Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Cell Line, Transformed”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed2003

Enhanced serine palmitoyltransferase expression in proliferating fibroblasts, transformed cell lines, and human tumors.

Metastatic processes, including cell invasion, extracellular matrix degradation, and tissue remodeling, require cellular reorganization and proliferation. The cell signaling molecules required and the proteins involved in cell restructuring have not been completely elucidated. We have been studying the role of sphingolipids in normal cell activity and in several pathophysiological states. In this study we used immunohistochemistry to observe the presence of the two known subunits of serine palmitoyltransferase (SPT) in proliferating cells, in an in vitro model of wound repair, and in human malignant tissue. We report increased expression of the two subunits, SPT1 and SPT2, in the proliferating cells in these models. We also demonstrate a change in subcellular localization of the SPT subunits from predominantly cytosolic in quiescent cells to nuclear in proliferating cells. In addition, we observed SPT1 and SPT2 immunoreactivity in reactive stromal fibroblasts surrounding the carcinoma cells of some of the tumors. This enhanced SPT expression was absent in the stromal fibroblasts surrounding normal epithelial cells. Our results suggest a potential role for overexpression of SPT in the processes of cell metastasis.

Acyltransferases↗
PubMed1995

[Establishment of superoxide production assay system using Epstein-Barr virus transformed cell line with chemiluminescence].

We established the system to detect superoxide produced by Epstein Barr virus lymphoblastoid cell line (EB-LCL). Superoxide production of EB-LCL was evaluated by measuring chemiluminescence (CL) enhanced with addition of horseradish peroxidase (HRP). Using this system, we measured CL of EB-LCL established from 13 patients with chronic granulomatous disease (CGD) and 8 normal individuals. Significant elevation of CL was observed in all control EB-LCLs, however, no remarkable CL was seen in any patients' EB-LCLs. We examined the effect of recombinant human interferon gamma (rh-IFN-gamma) and granulocyte colony stimulating factor (G-CSF) on CL of EB-LCL in vitro. With addition of rh-IFN-gamma, CL of normal control EB-LCL was significantly enhanced (p < 0.05), on the other hand, G-CSF was shown to have no effect. No significant CL was observed in any CGD patients' EB-LCLs even with addition of rh-IFN-gamma or G-CSF. It was suggested that superoxide produced by EB-LCL detected in this system was dependent on the same NADPH oxidase system which presents in phagocyte.

B-Lymphocytes↗
PubMed1986

Generation of human anti-rubella monoclonal antibodies from human hybridomas constructed with antigen-specific Epstein-Barr virus transformed cell lines.

Human monoclonal antibodies (humab) directed against viral antigens were developed by combining immortalization of human primary B lymphocytes by Epstein-Barr virus (EBV) infection with consecutive fusion of selected immortalized lymphoblasts with an established, human lymphoblastoid cell line. Using EBV infection a high rate of immortalized B lymphoblastoid cells was obtained which unfortunately could not be cloned because at least 10 cells per microtiter well had to be seeded to get cells growing. However, fusion of these immortalized lymphoblastoid cells which had been selected for antiviral humab production with an established cell line resulted in hybridomas which could easily be cloned. Among the antiviral humab producing hybridomas thus generated, were three which produced anti-rubella humab. Rubella virus consists of three structural proteins, the core protein C and the two envelope proteins E1 and E2. By the western blot technique we were able to show that two humab reacted with the core protein and the third humab with the envelope protein E1. From the hybridomas grown in stationary cultures, highly purified humab preparations were obtained by subjecting the concentrated culture supernatant to immuno-affinity chromatography.

Animals↗
PubMed1986

Epstein-Barr virus-specific cytoskeletal early antigen in EBV-transformed cell lines.

An Epstein-Barr virus (EBV)-specific determinant of early antigen (EA) character was found to be associated with intermediate filaments of EBV genome-activated cells. This determinant was defined with a murine monoclonal antibody (MAb) and with human MAb derived from lymphoblastoid cell lines of patients with acute infectious mononucleosis (IM). Such patients' antibodies either recognized intermediate filament determinants in general, or were restricted to the intermediate filament determinant of EBV genome-activated cells, as also recognized with the 1B6 murine MAb. The 1B6 determinant was a component of EA as defined by phosphonoacetate-resistance, methanol-sensitivity, and various co-staining and antibody-blocking experiments. While anti-intermediate filament antibodies have been reported after various viral illnesses, the 1B6 and some patients' antibodies recognize an EBV-specific determinant which might function in the lytic cycle of these cells.

