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PubMed1979

Establishment of cell lines from the wild rodent Millardia meltada and tests for endogenous virus.

Four cell lines were established from the wild rodent, Millardia meltada; an untransformed cell line (MM-D), a non-producer (NP) cell line transformed with murine sarcoma virus (MM-CL4), and SV40-transformed cell lines (MM-8 MM-663). MM-D is epithelioid and contact-inhibited, whereas MM-CL4, MM-8, and MM-663 are fibroblastic and grow piling up. No endogenous virus was induced in Millardia cell lines by a long-term culture with various inducers. Millardia cell DNA has no nucleotide sequence homology with cDNA of either murine leukemia virus or rat endogenous virus.

Animals↗
PubMed1999

Dependence of fibroblast autofluorescence properties on normal and transformed conditions. Role of the metabolic activity.

The dependence of autofluorescence properties on the metabolic and functional engagement and on the transformation condition was studied on single cells. Normal Galliera rat fibroblasts at low subculture passage (cell strain), at high subculture passage (stabilized cell line), and transformed cell line derived from a rat sarcoma were used as a cell model. The study was performed by microspectrofluorometric and fluorescence imaging technique. The autofluorescence properties of cells were studied by excitation at two wavelengths, namely 366 nm and 436 nm, that are known to favor the emission of different fluorophores. Spectral shape analysis indicated that under excitation at 366 nm autofluorescence is ascribable mainly to coenzyme molecules, particularly to reduced pyridine nucleotides, while under excitation at 436 nm, flavin and lipopigment emission is favored. The energetic metabolic engagement of the different cell lines was analyzed in terms both of parameters related to anaerobic-aerobic pathways (biochemical assay) and of mitochondrial features (supravital cytometry). The results showed that the cell strain and the stabilized and transformed cell lines can be distinguished from one another on the basis of both overall fluorescence intensity and the relative contributions of spectral components. These findings indicated a relationship between autofluorescence properties and energetic metabolism engagement of the cells that, in turn, is dependent on the proliferative activity and the transformed condition of the cells. In that it is a direct expression of the energetic metabolic engagement, autofluorescence can be assumed as an intrinsic parameter of the cell biological condition, suitable for diagnostic purposes.

Animals↗
PubMed1990

[3H]PN200-110 binding in a fibroblast cell line transformed with the alpha 1 subunit of the skeletal muscle L-type Ca2+ channel.

We examined the binding of the 1,4-dihydropyridine (DHP) [3H]PN200-110 to membranes from a fibroblast cell line transfected with the alpha 1 subunit (DHP receptor) of the L-type Ca2+ channel from rabbit skeletal muscle. Binding site affinity (KD) and density (Bmax) were 1.16 +/- 0.31 nM and 142 +/- 17 fmoles/mg protein, respectively. This affinity corresponded closely with that observed in native skeletal muscle. The Ca2+ channel antagonists diltiazem and MDL 12,330A stimulated [3H]PN200-110 binding in a dose-dependent manner while flunarizine, quinacrine and trifluoperazine inhibited binding. Surprisingly, D600 also stimulated [3H]PN200-110 binding in a dose-dependent and stereoselective manner. It is concluded that the fibroblast cells used in this study provide a unique system for interactions of the Ca2+ channel ligands with the alpha 1 subunit of the skeletal muscle L-type Ca2+ channel.

Animals↗
PubMed1983

Specific DNA binding activity of T antigen subclasses varies among different SV40-transformed cell lines.

Large tumor antigen (T antigen) occurs in at least three different oligomeric subclasses in cells infected or transformed by simian virus 40 (SV40): 5-7 S, 14-16 S, and 23-25 S. The 23-25 S form is complexed with a host phosphoprotein (p53). The DNA binding properties of these three subclasses of T antigen from nine different cell lines and free p53 protein were compared using an immunoprecipitation assay. All three subclasses of T antigen bound specifically to SV40 DNA sequences near the origin of replication. However, the DNA binding activity varied between different cell lines over a 40- to 50-fold range. The 23-25 S and 14-16 S forms from most of the cell lines tested bound much less SV40 origin DNA than 5-7 S T antigen. The free p53 phosphoprotein did not bind specifically to any SV40 DNA sequences.

Animals↗
PubMed2005

Expression analysis of secreted and cell surface genes of five transformed human cell lines and derivative xenograft tumors.

