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Results for “Cell Line, Transformed”

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At least 19 recordsLinked to original sources

PubMed2002

Differential induction of numerical chromosome changes by sodium butyrate in two transformed cell lines.

Transformed cell lines generally exhibit similar response to a given chemical. However, when two transformed cell lines, the Chinese hamster (CHO 9) and mouse (L929) were treated with sodium butyrate (SB) to investigate its effect on chromosome distribution, the two lines behaved differently from each other. At concentrations as low as 10(-7) M, the CHO 9 cells exhibited polyploidy as well as errors of numerical distributions resulting in aneuploidy. The majority of aneuploid cells were in quasitetraploid range indicating an association between the induction of polyploidy and aneuploidy. Upon staining with spindle antibody, the CHO cells exhibited a disarray of spindle microtubules as well as an abnormal cytoskeleton. In many instances the metaphase chromosomes were found to have a distorted spindle or lack an associated spindle altogether. The L929 cells, however, turned out to be far less sensitive to SB: a 100-fold increase in concentration of sodium butyrate (10(-5) M) did not result in production of polyploid cells. However, when the extent of aneuploidy induction was measured by using a marker chromosome, both loss and gain of the chromosome was noticed. The effect of SB on the spindle was much more modest than it was the case with CHO cells as only minor disarray in cytoskeleton or spindle morphology was observed. The L929 cells, however, showed some effect on microtubule orientation as well as an effect on the segmentation of midbody. The application of SB resulted in less intense and more diffuse phosphorylation; the chromosomes had a punctate appearance of the label compared with the solid appearance on untreated cells. This was ture for both species. In mouse, the centromeric heterochromatin, which generally is intensely labeled, appeared to be labeled only as intensely as euchromatin. The data show that different transformed cell lines do not respond similarly to SB.

Aneuploidy↗

PubMed1990

Increased uracil-DNA glycosylase, AP-DNA binding protein and deoxyribonuclease activities in tumor and SV40-transformed cell lines of human origin.

The activities of three human DNA metabolizing enzymes--uracil-DNA glycosylase, apurinic/apyrimidinic(AP)-DNA binding protein (an AP-DNA endonuclease) and the major cellular deoxyribonuclease (presumably DNase III and/or DNase IV)--were measured in logarithmic growing (diploid non-established) fibroblast strains, tumor-derived cell lines and SV40-transformed cell lines. The levels of activity of uracil-DNA glycosylase and DNase were increased, on average, 5- to 6-fold in tumor cell lines and 10-fold in SV40-transformed cell lines compared to those observed in normal fibroblast strains. AP-DNA binding activity was only 2- to 3-fold higher in both tumor-derived and SV40-transformed cell lines. Measurements in serum-deprived (and hence growth-retarded) SV40-transformed cells indicated that the observed increase in enzyme activity was only partially due to a higher proportion of S-phase cells in the rapidly growing transformed lines. Cell extract mixing experiments indicated that the relatively low levels of activity of the three enzymes in normal fibroblasts could not be ascribed to the presence of an inhibitory factor(s) in the crude extract.

Cell Line↗

PubMedDate not supplied

Fucolipid patterns of cell lines transformed by highly and weakly tumorigenic simian virus 40 and herpes simplex virus.

The fucolipids of simian virus 40 (SV40)-transformed Balb/c mouse and herpes simplex virus (HSV)-transformed hamster cells of varying degrees of tumorigenicity were examined. In the virus-transformed cell lines and in a spontaneously transformed cell line, as compared to non-transformed cell lines, there was a decrease in the incorporation of fucose radioactivity into fucolipid IV. Fucolipid IV is the least chromatographically mobile, presumably most complex fucolipid. Only in the highly transplantable SV40- and HSV-transformed cell lines was the decrease in incorporation of radioactivity in fucolipid IV as marked as that observed in oncornavirus-transformed cell lines. Similarly, only in the highly tumorigenic DNA-virus-transformed cell lines was there a significant increase in incorporation of radioactivity from radioisotopically-labeled fucose into fucolipid III as has been observed in oncornavirus-transformed cell lines.

