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Find video protocols related to scientific articles indexed in Pubmed.
Bufalin enhances TRAIL-induced apoptosis by redistributing death receptors in lipid rafts in breast cancer cells.
Anticancer Drugs
PUBLISHED: 04-09-2014
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Studies have shown that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in cancer cells. However, breast cancer cells are generally resistant to TRAIL. In the present study, we explored the effect of bufalin on TRAIL-induced breast cancer cell apoptosis. The results showed that bufalin enhanced TRAIL-induced apoptosis in MCF-7 and MDA-MB-231 breast cancer cells by activating the extrinsic apoptotic pathway. Bufalin also promoted the clustering of death receptor 4 (DR4) and DR5 in aggregated lipid rafts. The cholesterol-sequestering agent methyl-?-cyclodextrin reversed the DR4 and DR5 clustering and reduced bufalin+TRAIL-induced apoptosis. Overall, these results indicate that bufalin enhanced TRAIL-induced apoptosis in breast cancer cells by the partial redistribution of DRs in lipid rafts.
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Quercetin enhances apoptotic effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in ovarian cancer cells through reactive oxygen species (ROS) mediated CCAAT enhancer-binding protein homologous protein (CHOP)-death receptor 5 pathway.
Cancer Sci.
PUBLISHED: 02-10-2014
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Although tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has shown efficacy in a phase 2 clinical trial, development of resistance to TRAIL by tumor cells is a major roadblock. We investigated whether quercetin, a flavonoid, can sensitize human ovarian cancer cells to TRAIL. Results indicate that quercetin sensitized cancer cells to TRAIL. The quercetin induced expression of death receptor DR5 but did not affect expression of DR4 in cancer cells. The induction of DR5 was mediated through activation of JNK and through upregulation of a transcription factor CCAAT enhancer-binding protein homologous protein (CHOP); as silencing of these signaling molecules abrogated the effect of quercetin. Upregulation of DR5 was mediated through the generation of reactive oxygen species (ROS), as ROS scavengers reduced the effect of quercetin on JNK activation, CHOP upregulation, DR induction, TRAIL sensitization, downregulated the expression of cell survival proteins and upregulated the proapoptotic proteins. Furthermore, quercetin enhances TRAIL mediated inhibition of tumor growth of human SKOV-3 xenograft was associated with induction of apoptosis, activation of caspase-3, CHOP and DR5. Overall, our data suggest that quercetin enhances apoptotic death of ovarian cancer cells to TRAIL through upregulation of CHOP-induced DR5 expression following ROS mediated endoplasmic reticulum-stress.
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Autocrine interleukin-6 drives skin-derived mesenchymal stem cell trafficking via regulating voltage-gated Ca(2+) channels.
Stem Cells
PUBLISHED: 01-25-2014
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Mesenchymal stem cells (MSCs) have demonstrated promising therapeutic potential for a variety of diseases including autoimmune disorders. A fundamental requirement for MSC-mediated in vivo immunosuppression is their effective trafficking. However the mechanism underlying MSC trafficking remains elusive. Here we report that skin-derived MSCs (S-MSCs) secrete high levels of interleukin-6 (IL-6) in inflammatory conditions. Disruption of the il6 or its signaling transducer gp130 blocks voltage-gated calcium (Ca(2+) ) channels (VGCC) critically required for cell contraction involved in the sequential adhesion and de-adhesion events during S-MSC migration. Deletion of il6 gene leads to a severe defect in S-MSC's trafficking and immunosuppressive function in vivo. Thus, this unexpected requirement of autocrine IL-6 for activating Ca(2+) channels uncovers a previously unrecognized link between the IL-6 signaling and the VGCC and provides novel mechanistic insights for the trafficking and immunomodulatory activities of S-MSCs.
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The SORL1 polymorphism rs985421 may confer the risk for amnestic mild cognitive impairment and Alzheimer's disease in the Han Chinese population.
Neurosci. Lett.
PUBLISHED: 01-14-2014
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Although the pathogenetic mechanisms driving Alzheimer's disease (AD) are unclear, genetic variations may play an important role. Previous studies have identified that single nucleotide polymorphisms (SNPs) in the sortilin-related receptor, L (DLR class) A repeats containing (SORL1) gene are associated with AD or amnestic mild cognitive impairment (aMCI) patients. However, the association of SORL1 variants with AD or aMCI susceptibility in the Han Chinese population has not been adequately reported. Thus, we conducted a case-control study in 106 sporadic AD patients, 67 aMCI patients, and 179 healthy control Han Chinese subjects to determine whether SORL1 genetic variations alter the risk for AD or aMCI. Using the LDR-PCR method to genotype five polymorphisms in SORL1, we found significant associations (for AD: OR=1.968, 95% CI=1.273-3.042; for aMCI: OR=2.210, 95% CI=1.353-3.610) between the 'A' allele of the SORL1 SNP rs985421 and AD and aMCI, which may represent an ApoE ?4-independent risk factor for SAD. These findings suggest that the SORL1 SNP rs985421 may alter the risk for sporadic AD and aMCI in the Han Chinese population.
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CCR6 is a prognostic marker for overall survival in patients with colorectal cancer, and its overexpression enhances metastasis in vivo.
