of CL and FR are related to inhibition of proliferation and induction of apoptosis.

Knockdown of glycogen phosphorylase and glycogen synthase influences expression of chitin synthesis genes of rice brown planthopper Nilaparvata lugens

Dao-Wei Zhang,Hui-Juan Wang,Xing Jin,Bi-Ying Pan,Bo-Ping Zeng,Zhong-Jiu Xiao,Cai-Di Xu,Bin Tang 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.3

Glycogen synthase (GS) and glycogen phosphorylase (GP) are two key enzymes in the glycogen synthesis pathway, which catalyze trehalose and glucose transformation in insects. GS and GP can be regulated by trehalose metabolism, which plays an important role in insect growth. However, it is not known whether these genes can be targeted for pest control through regulation of chitin metabolism. We studied the function of Nilaparvata lugens GS and GP (NLGS and NLGP, respectively) using RNA interference, and reported that trehalose and the chitin biosynthesis pathways are regulated by GP and GS, especially TPS3, TRE1-1, and G6PI1, which decreased following knockdown of these two genes. The expression levels of TPS1, TPS2, and several chitin synthesis pathway family genes were significantly increased following dsNlGP injection. Additionally, despite there being no apparent change to the chitin content, an abnormal molting phenotype and wing deformity appeared, and close to 25% insects died. These results demonstrate that silencing of NLGP or NLGS can lead to molting deformities and an elevated mortality rate through the regulation of chitin pathway genes and chitinase genes. NLGP may play a key role in chitin synthesis due to the number of genes regulated, and higher deformity and mortality rates resulting from its knockdown.

Morphology-controlled SWCNT/polymeric microsphere arrays by a wet chemical self-assembly technique and their application for sensors

Huang, Xing-Jiu,Li, Yue,Im, Hyung-Soon,Yarimaga, Oktay,Kim, Ju-Hyun,Jang, Doon-Yoon,Cho, Sung-Oh,Cai, Wei-Ping,Choi, Yang-Kyu IOP Pub 2006 Nanotechnology Vol.17 No.12

<P>Large-scale morphology-controlled SWCNT/polymeric microsphere arrays can be obtained by a wet chemical self-assembly technique. The loading of SWCNTs, the length of SWCNTs, and the size and nature of polymeric microspheres can easily be controlled. Similar results can also be reached using this method for MWCNTs. In both types of CNTs, they form an interesting interactive ‘net’ structure on spheres and sphere joints. The SWCNT/PS-modified Au electrode was used for detection of uric acid by cyclic voltammetry and single-potential time-based techniques. The preliminary results show that the modified electrode presents good sensitivity and stability to uric acid. </P>

Experimental and numerical studies of stress/strain characteristics in riveted aircraft lap joints

Chao Zeng,Wei Tian,Xiang Yao Liu,Jiu Tian Xue 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.7

The fatigue property of riveted lap joint is greatly related to the riveting-induced residual stress, especially the stress distribution on the faying surface. However, an accurate study of the residual stress characteristics in the riveted sheet could be very difficult. In this paper, both numerical and experimental investigations were carried out on the stress/strain characteristics in riveted aircraft lap joints. A special specimen was designed for the test of strain variations on the faying surface of the sheet by microstrain gages. For the numerical simulation, the rivet squeezing process was analyzed using the explicit dynamic finite element (FE) method, whilst a general static FE analysis was employed for the elastic springback after the squeeze force was removed. A comparison of the strain variations between the experimental results and FE simulations shows a general good agreement, although there may be some difference for points measured near the hole surface. The FE analysis reveals that both compressive and tensile residual stresses could be introduced in the riveted sheet. Massive compressive residual stress can be created in the near-surface layer of the hole. However, the stress level is not always increased with increasing the squeeze force, and so is the improvement of fatigue life observed. Further study is still necessary to account for the fatigue life decreasing effect caused by a high squeeze force.

Influencing Factors Analysis of Degradation and Damage and the Effect on Steel Frame

Meng Wang,Yong-Jiu Shi,Yuan-Qing Wang,Wei Guo Yang 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.1

In order to discuss the influencing factors of damage and degradation and the effect on steel frame subject to strongearthquakes, firstly, a constitutive model was proposed for 3D finite element models to calculate the seismic behaviors of steelframe more accurately. The model was proved correct and applicable due to typical quasi-static tests. Then, based on theverified model, the damage and degradation factors were discussed by parametric analyses, including the panel zone, loadinghistory, loading amplitude, the width to thickness ratio and yield strength. The cumulative damage phenomena of steel frameconnections were further studied and the degradation distribution curve was obtained. Finally, the traditional beam elementmodel and proposed shell element model of structure were established by ABAQUS for time history analysis. The effect ofdamage and degradation on seismic behaviors of steel frames were compared and discussed. The tests and analysis resultsrevealed that: panel zone strength, loading amplitude and width-thickness ratios of plates had significant impact on damage anddegradation behaviors and failure modes of connections. Premature weld cracking would lead to earlier damage and degradationunder “strong to weak” earthquake, which would seriously affect the overall mechanical properties of the structure. Once localbuckling caused damage, the results of the beam element model and accurate shell element model were remarkably different. Beam element model without considering damage and degradation underestimated the structural deformations, which shouldbe paid more attention for design safety.

Polymer Nanostructured Components Machined Directly by the Atomic Force Microscopy Scratching Method

Yong Da Yan,Da Wei Gao,Zhen Jiang Hu,Xue Sen Zhao,Jiu Chun Yan 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.

This study aims to machine complex three dimensional nano-structures on polymer surfaces directly using the Atomic Force Microscopy (AFM)-based nano-mechanical processing method. Processing parameters including the normal load, the feed rate, the machining speed and the scanning direction are optimized by the Taguchi method. Their effects on the machined depth and the surface roughness of the machined structures are analyzed. Meanwhile, the AFM PZT tube is controlled to achieve the tip’s three-dimensional motions in space. Using the optimized processing parameters, three-dimensional nanostructures on the surface of PMMA are directly fabricated. It is a novel low-cost manufacturing method for machining complex three-dimensional nano-structures or nano parts on polymer surfaces directly.