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At least 955 records · Page 53Linked to original sources
PubMed1984

Spontaneous transformation of a cloned cell line of normal diploid bovine vascular endothelial cells.

We report here the spontaneous transformation of a normal diploid bovine fetal aortic endothelial cell line. This cell line showed a period of rapid proliferation, followed by a period of declining proliferative activity, as judged by both a decline in the number of population doublings achieved from seeding to subcultivation and a decrease in the fraction of cells incorporating [3H]thymidine. During the decline in proliferation, foci of small cells appeared amid a background of larger senescent-appearing cells. The cultures then regained proliferative activity and have been maintained in our laboratory for more than 22 months. The transformants are characterized by (a) an indefinite life span, (b) a morphology that is more spindle shaped as compared to pretransformants , and (c) heteroploidy with chromosome translocations.

Animals↗
PubMed1980

Feline sarcoma virus induced in vitro progression from premalignant to neoplastic transformation of human diploid cells.

Human diploid cells morphologically transformed by feline sarcoma virus were serially propagated under selective cell culture conditions. When injected into nude mice prior to passage in soft agar (0.35%), morphologically transformed cells did not produce tumors. However, when propagated under selective cell culture conditions, transformed cells grew in soft agar and, when injected subcutaneously into the subcapsular region of the n mu/n mu mice, produced neoplastic nodules histopathologically interpreted as fibromas. Karyological examination of cell populations grown out from the tumors confirmed that the tumors were composed of human cells. Examination of electron micrographs of the excised tumor tissue revealed the presence of budding virus particles. Tumor cells isolated from nude mice and morphologically transformed cells both contained the feline oncornavirus-associatied cell membrane antigen. It was concluded that expression of feline oncornavirus-associated cell membrane antigen is associated with an early stage of feline retrovirus-induced carcinogenesis, namely focus formation. In addition, it was shown that FeLV-FeSV can induce morphological transformation in human cells in vitro and that there is a requirement for the cells to passage through soft agar before subsequent tumor formation (neoplastic transformation) can be demonstrated.

Animals↗
PubMed1983

Transport of L-histidine by human diploid fibroblasts in culture.

The transport of L-histidine has been characterized in skin derived diploid human fibroblasts, cultured under strictly controlled conditions. The transport measurements were made on cells grown to subconfluency after 60 to 90 min timed preincubation. The data, at substrate concentrations ranging from 0.050 to 10 mmol/l, were analyzed by a computer program. A saturable transport system (Km = 0.25 mmol/l, Vmax = 17 nmol/mg protein per min) and a nonsaturable component of influx (Kd = 1.6 +/- 0.4 nmol/mg protein/min per mmol) were found. L-Histidine displayed no Na+ requirement at either low or high concentrations. Inhibition analysis demonstrated that L-histidine uptake at low concentration was poorly inhibited by amino acids known to be effective inhibitors of system A. The largest fraction of L-histidine uptake was inhibited by 2-amino-bicyclo (2,2,1)-heptane-2-carboxylic acid (BCH), leucine, and tryptophan. These results indicated that L-histidine is transported in human fibroblasts mainly by the Na+ independent system L. The differences between this cell type and others studied previously are discussed.

Amino Acids↗
PubMed1984

Isolation and characterization of a near-diploid differentiated cell line from a murine teratocarcinoma that differentiates into muscle.

Cell lines corresponding to various cell lineages of the mouse embryo have been isolated from murine teratocarcinomas. Embryonal carcinoma cell lines are developmentally equivalent to the embryonic ectoderm or inner cell mass. Most of these cell lines have a modal chromosome number equal or close to 40, the normal mouse complement. However, cell lines corresponding to more advanced cell lineages (e.g., endoderm) are tetraploid or hypotetraploid and display multiple chromosomal rearrangements. This paper describes the isolation of a near-diploid differentiated cell line (LT-D) from an LT teratocarcinoma. The modal chromosome number of LT-D is 40, and this number is stable during at least 12 mo of continuous culture. LT-D cells are morphologically distinct from embryonal carcinoma cells and no longer express the SSEA-1 cell surface antigen or high alkaline phosphatase activity characteristic of embryonal carcinoma cells. LT-D cells can be induced to fuse into structures resembling myotubes. The formation of these structures is accompanied by expression of the muscle-specific isozyme of creatine phosphokinase and desmin, a muscle-specific component of intermediate filaments. Lastly, LT-D cells do not form tumors in syngenetic mice.

