Search results for "Gene expression"
showing 10 items of 4085 documents
Transcriptomic responses generated by hepatocarcinogens in a battery of liver-based in vitro models
2013
As the conventional approach to assess the potential of a chemical to cause cancer in humans still includes the 2-year rodent carcinogenicity bioassay, development of alternative methodologies is needed. In the present study, the transcriptomics responses following exposure to genotoxic (GTX) and non-genotoxic (NGTX) hepatocarcinogens and non-carcinogens (NC) in five liver-based in vitro models, namely conventional and epigenetically stabilized cultures of primary rat hepatocytes, the human hepatoma-derived cell lines HepaRG and HepG2 and human embryonic stem cell-derived hepatocyte-like cells, are examined. For full characterization of the systems, several bioinformatics approaches are emp…
A placenta-specific gene ectopically activated in many human cancers is essentially involved in malignant cell processes.
2007
Abstract The identification and functional characterization of tumor-specific genes is a prerequisite for the development of targeted cancer therapies. Using an integrated data mining and experimental validation approach for the discovery of new targets for antibody therapy of cancer, we identified PLAC1. PLAC1 is a placenta-specific gene with no detectable expression in any other normal human tissue. However, it is frequently aberrantly activated and highly expressed in a variety of tumor types, in particular breast cancer. RNAi-mediated silencing of PLAC1 in MCF-7 and BT-549 breast cancer cells profoundly impairs motility, migration, and invasion and induces a G1-S cell cycle block with n…
Stable expression of rat cytochrome P450IA2 cDNA and hydroxylation of 17β-estradiol and 2-aminofluorene in V79 Chinese hamster cells
1991
In continuation of our work toward the establishment of a working cell bank for metabolic and toxicological studies, V79 Chinese hamster cells were genetically engineered for stable expression of rat cytochrome P450IA2. Full-length cDNA encoding rat P450IA2 was obtained by searching a cDNA library made from Aroclor 1254-induced rat liver mRNA and by joining a small 5'-end fragment to a fragment containing the rest of the cDNA. The sequence of the cDNA was confirmed by DNA sequencing and comparison to a previously published cDNA sequence. The reconstructed full-length cDNA was inserted into a simian virus 40 early promoter-containing eukaryotic expression vector and cotransferred with the ne…
The AC133 epitope, but not the CD133 protein, is lost upon cancer stem cell differentiation.
2010
Abstract Colon cancer stem cells (CSC) can be identified with AC133, an antibody that detects an epitope on CD133. However, recent evidence suggests that expression of CD133 is not restricted to CSCs, but is also expressed on differentiated tumor cells. Intriguingly, we observed that detection of the AC133 epitope on the cell surface decreased upon differentiation of CSC in a manner that correlated with loss of clonogenicity. However, this event did not coincide with a change in CD133 promoter activity, mRNA, splice variant, protein expression, or even cell surface expression of CD133. In contrast, we noted that with CSC differentiation, a change occured in CD133 glycosylation. Thus, AC133 …
Acquired resistance of melanoma cells to the antineoplastic agent fotemustine is caused by reactivation of the DNA repair gene mgmt
2001
Acquired resistance to antineoplastic agents is a frequent obstacle in tumor therapy. Malignant melanoma cells are particularly well known for their unresponsiveness to chemotherapy; only about 30% of tumors exhibit a transient clinical response to treatment. In our study, we investigated the molecular mechanism of acquired resistance of melanoma cells (MeWo) to the chloroethylating drug fotemustine. Determination of O6-methylguanine-DNA methyltransferase (MGMT) activity showed that MeWo cells that acquired resistance to fotemustine upon repeated treatment with the drug display high MGMT activity, whereas the parental cell line had no detectable MGMT. The resistant cell lines exhibit cross-…
Activating mutations in human c-Ha-ras-1 protooncogene induced by stereoisomeric fjord-region benzo[c]chrysene diol-epoxides.
1995
The mutagenicity of fjord-region benzo[c]chrysene diol-epoxide (BcCDE) stereoisomers((+) anti-BcCDE, (-)anti-BcCDE, (+)syn-BcCDE, and (-)syn-BcCDE) was studied in a forward-mutation system. pEC plasmid containing the human c-Ha-ras-1 proto-oncogene was reacted in vitro with each optically active isomer separately and transfected into NIH/3T3 cells. Morphologically transformed foci were cloned, and DNA obtained from these foci was tested for the presence of Ha-ras-1 sequence by Southern blot analysis. A total of 50 transformed foci (11-14 for each diastereomer) were generated. To determine the nature of mutations responsible for activating the proto-oncogene, regions of the gene likely to co…
Allelic loss but absence of mutations in the polyspecific transporter geneBWR1Aon 11p15.5 in hepatoblastoma
2004
Chromosomal region 11p15.5 shows frequent maternal allelic loss in embryonal tumors, including rhabdomyosarcoma (RMS), Wilms' tumor (WT) and hepatoblastoma (HB), consistent with the presence of at least one tumor suppressor gene in this region, which should be paternally imprinted, i.e., expressed from the maternal allele only. The BWR1A gene encodes a polyspecific transmembrane transporter and is located on 11p15.5. It is highly expressed in liver, paternally imprinted and was found to be mutated in an RMS cell line, making it a plausible tumor suppressor gene for HB. We therefore screened 62 HBs, 3 HB cell lines and 1 pediatric hepatocellular carcinoma for BWR1A mutations using single-str…
Stochastic Loss of Silencing of the Imprinted Ndn/NDN Allele, in a Mouse Model and Humans with Prader-Willi Syndrome, Has Functional Consequences
2013
Genomic imprinting is a process that causes genes to be expressed from one allele only according to parental origin, the other allele being silent. Diseases can arise when the normally active alleles are not expressed. In this context, low level of expression of the normally silent alleles has been considered as genetic noise although such expression has never been further studied. Prader-Willi Syndrome (PWS) is a neurodevelopmental disease involving imprinted genes, including NDN, which are only expressed from the paternally inherited allele, with the maternally inherited allele silent. We present the first in-depth study of the low expression of a normally silent imprinted allele, in path…
Presence of the Transmembrane Protein Neuropilin in Cytokine-induced Killer Cells
2020
Background/aim Cytokine-induced killer (CIK) cells are a heterogenous population of immune cells showing promising applications in immunotherapeutic cancer treatment. Neuropilin (NRP) proteins have been proven to play an important role in cancer development and prognosis. In this study, CIK cells were tested for expression of NRPs, transmembrane proteins playing a role in the proliferation and survival of cancer cells. Materials and methods CIK cells were analyzed at different time points via flow cytometry and quantitative real-time polymerase chain reaction for neuropilin expression. Results Phenotyping results showed CIK cells having developed properly, and low levels of NRP2 were detect…
MiRNA profiling by NGS in resectable non-small cell lung cancer: Prognostic implications.
2014
7559 Background: MicroRNAs (miRNA) regulate gene expression, and are implicated in several processes like tumorogenesis. Here, we applied a multiplexed NGS approach to study differentially expressed miRNAs (tumor/ normal) in a cohort of resectable NSCLC patients and its correlation with clinical outcome. Methods: RNA was isolated from frozen lung specimens (tumor/ normal) from 33 patients. High-quality samples were analyzed and enriched in the miRNA fraction. Libraries were prepared according to manufactured instruction (SOLID), and miRNAs were sequenced. Data analysis was carried out using CLCbio software. First, raw data were annotated using miRBase and normalized by total reads followed …