272 research outputs found
The relative retrotransposition efficiencies of human and mouse short interspersed DNA elements (SINEs) in a HeLa cell culture assay
Short interspersed DNA elements (SINEs) and long interspersed DNA elements (LINEs) represent two families of transposable elements (TEs) within mammalian genomes. About 45% of the human genome consists of TE derived sequences. SINEs do not encode protein, so they cannot be autonomously propagated and require additional cellular machinery, most likely LINE proteins (ORF1p and ORF2p), for their mobilization, which has been supported by a cell culture-based retrotransposition assay. SINEs are ancestrally derived from either the 7SL RNA gene or from various tRNA genes. Sequence data support the co-evolution of some tRNA-derived SINEs with LINEs. This study involved testing whether or not tRNAderived SINEs could mobilize in the absence of LINE ORF1p, as well as assessing a coevolution of both SINEs and LINEs using the retrotransposition assay. A series of SINE constructs containing Alu, B2, and B1 elements were created and analyzed. No evidence to support a co-evolution of SINEs and LINEs was found; however, it was discovered that tRNA-derived SINEs do not require ORF1p to mobilize. Interestingly, both tRNA and 7SL RNA-derived SINEs mobilize more effectively in the absence of ORF1p
Pattern Formation of Glioma Cells: Effects of Adhesion
We investigate clustering of malignant glioma cells. \emph{In vitro}
experiments in collagen gels identified a cell line that formed clusters in a
region of low cell density, whereas a very similar cell line (which lacks an
important mutation) did not cluster significantly. We hypothesize that the
mutation affects the strength of cell-cell adhesion. We investigate this effect
in a new experiment, which follows the clustering dynamics of glioma cells on a
surface. We interpret our results in terms of a stochastic model and identify
two mechanisms of clustering. First, there is a critical value of the strength
of adhesion; above the threshold, large clusters grow from a homogeneous
suspension of cells; below it, the system remains homogeneous, similarly to the
ordinary phase separation. Second, when cells form a cluster, we have evidence
that they increase their proliferation rate. We have successfully reproduced
the experimental findings and found that both mechanisms are crucial for
cluster formation and growth.Comment: 6 pages, 6 figure
Bioactive Curcumin and its Effects on Lowering Systemic Inflammation as Measured by CRP: A Systematic Review
Objectives: The purpose of this study was to analyze and evaluate evidence supporting curcumin lowering the systemic inflammatory marker, CRP in humans. Methods: A systematic literature search was completed using PubMed and MEDLINE databases. Results: After inclusion and exclusion criteria, 9 studies were evaluated, and the percent change of CRP blood levels was calculated and analyzed. Results: The results for these studies show strong statistical significance for the C3 complex with Bioperine and nano curcumin. Bioactive curcumin exhibits a higher percent decrease of blood level CRP than trials using only curcumin or turmeric. Conclusion: Overall bioactive curcumin/ curcumin with Bioperine are alternative treatments for lowering the systemic inflammation marker, CRP
Modeling Elasticity in Crystal Growth
A new model of crystal growth is presented that describes the phenomena on
atomic length and diffusive time scales. The former incorporates elastic and
plastic deformation in a natural manner, and the latter enables access to times
scales much larger than conventional atomic methods. The model is shown to be
consistent with the predictions of Read and Shockley for grain boundary energy,
and Matthews and Blakeslee for misfit dislocations in epitaxial growth.Comment: 4 pages, 10 figure
Metabolic stress-induced microRNA and mRNA expression profiles of human fibroblasts
Metabolic and oxidative stresses induce physiological adaptation processes, disrupting a finely tuned, coordinated network of gene expression. To better understand the interplay between the mRNA and miRNA transcriptomes, we examined how two distinct metabolic stressors alter the expression profile of human dermal fibroblasts.Primary fibroblast cultures were obtained from skin biopsies of 17 healthy subjects. Metabolic stress was evoked by growing subcultured cells in glucose deprived, galactose enriched (GAL) or lipid reduced, cholesterol deficient (RL) media, and compared to parallel-cultured fibroblasts grown in standard (STD) medium. This was followed by mRNA expression profiling and assessment of >1000 miRNAs levels across all three conditions. The miRNA expression levels were subsequently correlated to the mRNA expression profile.Metabolic stress by RL and GAL both produced significant, strongly correlated mRNA/miRNA changes. At the single gene level four miRNAs (miR-129-3p, miR-146b-5p, miR-543 and miR-550a) showed significant and comparable expression changes in both experimental conditions. These miRNAs appeared to have a significant physiological effect on the transcriptome, as nearly 10% of the predicted targets reported changes at mRNA level. The two distinct metabolic stressors induced comparable changes in the miRNome profile, suggesting a common defensive response of the fibroblasts to altered homeostasis. The differentially expressed miR-129-3p, miR-146b-5p, miR-543 and miR-550a regulated multiple genes (e.g. NGEF, NOVA1, PDE5A) with region- and age-specific transcription in the human brain, suggesting that deregulation of these miRNAs might have significant consequences on CNS function. The overall findings suggest that analysis of stress-induced responses of peripheral fibroblasts, obtained from patients with psychiatric disorders is a promising avenue for future research endeavors. © 2013 Elsevier Inc
Transcription factor Sp1 induces ADAM17 and contributes to tumor cell invasiveness under hypoxia