Animals↗

PubMed1980

Kirsten murine sarcoma virus transformed cell lines and a spontaneously transformed rat cell-line produce transforming factors.

We have examined culture fluids from a variety of Kirsten murine sarcoma virus (KiMSV) transformed rat and mouse cells for the presence of factors which induce normal Rat-1 cells to assume the transformed phenotype. All KiMSV transformants produced transforming factor (TF). Revertants of KiMSV transformed rat or mouse failed to release TF as did normal rat or mouse cells. Cells transformed by a temperature sensitive mutant of KiMSV produced TF at the permissive temperature but not at the nonpermissive temperature. Further, cells from a spontaneous transformant of Rat-1 cells also produced TF. TF is a small polypeptide which competes for the epidermal growth factor receptor. Its effect upon normal cells is reversible and requires de novo RNA and protein synthesis. Cells treated with TF lose the actin fibers observed in normal fibroblasts, assume a transformed cell morphology, become anchorage independent for growth, grow in low concentrations of serum, grow to a high cell density, and have an increased rate of hexose uptake.

Actins↗

PubMed1997

Inducible knockout of the interleukin-2 receptor alpha chain: expression of the high-affinity IL-2 receptor is not required for the in vitro growth of HTLV-I-transformed cell lines.

Adult T cell leukemia (ATL) is an aggressive malignancy that is associated with HTLV-I infection and characterized by constitutive expression of the high-affinity interleukin-2 receptor. The alpha subunit of the high-affinity receptor (IL-2Ralpha), which is normally present only on activated T cells, is specifically upregulated by HTLV-I and constitutively expressed on fresh leukemic cells from ATL patients as well as cell lines transformed by HTLV-I in vitro. Here we directly address the functional significance of IL-2Ralpha expression in HTLV-I transformed cell lines by using an endoplasmic reticulum-targeted single-chain antibody to inhibit the cell surface expression of IL-2Ralpha. Using constitutive and tetracycline-repressible systems to express the ER-targeted antibody against IL-2Ralpha, we have reduced cell surface expression of IL-2Ralpha by more that 2 logs of mean fluorescence intensity to virtually undetectable levels in the IL-2-independent HTLV-I-transformed cell lines C8166-45 and HUT102. No toxicity was associated with the intracellular retention of IL-2Ralpha, and the growth rate of the IL-2Ralpha-negative cells was in each case comparable to that of the parental cell line. We conclude that cell surface expression of IL-2Ralpha is dispensable for the in vitro growth of these HTLV-I-transformed cells.

Cell Division↗

PubMed1984

Characterization of nude mouse skin fibroblast cell lines transformed by combined action of SV40 and 3-methylcholanthrene.

Properties of transformed cell lines derived from secondary cultures of newborn NMRI nu/nu (nude) mouse skin fibroblasts by the sequential exposure of 3-methylcholanthrene and a DNA virus, SV40, were studied. Such transformants were compared to cells transformed by 3-methylcholanthrene or SV40 alone for the tumourigenicity, T-antigen expression, different in vitro growth characteristics and natural killer (NK) cell sensitivity. Despite a considerable variation within a group, the cell lines transformed by the combination treatment as a group were more tumourigenic than cell lines of other groups. In addition, the cell lines transformed by the combination treatment showed increased amounts of T-antigen as compared to cell lines transformed by SV40 alone. They also had, on an average, shorter population doubling time, higher cell saturation density, and a higher amount of DNA per cell than cell lines transformed by SV40 alone. Combination treatment cell lines (5 out of 8) grew in soft agar, whereas cell lines transformed by SV40 or 3-methylcholanthrene alone did not. In conclusion, the cell lines transformed by the combination treatment of 3-methylcholanthrene and SV40 had properties related to malignancy more often than cell lines transformed by SV40 or 3-methyl cholanthrene alone.

Animals↗

PubMed1992

Effect of interferon gamma on the sensitivity of bovine-papilloma-virus(BPV1)-transformed cell lines to cell-mediated cytotoxicity.

