Contact-inhibited revertant cell lines isolated from SV40-transformed cells VIII. Membrane protein and glycoprotein composition

Virology ◽  
1978 ◽  
Vol 86 (2) ◽  
pp. 556-561 ◽  
Author(s):  
Adele R. Vessey ◽  
Lloyd A. Culp
Keyword(s):  
Membrane Protein ◽  
Cell Lines ◽  
Transformed Cells

Transforming growth factor β1 selectively regulates ferritin gene expression in malignant H-ras-transformed fibrosarcoma cell lines

2000 ◽  
Vol 78 (4) ◽  
pp. 527-535 ◽  
Author(s):  
James Lo ◽  
Robert AR Hurta
Keyword(s):  
Gene Expression ◽  
Cell Proliferation ◽  
Growth Factor ◽  
Malignant Transformation ◽  
Cell Lines ◽  
Transforming Growth Factor ◽  
Malignant Potential ◽  
Transformed Cells ◽  
Protein Synthesis Inhibitor ◽  
Ferritin Gene

Transforming growth factor β1 is an important growth regulator in many cell types, usually exerting a negative effect on cellular growth. Inhibition of DNA synthesis and cell proliferation is frequently lost during malignant transformation, and in some cases, tumor cell proliferation is actually stimulated by TGF-β1. The present study demonstrates a novel link between alterations in TGF-β1 regulation during malignant conversion, and the expression of ferritin, an important activity involved in a number of biological functions including iron homeostasis and cell-growth control. A series of H-ras-transformed mouse 10 T 1/2 cell lines, exhibiting increasing malignant potential, was investigated for possible TGF-β1-mediated changes in ferritin gene expression. Selective induction of gene expression was observed, since only H-ras-transformed cells with malignant potential exhibited marked elevations in ferritin gene expression, in particular, alterations in H-ferritin gene expression. The regulation of H-ferritin gene expression in response to TGF-β 1 did not involve alterations in transcription, but occurred through mechanisms of post-transcriptional stabilization of the H-ferritin mRNA. Additionally, evidence was obtained for a cycloheximide-sensitive regulator of H-ferritin gene expression, since the presence of this protein synthesis inhibitor increased H-ferritin message levels, and in combination with TGF-β1, cooperated in an additive manner to augment H-ferritin gene expression. These results show for the first time that TGF-β1 can regulate ferritin gene expression in malignant H-ras transformed cells, and suggest a mechanism for growth factor stimulation of malignant cells, in which early alterations in the control of H-ferritin gene expression are important.Key words: TGF-β1, ferritin gene expression, malignant transformation.

scholarly journals Identification of a BALB/c-3T3 cell protein modulated by platelet-derived growth factor.

1983 ◽  
Vol 3 (1) ◽  
pp. 70-81 ◽  
Author(s):  
C D Scher ◽  
R L Dick ◽  
A P Whipple ◽  
K L Locatell
Keyword(s):  
Growth Factor ◽  
Dna Synthesis ◽  
Cell Lines ◽  
Actinomycin D ◽  
Platelet Derived Growth Factor ◽  
Cell Protein ◽  
Transformed Cells ◽  
Antigenic Determinants ◽  
3T3 Cells ◽  
Constitutive Synthesis

The platelet-derived growth factor (PDGF) stimulates density-arrested BALB/c-3T3 cells to synthesize a protein (pII; Mr, 35,000) that is constitutively synthesized by spontaneously transformed BALB/c-3T3 (ST2-3T3) cells which do not require PDGF for growth. Antisera against a major excreted protein family (MEP) of retrovirus-transformed cells quantitatively precipitated cellular pII. PDGF-stimulated pII has the same molecular weight, a similar charge, and similar antigenic determinants as authentic MEP isolated from ST2-3T3 or retrovirus-transformed cells. MEP represented about 2% of the nonnuclear proteins synthesized by ST2-3T3 cells and 0.3 to 0.6% of the proteins synthesized by PDGF-treated BALB/c-3T3 cells, a three- to sixfold increase over the background. In BALB/c-3T3 cells, less PDGF was required for pII (MEP) synthesis than for DNA synthesis. PDGF induced a selective increase in pII (MEP) within 40 min. Such preferential synthesis was inhibited by brief treatment with actinomycin D, suggesting a requirement for newly formed RNA. The constitutive synthesis of pII (MEP) by ST2-3T3 cells was not inhibited by actinomycin D. Five spontaneously or chemical carcinogen-transformed tumorigenic BALB/c-3T3 cell lines were studied; they neither required PDGF for growth nor responded to it. These cell lines became arrested at confluence with a G1 DNA content. Each of these independently isolated lines synthesized pII (MEP) constitutively. Thus, the synthesis of pII (MEP) may be required, but is not sufficient, for PDGF-modulated DNA synthesis.

scholarly journals Wild-type p53 induces diverse effects in 32D cells expressing different oncogenes.