<p>Abstract</p> <p>Background</p> <p>Expression of the Sp1 transcription factor is induced by hypoxia, and the ADAM17 promoter contains predicted Sp1 binding sites. ADAM17 contributes to hypoxic-induce invasiveness of glioma. In this study, we investigated whether Sp1 transcription factor induces ADAM17 and/or contributes to tumor cell invasiveness in hypoxia.</p> <p>Methods</p> <p>Employing RT-PCR and Western blot, we examined the role of Sp1 in ADAM17 transcription/expression under normoxic and hypoxic conditions, and whether it binds to the ADAM17 GC-rich promoter region using a chromatin immunoprecipitation assay. Additionally, we tested the effect of Sp1 suppression in tumor cell invasion and migration, using Matrigel basement membrane invasion chambers, a scratch wound-healing assay, and small interfering RNA.</p> <p>Results</p> <p>Here, we found that Sp1 binds to the ADAM17 promoter, and that Sp1 regulates ADAM17 expression under hypoxia. Furthermore, suppression of Sp1 decreases invasiveness and migration in U87 tumor cells.</p> <p>Conclusion</p> <p>Our findings suggest the Sp1 transcription factor mediates ADAM17 expression under hypoxia, regulates glioma invasiveness, and thus, may be a target for anti-invasion therapies.</p
The emerging role of exosome and microvesicle- (EMV-) based cancer therapeutics and immunotherapy
This document is the Accepted Manuscript version of the following article: Colin Moore, Uchini Kosgodage, Sigrun Lange, and Jameel M. Inal, ‘The emerging role of exosome and microvesicle- (EMV-) based cancer therapeutics and immunotherapy’, International Journal of Cancer, Vol. 141 (3): 428-436, August 2017. DOI: https://doi.org/10.1002/ijc.30672. © 2017 UICC. This manuscript version may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.There is an urgent need to develop new combination therapies beyond existing surgery, radio- and chemo-therapy, perhaps initially combining chemotherapy with the targeting specificities of immunotherapy. For this, strategies to limit inflammation and immunosuppression and evasion in the tumour microenvironment are also needed. To devise effective new immunotherapies we must first understand tumour immunology, including the roles of T cells, macrophages, myeloid suppressor cells and of exosomes and microvesicles (EMVs) in promoting angiogenesis, tumour growth, drug resistance and metastasis. One promising cancer immunotherapy discussed uses cationic liposomes carrying tumour RNA (RNA-lipoplexes) to provoke a strong anti-viral-like (cytotoxic CD8+ ) anti-tumour immune response. Mesenchymal stem cell-derived EMVs, with their capacity to migrate towards inflammatory areas including solid tumours, have also been used. As tumour EMVs clearly exacerbate the tumour microenvironment, another therapy option could involve EMV removal. Affinity-based methods to deplete EMVs, including an immunodepletion, antibody-based affinity substrate, are therefore considered. Finally EMV and exosome-mimetic nanovesicles (NVs) delivery of siRNA or chemotherapeutic drugs that target tumours using peptide ligands for cognate receptors on the tumour cells are discussed. We also touch upon the reversal of drug efflux in EMVs from cancer cells which can sensitize cells to chemotherapy. The use of immunotherapy in combination with the advent of EMVs provides potent therapies to various cancers.Peer reviewe
Therapeutic prospects of extracellular vesicles in cancer treatment
Extracellular vesicles (EVs) are released by all cells within the tumor microenvironment, such as endothelial cells, tumor-associated fibroblasts, pericytes and immune system cells. The EVs carry the cargo of parental cells formed of proteins and nucleic acids, which can convey cell-to-cell communication influencing the maintenance and spread of the malignant neoplasm, for example promoting angiogenesis, tumor cell invasion and immune escape. However, EVs can also suppress tumor progression, either by the direct influence of the protein and nucleic acid cargo of the EVs or via antigen presentation to immune cells as tumor derived EVs carry on their surface some of the same antigens as the donor cells. Moreover, dendritic cell-derived EVs carry MHC class I and class II/peptide complexes and are able to prime other immune system cell types and activate an anti-tumor immune response. Given the relative longevity of vesicles within the circulation and their ability to cross blood-brain barriers, modification of these unique organelles offers the potential to create new biological-tools for cancer therapy. This review examines how modification of the EV cargo has the potential to target specific tumor mechanisms responsible for tumor formation and progression to develop new therapeutic strategies and to increase the efficacy of antitumor therapies
Overexpression of miR‑145 in U87 cells reduces glioma cell malignant phenotype and promotes survival after in vivo implantation
In the present study, we sought to elucidate the effect of miR‑145 on glioma cell progression and its mechanisms of action. We examined the effects of miR‑145 on proliferation and invasion of U87 glioma cells and on capillary tube formation. Our data show that restoration of miR‑145 in U87 glioma cells significantly reduced their in vitro proliferation, invasion and angiogenesis. However, decreased miR‑145 expression promoted U87 glioma cell proliferation, invasion and angiogenesis, and reduced-expression of miR‑145 increased ADAM17 and EGFR expression in U87 cells. Overexpression of miR‑145 reduced ADAM17 and EGFR expression. VEGF secretion and VEGF expression were decreased by increased miR‑145 expression in U87 cells and were reversed by miR‑145 downregulation in vitro. Nude mice with intracerebral implantation of U87 overexpressing miR‑145 cells exhibited significantly reduced tumor growth and promoted survival compared with control groups. Taken together, these results suggest a role for miR‑145 as a tumor suppressor which inhibits glioma cell proliferation, invasion and angiogenesis in vitro and reduces glioma growth in vivo
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