Search results for "transfection"

2019

Parthenolide (PT) is a sesquiterpene lactone isolated from Tanacetum parthenium. In this study, PT showed varying cytotoxic effects against different solid tumor cell lines. HCT116 (p53+/+) colon carcinoma cells and their parental HCT116 knockout p53 (p53-/-) cell lines showed a resistance degree of 2.36. On the other hand, wild-type U87.MG cells or cells transfected with a deletion-activated EGFR cDNA (U87.MGΔEGFR) exhibited slight sensitivity toward PT. Multidrug-resistant MDA-MB-231-BCRP cells were even more sensitive toward PT than sensitive MDA-MB-231-pcDNA cells with a resistance degree of 0.07 (collateral sensitivity). To the best of our knowledge, hypersensitivity (collateral sensit…

2014

Oligodendrocytes are the myelinating glial cells of the central nervous system. In the course of brain development, oligodendrocyte precursor cells migrate, scan the environment and differentiate into mature oligodendrocytes with multiple cellular processes which recognize and ensheath neuronal axons. During differentiation, oligodendrocytes undergo dramatic morphological changes requiring cytoskeletal rearrangements which need to be tightly regulated. The non-receptor tyrosine kinase Fyn plays a central role in oligodendrocyte differentiation and myelination. In order to improve our understanding of the role of oligodendroglial Fyn kinase, we have identified Fyn targets in these cells. Pur…

Subcellular targeting of multiligand-binding protein gC1qR.

1999

Abstract gC1q receptor, a protein originally described as the cell surface receptor for the globular heads of complement factor C1q, has been found to bind human H-kininogen with high affinity and specificity. Therefore, gC1qR has been considered candidate kininogen docking site on the surfaces of platelets, neutrophils and endothelial cells. Recent work demonstrating that gC1qR is an intracellular protein that is tightly associated with mitochondria rather than targeted to the cell surface has challenged this view. To further probe cellular trafficking routes of gC1qR, we overexpressed human gC1qR in a mammalian cell and monitored cell surface exposure of recombinant gC1qR by virtue of its…

Alternative Polyadenylation Events Contribute to the Induction of NF-ATc in Effector T Cells

1999

Abstract The transcription factor NF-ATc is synthesized in three prominent isoforms. These differ in the length of their C terminal peptides and mode of synthesis. Due to a switch from the use of a 3′ polyA site to a more proximal polyA site, NF-ATc expression switches from the synthesis of the two longer isoforms in naive T cells to that of short isoform A in T effector cells. The relative low binding affinity of cleavage stimulation factor CstF-64 to the proximal polyA site seems to contribute to its neglect in naive T cells. These alternative polyadenylation events ensure the rapid accumulation of high concentrations of NF-ATc necessary to exceed critical threshold levels of NF-ATc for g…

Role of reactive oxygen species in the regulation of HIF-1 by prolyl hydroxylase 2 under mild hypoxia

2012

The function and survival of eukaryotic cells depends on a constant and sufficient oxygen supply. Cells recognize and respond to hypoxia by accumulation of the transcription factor hypoxia-inducible factor 1 (HIF-1), composed of an oxygen-sensitive HIF-1α and a constitutive HIF-1β subunit. Besides physiology, HIF-1 induction is involved in major pathological processes such as cardiovascular disease, inflammation and cancer, which are associated with the formation of reactive oxygen species (ROS). ROS have been reported to affect HIF-1 activity but the role for ROS in regulating HIF-1 has not been definitely settled. In order to shed light on the redox-regulation of HIF-1 by ROS, we studied …

Proliferative activity and tumorigenic conversion: impact on cellular metabolism in 3-D culture

2001

Oxygen consumption, glucose, lactate, and ATP concentrations, as well as glucose and lactate turnover rates, have been studied in a three-dimensional carcinogenesis model of differently transformed rat embryo fibroblasts (spontaneously immortalized Rat1 and myc-transfected M1, and the ras-transfected, tumorigenic descendants Rat1-T1 and MR1) to determine metabolic alterations that accompany tumorigenic conversion. Various bioluminescence techniques, thymidine labeling, measurement of[Formula: see text] distributions with microelectrodes, and determination of cellular oxygen uptake rates (Q˙[Formula: see text]) have been applied. In the ras-transfected, tumorigenic spheroid types, the size d…

RGD motifs on the surface of baculovirus enhance transduction of human lung carcinoma cells.

2006

Baculovirus vectors have been shown to enter a variety of mammalian cell lines and gene transfer with wild-type baculovirus (WT) has been demonstrated both in vitro and in vivo. Different protein motifs have been displayed on the viral surface to serve as ligands for cell-specific receptor molecules. We have generated recombinant baculovirus vectors displaying an RGD-motif, recognized by alphaV integrin, on the viral surface. The RGD motifs within the C-terminus of coxsackie virus A9 and human parechovirus 1 VP1 proteins were fused to the N-terminus of the major envelope glycoprotein, gp64, of Autographa californica multiple nucleopolyhedrovirus. The recombinant RGD-presenting viruses bound…

SiRNA-mediated selective inhibition of mutant keratin mRNAs responsible for the skin disorder pachyonychia congenita.

2006

RNA interference offers a novel approach for treating genetic disorders including the rare monogenic skin disorder pachyonychia congenita (PC). PC is caused by mutations in keratin 6a (K6a), K6b, K16, and K17 genes, including small deletions and single nucleotide changes. Transfection experiments of a fusion gene consisting of K6a and a yellow fluorescent reporter (YFP) resulted in normal keratin filament formation in transfected cells as assayed by fluorescence microscopy. Similar constructs containing a single nucleotide change (N171K) or a three-nucleotide deletion (N171del) showed keratin aggregate formation. Mutant-specific small inhibitory RNAs (siRNAs) effectively targeted these site…

The effect of 3-aminobenzamide, inhibitor of poly(ADP-ribose) polymerase, on human osteosarcoma cells

2003

This study demonstrates that in human osteosarcoma cells treatment with 3-aminobenzamide (3-AB), a potent inhibitor of poly(ADP-ribose) polymerase (PARP), induces morphological and biochemical features of differentiation, the duration of which depends on whether or not the normal RB gene is expressed. In Saos-2 cells expressing a non-functional Rb protein, 3-AB treatment induced the formation of transient, short dendritic-like protrusions. In RB-transfected-Saos-2 cells (a clone previously generated in our laboratory that shows stable expression of wild-type Rb protein), 3-AB induced marked and prolonged changes with the formation of long dendritic-like protrusions and the appearance of ste…

Characterization of a mutant form of human apolipoprotein B (Thr26_Tyr27del) associated with familial hypobetalipoproteinemia

2016

We have previously identified a deletion mutant of human apoB [apoB (Thr26_Tyr27del)] in a subject with primary hypobetalipoproteinemia. The present study determined the effect of Thr26_Tyr27del mutation on apoB secretion using transfected McA-RH7777 cells. Transient or stable transfection of apoB-48 containing the Thr26_Tyr27del mutation showed drastically reduced secretion of the mutant as compared to wild-type apoB-48. No lipoproteins containing the mutant apoB-48 were secreted into the medium. Incubation of transfected cells in a lipid-rich medium in the presence of cycloheximide showed rapid turnover of cell-associated mutant apoB-48 as compared to that of wild-type apoB-48. Immunofluo…