2018
Permanent URI for this collectionhttps://hdl.handle.net/1807/81037
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Item Steroid receptor coactivator-1 regulates glioma angiogenesis through polyomavirus enhancer activator 3 signaling(Canadian Science Publishing, 2018-08-23) Zhang, Yi; Shi, WeiSteroid receptor coactivator 1 (SRC-1) is a transcriptional coactivator for steroid receptors and other transcription factors. SRC-1 has been shown to play an important role in the progression of breast cancer and prostate cancer. However, its role in glioma progression remains unknown. Here, in this study, we reported that SRC-1 is upregulated in the vessels of human glioma and exerts important regulatory functions. Specifically, SRC-1 expression significantly enhanced bFGF-mediated angiogenesis in vivo. Downregulating of SRC-1 expression suppressed endothelial cell migration and tube formation in vitro and upregulated the expression of pro-angiogenic factors including VEGF and MMP-9 in glioma cells. These SRC-1-mediated effects were depended on the activation of polyomavirus enhancer activator 3 (PEA3) transcriptional activity. VEGF and VEGF inducer GS4012 induced the direct binding of SRC-1 and PEA3 in glioma cell, and PEA3 could directly bind with VEGF and MMP-9 promoter under GS4012 treatment in glioma cell. The SRC-1 induced pro-angiogenic factors expression was abrogated by sh-PEA3 knockdown. Taken together, these novel outcomes indicated that SRC-1 modulated endothelial cell (EC) function and facilitated a pro-angiogenic microenvironment through PEA3 signaling. Moreover, a combination of targeting SRC-1 and PEA3 signaling in glioma might be a promising strategy by suppressing tumor angiogenesis.Item miR-3666 inhibits lung cancer cell proliferation, migration and invasion by targeting BPTF(Canadian Science Publishing, 2018-11-21) Pan, Linqing; Tang, Zhipeng; Pan, Lina; Tang, RanranOur previous study suggested that BPTF overexpression was observed in lung adenocarcinoma, and closely associated with advanced clinical stage, more metastatic lymph nodes, present distant metastasis, low histological grade and poor prognosis. Down-regulation of BPTF inhibited lung adenocarcinoma cells proliferation and promoted lung adenocarcinoma cells apoptosis. The purpose of this study is to identify valuable microRNAs (miRNAs), which target BPTF to modulate lung adenocarcinoma cells proliferation. In our results, we found that miR-3666 was notably reduced in lung adenocarcinoma tissues and cell lines. By using miR-3666 mimics, cells proliferation, migration, and invasion were suppressed by miR-3666 overexpression, while were enhanced by reduction of miR-3666. Moreover, bioinformatics analysis using Targetscan database and miRanda software suggested a putative targeting site in BPTF 3â -UTR. Furthermore, we verified that miR-3666 directly targeted to 3â -UTR of BPTF by luciferase reporter assay. Overexpression of miR-3666 negatively regulated protein expression of BPTF by western blot. Finally, PI3K/AKT and EMT was demonstrated to be inhibited by miR-3666 overexpression in lung cancer cells. In conclusion, our data indicate that miR-3666 might play an essential role in cell proliferation, migration and invasion by targeting BPTF and partly inhibited PI3K/AKT and EMT signaling pathways in human lung cancers.Item Ginsenoside metabolite compound K induces apoptosis and autophagy in non-small cell lung cancer cells via AMPK/mTOR and JNK pathways(Canadian Science Publishing, 2018-11-20) Li, Chen; Dong, Yuchao; Wang, Libo; Xu, Gongbin; Yang, Qing; Tang, Xiaofei; Qiao, Yingying; Cong, ZhonghuangCompound K (C-K, 20-O-(β-D-glucopyranosyl)-20(S)-protopanaxadiol), as a metabolite of ginsenoside, has been verified to have antitumor effects in various cancers, including non-small cell lung cancer (NSCLC). However, the detailed mechanisms of C-K in NSCLC remain largely unknown. In this study, we aimed to evaluate the effect of C-K on apoptosis and autophagy in NSCLC cells as well as its related mechanisms. According to the results, C-K suppressed the proliferation, led to G1 phase arrest and apoptosis in A549 and H1975 cells. Subsequently, C-K promoted autophagy as confirmed by enhanced rate of positive acridine orange staining cells, increased LC3II and Beclin-1 levels, while decreased p62 level in A549 and H1975 cells. Moreover, 3-Methyladenine (3-MA, an inhibitor of autophagy) effectively