BACKGROUND: Since the early stages of tumorigenesis involve adhesion, escape from immune surveillance, vascularization and angiogenesis, we devised a strategy to study the expression profiles of all publicly known and putative secreted and cell surface genes. We designed a custom oligonucleotide microarray containing probes for 3531 secreted and cell surface genes to study 5 diverse human transformed cell lines and their derivative xenograft tumors. The origins of these human cell lines were lung (A549), breast (MDA MB-231), colon (HCT-116), ovarian (SK-OV-3) and prostate (PC3) carcinomas. RESULTS: Three different analyses were performed: (1) A PCA-based linear discriminant analysis identified a 54 gene profile characteristic of all tumors, (2) Application of MANOVA (Pcorr < .05) to tumor data revealed a larger set of 149 differentially expressed genes. (3) After MANOVA was performed on data from individual tumors, a comparison of differential genes amongst all tumor types revealed 12 common differential genes. Seven of the 12 genes were identified by all three analytical methods. These included late angiogenic, morphogenic and extracellular matrix genes such as ANGPTL4, COL1A1, GP2, GPR57, LAMB3, PCDHB9 and PTGER3. The differential expression of ANGPTL4 and COL1A1 and other genes was confirmed by quantitative PCR. CONCLUSION: Overall, a comparison of the three analyses revealed an expression pattern indicative of late angiogenic processes. These results show that a xenograft model using multiple cell lines of diverse tissue origin can identify common tumorigenic cell surface or secreted molecules that may be important biomarker and therapeutic discoveries.

Analysis of Variance↗
PubMed1994

Periodic fluctuations in proliferation of SV-40 transformed human skin fibroblast lines with prolonged lifespan.

A human fibroblastic cell line transformed by the SV40-T antigen sequence and continuously cultured for 7 months displayed large periodic variations in cell proliferation. This contrasted with other characteristics of this cell line that remained constant: mosaic cell shape, absence of cell contact inhibition, and predominance of a hypodiploid population. Similar fluctuations in proliferative capacity were also found during the long-term growth of a transformed but nonimmortalized human fibroblastic line prior to senescence, and in the established hamster fibroblastic Nil cell line. This growth pattern suggests a recurrent stimulation of growth in these three transformed cell lines. The proliferation pattern from cultured transformed cells may thus be complex and requires further investigation. These variations presumably influence major cell functions. This observation has important implications for the analysis of data from such cell lines.

Animals↗
PubMed1981

Transformation of rodent cells by a cloned DNA fragment of herpes simplex virus type 2.

Transformation of rodent cells with isolated restriction endonuclease fragments of herpes simplex virus type 2 DNA identified a region of the genome located between map positions 0.58 and 0.62. These sequences were cloned into pBR322, and the recombinant plasmid was used to transform primary rat embryo cells and NIH 3T3 cells. The transformants were selected for their ability to form dense foci on a monolayer or to form colonies in semisolid medium. In contrast to the parental rat or mouse cells, cell lines transformed with the cloned herpes simplex virus type 2 fragment grow to high saturation densities, replicate in medium containing 1% serum, form colonies in dilute methylcellulose, show reduced levels of fibronectin, and are tumorigenic in nude mice and in their syngeneic hosts. Southern blot hybridizations have detected sequences homologous to the viral fragment in high-molecular-weight DNA from the transformed cell lines that are not present in DNA from normal rodents. In all cases, the plasmid DNA was present in less than one copy per cell, and the patterns of viral sequences changed with passage of the cell line in vivo.

Animals↗
PubMed1991

Murine endothelioma cell lines transformed by polyoma middle T oncogene as target for and producers of cytokines.

We studied cytokine-related functional properties of four mouse endotheliomas from different anatomical sites obtained by transformation with middle T oncogene. We examined mRNA expression of IL-6, IL-1 alpha, macrophage-CSF, granulocyte/macrophage-CSF, and two members of an emerging super-family of chemotactic cytokines (JE/monocyte chemoattractant protein-1 (MCP-1) and KC). Exposure to IL-1 augmented or induced cytokine gene transcripts in three endothelioma lines (eEnd.1, sEnd.1, and tEnd) with maximal expression in tEnd.1 cells. Endothelioma cells also responded to TNF-alpha and LPS. Levels of IL-6 and monocyte chemotactic activity (a JE/MCP activity) correlated with mRNA expression. IL-1 also induced production of procoagulant activity and platelet-activating factor in endothelioma cells, with heterogeneity in the levels of response among individuals lines. Murine melanoma B16-F1, human colon carcinoma HT29 cells, CB33MT lymphoblastoid cells, and monocytes adhered to endothelioma monolayers and the adhesive properties of these cell lines were modulated by IL-1 beta, with marked differences among themselves. Murine EC derived from brain capillaries, used as control, shared several properties with bEnd.4 line. Endothelioma lines cause tumors by recruiting host cells. The capacity to produce cytokines that directly or indirectly attract host vascular cells, may play an important role in hemangioma induction in vivo. Murine endothelioma lines, generated by transformation with the polyoma middle T oncogene, retain functional properties of normal endothelium, and may represent an invaluable tool for analysis of the immunobiology and heterogeneity of EC in different tissues.

Animals↗
PubMedDate not supplied

Cytomegalovirus and cancer of the prostate: in vitro transformation of human cells.