PLoS ONE
PUBLISHED: 01-01-2014
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The chemokine receptor CCR6 has been recently shown to be associated with colorectal cancer (CRC) progression. However, the direct evidence for whether CCR6 in tumors is a prognostic marker for the survival of patients with CRC and whether it plays a critical role in CRC metastasis in vivo is lacking. Here we show that the levels of CCR6 were upregulated in CRC cell lines and primary CRC clinical samples. CCR6 upregulation was closely correlated with disease stages and the survival time of CRC patients. Knockdown of CCR6 inhibited the migration of CRC cells in vitro. Overexpression of CCR6 in CRC cells increased their proliferation, migration, and colony formation in vitro and promoted their metastatic potential in vivo. CCR6 activated Akt signaling, upregulated metastasis genes and downregulated metastasis suppressor genes. Selective targeting of CCR6 in tumors dramatically inhibited the growth of CRC in mice. Thus, the tumor expression of CCR6 plays a critical role in CRC metastasis, upregulated CCR6 predicts poor survival in CRC patients, and targeting CCR6 expression in tumors may be a potential therapeutic strategy for CRC.
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Quantitative analysis of the flexibility effect of cisplatin on circular DNA.
Phys Rev E Stat Nonlin Soft Matter Phys
PUBLISHED: 04-03-2013
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We study the effects of cisplatin on the circular configuration of DNA using atomic force microscopy (AFM) and observe that the DNA gradually transforms to a complex configuration with an intersection and interwound structures from a circlelike structure. An algorithm is developed to extract the configuration profiles of circular DNA from AFM images and the radius of gyration is used to describe the flexibility of circular DNA. The quantitative analysis of the circular DNA demonstrates that the radius of gyration gradually decreases and two processes on the change of flexibility of circular DNA are found as the cisplatin concentration increases. Furthermore, a model is proposed and discussed to explain the mechanism for understanding the complicated interaction between DNA and cisplatin.
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Homologous HAP5 subunit from Picea wilsonii improved tolerance to salt and decreased sensitivity to ABA in transformed Arabidopsis.
Planta
PUBLISHED: 03-30-2013
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HAP is a ubiquitous transcription factor family which consists of three distinct subunits, namely HAP2, HAP3, and HAP5. Among them, HAP2 and HAP3 subunits have been reported to be involved in plant response to abiotic stress. Here, a HAP5 subunit was identified from Picea wilsonii Mast. and transformed to Arabidopsis to investigate its functions in plant stress response. We found that transformed Arabidopsis with over-expressing PwHAP5 exhibited higher seed germination under salinity, osmotic and abscisic acid (ABA) stress treatment compared to Col-0 plants. The seedlings of transformed Arabidopsis also showed improved tolerance to salinity and decreased sensitivity to ABA treatment. Over-expression of PwHAP5 in Arabidopsis athap5 mutant rescued partly tolerance to NaCl, mannitol and ABA treatment. Furthermore, we examined transcription levels of several stress-related genes in transformed seedlings. Among them, mRNA expression levels of COR15a, KIN1, DREB2A, and RD29A genes were substantially higher in transformed Arabidopsis than those in wild-type (Col-0) plants. Therefore, our data revealed that PwHAP5 plays positive roles in response to salinity, osmotic and ABA stress at different developmental stages in plants, respectively, via possibly regulating stress-related genes.
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Facial corticobulbar motor-evoked potential monitoring during the clipping of large and giant aneurysms of the anterior circulation.
J Clin Neurosci
PUBLISHED: 01-11-2013
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Surgical outcomes for large and giant intracranial aneurysms are suboptimal. Two important reasons for higher complication rates are either occlusion of perforators or parent arteries during aneurysm clipping, or prolonged temporary occlusion of the main arteries. Somatosensory-evoked potential (SSEP) monitoring and transcranial motor-evoked potential (TcMEP) monitoring are standard techniques for monitoring ischemia either during temporary arterial occlusion or after permanent clipping. In our study, facial corticobulbar motor-evoked potential (FCoMEP) monitoring was included to determine whether this modality improved intraoperative monitoring. FCoMEP were recorded intraoperatively in 21 patients undergoing surgical clipping of large and giant aneurysms of the anterior circulation. Valid TcMEP parameters were obtained for all patients. A correlation tending to significance between a prolonged temporary clipping time and TcMEP decrement was observed. In addition to this, the inclusion of FCoMEP improved the sensitivity of extremity muscle motor-evoked potential (ExMEP, which included TcMEP) monitoring (from 80% to 100%). In the long-term assessment, a favorable outcome was achieved in 16 of the 21 patients (76%). In conclusion, FCoMEP provides complementary corticobulbar tract information for detecting perforating vessel compromise that may lead to motor impairment and that is not identified by ExMEP.
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Receptor activator for nuclear factor ? B expression predicts poor prognosis in breast cancer patients with bone metastasis but not in patients with visceral metastasis.
J. Clin. Pathol.
PUBLISHED: 11-02-2011
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It was recently reported that receptor activator for nuclear factor ? B ligand (RANKL)/receptor activator for nuclear factor ? B (RANK) pathway is critical for RANK-expressing cancer cells to home to bone and associates with disease progression of cancer. The present study was aimed to evaluate the effect of RANK on prognosis in breast cancer patients with bone metastasis and patients with visceral metastasis.