suppressed proliferation inhibition and apoptosis induced by C-K. Finally, C-K treatment promoted the activation of AMPK/mTOR and JNK signaling pathways. Treatment with compound C (AMPK inhibitor) or SP600125 (JNK inhibitor) significantly restrained C-K-induced proliferation inhibition, apoptosis and autophagy in A549 and H1975 cells. In conclusion, this study demonstrates that C-K promotes autophagy-mediated apoptosis in NSCLC via AMPK/mTOR and JNK signaling pathways.Item How Alcohol Drinking Affects our Genes: an Epigenetic Point of View(Canadian Science Publishing, 2018-11-05) Ciafrè, Stefania; Carito, Valentina; Ferraguti, Giampiero; Greco, Antonio; Chaldakov, George N; Fiore, Marco; Ceccanti, MauroThis work highlights recent studies in epigenetic mechanisms that play a role in alcoholism, a complex multifactorial disorder. A large body of evidence has shown that alcohol can modify gene expression through epigenetic processes, namely DNA methylation and nucleosomal remodeling via histone modifications. In that vein, chronic ethanol exposure modifies DNA and histone methylation, histone acetylation, and microRNA expression. The alcohol-mediated chromatin remodeling in the brain promotes the transition from use to abuse and addiction. Unravelling the multiplex pattern of molecular modifications induced by ethanol involves the ability to develop new, epigenetic processes-targeting therapies for alcoholism and drug addiction.Item Lysophosphatidic acid represses autophagy in prostate carcinoma cells(Canadian Science Publishing, 2018-11-05) Genc, Gizem Esra; Hipolito, Victoria E.B.; Botelho, Roberto J.; Gumuslu, SaadetLysophosphatidic acid (LPA) is a small signaling phospholipid that mediates diverse functions including cell proliferation, migration and survival by engaging LPA-agonized G-protein coupled receptors. Autophagy is a survival mechanism in response to nutrient depletion or organellar damage that encloses idle or damaged organelles within autophagosomes that are then delivered to lysosomes for degradation. However, the relationship between LPA and autophagy is largely unknown. The purpose of this study is to elucidate whether LPA affects autophagy through the ERK1/2 and/or the Akt/mTOR signaling pathways. In this study, we investigated the effect of LPA on autophagy-regulating pathways in various prostate-derived cancer cells including PC3, LNCaP and Du145 cells grown in complete medium and exposed to serum-free medium. Using Western blotting and ELISA, we determined that LPA stimulates the ERK and mTOR pathways in complete and serum-free medium. The mTOR pathway led to phosphorylation of S6K and ULK, which respectively stimulates protein synthesis and arrests autophagy. Consistent with this, LPA exposure suppressed autophagy as measured by LC3 maturation and formation of GFP-LC3 puncta. Altogether, these results suggest that LPA suffices to activate mTORC1 and suppress autophagy in prostate cancer cells.Item Carboxypeptidase E-ΔN promotes migration, invasiveness, and epithelial–mesenchymal transition of human osteosarcoma cells via the Wnt–β-catenin pathway(Canadian Science Publishing, 2018-11-05) Fan, Shuli; Gao, Xiang; Chen, Peng; Li, XuOsteosarcoma (OS) is the most common malignant bone tumor in children and adolescents, and metastatic OS is the major cause of OS-related death. Carboxypeptidase E (CPE) is known to be highly expressed in some cancer types, and its N-terminal truncated form, CPE-ΔN, is implicated in tumor metastasis and poor prognosis. In this study, we investigated the effect of CPE-ΔN on cell migration, invasiveness, and the epithelial–mesenchymal transition (EMT) of OS cells, and illustrated the molecular mechanisms. We first constructed CPE-ΔN overexpressing human OS cell lines (143B and U2OS cells), and found that ectopic CPE-ΔN expression in OS cells enhanced cell migration and invasiveness, and promoted the EMT process. Further, overexpression of CPE-ΔN increased the levels of c-myc and nuclear β-catenin in OS cells, which suggested the CPE-ΔN promotes activation of the Wnt–β-catenin pathway in OS cells. Treatment with β-catenin small interfering RNA (siRNA) inhibited the migration and invasiveness of CPE-ΔN-overexpressing cells, and reduced the expression of E-cadherin. Together, these results suggest that CPE-ΔN promotes migration, invasiveness, and the EMT of OS cells via the Wnt–β-catenin signaling pathway.Item