1996 ◽  
Vol 16 (2) ◽  
pp. 487-495 ◽  
Author(s):  
S Soddu ◽  
G Blandino ◽  
R Scardigli ◽  
R Martinelli ◽  
M G Rizzo ◽  
...  
Keyword(s):  
Cell Lines ◽  
Apoptotic Cell ◽  
Leukemia Cell ◽  
P53 Gene ◽  
Neoplastic Cell ◽  
Transformed Cells ◽  
Wild Type ◽  
Monocytic Differentiation ◽  
P53 Overexpression ◽  
Cellular Environment

Expression of exogenous wild-type (wt) p53 in different leukemia cell lines can induce growth arrest, apoptotic cell death, or cell differentiation. The hematopoietic cell lines that have been used so far to study wt p53 functions have in common the characteristic of not expressing endogenous p53. However, the mechanisms involved in the transformation of these cells are different, and the cells are at different stages of tumor progression. It can be postulated that each type of neoplastic cell offers a particular environment in which p53 might generate different effects. To test this hypothesis, we introduced individual oncogenes into untransformed, interleukin-3 (IL-3)-dependent myeloid precursor 32D cells to have a single transforming agent at a time. The effects induced by wt p53 overexpression were subsequently evaluated in each oncogene-expressing 32D derivative. We found that in not fully transformed, v-ras-expressing 32D cells, as already shown for the parental 32D cells, overexpression of the wt p53 gene caused no phenotypic changes and no reduction of the proliferative rate as long as the cells were maintained in their normal culture conditions (presence of IL-3 and serum). An accelerated rate of apoptosis was observed after IL-3 withdrawal. In contrast, in transformed, IL-3-independent 32D cells, wt p53 overexpression induced different effects. The v-abl-transformed cells manifested a reduction in growth rate, while the v-src-transformed cells underwent monocytic differentiation. These results show that the phenotype effects of wt p53 action(s) can vary as a function of the cellular environment.

Extinction and activation of the thyroglobulin promoter in hybrids of differentiated and transformed thyroid cells

1990 ◽  
Vol 10 (3) ◽  
pp. 1033-1040
Author(s):  
I M Bonapace ◽  
M Sanchez ◽  
S Obici ◽  
A Gallo ◽  
S Garofalo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Lines ◽  
Selectable Marker ◽  
Hybrid Cell ◽  
Transformed Cells ◽  
Thyroid Cells ◽  
Dominant Selectable Marker ◽  
Thyroglobulin Gene ◽  
Rat Thyroid ◽  
Hybrid Cell Lines

Thyroglobulin gene expression was repressed in a rat thyroid cell line transformed with Kirsten murine sarcoma virus. Expression of a dominant selectable marker driven by the thyroglobulin promoter was also inhibited. Somatic cell hybridization of transformed and differentiated thyroid cells resulted in extinction of thyroglobulin gene expression. When transformed cells carrying a dominant selectable marker driven by the thyroglobulin promoter were fused to differentiated cells and expression of this marker was selected, we obtained stable hybrid cell lines expressing both the endogenous and the exogenous thyroglobulin promoters. Although the expression of v-ras remained unchanged compared with expression in the parental transformed cells, transformation was suppressed in the hybrid cell lines. The other thyroid differentiation markers, iodide uptake and thyroid-stimulating hormone-dependent growth, were inhibited in all the hybrids tested. We show that activity of the thyroglobulin promoter correlates with the presence of a thyroid nuclear factor that binds the promoter at position -60 from the transcription start site. Loss of this factor accompanies the extinction of thyroglobulin gene expression in hybrids selected for expression of a non-thyroid-specific promoter.

scholarly journals Prognostic Significance of Serum Free Amino Acids in Head and Neck Cancers