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Proteasome inhibitor bortezomib (PS-341) enhances RANKL-induced MDA-MB-231 breast cancer cell migration.
Mol Med Rep
PUBLISHED: 09-16-2011
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The receptor activator of nuclear factor ?B ligand/receptor activator of nuclear factor ?B (RANKL/RANK) pathway is crucial for the migration of RANK-expressing cancer cells. The ubiquitin-proteasome protein degradation pathway plays a significant role in tumor metastasis. However, the relationship between these two pathways in tumor cell migration is unclear. In the present study, we explored the effect of the proteasome inhibitor bortezomib (PS-341) on RANKL-induced MDA-MB-231 breast cancer cell migration. Transwell migration assay showed that RANKL-induced MDA-MB-231 cell migration was significantly blocked by the decoy receptor osteoprotegerin (OPG), and was also inhibited by the PI3-K inhibitor LY294002. Western blotting results showed that Akt was rapidly activated by soluble RANKL treatment. PS-341 signi?cantly enhanced RANKL-induced MDA-MB-231 cell migration. Further study showed that the enhancement of migration by PS-341 involved upregulation of activated Akt and RANK. Our results for the first time support the theory that PS-341 treatment may be unsuitable for RANK-positive breast cancer patients.
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Comparative proteomic analysis of a Haemophilus parasuis SC096 mutant deficient in the outer membrane protein P5.
Microb. Pathog.
PUBLISHED: 08-17-2011
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Outer membrane protein A (OmpA) is a major structural component of the outer membranes and functions as a multifaceted molecular with many diverse roles in Gram-negative bacteria. In Haemophilus parasuis, OmpA has been recognized and named as OmpP5 in genomic literature. In this study, to determine the precise functions of OmpP5, an ompP5 deficient mutant (?ompP5) of a H. parasuis serovar 4 filed strain SC096 was constructed using a natural transformation method. Compared to the wild-type SC096 strain, the ?ompP5 mutant displayed a detectable delay in growth. However, the wild-type and mutant strains were indistinguishable with respect to the other phenotypes including resistance to killing by porcine and rabbit sera, adhesion to and invasion of porcine umbilicus veins endothelial cells (PUVEC) and porcine kidney epithelial cells (PK-15). To analyze the differences of proteome expression between wild-type and mutant strains, a 2-dimensional gel electrophoresis (2-DE)-based proteomics comparison was performed. There were 24 differentially expressed proteins which were mainly involved in carbohydrate, lipid, nucleotide and amino acid metabolism, or served as transcription and translation factors and chaperone proteins. Collectively, loss of OmpP5 expression in the H. parasuis SC096 strain resulted in global protein expression changes which might be responsible for novel phenotypes occurred in ?ompP5 mutant.
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Phloem unloading follows an extensive apoplasmic pathway in cucumber (Cucumis sativus L.) fruit from anthesis to marketable maturing stage.
Plant Cell Environ.
PUBLISHED: 07-26-2011
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The phloem unloading pathway remains unclear in fruits of Cucurbitaceae, a classical stachyose-transporting species with bicollateral phloem. Using a combination of electron microscopy, transport of phloem-mobile symplasmic tracer carboxyfluorescein, assays of acid invertase and sucrose transporter, and [(14)C]sugar uptake, the phloem unloading pathway was studied in cucumber (Cucumis sativus) fruit from anthesis to the marketable maturing stage. Structural investigations showed that the sieve element-companion cell (SE-CC) complex of the vascular bundles feeding fruit flesh is apparently symplasmically restricted. Imaging of carboxyfluorescein unloading showed that the dye remained confined to the phloem strands of the vascular bundles in the whole fruit throughout the stages examined. A 37 kDa acid invertase was located predominantly in the cell walls of SE-CC complexes and parenchyma cells. Studies of [(14)C]sugar uptake suggested that energy-driven transporters may be functional in sugar trans-membrane transport within symplasmically restricted SE-CC complex, which was further confirmed by the existence of a functional plasma membrane sucrose transporter (CsSUT4) in cucumber fruit. These data provide a clear evidence for an apoplasmic phloem unloading pathway in cucumber fruit. A presumption that putative raffinose or stachyose transporters may be involved in soluble sugars unloading was discussed.
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Serum resistance in Haemophilus parasuis SC096 strain requires outer membrane protein P2 expression.
FEMS Microbiol. Lett.
PUBLISHED: 07-25-2011
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Haemophilus parasuis outer membrane protein P2 (OmpP2), the most abundant protein in the outer membrane, has been identified as an antigenic protein and a potential virulence factor. To study the precise function of OmpP2, an ompP2-deficient mutant (?ompP2) of a H. parasuis serovar 4 clinical strain SC096 was constructed by a modified natural transformation system. Compared with the wild-type SC096 strain, the ?ompP2 mutant showed a pronounced growth defect and exhibited significantly greater sensitivity to the bactericidal action of porcine and rabbit sera, whereas the complemented strain could restore the growth and serum resistance phenotypes. The results indicated that H. parasuis OmpP2 from SC096 strain is an important surface protein involved in serum resistance.