GBP1 exerts inhibitory effects on acute viral myocarditis by inhibiting the inflammatory response of macrophages in mice(Canadian Science Publishing, 2018-12-11) Zhao, Ya-Nan; Xu, Guang-Jun; Yang, PingViral myocarditis (VMC) is a condition that could potentially progress to dilated cardiomyopathy or congestive heart failure, making it the leading cause of the untimely death in young adults. Interferon-induced GBP1 encodes much GTPase induced by interferon gamma in many eukaryotic cells. However, there is little known regarding the effect of GBP1 on acute VMC (AVMC). Hence, this study is aimed to assess the effect of GBP1 on AVMC. Once the AVMC mouse models were established, the functional role of GBP1 was determined in AVMC. Serum IL-6, TNF-α, and TGF-β levels and GBP1, MIF, iNOS and COX-2 expression were detected, with the viability and apoptosis of cardiomyocytes. AVMC mice presented with increased levels of TGF-β, IL-6, TNF-α, MIF, iNOS and COX-2, and cell apoptosis, but lower expression of GBP1 and viability of cardiomyocytes. Restored GBP1 or depleted macrophages could result in decreased levels of TGF-β, IL-6, TNF-α, MIF, iNOS and COX-2 as well as cardiomyocyte apoptosis while increasing its viability. In conclusion, our results highlighted the potential role of GBP1 in inhibting AVMC development. The experimental results indicated that GBP1 up-regulation and macrophage depletion can alleviate AVMC-related cardial damage by inhibiting inflammatory response and cardiomyocyte apoptosis while increasing cardiomyocyte viability.Item Ziziphus spina-christi leaves methanolic extract alleviates diethylnitrosamine-induced hepatocellular carcinoma in rats(Canadian Science Publishing, 2018-11-29) El-Din, Manar Salah; Taha, AlShaimaa Mohamed; Sayed, Ahmed Abdel-Aziz; Salem, Ahmed MohamedThe present study aimed to evaluate the antitumor activity of Ziziphus spina-christi leaves extract (ZSCL) against diethylnitrosamine (DENA)-induced hepatocarcinogenesis in rats. The phytochemical constituents, in vitro antioxidant and cytotoxic activities of ZSCL extract were investigated. Male Wistar rats were divided into 6 groups: normal control, ZSCL1-administered rats (100 mg/ Kg body weight â b.w.â ), ZSCL2-administered rats (300 mg/ Kg b.w.), DENA-induced hepatocarcinogenesis, hepatocarcinogenesis-bearing rats treated either with ZSCL1 or ZSCL2. Serum liver function oxidative stress tests were assayed. The expression of hepatocyte growth factor, insulin-like growth factor-1 receptor, B cell lymphoma-2, and matrix metalloproteinase-9 oncogenes were quantified in liver. Histological examination of liver tissues was performed. ZSCL methanolic extract was rich in essential fatty acids, phytol, and polyphenolic flavones (luteolin and quercetin) with strong free radical peroxide scavenging activities and cytotoxic activity. Administration of ZSCL1 and ZSCL2 to rats did not alter the studied parameters. DENA induced hepatocellular carcinoma and cholangioma by producing oxidative stress and upregulating liver oncogenes expression. Treatment of DENA-induced hepatocarcinogenesis with ZSCL2 ameliorated all the abnormalities induced by DENA except for cholangioma. In conclusion, ZSCL methanolic extract (300mg/ Kg b.w.) possessed a strong therapeutic activity against DENA-induced hepatocellular carcinoma via targeting oxidative stress and oncogenes.Item Fetal alcohol spectrum disorder (FASD) affects the hippocampal levels of histone variant H2A.Z-2(Canadian Science Publishing, 2018-11-29) Gretzinger, Taylor L.; Tyagi, Monica; Fontaine, Christine J.; Cheema, Manjinder S.; González-Perez, María; Freeman, Melissa E.; Christie, Brian R.; Ausio, JuanFetal Alcohol Spectrum disorder (FASD) is caused by the prenatal exposure to ethanol and has been linked to neurodevelopmental impairments. Alcohol has the potential to alter some of the epigenetic components which play a critical role during development. Previous studies have provided evidence that prenatal ethanol exposure results in abnormal epigenetic patterns (i.e. hypomethylation) of the genome. The aim of this study was to determine how prenatal exposure to ethanol in rats affects the hippocampal levels of expression of two important brain epigenetic transcriptional regulators involved in synaptic plasticity and memory consolidation: methyl CpG-binding protein 2 (MeCP2) and histone variant H2A.Z. Unexpectedly, under the conditions