The effect of interferon gamma (IFN gamma) on the immunogenicity and immunosensitivity of mouse cell lines transformed by bovine papillomavirus type 1 (BPV1) DNA was examined in a syngeneic mouse model. The overnight incubation of BPV1-transformed cell lines with 100 IU/ml IFN gamma did not affect their ability to induce the generation of cytotoxic effector cells but it clearly increased their sensitivity to lysis by interleukin-2-induced lymphokine-activated killer (LAK) cells and by non-specific LAK-type effector cells induced by BPV-1-transformed cell lines. The treatment of two allogeneic lymphoid tumour cell lines, P815X2 and YAC-1, with IFN gamma either decreased or had no effect on their sensitivity to LAK-cell-mediated lysis.

Animals↗

PubMed1987

Immunological evidence for the association of p53 with a heat shock protein, hsc70, in p53-plus-ras-transformed cell lines.

A rabbit antiserum was prepared against the C-terminal peptide of 21 amino acids from the human heat shock protein hsp70. These antibodies were shown to be specific for this highly inducible heat shock protein (72 kilodaltons [kDa] in rat cells), and for a moderately inducible, constitutively expressed heat shock protein, hsc70 (74 kDa). In six independently derived rat cell lines transformed by a murine cDNA-genomic hybrid clone of p53 plus an activated Ha-ras gene, elevated levels of p53 were detected by immunoprecipitation by using murine-specific anti-p53 monoclonal antibodies. In all cases, the hsc70, but not the hsp70, protein was coimmunoprecipitated with the murine p53 protein. Similarly, antiserum to heat shock protein coimmunoprecipitated p53. Western blot (immunoblot) analysis demonstrated that the hsc70 and p53 proteins did not share detectable antigenic epitopes. The results provide clear immunological evidence for the specific association of a single heat shock protein, hsc70, with p53 in p53-plus-ras-transformed cell lines. A p53 cDNA clone, p11-4, failed to produce clonable cell lines from foci of primary rat cells transfected with p11-4 plus Ha-ras. A mutant p53 cDNA clone derived from p11-4, SVKH215, yielded a 2- to 35-fold increase in the number of foci produced after transfection of rat cells with SVKH215 plus Ha-ras. When cloned, 87.5% of these foci produced transformed cell lines. SVKH215 encodes a mutant p53 protein that binds preferentially to the heat shock proteins of 70 kDa compared with binding by the parental p11-4 p53 gene product. These data suggest that the p53-hsc70 protein complex could have functional significance in these transformed cells.

Amino Acid Sequence↗

PubMed1994

Downregulation of peptide transporter genes in cell lines transformed with the highly oncogenic adenovirus 12.

The expression of class I major histocompatibility complex antigens on the surface of cells transformed by adenovirus 12 (Ad12) is generally very low, and correlates with the high oncogenicity of this virus. In primary embryonal fibroblasts from transgenic mice that express both endogenous H-2 genes and a miniature swine class I gene (PD1), Ad12-mediated transformation results in suppression of cell surface expression of all class I antigens. Although class I mRNA levels of PD1 and H-2Db are similar to those in nonvirally transformed cells, recognition of newly synthesized class I molecules by a panel of monoclonal antibodies is impaired, presumably as a result of inefficient assembly and transport of the class I molecules. Class I expression can be partially induced by culturing cells at 26 degrees C, or by coculture of cells with class I binding peptides at 37 degrees C. Analysis of steady state mRNA levels of the TAP1 and TAP2 transporter genes for Ad12-transformed cell lines revealed that they both are significantly reduced, TAP2 by about 100-fold and TAP1 by 5-10-fold. Reconstitution of PD1 and H-2Db, but not H-2Kb, expression is achieved in an Ad12-transformed cell line by stable transfection with a TAP2, but not a TAP1, expression construct. From these data it may be concluded that suppressed expression of peptide transporter genes, especially TAP2, in Ad12-transformed cells inhibits cell surface expression of class I molecules. The failure to fully reconstitute H-2Db and H-2Kb expression indicates that additional factors are involved in controlling class I gene expression in Ad12-transformed cells. Nevertheless, these results suggest that suppression of peptide transporter genes might be an important mechanism whereby virus-transformed cells escape immune recognition in vivo.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

p53 mutation in fresh lymphocytes, B-lymphoblastoid cell lines and their transformed cell lines originating from Bloom syndrome patients.