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PwHAP5, a CCAAT-binding transcription factor, interacts with PwFKBP12 and plays a role in pollen tube growth orientation in Picea wilsonii.
J. Exp. Bot.
PUBLISHED: 07-22-2011
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The HAP complex occurs in many eukaryotic organisms and is involved in multiple physiological processes. Here it was found that in Picea wilsonii, HAP5 (PwHAP5), a putative CCAAT-binding transcription factor gene, is involved in pollen tube development and control of tube orientation. Quantitative real-time reverse transcription-PCR showed that PwHAP5 transcripts were expressed strongly in germinating pollen and could be induced by Ca(2+). Overexpression of PwHAP5 in pollen altered pollen tube orientation, whereas the tube with PwHAP5RNAi showed normal growth without diminishing pollen tube growth. Furthermore, PwFKBP12, which encodes an FK506-binding protein (FKBP) was screened and a bimolecular fluorescence complementation assay performed to confirm the interaction of PwHAP5 and PwFKBP12 in vivo. Transient expression of PwFKBP12 in pollen showed normal pollen tube growth, whereas the tube with PwFKBP12RNAi bent. The phenotype of overexpression of HAP5 on pollen tube was restored by FKBP12. Altogether, our study supported the role of HAP5 in pollen tube development and orientation regulation and identified FKBP12 as a novel partner to interact with HAP5 involved in the process.
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C-Src-mediated RANKL-induced breast cancer cell migration by activation of the ERK and Akt pathway.
Oncol Lett
PUBLISHED: 06-21-2011
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The receptor activator for nuclear factor ?B ligand/receptor activator for nuclear factor ?B (RANKL/RANK) pathway is critical for RANK-expressing cancer cells to home to bones, and c-Src is critical for cancer progression. The objective of this study was to explore the effect of c-Src in the RANKL/RANK pathway and migration activity in human breast cancer cells. Breast cancer cell lines MCF-7, MDA-MB-231 and BT-474 were obtained and cultured. Flow cytometry was used to examine RANK expression. The results showed that RANK was expressed in breast cancer cell lines MCF-7, MDA-MB-231 and BT-474, and soluble RANKL (sRANKL)-triggered migration of breast cancer cells by activating ERK1/2, Akt and c-Src. The sRANKL-induced migration was blocked with RANKL inhibitor osteoprotegerin (OPG), MEK inhibitor PD98059, PI3K inhibitor LY294002 and Src inhibitor PP2. Inhibition of c-Src function with PP2 blocked the activation of Akt and ERK1/2, resulting in the inhibition of RANKL-induced migration. In conclusion, RANKL was found to increase the migration of breast cancer cells by activating the c-Src-Akt and c-Src-ERK signaling pathways.
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Antimicrobial susceptibility and PFGE genotyping of Haemophilus parasuis isolates from pigs in South China (2008-2010).
J. Vet. Med. Sci.
PUBLISHED: 04-04-2011
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H. parasuis isolates (n=112) from pigs were tested for antimicrobial susceptibility against 23 antimicrobial agents by the disk diffusion method. All isolates were sensitive to Florfenico and most strains were sensitive to Cefotaxime (103/112; 92%), Ceftazidime (99/112; 88.4%), Chloramphenicol (90/112; 80.4%) and Gentamicin (85/112; 75.9%). High resistance levels to Nalidixic acid (84.8%), TMP (67.9%) and Trimethoprim+Sulfamethoxazole (58%) were observed. Genomic DNA extracted from 52 isolates resistant to at least seven antimicrobial agents was analyzed by PFGE and 46 distinct PFGE patterns identified. Diverse variation was observed between the drug-resistant H. parasuis isolates examined, suggesting that resistance traits were acquired independently by the respective isolates.
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Selectivity and temperature dependence of phase and phase transition in diblock copolymer solution.
Eur Phys J E Soft Matter
PUBLISHED: 03-28-2011
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In order to study the effects of solvent selectivity and temperature on phase behavior and transition of diblock copolymer solution, self-consistent field theory is modified to incorporate the short-range interaction and non-local effects. Inhomogeneous free-energy density is shown to be dependent on solvent selectivity, temperature and copolymer concentration. Enthalpic quantity and entropic contributions are crucial to phase diagrams of diblock copolymer solution. Three selective strengths of solvent --weak, moderate and strong-- are chosen for comparison. For a weakly selective solvent, theoretical and experimental results illustrate the same variation tendency in the phase boundary of the order-disorder transition for a symmetric diblock of polystyrene and polyisoprene. Self-consistent field equations can be used to calculate the exact FCC-BCC structural phase transition temperatures in moderately and strongly selective solvents. Detailed comparison with the experimental phase diagrams including lamellar, cylindrical and spherical structures is presented.
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Epirubicin enhances TRAIL-induced apoptosis in gastric cancer cells by promoting death receptor clustering in lipid rafts.