used in this work we were not able to detect any changes in MeCP2. Interestingly however, we observed a significant decrease in H2A.Z accompanied by its chromatin redistribution in both female and male FASD rat pups. Moreover, RT-qPCR data later confirmed that this decrease in H2A.Z is mainly due to down-regulation of its H2A.Z-2 isoform gene expression. Altogether, these data provide strong evidence that prenatal ethanol exposure alters histone variant H2A.Z during neurogenesis of rat hippocampus.Item Methylation of bone SOST impairs SP7, RUNX2, and ERα transactivation in patients with postmenopausal osteoporosis(Canadian Science Publishing, 2018-09-18) Shan, Yu; Wang, Liang; Li, Guangfei; Shen, Guangsi; Zhang, Peng; Xu, YoujiaSclerostin (SOST), a glycoprotein predominantly secreted by bone tissue osteocytes, is an important regulator of bone formation, and loss of SOST results in Van Buchem disease. DNA methylation regulates SOST expression in human osteocytes, although the detailed underlying mechanisms remain unknown. In this study, we compared 12 patients with bone fractures and postmenopausal osteoporosis with eight patients without postmenopausal osteoporosis to understand the mechanisms via which SOST methylation affects osteoporosis. Serum and bone SOST expression was reduced in patients with osteoporosis. Bisulfite sequencing-polymerase chain reaction (PCR) revealed that the methylation rate was higher in patients with osteoporosis. We identified osterix (SP7), Runt-related transcription factor 2 (RUNX2), and estrogen receptor (ER) as candidate transcription factors activating SOST expression. Increased SOST methylation impaired the transactivation function of SP7, RUNX2, and ER in MG-63 cells. AzadC treatment and SOST overexpression in MG-63 cells altered cell proliferation and apoptosis. Chromatin immunoprecipitation showed that higher methylation was associated with reduced SP7, RUNX2, and ER binding to the SOST promoter in patients with osteoporosis. Our studies provide new insight into the role of SOST methylation in osteoporosis.Item ARS2 is required for retinal progenitor cell S-phase progression and Müller glial cell fate specification.(Canadian Science Publishing, 2018-11-23) O'Sullivan, Connor Seamus; Nickerson, Philip E.B.; Krupke, Oliver; Christie, Jennifer; Chen, Li-Li; Mesa-Peres, Monica; Zhu, Minyan; Ryan, Bridget; Chow, Robert L.; Howard, Perry L.During a developmental period that extends postnatally in the mouse, proliferating multipotent retinal progenitor cells (RPCs) produce one of seven major cell types (rod, cone, bipolar, horizontal, amacrine, ganglion, and Müller glial cells) as they exit the cell cycle in consecutive waves. Cell production in the retina is tightly regulated by intrinsic, extrinsic, spatial, and temporal cues and is coupled to the timing of cell cycle exit. ARS2 (also known as Srrt) is a component of the nuclear cap-binding complex involved in RNA Polymerase II transcription, and is required for cell cycle progression. We show that postnatal RPCs require ARS2 for proper progression through S phase, and ARS2 disruption leads to early exit from the cell cycle. Furthermore, we observe an increase in the proportion of cells expressing a rod photoreceptor marker, and a loss of Müller glia marker expression, indicating a role for ARS2 in regulating cell fate specification or differentiation. Knockdown of FLASH, which interacts with ARS2 and is required for cell cycle progression and 3’-end processing of replication-dependent histone transcripts, phenocopies ARS2 knockdown. These data implicate ARS2/FLASH-mediated histone mRNA processing in regulating RPC cell cycle kinetics and neuroglial cell fate specification during postnatal retinal development.Item Biological Activity of Echinops spinosus on Inhibition of Paracetamol- Induced Renal Inflammation(Canadian Science Publishing, 2018-09-28) Hegazy, Marwa; Emam, Manal; Khattab, Hemmat; Helal, NesmaThis study was designed to evaluate the possible mechanisms through which Echinops Spinosus (ES) extract demonstrates nephroprotective effect on paracetamol (APAP)-induced nephrotoxicity in rat. Twenty-Four Swiss albino rats were divided into four groups (six rats each). Placebo group was orally administered sterile saline; APAP group received APAP (200 mg/kg/day i.p) daily; ES group was given orally ES extract (250 mg/kg); (APAP+ES) group: received APAP as for APAP group