To elucidate the molecular basis for malignant and premalignant states in Bloom syndrome (BS), p53 mutations were analyzed using Southern blot analysis and DNA sequencing of exons 5-9. p53 point mutations with and without loss of heterozygosity on 17p were detected in malignantly transformed BS cell lines carrying malignant lymphoma (ML) and stomach cancer (STC) antigens on the cell surface. However, p53 mutations were not detected in fresh lymphocytes and B-lymphoblastoid cell lines from four BS patients carrying high sister chromatid exchange (SCE) levels, using Southern blot and DNA sequencing of exons 5-9. Based on these results, we concluded that the p53 gene may not play a key role in the high spontaneous mutation rates (HGPRT locus) in somatic cells of BS patients and that the p53 mutation with an allelic loss of the p53 gene is an important factor in malignant conditions in BS.

Base Sequence↗

PubMed1969

Rescue of Simian Virus 40 from Cell Lines Transformed at High and at Low Input Multiplicities by Unirradiated or Ultraviolet-irradiated Virus.

The relation between simian virus 40 (SV40) input multiplicity during transformation of primary mouse kidney cultures and the subsequent rescue of SV40 from clonal lines of transformed cells has been studied. Primary mouse kidney cultures were transformed with unirradiated SV40 at input multiplicities varying from 0.06 to 200 plaque-forming units (PFU) /cell or with SV40 irradiated with ultraviolet (UV) light to a survival of 0.04 to 0.01. All of the transformed lines contained the intranuclear SV40 T antigen, but cell-free extracts prepared from the transformed cell lines failed to yield infectious virus when assayed on monkey kidney cell (CV-1) monolayers. After fusion with susceptible CV-1 cells induced by UV-inactivated Sendai, all of the lines transformed by unirradiated virus yielded infectious SV40. The frequency of induction and the incidence of successful trials did not depend on the multiplicity of infection. "Good" yielders were obtained from mouse kidney cells transformed at the low input multiplicity of 0.06 PFU /cell. In contrast, only 4 of 12 clonal lines transformed at moderately low input multiplicity, and none of the lines transformed at very low input multiplicity with UV-irradiated virus yielded infectious SV40. The four positive lines have been classified as "poor" or "rare" yielders.

Journal Article↗

PubMed1981

Expression of Forssman antigen of avian lymphoblastoid cell lines transformed by Marek's disease virus or avian leukosis virus.

The expression of Forssman-type heterophile antigen on Marek's disease (MD) virus (MDV)-transformed cell lines, MDCC-MSBI 1, -HP1, -RP1 and -BP1, and avian leukosis virus (ALV)-transformed cell lines, LSCC-1104B1 and -1104X5 was investigated by membrane immunofluorescence and complement-dependent antibody cytotoxicity tests. Forssman antigen was detected on a high percentage of the cells in two ALV-transformed cell lines and on a smaller percentage of splenic lymphocytes from normal chicken. Of the MDV-transformed cell lines tested only the RP1 and BP1 cell lines, derived from transplantable MD tumours, expressed Forssman antigen, while the MSB1 and HP1 cell lines, derived from MD lymphomas, did not. Forssman antigen appears to be unrelated to MD tumour-associated surface antigen (MATSA).

Animals↗

PubMed2000

UVs syndrome: establishment and characterization of fibroblastic cell lines transformed with simian virus 40 DNA.