Mol Med Rep
PUBLISHED: 02-04-2011
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Gastric cancer cells are usually insensitive to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In the present study, in MGC803 cells treated with 100 ng/ml TRAIL for 24 h, the inhibition rate of cell proliferation was 9.76±2.39% and the rate of cell apoptosis was only 4.37 ± 1.45%. Treatment with epirubicin (1.18 µg/ml, IC50 dose for 24 h) and TRAIL (100 ng/ml for 24 h) led to a marked increase in the inhibition rate of cell proliferation and apoptosis compared to treatment with epirubicin or TRAIL alone (P<0.05). Moreover, even more notable cleavage of caspase-3 and 8 was detected with the combination of epirubicin and TRAIL. TRAIL (100 ng/ml) induced only light lipid raft aggregation and DR4 and DR5 clustering. Epirubicin significantly promoted lipid raft DR4 and DR5 aggregation, as well as the localization of DR4 and DR5 in the lipid rafts. Similar results were detected with the combination of epirubicin and TRAIL. Pretreatment with 50 µg/ml nystatin, a cholesterol-sequestering agent, partially prevented epirubicin-induced lipid raft aggregation and DR4 and DR5 clustering. Pretreatment with nystatin did not markedly inhibit epirubicin-induced apoptosis, while nystatin partially suppressed epirubicin and TRAIL-induced apoptosis (P<0.05). Our data demonstrate that epirubicin enhanced TRAIL-induced apoptosis in gastric cancer MGC803 cells, at least partially, through death receptor redistribution in the lipid rafts.
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The inflammatory changes of adipose tissue in late pregnant mice.
J. Mol. Endocrinol.
PUBLISHED: 01-01-2011
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The infiltration of classically activated macrophages (M1) and alternatively activated macrophages (M2) in subcutaneous adipose tissue (SAT) and parametrial adipose tissue (PAT) was analyzed to investigate whether local inflammatory change in adipose tissue occurs in late pregnancy. C57BL/6N female mice at 6 weeks of age were fed a normal chow diet for 4 weeks prior to mating at 10 weeks of age and were sampled on day 17 of pregnancy. The serum levels of adipokines and biochemical markers were measured using ELISA and enzymatic methods. The identification of M1 and M2 was analyzed by double immunofluorescence with anti-F4/80 and anti-CD11c antibodies. The gene expression of adipokines in adipose tissues was analyzed by quantitative RT-PCR. The pregnant group showed adipocyte hypertrophy, higher macrophage infiltration, and higher M1/M2 in both SAT and PAT compared with the non-pregnant (NP) group. Serum levels of free fatty acids, tumor necrosis factor ? (TNF?), interleukin 6 (IL6), and IL10 were higher, and serum levels of adiponectin were lower in the pregnant group than those in the NP group. The gene expressions of CD68, Itgax, CCR2, TNF?, and PAI1 in SAT during pregnancy were significantly higher than those in the NP group, as were the gene expressions of CD68, Emrl, Itgax, MCP1, TNF?, IL6, PAI1, adiponectin, and IL10 in PAT. These results suggest that the low-grade inflammation of adipose tissue indicated by increased macrophage infiltration occurs in late normal pregnancy.
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The predominance of the apoplasmic phloem-unloading pathway is interrupted by a symplasmic pathway during Chinese jujube fruit development.
Plant Cell Physiol.
PUBLISHED: 04-16-2010
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Phloem unloading plays a pivotal part in photoassimilate transport and partitioning into sink organs. However, it remains unclear whether the unloading pathway alters to adapt to developmental transitions in sinks, especially in fleshy fruits accumulating a high level of soluble sugars. Using a combination of electron microscopy, transport of the phloem-mobile symplasmic tracer carboxyfluorescein and assays of acid invertase, the pathway of unloading was investigated in different varieties of Chinese jujube fruit (Zizyphus jujuba Mill. cv Dongzao and Lizao). Structural investigation showed that the sieve element-companion-cell complex of bundles feeding the fruit flesh is symplasmically connected with surrounding parenchyma cells at the middle stage, and isolated during the early and late stages. Numerous plasmodesmata are present between phloem parenchyma cells and flesh cells throughout fruit development. Confocal laser scanning images of carboxyfluorescein unloading showed that the dye remained confined to the phloem strands during the early and late stages of fruit development, whereas it was released from the functional phloem at the middle stage. The levels of both the expression and activities of cell wall acid invertase and soluble acid invertase varied in an inverse pattern relative to fruit development. These results provided clear evidence for the predominance of an apoplasmic phloem unloading pathway interrupted with a symplasmic pathway and simultaneous symplasmic and apoplasmic unloading pathways in post-phloem transport during fruit development. Similar unloading pathways were obtained in different varieties of jujube fruit. The mechanisms and significance of the adaptive switch in the phloem-unloading pathway during fruit development were discussed.
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Mutual inhibition of RecQ molecules in DNA unwinding.