and administrated ES extract as for ES group. Pretreatment of methyl alcohol extract of ES reduced the protein expression of inflammatory parameters including cyclooxygenase-2 (COX-2) and nuclear factor kappa B (NF-κB) in kidney. It also reduced the mRNA gene expression of tumor necrosis factor-α (TNF-α) and Interleukin-1β (IL-1β). ES extract compensated deficits in the total antioxidant activity, suppressed lipid peroxidation and amended the APAP induced histopathological kidney alterations. Moreover, ES treatment restored the elevated levels of urea nitrogen in blood and creatinine in serum by acetaminophen. ES extract attenuated the acetaminophen-induced elevations in renal nitric oxide levels. We clarified that ES extract has the potential to defend kidney from APAP-induced inflammation, and protection mechanism might by through decreasing oxidative stress and regulating the inflammatory signaling pathway through modulating key signaling inflammatory biomarkers.Item Coordinated Tcf7l2 regulation in a mouse model implicates Wnt signaling in Fetal Alcohol Spectrum Disorders(Canadian Science Publishing, 2018-10-29) Chater-Diehl, Eric J; Sokolowski, Dustin J; Alberry, Bonnie LJ; Singh, Shiva MMouse models of fetal alcohol spectrum disorders (FASD) have repeatedly identified genes with long-term changes in expression, DNA methylation, noncoding RNA and histone modifications in response to neurodevelopmental alcohol exposure. Articulation of FASD is achieved via alcoholâ s effect on gene expression, likely involving epigenetic regulation. The list of genes affected is large and heterogeneous, depending on experimental protocol. We present reanalysis and synthesis of results highlighting Wnt transcription factor 7 like 2 (Tcf7l2) gene as uniquely compatible with hippocampal DNA methylation, histone modifications, and gene expression changes in a coordinated response to neurodevelopmental alcohol exposure. We data-mined literature for Tcf7l2 alterations in response to prenatal alcohol exposure. Four studies identified changes in brain Tcf7l2 expression in different FASD models. Further, we performed an in silico TCF7L2 binding site analysis for FASD mouse model datasets. Seven of these published gene lists were significantly enriched for TCF7L2 binding, indicating potential functional relationships. Finally, TCF7L2 is involved in regulation of hundreds of genes, with a role in brain development, myelination, and neuronal function. Tcf7l2 may be involved in neurological defects associated with alcohol exposure via dysregulation of many genes through Wnt signaling. Further functional work is warranted to validate this model for FASD.Item On the Oxidative Damage by Cadmium on Kidney Mitochondrial Functions(Canadian Science Publishing, 2018-09-05) Pavon, Natalia; Buelna-Chontal, Mabel; Macias-Lopez, Arturo; Correa, Francisco; Uribe-Alvarez, Cristina; Hernández-Esquivel, Luz; Chavez, EdmundoIn the kidney, the accumulation of heavy metals, such as Cd2+, produce mitochondrial dysfunctions, i.e., uncoupling of the oxidative phosphorylation, inhibition of the electron transport through the respiratory chain, and collapse of the transmembrane electrical gradient. This derangement may be due to the fact that Cd2+ induces the transition of membrane permeability from selective to non-selective via the opening of a transmembrane pore. In fact, Cd2+ produces this injury through the stimulation of oxygen-derived radical generation conducing to oxidative stress. Several molecules have been used to avoid or even reverse the Cd2+-induced mitochondrial injury, for instance, cyclosporin A, resveratrol, dithiocarbamates, and even EDTA. The aim of the present study was to explore the possibility that tamoxifen, an antioxidant reagent, may preserve mitochondrial function from the deleterious effects of Cd2+. Our results indicate that addition of 1 ÎźM Cd2+ to mitochondria collapsed the transmembrane electrical gradient, induced the release of cytochrome c, and increased both the generation of H2O2 and the oxidative damage to mitochondrial DNA (among other measured parameters). Of interest, these mitochondrial dysfunctions were ameliorated after the addition of tamoxifen.Item Alteration of Bcl11b upon stimulation of both MAP Kinase- and Gsk3-dependent signaling pathways in double negative thymocytes(Canadian Science Publishing, 2018-10-17) Selman, Wisam Hussein; Esfandiari, Elahe; Filtz, Theresa