Antibodies, Monoclonal↗
PubMed1996

An antibody that binds domain 1 of CD4 inhibits replication of HIV-1, but not HTLV-I, in a CD4-positive/p56lck-negative HTLV-I-transformed cell line.

mAbs that bind to the Ig CDR3-like region in D1 domain of the CD4 molecule can inhibit the HIV-1 life cycle in CD4-positive T cells and lymphoblastoid cell lines at the stage of transcription. This antiviral effect requires the integrity of the cytoplasmic tail of CD4, which acts as a signal transduction region through its association with protein tyrosine kinases such as p56Ick. Here we investigated the role of p56Ick in the cascade of molecular events that control HIV-1 transcription in cells treated with anti-CD4 mAb directed against the Ig CDR3-like region. The Ig CDR3-like region-specific mAb, 13B8-2, blocked HIV-1 production in CD4-positive/p56Ick-negative HTLV-I-producing MT2 cells superinfected by HIV-1Lai, but had no effect on HTLV-I production, although it did inhibit Tax-induced NF-kappa B translocation. These results raise the possibility that an as yet unidentified tyrosine kinase may be capable of associating with CD4 and mediating intracellular signaling.

Antibodies, Monoclonal↗
PubMed1978

Mapping of the herpes simplex virus DNA sequences in three herpes simplex virus thymidine kinase-transformed cell lines.

We have made use of a novel filter hybridization approach in order to map the herpes simplex virus (HSV) DNA sequences which are present in three HSV thymidine kinase (TK)-transformed cell lines. The cell line 33A+ which was produced by infection of 3T3 TK- cells with UV-irradiated HSV-2 (333) was found to contain one contiguous stretch of viral DNA sequences which maps between 0.15 and 0.57 on the HSV-2 genome. The sequences mapping from 0.31 to 0.37 were present in 3--4-fold higher abundance than the rest of the viral DNA sequences in this cell line. Cell lines 5A and 8N were produced by transfection of mouse CL1D cells with sheared HSV-1 (1023) DNA. The cell line 5A was found to contain a contiguous set of viral DNA sequences mapping between 0.26 and 0.41 on the HSV-1 genome. The cell line 8N was found to contain three non-contiguous sets of viral DNA sequences, mapping between 0.09 and 0.41, 0.53 and 0.58, and 0.94 and 1.0 on the HSV-1 genome. These results seem to indicate that many different sets of viral DNA sequences can be incorporated into the cell during HSV-mediated biochemical transformation.

Animals↗
PubMed2001

Platelet-derived growth factor mediated altered expression and regulation of ornithine decarboxylase in H-ras-transformed cell lines.

This study demonstrates a novel link between alterations in platelet-derived growth factor (PDGF) regulation of ornithine decarboxylase (ODC) expression during malignant conversion. H-ras-transformed cell lines exhibited PDGF-mediated alterations in ODC gene expression. These alterations involved transcriptional, posttranscriptional, and cycloheximide-mediated events. PDGF-mediated alterations in ODC gene expression in NR3 cells (capable of only benign tumour formation) were ras-dependent, involved a tyrosine kinase activity and mitogen-activated protein (MAP) kinase-mediated signalling events, and were independent of both protein kinase C (PKC) events and pertussis toxin-sensitive (PTS) G-protein-mediated signalling. PDGF-mediated alterations in ODC gene expression in C2 cells [capable of malignant progression (metastasis formation)] were ras-dependent, required a tyrosine kinase activity, involved both MAP kinase-mediated events and phosphatidylinositol-3-kinase (PI-3-kinase)-mediated events, and were dependent upon PTS G-protein-mediated signalling but independent of PKC-mediated events. PDGF-mediated regulation of ODC gene expression changes in response to H-ras-mediated cellular transformation and malignant progression.

Animals↗
PubMed1995

Effect of tumor necrosis factor-alpha on a cell line transformed by a secreted form of human fibroblast growth factor-1 gene and on its parental cell line.

In the present study we characterized the responses of the cell line HST-alpha, stably transformed by a secreted form of human fibroblast growth factor-1 (acidic FGF) gene, and its parental NIH 3T3 cell line to recombinant murine (rMu) TNF-alpha. Treatment of HST-alpha cells with rMu TNF-alpha can significantly reduce the number of foci formed in the in vitro transformation assay. In the presence of the RNA polymerase inhibitor actinomycin-D, the transformed HST-alpha cell is more susceptible to the cytotoxicity of rMu TNF-alpha than is its parental NIH 3T3 cell. The median lethal concentrations (LC50) of rMu TNF-alpha to HST-alpha cell and NIH 3T3 cell were 0.35 ng/ml and 4.56 ng/ml respectively. These results demonstrated that the introduction of a single oncogene or a growth factor gene to a cell can change the cell's response to cytokines.