J. Biol. Chem.
PUBLISHED: 03-15-2010
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Helicases make conformational changes and mechanical movements through hydrolysis of NTP to unwind duplex DNA (or RNA). Most helicases require a single-stranded overhang for loading onto the duplex DNA substrates. Some helicases have been observed to exhibit an enhanced unwinding efficiency with increasing length of the single-stranded DNA tail both by preventing reannealing of the unwound DNA and by compensating for premature dissociation of the leading monomers. Here we report a previously unknown mutual inhibition of neighboring monomers in DNA unwinding by the monomeric Escherichia coli RecQ helicase. With single molecule fluorescence resonance energy transfer microscopy, we observed that the unwinding initiation of RecQ at saturating concentrations was more delayed for a long rather than a short tailed DNA. In stopped-flow kinetic studies under both single and multiple turnover conditions, the unwinding efficiency decreased with increasing enzyme concentration for long tailed substrates. In addition, preincubation of RecQ and DNA in the presence of 5-adenylyl-beta,gamma-imidodiphosphate was observed to alleviate the inhibition. We propose that the mutual inhibition effect results from a forced closure of cleft between the two RecA-like domains of a leading monomer by a trailing one, hence the forward movements of both monomers are stalled by prohibition of ATP binding to the leading one. This effect represents direct evidence for the relative movements of the two RecA-like domains of RecQ in DNA unwinding. It may occur for all superfamily I and II helicases possessing two RecA-like domains.
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Structure-activity relationships of diphenylpiperazine N-type calcium channel inhibitors.
Bioorg. Med. Chem. Lett.
PUBLISHED: 01-04-2010
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A novel series of compounds derived from the previously reported N-type calcium channel blocker NP118809 (1-(4-benzhydrylpiperazin-1-yl)-3,3-diphenylpropan-1-one) is described. Extensive SAR studies resulted in compounds with IC(50) values in the range of 10-150 nM and selectivity over the L-type channels up to nearly 1200-fold. Orally administered compounds 5 and 21 exhibited both anti-allodynic and anti-hyperalgesic activity in the spinal nerve ligation model of neuropathic pain.
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Thalidomide improves prevention of chemotherapy-induced gastrointestinal side effects following a modified FOLFOX7 regimen: results of a prospective randomized crossover study.
Tumori
PUBLISHED: 12-03-2009
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Thalidomide was firstly evaluated for the control of chemotherapy-induced gastrointestinal side effects following a modified FOLFOX7 (mFOLFOX7) regimen.
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Scaffold-based design and synthesis of potent N-type calcium channel blockers.
Bioorg. Med. Chem. Lett.
PUBLISHED: 09-01-2009
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The therapeutic agents flunarizine and lomerizine exhibit inhibitory activities against a variety of ion channels and neurotransmitter receptors. We have optimized their scaffolds to obtain more selective N-type calcium channel blockers. During this optimization, we discovered NP118809 and NP078585, two potent N-type calcium channel blockers which have good selectivity over L-type calcium channels. Upon intraperitoneal administration both compounds exhibit analgesic activity in a rodent model of inflammatory pain. NP118809 further exhibits a number of favorable preclinical characteristics as they relate to overall pharmacokinetics and minimal off-target activity including the hERG potassium channel.
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SUN: Top-down saliency using natural statistics.
Vis cogn
PUBLISHED: 08-01-2009
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When people try to find particular objects in natural scenes they make extensive use of knowledge about how and where objects tend to appear in a scene. Although many forms of such "top-down" knowledge have been incorporated into saliency map models of visual search, surprisingly, the role of object appearance has been infrequently investigated. Here we present an appearance-based saliency model derived in a Bayesian framework. We compare our approach with both bottom-up saliency algorithms as well as the state-of-the-art Contextual Guidance model of Torralba et al. (2006) at predicting human fixations. Although both top-down approaches use very different types of information, they achieve similar performance; each substantially better than the purely bottom-up models. Our experiments reveal that a simple model of object appearance can predict human fixations quite well, even making the same mistakes as people.
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Forces-induced pinpoint denaturation of short DNA.
Biochem. Biophys. Res. Commun.
PUBLISHED: 07-15-2009
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A method that can pinpoint control DNA denaturation is reported. In the single molecule experiment using spFRET, DNA adhered on a quartz surface is acted upon by both a weak laser field force and a fast temporal mechanical force. The experiment showed that increasing strengths of laser power result in increasing percentage of denatured DNA; different mechanical forces produce different numbers of DNA opening. Besides the methods simplicity and convenience for DNA melting, its crucial advantage and potential application is the ability to denature DNA at specified locations, i.e., a weak laser and a fast temporal mechanical force can be used in pinpoint denaturation of short DNA.
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Overexpression of PwTUA1, a pollen-specific tubulin gene, increases pollen tube elongation by altering the distribution of alpha-tubulin and promoting vesicle transport.
J. Exp. Bot.
PUBLISHED: 05-19-2009
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Tubulin genes are intimately associated with cell division and cell elongation, which are central to plant secondary cell wall development. However, their roles in pollen tube polar growth remain elusive. Here, a TUA1 gene from Picea wilsonii, which is specifically expressed in pollen, was isolated. Semi-quantitative RT-PCR analysis showed that the amount of PwTUA1 transcript varied at each stage of growth of the pollen tube and was induced by calcium ions and boron. Transient expression analysis in P. wilsonii pollen indicated that PwTUA1 improved pollen germination and pollen tube growth. The pollen of transgenic Arabidopsis overexpressing PwTUA1 also showed a higher percentage of germination and faster growth than wild-type plants not only in optimal germination medium, but also in medium supplemented with elevated levels of exogenous calcium ions or boron. Immunofluorescence and electron microscopy showed alpha-tubulin to be enriched and more vesicles accumulated in the apex region in germinating transgenic Arabidopsis pollen compared with wild-type plants. These results demonstrate that PwTUA1 up-regulated by calcium ions and boron contributes to pollen tube elongation by altering the distribution of alpha-tubulin and regulating the deposition of pollen cell wall components during the process of tube growth. The possible role of PwTUA1 in microtubule dynamics and organization was discussed.