MBcl11b is a transcription factor critical for thymocyte development. We previously characterized the kinetic post-translational modifications (PTMs) of Bcl11b in double positive (DP) thymocytes during stimulation of the T cell receptor-activated MAP kinase pathway. However, the PTMs of Bcl11b in thymocytes from other developmental stages in the thymus, primarily double negative (DN) cells, have not been previously identified. We found that kinetic modifications of Bcl11b in DN cells are somewhat different than the patterns observed in DP cells. Distinct from DP thymocytes, phosphorylation and sumoylation of Bcl11b in DN cells were not oppositely regulated in response to activation of MAP kinase, even though hyper-phosphorylation of Bcl11b coincided with near complete desumoylation. Additionally, prolonged stimulation of the MAP kinase pathway in DN cells, unlike DP thymocytes, did not alter Bcl11b levels of sumoylation or ubiquitinylation, or stability. On the other hand, activation of Wnt/Gsk3-dependent signaling in DN cells resulted in composite dephosphorylation and sumoylation of Bcl11b. Moreover, stimulation of MAP kinase and/or Wnt signaling pathways differentially affects gene expression of some Bcl11b target and maturation- associated genes. Defining the signaling pathways and regulation of sequence-specific transcription factors (SSTFs) by PTMs at various stages of thymopoiesis may improve our understanding of leukemogenesis.Item Long noncoding RNA NEAT1 promoted the growth of cervical cancer cells via sponging miR-9-5p(Canadian Science Publishing, 2018-08-02) Xie, Qiuxian; Lin, Shanna; Zheng, Manjia; Cai, Qiutao; Tu, YaAccumulating evidence has demonstrated that the long non-coding RNAs (lncRNAs) participate in the initiation and progression of cancers. In this study, we found that the lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) was significantly increased in both cervical cancer tissues and cell lines. Overexpression of NEAT1 promoted the proliferation and migration of cervical cancer cells. Molecular study uncovered that NEAT1 functioned as competitive endogenous RNA (ceRNA) to bind miR-9-5p and suppress the expression of miR-9-5p. Consistently, highly expressed NEAT1 attenuated the inhibitory effect of miR-9-5p on the expression of PTEN and POU2F1, which were the targets of miR-9-5p. In agreement with the negative regulation of NEAT1 on miR-9-5p, restoration of miR-9-5p inhibited the promotion of NEAT1 on the growth of cervical cancer cells. Taken together, these results indicated that NEAT1 played important roles in regulating the growth of cervical cancer cells via targeting miR-9-5p. Our findings characterized the possible mechanism of NEAT in cervical cancer.Item Silencing of Astrocyte elevated gene-1 (AEG-1) inhibits proliferation, migration and invasion, and promotes apoptosis in pancreatic cancer cells(Canadian Science Publishing, 2018-10-17) Yang, Xing; Song, ShaoweiTo investigate the role of Astrocyte elevated gene-1 (AEG-1) in the development and progress of pancreatic cancer, the short hairpin RNA (shRNA) was inserted into the RNA interference vector to knock down the endogenous AEG-1 in two pancreatic cancer cell lines, AsPC-1 and PANC-1. Our results showed that silencing of AEG-1 suppressed the proliferation, colony formation ability and cell stemness of AsPC-1 and PANC-1 cells, and inhibited their G1 to S phase transition. Results from apoptosis assay showed that knockdown of AEG-1 led to cell apoptosis. The expression of the anti-apoptotic Bcl-2 was downregulated and that of the pro-apoptotic Bax and cleaved Caspase-3 was upregulated in AEG-1-silenced pancreatic cancer cells. Further, the capability of AEG-1-silenced cells to migrate and to invade through the Matrigel-coated membrane was weaker, and the expression of matrix metallopeptidase 2 (MMP-2) and MMP-9 were decreased. Moreover, AKT/β-catenin signaling pathway was inhibited in these cells knockdown of AEG-1. In addition, the growth of xenograft tumors formed by AsPC-1 and PANC-1 cells was suppressed by AEG-1 shRNA. In conclusion, our study demonstrates that pancreatic cancer cells require AEG-1 to maintain their survival and metastasis, suggesting AEG-1 as a potential target for the treatment of pancreatic cancers.Item Temperature and serine phosphorylation regulate glycerol-3-phosphate dehydrogenase in skeletal muscle of hibernating Richardson’s