Ultraviolet-sensitive syndrome (UVsS) is a newly established photosensitive disorder. Patients with UVsS showed mild clinical manifestations similar to classical types of xeroderma pigmentosum, and had biochemical phenotypes of Cockayne syndrome but not those of xeroderma pigmentosum. Fibroblasts from a UVsS patient were treated with simian virus 40 DNA containing the large T antigen with a defective origin of DNA replication to establish a transformed cell line. We obtained two independent transformed cell lines (Kps3SVY and Kps3SVI3) and report their initial characterization. These cells showed the same pattern in variable number of tandem repeat analyses as a primary fibroblast cell strain, Kps3, and retain the UVsS phenotype as demonstrated by increased UV sensitivity (three to four times more sensitive to UV than normal cells) and by reduced recovery of RNA synthesis after UV irradiation (20% - 30% of that of normal cells). These cells, however, showed different phenotypes as regards plating efficiency, doubling time, and transfection efficiency in spite of the fact that the same method was used to transform the cells. Kps3SVY cells were closer in phenotype to Kps3 cells than Kps3SVI3 cells. As a variable number of tandem repeat analyses also showed that Kps3SVI3 cells have lost one of the two alleles in some chromosomes, this may explain the different phenotypes between Kps3SVY and Kps3SVI3 cells. Moreover, these cells were distinct from cells with Cockayne syndrome group A or B. Thus, these cell lines provide the opportunity to conduct transfection studies on cells with the UVsS defect in DNA repair and transcription.

Cell Line, Transformed↗

PubMed1988

Activated Ki-ras genes in bladder epithelial cell lines transformed by treatment of primary mouse bladder explant cultures with 7,12-dimethylbenz[a]anthracene.

DNA from five lines of transformed bladder epithelial cells derived from cultures of primary cells that had been treated with 7,12-dimethylbenz[a]anthracene (DMBA) can transform NIH 3T3 mouse fibroblasts in DNA transfection experiments. Southern analysis of DNA from NIH 3T3 primary and secondary transformants established that four of the DMBA-transformed cell lines contained activated cellular Ki-ras, while the remaining cell line contained a transforming gene that is unrelated to Ki-ras, N-ras, and Ha-ras. The point mutations responsible for Ki-ras activation were detected using oligonucleotide probes following selective amplification of Ki-ras specific sequences using the polymerase chain reaction. The results showed that activation of Ki-ras invariably involved a GC----AT transition mutation of the first position of codon 12. Surprisingly, a Ki-ras gene that was activated by a GC----AT transition mutation at the same position was also detected in a single transformed bladder urothelial cell line derived from control cultures of mouse bladder cells. Together, our results indicate that Ki-ras activation in the DMBA-transformed bladder cell lines may not be a direct consequence of interaction of activated DMBA metabolites with the Ki-ras gene.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1969

Properties of simian virus 40 rescued from cell lines transformed by ultraviolet-irradiated simian virus 40.

Simian virus 40 (SV40) strains have been rescued from various clonal lines of mouse kidney cells that had been transformed by ultraviolet (UV)-irradiated SV40. To learn whether some of the rescued SV40 strains were mutants, monkey kidney (CV-1) cells were infected with the rescued virus strains at 37 C and at 41 C. The SV40 strains studied included strains rescued from transformed cell lines classified as "good," "average," "poor," and "rare" yielders on the basis of total virus yield, frequency of induction, and incidence of successful rescue trials. Four small plaque mutants isolated from "poor" yielder lines and fuzzy and small plaque strains isolated from an "average" and a "good" yielder line, respectively, were among the SV40 strains tested. Virus strains rescued from all classes of transformed cells were capable of inducing the transplantation antigen, and they induced the intranuclear SV40-T-antigen, thymidine kinase, deoxyribonucleic acid (DNA) polymerase, and cellular DNA synthesis at 37 C and at 41 C. With the exception of four small plaque strains rescued from "poor" yielders, the rescued SV40 strains replicated their DNA and formed infectious virus with kinetics similar to parental SV40 at either 37 or 41 C. The four exceptional strains did replicate at 37 C, but replication was very poor at 41 C. Thus, only a few of the rescued virus strains exhibited defective SV40 functions in CV-1 cells. All of the virus strains rescued from the "rare" yielder lines were similar to parental SV40. Several hypotheses consistent with the properties of the rescued virus strains are discussed, which may account for the significant variations in virus yield and frequency of induction of the transformed cell lines.