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Enhanced adherence to and invasion of PUVEC and PK-15 cells due to the overexpression of RfaD, ThyA and Mip in the ?ompP2 mutant of Haemophilus parasuis SC096 strain.
Vet. Microbiol.
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In Gram-negative bacteria, porins not only contribute to bacterial homeostasis, but also are involved in adherence to and invasion of host cells. Haemophilus parasuis outer membrane protein P2 (OmpP2), a member of the porin family, is an important surface protein involved in serum resistance. To further determine the features of OmpP2, the ability of ompP2 deficient mutant (?ompP2) of a H. parasuis SC096 strain to interact with porcine umbilicus veins endothelial cells (PUVEC) and porcine kidney epithelial cells (PK-15) was evaluated in this study. The ?ompP2 mutant exhibited dramatically increased ability to adhere to and invade PUVEC and PK-15 cells. Conversely, pretreatment of cell lines with purified native OmpP2 porins significantly inhibited adhesion and invasion of the SC096 strain to the both host cells. To explain the unexpected phenomenon, a 2-dimensional gel electrophoresis-based proteomics comparison was performed between the wild-type SC096 and ?ompP2 mutant strains. There were 55 differentially expressed proteins identified from mutant. Among them, three overexpressed proteins of the ADP-l-glycero-d-mannoheptose-6-epimerase RfaD, thymidylate synthase ThyA and putative macrophage infectivity potentiator-related protein Mip were confirmed as molecular targets that modulated adherence and invasion capacities of the ?ompP2 mutant. Collectively, the OmpP2 of the H. parasuis SC096 strain mediated the adherence to and invasion of cells and loss of OmpP2 expression resulted in promoted cell-adherence and invasion properties which were due to the overexpression of RfaD, ThyA and Mip.
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The role of galU and galE of Haemophilus parasuis SC096 in serum resistance and biofilm formation.
Vet. Microbiol.
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In our previous study, an ompP2 mutant of a Haemophilus parasuis SC096 strain showed sensitivity to serum bactericidal activity. In this study, we inactivated two gal genes, galU and galE, and these mutants were found to be serum sensitive to porcine sera. Furthermore, the galE mutant exhibited greater sensitivity than the galU mutant in serum sensitivity assays. Biofilm formation ability was also investigated. The galU mutant is unable to form biofilms, while more biofilm mass was produced by the galE mutant compared with SC096. Lack of expression of GalU protein by the galU mutant increased its tendency to autoagglutinate. The results indicated that the galU plays a role in autoagglutination and biofilm formation, while galE may affect the biofilm production indirectly. Both genes are significant for serum resistance in the H. parasuis SC096 strain.
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Involvement of lipooligosaccharide heptose residues of Haemophilus parasuis SC096 strain in serum resistance, adhesion and invasion.
Vet. J.
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Haemophilus parasuis is the causative agent of Glässers disease. To investigate the role of lipooligosaccharide (LOS) in H. parasuis infection, ?opsX, ?rfaF and ?waaQ mutants defective in expressing opsX, rfaF and waaQ heptosyltransferases were constructed by transformation. Compared to the wild-type SC096 strain, the ?opsX and ?rfaF mutants, but not the ?waaQ mutant, produced severely truncated LOS. The mutants exhibited various degrees of reduction in resistance to complement-mediated killing in porcine and rabbit sera. In addition, the ?opsX and ?rfaF mutant strains showed impaired ability to adhere to and invade porcine kidney epithelial cells (PK-15) and porcine umbilical vein endothelial cells, indicating roles for heptose I and II residues in the interaction with host cells. The ?waaQ mutant strain, with no obvious truncation of LOS structure, did not exhibit significant defects in adhesion to and invasion of host cells. This study provides insight into the contribution of the inner core oligosaccharide, especially heptose I and heptose II residues, to the virulence-associated properties of H. parasuis.
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Tumor response and survival in patients with advanced non-small-cell lung cancer: the predictive value of chemotherapy-induced changes in fibrinogen.
BMC Cancer
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Hyperfibrinogenemia is a common problem associated with various carcinomas, and is accompanied by hypercoagulablity. In advanced non-small-cell lung cancer (NSCLC) it remains unclear whether or not chemotherapy-induced changes in fibrinogen level relate to chemotherapeutic response and prognosis. The purposes of this study were to: 1) analyze the association between chemotherapy-induced changes in plasma fibrinogen level and the chemotherapeutic response after the first two courses of standard first-line platinum-based chemotherapy; and 2) evaluate the prognostic significance of the basal plasma fibrinogen level in patients with advanced NSCLC.
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MicroRNA-125b down-regulates matrix metallopeptidase 13 and inhibits cutaneous squamous cell carcinoma cell proliferation, migration, and invasion.