3T3 Cells↗
PubMed1975

Mapping of adenovirus 2 RNA sequences in lytically infected cells and transformed cell lines.

The strands of the six EcoRI fragments and the HpaI fragments E and C of Ad2 DNA were separated by electrophoresis in agarose gels. Using 32P-labeled fragment strands in solution hybridization experiments, the fraction of each strand complementary to RNA extracted from infected or transformed cells was assayed by chromatography on hydroxylapatite. In this manner, a tentative map of the cytoplasmic RNA sequences has been constructed for viral RNA extracted from cells both early and late during infection (see Fig. 16; in the map shown, the two strands of Ad2 are named the r and l strands following the bacteriophage convention). Since early cytoplasmic RNA anneals to four distinct regions of the genome, Ad2 probably codes for at least four early gene functions. Summation experiments have shown that all RNA sequences found in the cytoplasm of cells early during infection are also present in the cells' cytoplasm at late times. Viral RNA sequences in five independently isolated and cloned transformed rat cell lines were also mapped on the Ad2 genome. One class of Ad2-transformed rat cells contains RNA sequences complementary to only the segment of Ad2 DNA from 0.03-0.10 on the physical map, and this corresponds to one of the four regions of the genome expressed early during infection. If a viral gene product is necessary to maintain the transformed phenotype of the cell or codes for the virus-specific tumor (T) antigen, this genetic information must be at the left end of the genome (see Fig. 16). The two other classes of Ad2-transformed rat cells contain viral RNA sequences complementary to two or three of the regions of the genome transcribed into early cytoplasmic RNA. At both early and late times during the lytic cycle, the nucleus of the infected cell contains viral RNA sequences that are not transported to the cell's cytoplasm, suggesting that RNA processing and selection may play a role in the regulation of viral mRNA production.

Adenoviridae↗
PubMed1986

Fibroblast growth factor induces the soft agar growth of two non-transformed cell lines.

Recent studies have determined that fibroblast growth factor (FGF) potentiates the soft agar growth responses of NRK-49F cells to several combinations of transforming growth factors (TGFs). In the current study, two other non-transformed cell lines, NR-6 and AKR-2B, which do not spontaneously form colonies in soft agar, were examined for their soft agar growth responses to FGF. Both the acidic form and basic form of FGF were found to induce the soft agar growth of these cells. In the case of NR-6 cells, the effects of TGF-beta were also examined. TFG-beta potentiated the soft agar growth response of NR-6 cells to FGF, but on its own did not induce soft agar growth. Attempts to identify other factors capable of modulating the response of these cells to FGF, led to the finding that both 12-O-tetra-decanoylphorbol-13-acetate and retinoic acid suppress FGF-induced soft agar growth of NR-6 cells and AKR-2B cells. The finding that FGF induces the soft agar growth of both non-transformed cell lines, together with the findings of others that both forms of FGF are angiogenic, lends further support to the suggestion that FGF plays a significant role in the in vivo growth of some, and possibly many, tumors.

Animals↗
PubMed1993

Cell adhesion markers are expressed by a stable human endothelial cell line transformed by the SV40 large T antigen under vimentin promoter control.

Markers of endothelium have been studied in a new endothelial cell line derived from human umbilical cord vein cells by microinjection of a recombinant gene that includes a deletion mutant of the human vimentin gene regulatory region controlling the large T and small t antigen coding region of the SV40 virus. In culture, this immortalized venous endothelial cell line (IVEC) demonstrated morphological characteristics of endothelium; uptake of acetylated low density lipoprotein and presence of the Factor VIII-related antigen. Treatment of IVEC cells with Interleukin-1 beta (IL-1 beta) at 10 U.ml-1 activates the expression of cell adhesion molecules such as endothelial leucocyte adhesion molecule (ELAM-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1), as observed in primary culture. Prostacyclin secretion was induced in the IVEC cells by 100 nM PMA treatment and thrombin at 0.5 U/ml. Angiotensin converting enzyme (ACE) activity detected in IVEC cells was present but lower than ACE activity in primary endothelial cells and was completely blocked by enalaprilat (1 microM), a specific ACE inhibitor. The presence of ACE mRNA was also demonstrated in IVEC cells by RT-PCR amplification. Our data demonstrate that endothelial cells immortalized by use of this recombinant gene retain the morphological organization and numerous differentiated properties of endothelium.

Antigens, Polyomavirus Transforming↗
PubMed1989

Effect of cell surface trypsinization on ethanolamine base exchange enzymatic activity of astrocyte primary cultures and derived spontaneously transformed cell lines.