Animals↗

PubMed1984

OK10-transformed cell lines: viral component generation and tumorigenicity.

Stable nonproducer (NP) cell lines transformed by the avian acute leukemia virus OK10 were established. All 13 studied NP quail cell lines released into the culture medium noninfectious, mostly reverse-transcriptase-negative particles containing the usual gag proteins. Infectious, transforming OK10 virus pseudotypes could be recovered by rescue with helper virus. p200, the putative transforming protein of OK10, was identified in in vitro translates of RNA from the noninfectious particles and in immunoprecipitates of cell extracts of the NP clones analyzed. Two NP clones, the reverse-transcriptase-negative B5 and -positive 9C cell lines, displayed striking differences in in vivo tumorigenicity. Although B5 induced no tumors in quails, 9C caused multiple tumors and cells derived from several tumors could be passaged in vitro. At no time during the in vivo passage or during more than 1 year of in vitro culture have the particles released by 9C cells acquired infectious properties. Possible reasons for the observed differences in tumorigenicity between the OK10 virus-transformed 9C and B5 NP cell lines are discussed.

Animals↗

PubMed1994

Avian myeloblastic cell lines transformed by two nuclear oncoproteins, P135gag-myb-ets and p61/63myc: a model of retinoic acid-induced differentiation not abrogated by v-erbA.

We previously demonstrated that the retroviral construct MHE226 transducing both the P135gag-myb-ets and p61/63myc nuclear proteins induces solid hemopoietic tumors in early chicken embryos. In the present paper, we report the characterization of two MHE226-transformed cell lines established from such hemopoietic tumors retrieved from the heart of a 13-day embryo. Cytological analysis indicated a myeloblastic phenotype. These MHE226 cell lines were positive for the MEP17 monoclonal antibody but were negative for the myeloblast-specific 51/2 monoclonal antibody. MHE226 cell lines displayed a doubling time of about 20-24 h and were maintained for at least 1 year. Contrary to E26 myeloblastic cell lines, MHE226 cell lines were independent of chicken myelomonocytic growth factor and could be maintained in serum-free medium. MHE226 cell lines could be induced to differentiate toward the monocytic lineage by retinoic acid. Retinoic acid inhibited proliferation of MHE226 cell lines as early as day 1. After 3 days, MHE226 cells displayed cytological, enzymatic (alpha-naphthyl acetate esterase and chloroacetate esterase), and functional (phagocytosis) characteristics of monocytic cells. The retinoic acid-induced differentiation of MHE226 cells could not be inhibited by v-erbA. Thus, MHE226-transformed cell lines represent a novel model of cell transformation by two nuclear oncoproteins. Furthermore, they provide a model to study molecular mechanisms implicated in the monocytic differentiation program.

Animals↗

PubMedDate not supplied

Ad-fRNK and Ad-p53 cooperate to augment drug-induced death of a transformed cell line.

BACKGROUND: Transformed cells have abnormalities in the survival pathways contributing to drug resistance. These abnormalities include p53 mutations and increased focal adhesion kinase (FAK) expression. Because FAK regulates cell survival via p53-dependent and -independent pathways, it was hypothesized that combined therapy using wild-type p53 and an inhibitor of FAK (FRNK) would sensitize cells to anticancer drugs. MATERIALS AND METHODS: RPMI 2650 cells were infected with recombinant adenoviruses causing overexpression of p53 (Ad-p53) and FRNK (Ad-FRNK). Cell viability and apoptosis were measured using in vitro assays, whereas protein expression was determined by Western blotting. RESULTS: Co-infection of cells with Ad-p53 and Ad-FRNK induced more cellular apoptosis than transfection with either agent alone. Likewise, the co-transfection of cells with Ad-FRNK and Ad-p53 improved the cytotoxic response to four commonly used anticancer drugs relative to cells transfected with Ad-FRNK alone, Ad-p53 alone, or the equivalent amount of control adenovirus. This effect was associated with loss of endogenous FAK protein.

Adenoviridae↗