Urogenital tissue specimens were maintained in culture for 2 years. Epithelioid growth was enhanced with use of collagenase digestion rather than trypsinization. Twenty of 34 prostate cancer cell cultures survived more than ten in vitro passages, during which time four of 20 demonstrated epithelioid morphology. One epithelioid line (T-157) survived 32 in vitro passages. The cells demonstrated lack of contact inhibition in culture, were slightly positive in acid phosphatase tests, and reacted positively with cytomegalovirus (CMV)-immune sera in indirect immunofluorescence (IF) tests. These cells, which were proven to be of human male origin, failed to yield infectious virus and could be re-isolated from a nodule induced by the cells when injected sc into weanling athymic nude mice. The serum of the patient from which the tumor cells were derived demonstrated high CMV antibody titers and reacted with the virus-specific membrane and intracellular antigens of CMV-transformed human cells in IF tests. A CMV strain isolated from one of the normal prostate cell cultures established an in vitro long-term persistent infection of human embryo lung cells which resulted in the development of two transformed cell lines. The transformed cells possessed CMV antigenic markers and induced non-differentiated tumors when transplanted into athymic nude mice. The results constitute further evidence of the transforming capacity of CMV, and suggest that the virus may be oncogenic in its natural (human) host.

Animals↗
PubMed1980

Abelson murine leukemia virus-induced tumors elicit antibodies against a host cell protein, P50.

When BALB/c mice were injected with a syngeneic cell line transformed by Abelson murine leukemia virus (A-MuLV), the tumor was usually lethal. In sera from tumor-bearing mice, and at highest levels in sera from mice that reject their tumors, was an antibody that immunoprecipitates a specific protein from [35S]-methionine-labeled A-MuLV-transformed BALB/c cells. This protein was not the previously characterized A-MuLV-specific protein (P120) but a 50,000-molecular-weight protein (P50). Such sera may also immunoprecipitate P120, but no other protein was reproducibly precipitated by them. A monoclonal antibody (RA3-2C2) that has been shown to stain normal B-lymphocytes also selectively immunoprecipitated P50. P50 was present in A-MuLV-transformed lymphoid and fibroblastic cells of a variety of mouse strains. One A-MuLV-transformed cell line had a very low P50 level, the L1-2 tumor of C57L origin. This tumor was previously shown to be rejected by C57L mice and is used to produce anti-P120 (anti-AbT) sera. P50 was not a Moloney MuLV protein and was found at low levels in normal cells of cells transformed by agents other than A-MuLV; thus, it was probably a host cell protein whose concentration was selectively accentuated by A-MuLV transformation. P50 was phosphorylated and, by using indirect immunofluorescence, anti-P50 serum stained live A-MuLV-transformed cells. The protein was not glycosylated and did not label by lactoperoxidase-catalyzed iodination. Thus, P50 was very like P120 in its cellular localization and properties, but it did not exhibit proptein kinase activity in vitro. The selective accentuation of this protein in A-MuLV transformants and its strong antigenicity in syngeneic animals suggest that it is a unique and functionally important protein.

Abelson murine leukemia virus↗
PubMed1977

Host-determined differences in expression of surface marker characteristics on human and simian lymphoblastoid cell lines transformed by Epstein-Barr virus.

In an attempt to account for differences in the biologic behavior of Epstein-Barr virus in different primate species, we studied lymphocyte surface markers on primary and transformed cells. Among primary leukocytes, the distribution of cells with characteristics of bone-marrow-derived cells (B cells) was similar in humans, wooly monkeys, and cotton-top marmosets. However, after transformation by Epstein-Barr virus, cells from each species were characterically different. Transformed human umbilical cord cells expressed the complement receptor; monkey cells exhibited both this receptor and the receptor for IgG Fc (EA7S); and marmoset cells did not have either surface marker. We measured the transformation efficiency of human and marmoset leukocyte subpopulations enriched or depeleted in cells with the complement receptor. In both species the highest efficiencies of transformation were found in populations with the greatest numbers of cells with the receptor. The data therefore suggest that, in all species, a cell with the complement receptor is susceptible to transformation but that this receptor is not expressed on transformed marmoset cells. Thus, in Epstein-Barr virus-induced transformation it is necessary to distinguish between transformation of growth properties (immortalization) and transformation of cell surface properties.

Animals↗
PubMed1990

Isolation and characterization of flat revertant cell lines from A-MuLV-transformed fibroblasts.

Transformation of lymphoid and fibroblastic cells by Abelson murine leukemia virus (A-MuLV) is mediated by the viral tyrosine protein kinase. We do not yet know the important target proteins in the cell, the host proteins that modulate the kinase activity, or the host proteins involved in the signal-transduction pathway ultimately leading to altered patterns of cell growth. As a first step toward identifying these host proteins, we have isolated and characterized several flat revertant cell lines from transformed lines carrying v-abl. Clonal transformed cell lines used as parental strains were prepared by infecting Rat-2 fibroblasts with A-MuLV, using M-MuLV as helper. A rhodamine dye screening procedure was used to obtain three clones of morphologically flat revertant cells. Each of the three lines was non-refractile and contact inhibited. All the lines retained a transformation-competent copy of A-MuLV; all released high titers of virus capable of inducing foci on previously uninfected Rat-2 cells. Analyses of the revertant lines suggest that diverse mechanisms can lead to loss of transformed morphology.

Abelson murine leukemia virus↗