J. Biol. Chem.
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Cutaneous squamous cell carcinoma (cSCC) is the second most common human cancer. Although dysregulation of microRNAs (miRNAs) is known to be involved in a variety of cancers, the role of miRNAs in cSCC is unclear. In this study, we aimed to identify tumor suppressive and oncogenic miRNAs involved in the pathogenesis of cSCC. MiRNA expression profiles in healthy skins (n = 4) and cSCCs (n = 4) were analyzed using MicroRNA Low Density Array. MiR-125b expression was analyzed by quantitative real-time PCR and in situ hybridization in skin biopsies from 40 healthy donors, 13 actinic keratosis, and 74 cSCC patients. The effect of miR-125b was analyzed in wound closure, colony formation, migration, and invasion assays in two cSCC cell lines, UT-SCC-7 and A431. The genes regulated by miR-125b in cSCC were identified by microarray analysis and its direct target was validated by luciferase reporter assay. Comparing cSCC with healthy skin, we identified four up-regulated miRNAs (miR-31, miR-135b, miR-21, and miR-223) and 54 down-regulated miRNAs, including miR-125b, whose function was further examined. We found that miR-125b suppressed proliferation, colony formation, migratory, and invasive capacity of cSCC cells. Matrix metallopeptidase 13 (MMP13) was identified as a direct target suppressed by miR-125b, and there was an inverse relationship between the expression of miR-125b and MMP13 in cSCC. Knockdown of MMP13 expression phenocopied the effects of miR-125b overexpression. These findings provide a novel molecular mechanism by which MMP13 is up-regulated in cSCCs and indicate that miR-125b plays a tumor suppressive role in cSCC.
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c-Src expression is predictive of poor prognosis in breast cancer patients with bone metastasis, but not in patients with visceral metastasis.
APMIS
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c-Src expression is critical for breast cancer progression and it is particularly important for bone metastasis. In this study, we aimed to evaluate the effect of c-Src on prognosis in metastatic breast cancer patients, and to conduct subgroup analysis to explore the role of c-Src in bone metastasis and visceral metastasis respectively. We analyzed a total of 102 paraffin-embedded primary tumor tissue sections from metastatic breast cancer patients using immunohistochemical staining for c-Src, including 61 patients with bone metastases. Clinical data were collected retrospectively. We utilized survival analysis and the Cox proportional hazards model to explore the prognostic value of c-Src expression in metastatic breast cancer. The c-Src expression rate was 54.9% in the 102 metastatic breast cancer patients. Patients who exhibited c-Src expression demonstrated poor progression-free survival (PFS) (p = 0.044) and disease-specific survival (DSS) (p = 0.017). Subgroup analysis demonstrated that c-Src positive patients exhibited significantly worse bone metastasis-free survival (p = 0.027) and DSS (p = 0.024), whereas in patients with non-bone metastasis no significant difference was observed in PFS (p = 0.819) and DSS (p = 0.381). Multivariate analysis demonstrated that c-Src expression was an independent predictor of DSS for patients with bone metastasis. Our findings demonstrate that c-Src expression is a potential independent predictor of poor prognosis in breast cancer patients with bone metastasis.
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Structure-activity relationships of trimethoxybenzyl piperazine N-type calcium channel inhibitors.
Bioorg. Med. Chem. Lett.
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We previously reported the small organic N-type calcium channel blocker NP078585 that while efficacious in animal models for pain, exhibited modest L-type calcium channel selectivity and substantial off-target inhibition against the hERG potassium channel. Structure-activity studies to optimize NP078585 preclinical properties resulted in compound 16, which maintained high potency for N-type calcium channel blockade, and possessed excellent selectivity over the hERG (~120-fold) and L-type (~3600-fold) channels. Compound 16 shows significant anti-hyperalgesic activity in the spinal nerve ligation model of neuropathic pain and is also efficacious in the rat formalin model of inflammatory pain.
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Down-regulation of Cbl-b by bufalin results in up-regulation of DR4/DR5 and sensitization of TRAIL-induced apoptosis in breast cancer cells.
J. Cancer Res. Clin. Oncol.
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TNF-related apoptosis-inducing ligand (TRAIL) is a potential cancer therapeutic agent that preferentially induces apoptosis in cancer cells. However, breast cancer cells are generally resistant to TRAIL. Bufalin is a major active ingredient of the traditional Chinese medicine ChanSu. The present study aimed to assess the synergistic effect of bufalin and TRAIL and elucidate the underlying mechanisms in breast cancer cells.
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Photocurrent enhanced dye-sensitized solar cells based on TiO2 loaded K6SiW11O39Co(ii)(H2O)·xH2O photoanode materials.
Dalton Trans
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Through loading of TiO2 on the surface of K6SiW11O39Co(ii)(H2O)·xH2O (SiW11Co), a novel photoanode material has been created for dye-sensitized solar cells (DSSC). The absorbing band as well as photoelectricity response range of TiO2@SiW11Co is extended to the visible range. In addition, the absorption in the UV range is enhanced notably compared with P25 (raw TiO2). More importantly, the recombination of the TiO2 network is avoided. TiO2@SiW11Co is mixed with P25 powder (wt ?1?:?1) to assemble dye-sensitized (N719) solar cells, which exhibit a short-circuit photocurrent density as high as 18.05 mA cm(-2), which is 64% higher than blank samples under the standard AM1.5G global solar irradiation. In addition, the mechanisms for SiW11Co in DSSC are proposed.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.