Cells ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 428 ◽  
Author(s):  
Vit Vsiansky ◽  
Marketa Svobodova ◽  
Jaromir Gumulec ◽  
Natalia Cernei ◽  
Dagmar Sterbova ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Regression Model ◽  
Head And Neck ◽  
Cell Lines ◽  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Transformed Cells ◽  
Cox Proportional Hazards Regression ◽  
Proportional Hazards Regression

Despite distinctive advances in the field of head and neck squamous cell cancer (HNSCC) biomarker discovery, the spectrum of clinically useful prognostic serum biomarkers is limited. As metabolic activities in highly proliferative transformed cells are fundamentally different from those in non-transformed cells, specific shifts in concentration of different metabolites may serve as diagnostic or prognostic markers. Blood amino acids have been identified as promising biomarkers in different cancers before, but little is known about this field in HNSCC. Blood amino acid profiles of 140 HNSCC patients were examined using high-performance liquid chromatography. Cox proportional hazards regression model was used to assess the prognostic value of amino acid concentrations in serum. Colony forming assay was used to identify the effect of amino acids that were significant in Cox proportional hazards regression models on colony forming ability of FaDu and Detroit 562 cell lines. In the multivariable Cox regression model for overall survival (OS), palliative treatment was associated with an unfavourable prognosis while high serum levels of methionine have had a positive prognostic impact. In the relapse-free survival (RFS) multivariable model, methionine was similarly identified as a positive prognostic factor, along with tumor localization in the oropharynx. Oral cavity localization and primary radio(chemo)therapy treatment strategy have been linked to poorer RFS. 1mM serine was shown to support the forming of colonies in both tested HNSCC cell lines. Effect of methionine was exactly the opposite.

scholarly journals Isolation of cellular genes differentially expressed in mouse NIH 3T3 cells and a simian virus 40-transformed derivative: growth-specific expression of VL30 genes.

1985 ◽  
Vol 5 (10) ◽  
pp. 2590-2598 ◽  
Author(s):  
K Singh ◽  
S Saragosti ◽  
M Botchan
Keyword(s):  
Cell Lines ◽  
Simian Virus 40 ◽  
Mouse Cell ◽  
Simian Virus ◽  
Differentially Expressed ◽  
Transformed Cells ◽  
3T3 Cells ◽  
Transformed Cell ◽  
Nih 3T3 ◽  
Nih 3T3 Cells

We constructed and screened a cDNA library made from simian virus 40 (SV40)-transformed NIH 3T3 cells, and we isolated cDNAs representing genes that are differentially expressed between the parental cell and its SV40-transformed derivative. We found only a small number of cDNAs representing such genes. Two isolated cDNA clones represented RNAs expressed at elevated levels in the transformed cell line in a manner relatively independent of growth conditions. The expression of two other cDNAs was growth specific because transformed cells and nonconfluent parental cells contained higher levels of the homologous RNAs than did confluent, contact-inhibited parental cells. Another cDNA was well expressed in confluent parental and confluent transformed cells, but not in nonconfluent cells. The expression of some of these cDNAs varied strikingly in different mouse cell lines. Thus the genotype or histories of different cell lines can also affect the expression of certain genes. Interestingly, the only cDNA isolated that was expressed exclusively in the transformed cell was from an SV40 message. We focused on a growth-specific cDNA which we show is derived from a mouse endogenous retrovirus-like family called VL30. We sequenced the 3' long terminal repeat (LTR) of this transcriptionally active VL30 gene. This LTR has good homology with other VL30 LTR sequences, but differences occur, particularly upstream of the VL30 promoter. We found that VL30 gene expression varied in different mouse cell lines such that C3H cell lines had very low levels of VL30 transcripts relative to NIH 3T3 cell lines. However, Southern analysis showed that both cell lines had about the same number of VL30 genes homologous to our probe and that the position of the majority of these genes was conserved. We discuss possible explanations for this difference in VL30 expression.

scholarly journals Human malignant and mitogen-transformed cells contain retroviral P15E-related antigen.