Trypsinization of neonatal rat astrocyte primary cultures (normal cells) inhibited the activity of ethanolamine base exchange enzyme (EBEE) by 80%, whereas ethanolamine phosphotransferase (EPT) and choline base exchange (CBEE) enzymatic activities were not affected; subcellular fractionation demonstrated that trypsin treatment affected the intracellular EBEE activity. During trypsinization the enzyme was not taken up by cultured astrocytes but the cell surface was affected. In contrast, the same treatment did not alter EPT, CBEE and EBEE activities of spontaneously transformed cell lines derived from the primary cultures. However, treatment of the transformed cells with db-cAMP prior to trypsin, restored the pattern found in the primary culture, i.e. only EBEE activity was affected. These data suggest that a relationship exists between cell surface organization and intracellular EBEE activity in a culture system which possesses the property to control its own cell division or/and differentiation.

Animals↗
PubMed2002

Synthesis of platelet-activating factor (PAF) in transformed cell lines of a different origin.

Interest in the possible involvement of the platelet-activating factor (PAF) in tumor growth and invasiveness has been stimulated by the recognition that PAF influences various biological responses relevant to metastatic diffusion, such as angiogenesis, adhesiveness to endothelia and cellular motility. In the present study, we investigated the extent to which PAF is synthesized by a series of human and murine transformed cell lines of a different histotype. Synthesis of PAF was studied by combining the 14C-acetate incorporation into PAF with the quantitative analysis of PAF performed by a procedure based on gas chromatography-mass spectrometry with a negative ion chemical ionization. In the presence of the Ca2+ ionophore A23187, cultures of human melanoma (Hs294T), fibrosarcoma (HT1080) and colon carcinoma (LS180) cell lines synthesized conspicuous amounts of PAF, comparable to those produced by resident peritoneal macrophages. Substantial quantities of PAF were also synthesized by the murine melanoma (F10-M3 cells). PAF synthesis was rather limited in RSV-transformed Balb/c3T3 (B77-3T3) cells and in one of their high metastatic variants (B77-AA6 cells), although it was more abundant in the latter. We also investigated whether certain cytokines, such as TNFalpha and IFNgamma might induce PAF synthesis in our systems of cell lines which we found to express mRNAs encoding receptors for these cytokines. We observed that PAF synthesis was enhanced in human melanoma and colon carcinoma cell lines and in the murine B77-AA6 cells to levels comparable to those obtained with the Ca2+ ionophore. Synthesis of PAF was not inducible by TNFalpha in murine F10-M3 melanoma cells. IFNgamma also stimulated PAF synthesis in human and murine melanoma lines, and in human LS180 colon carcinoma line, but not in the B77-AA6 cells. PAF synthesis was also inducible by exogenous PAF in the human and murine melanoma lines, and in the human LS180 colon carcinoma line, all of which expressed cell surface PAF receptors. PAF synthesis was not inducible by exogenous PAF in the B77-AA6 cells, which do not express PAF receptors.

3T3 Cells↗
PubMed1992

Clonal evolution in a myeloid cell line transformed to interleukin-3 independent growth by retroviral transduction and expression of p210bcr/abl.

Current evidence suggests that the expression of the tyrosine kinase p210bcr/abl in chronic myelogenous leukemia (CML) may directly induce the initial phase of granulocytic hyperplasia. However, the dysregulation of additional genes appears to be required for transition to the acute leukemic phase, as inferred by the appearance of recurrent secondary cytogenetic abnormalities in the majority of patients. To determine whether the expression of p210bcr/abl alone is responsible for this genetic instability, we introduced and expressed the bcr/abl gene from a retroviral vector in a clone of the interleukin-3 (IL-3) dependent myeloblastic 32D C13(G) cell line. Clonal and polyclonal cells transformed to IL-3 independent growth were observed for a period extending up to 6 months for changes in the expression of p210bcr/abl, cell proliferation, inhibition by prostaglandin E1 (PGE1), forskolin, and cyclic adenosine monophosphate (cAMP) analogues, regulation of the cell cycle, and karyotype. Whereas the properties of control vector infected 32D C13(G)' cells remained stable over time, cells expressing p210bcr/abl were phenotypically unstable. In cells expressing p210bcr/abl, we observed selective modulation of p210bcr/abl mRNA and protein expression, evolution from partial to full abrogation of IL-3 dependence, reduced serum requirements, increased cell proliferation, decreased inhibition by PGE1 and cAMP analogues, and the appearance of new structural and numerical chromosomal abnormalities with successive cell passages. These results indicate that expression of p210bcr/abl can directly predispose 32D C13(G)' cells to genetic instability, promotes the emergence of clones with an increased proliferative advantage, and may represent an in vitro model suitable for the study of mechanisms underlying progression to the acute leukemic phase in CML.

Aneuploidy↗