ground squirrels(Canadian Science Publishing, 2018-09-18) Ruberto, Anthony Agostino; Logan, Samantha Michelle; Storey, Kenneth B.Glycerol-3-phosphate dehydrogenase (G3PDH) bridges carbohydrate and lipid metabolism by interconverting glycerol-3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP). This reversible reaction converts G3P derived from triglyceride hydrolysis to DHAP that can then enter glycolysis or gluconeogenesis and, in the reverse reaction, makes G3P for use in triglyceride biosynthesis. Small hibernating mammals rely almost exclusively on triglyceride reserves as their fuel for energy production during torpor and the recovery of glycerol after lipolysis is an important source of carbohydrate over the non-feeding winter months. G3PDH (~37 kDa) was purified from skeletal muscle of euthermic and hibernating Richardson’s ground squirrels (Urocitellus richardsonii) using three column chromatography steps. Analysis of enzyme kinetic properties revealed that G3PDH from hibernator muscle had higher affinities for G3P and NAD at low (5°C) assay temperature compared to high (21°C or 37°C), and a greater stability in the presence of denaturing agents (urea, guanidine hydrochloride) or high temperature (50°C). Immunoblotting showed that hibernator muscle G3PDH had a higher phosphoserine content than the enzyme from euthermic controls and incubation studies showed that enzyme affinity for G3P changed significantly by stimulating endogenous protein kinases or phosphatases. Overall, this study suggests that the properties of ground squirrel muscle G3PDH are modulated by temperature and post-translational phosphorylation to alter enzyme function under euthermic versus hibernating states.Item Small Hepatitis Delta Antigen Selectively Binds to Target mRNA in Hepatic Cells: A Potential Mechanism by Which Hepatitis D Virus Down-Regulates Glutathione S-Transferase P1 and Induces Liver Injury and Hepatocarcinogenesis(Canadian Science Publishing, 2018-08-23) Chen, Mianzhi; Du, Dan; Zheng, Wen; Liao, Mingheng; Liang, Ge; Zhang, Lu; Gong, MengLiver co-infection by hepatitis B virus (HBV) and hepatitis D virus (HDV) can result in a severe form of hepatocellular carcinoma with poor prognosis. Co-infection with HDV and HBV causes more deleterious effects than infection with HBV alone. Clinical research has shown that glutathione S-transferase P1 (GSTP1), a tumor suppressor gene, is typically down-regulated in liver samples from hepatitis-infected patients. In the present study, our data indicated that small HDV antigen (s-HDAg) could specifically bind to GSTP1 mRNA and significantly down-regulate GSTP1 protein expression. For the human fetal hepatocyte cell line L-02, cells transfected with s-HDAg, along with decreased GSTP1 expression, there was a significant accumulation of reactive oxygen species (ROS) and increased apoptotic ratios. Restoring GSTP1 expression through silencing s-HDAg via RNAi or over-expressing exogenous GSTP1 could largely recover the abnormal cell status. Our results revealed a novel potential mechanism of HDV-induced liver injury and hepatocarcinogenesis: s-HDAg can inhibit GSTP1 expression by directly binding to GSTP1 mRNA, which leads to accumulation of cellular ROS, resulting in high cellular apoptotic ratios and increased selective pressure for malignant transformation. To our knowledge, this is the first study to examine s-HDAg-specific pathogenic mechanisms through potential protein-RNA interactions.Item A crosslinked and ribosylated actin trimer does not interact productively with myosin(Canadian Science Publishing, 2018-09-05) Sidhu, Navneet; Dawson, John F.A purified F-actin derived actin trimer that interacts with end-binding proteins did not activate or bind the side-binding protein myosin under rigor conditions. Remodeling of the actin trimer by the binding of gelsolin did not rescue myosin binding, nor did the use of different means of inhibiting the polymerization of the trimer. Our results demonstrate that ADP-ribosylation on all actin subunits of an F-actin derived trimer inhibits myosin binding and that the binding of DNase-I to the pointed end subunits of a crosslinked trimer also remodels the myosin binding site. Taken together, this work highlights the need for a careful balance between modification of actin subunits and maintaining protein-protein interactions to produce a physiologically-relevant short F-actin complex.