1984 ◽  
Vol 159 (3) ◽  
pp. 964-969 ◽  
Author(s):  
G J Cianciolo ◽  
D Phipps ◽  
R Snyderman
Keyword(s):  
Cell Lines ◽  
Mononuclear Cells ◽  
Human Tumor ◽  
Malignant Cell ◽  
Transformed Cells ◽  
Blast Transformation ◽  
Structural Protein ◽  
Human Tumor Cells ◽  
Human Mononuclear Cells ◽  
Protein P15e

Virus-related oncogenes have been demonstrated in human tumor cells and may play a role in neoplastic transformation. Cancerous effusions contain inhibitors of monocyte function and are absorbed by monoclonal antibodies to the immunosuppressive retroviral structural protein, P15E. We therefore examined eight human malignant cell lines for P15E-related antigens, by indirect immunofluorescence. Up to 87% of fixed malignant cells were reactive with two different monoclonal anti-P15E antibodies, while under identical conditions approximately 7% of freshly isolated human mononuclear cells were positive. Differentiation of two tumor cell lines with dibutyryl cyclic AMP resulted in decreased anti-P15E reactivity. Blast transformation of human mononuclear cells with mitogens induced reactivity with anti-P15E. Thus human malignant and blast-transformed cells contain antigens related to P15E. Expression of this viral-related gene may occur during rapid cell division and be abnormally regulated in cancer cells, thus rendering them more resistant to immune destruction.

Antisense to the Epstein-Barr Virus (EBV)-Encoded Latent Membrane Protein 1 (LMP-1) Suppresses LMP-1 and Bcl-2 Expression and Promotes Apoptosis in EBV-Immortalized B Cells

Blood ◽  
1998 ◽  
Vol 92 (5) ◽  
pp. 1721-1727 ◽  
Author(s):  
Jamie L. Kenney ◽  
Mary E. Guinness ◽  
Tyler Curiel ◽  
Jill Lacy
Keyword(s):  
Membrane Protein ◽  
Cell Lines ◽  
Epstein Barr Virus ◽  
Antitumor Agents ◽  
Apoptotic Cell ◽  
Latent Membrane Protein ◽  
Therapeutic Effects ◽  
Inhibition Of Proliferation ◽  
Barr Virus ◽  
Epstein Barr

Abstract The Epstein-Barr virus (EBV)-encoded latent membrane protein (LMP-1) is required for viral transformation and functions to protect cells from apoptotic cell death, in part, by induction of antiapoptotic genes, including Bcl-2 and A20. We have used antisense oligodeoxynucleotides targeted to LMP-1 as a strategy to suppress LMP-1 expression and thereby inhibit its functions. We have shown that levels of LMP-1 protein in EBV-positive lymphoblastoid cell lines can be reduced by in vitro treatment with unmodified oligodeoxynucleotides targeted to the first five codons of the LMP-1 open-reading frame. Furthermore, suppression of LMP-1 was associated with molecular and phenotypic effects that included downregulation of the LMP-1–inducible antiapoptotic genes, Bcl-2 and Mcl-1, inhibition of proliferation, stimulation of apoptosis, and enhancement of sensitivity to the chemotherapeutic agent, etoposide. These effects were largely sequence-specific and observed in EBV-positive, but not EBV-negative cell lines. These studies suggest that lowering expression of LMP-1 in EBV-associated malignancy might have therapeutic effects and might synergize with other antitumor agents. © 1998 by The American Society of Hematology.

scholarly journals Calcein-Acetyoxymethyl Cytotoxicity Assay: Standardization of a Method Allowing Additional Analyses on Recovered Effector Cells and Supernatants

2001 ◽  
Vol 8 (6) ◽  
pp. 1131-1135 ◽  
Author(s):  
Simona Neri ◽  
Erminia Mariani ◽  
Alessandra Meneghetti ◽  
Luca Cattini ◽  
Andrea Facchini
Keyword(s):  
T Cells ◽  
Cell Lines ◽  
Human Cell ◽  
Transformed Cells ◽  
Human Cell Lines ◽  
Soluble Factors ◽  
Effector Cells ◽  
Cytotoxicity Assays ◽  
Calcein Am

ABSTRACT Cytotoxicity assays provide an in vitro evaluation of the lytic activity of NK and T cells against tumors or transformed cells. However, none of these methods allow the recovery of cells or supernatants after the assay. We standardized a microcytotoxicity test using calcein-acetoxymethyl (calcein-AM) dye that requires very small quantities of cells while maintaining the same sensitivity as the traditional 51Cr assay. The assay is applicable to resting as well as activated human effector cells and uses different targets such as human cell lines that are adherent or growing in suspension and resistant or sensitive. The most important feature of the method is the possibility of recovering cells and supernatants for additional analyses such as phenotyping and evaluation of soluble factors.

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