Alkaline Phosphatase↗
PubMed1986

Optimal parameters for the polybrene-induced DNA transfection of diploid human fibroblasts.

Recently it has been shown that Polybrene, in conjunction with dimethyl sulfoxide (DMSO) shock, can markedly increase frequency of DNA transfection of chicken embryo fibroblasts as compared with the frequency obtained with the standard calcium phosphate protocol. We have adapted this procedure for use with diploid human fibroblasts. Using plasmid DNA containing a dominant selectable marker gene (resistance to Geneticin), we have determined that treatment of the cells for 6 h in culture medium containing Polybrene at a concentration of 2 to 5 micrograms/ml, followed by a 4-min shock with 30% DMSO, resulted in the highest yield of transfectants, ca. 400/10(6) cells treated with as little as 100 ng of plasmid DNA. The selective agent could be added immediately after the DMSO shock. This allows transfection and selection to be carried out in the same dishes and ensures that each clone represents a unique event.

Cells, Cultured↗
PubMed1987

A new diploid nontumorigenic human breast epithelial cell line isolated and propagated in chemically defined medium.

A new, nontumorigenic human breast epithelial cell line, HMT-3522, has been established from fibrocystic breast tissue. Cells were explanted and propagated in chemically defined medium including insulin, transferrin, epidermal growth factor, hydrocortisone, estradiol, prolactin, and Na-selenite. The epithelial nature of the cell line was established by immunocytochemical detection of cytokeratins. Moreover, electronmicroscopy revealed monolayers of polarized cells connected by desmosomes and provided with apical microvilli. Milk fat globule membrane antigen, specific for the apical membrane domain of normal, luminal breast epithelial cells, was expressed only in confluent cultures where some cells overlaid others, indicating "stem cell"-like properties. After 25 to 30 passages, the cells are diploid with a few marker chromosomes and loss of chromosomes in the D-group. The cells are nontumorigenic in athymic mice; they lack estrogen receptors, and estradiol does not stimulate growth. The HMT-3522 cell line may represent a useful model for the study of breast cell differentiation and carcinogenesis in vitro.

Animals↗
PubMed1984

Effects of ferrous iron and transferrin on cell proliferation of human diploid fibroblasts in serum-free culture.

Iron-free RITC 80-7 defined medium was used to examine effects of ferrous iron and transferrin on cell proliferation of human diploid fibroblasts. Both ferrous iron and holo-transferrin stimulated cell proliferation in the medium, but apotransferrin did not. When 5 g/l human serum albumin (HSA) was added to the defined medium, excellent growth was obtained under hypoxic conditions, whereas a reduction of cellular growth during the culture periods was observed under aerobic conditions. When ferrous iron was added to the HSA medium alone, the reduction in growth increased in proportion to the concentrations, whereas the addition of transferrin prevented this reduction in a concentration-dependent manner. This suggests that the ferrous iron concentration in media causes a reduction in growth under aerobic conditions and transferrin prevents this reduction because it decreases the ferrous iron concentration. Further, serum albumin seems to be a source of iron in media.

Aerobiosis↗
PubMed1992

Expression of proliferating cell nuclear antigen during the cell cycle of human diploid fibroblasts.

Proliferating cell nuclear antigen mRNA levels were determined in human diploid fibroblasts as they progressed through the cell cycle. PCNA message levels were low at G0, gradually increased following entrance into G1, peaked at G1/S, and declined during S phase. PCNA mRNA was determined to have a half life of 12 hours when cells were blocked at the G1/S interface. PCNA protein levels increased two- to three-fold as cells moved from G0 to S phase.

Cells, Cultured↗
PubMed1982

Induction of myosin light chain synthesis in heterokaryons between normal diploid cells.

Quail myoblasts were maintained in an undifferentiated state by first blocking differentiation with 5-bromodeoxyuridine and then reversing the block in the presence of phorbol-12-myristate-13-acetate. The synthesis of quail skeletal myosin light chain 1 is induced in heterokaryons formed by fusing these undifferentiated quail myoblasts to differentiated chick myocytes. These results extend observations previously obtained using an established line of rat myoblasts and indicate that the induction is a result of regulatory interactions present in normal diploid cells.

Animals↗
PubMed1982

The effect of UV irradiation on proliferation and life span of human diploid fibroblast-like cells.

The effect of low dose UV irradiation on the reinitiation of proliferative activity and on the life span of human diploid fibroblast-like cells is described. Cells were exposed to UV at confluence or after maintenance in an arrested state. Cell division was stimulated immediately after UV irradiation or after an additional post-UV incubation period. Arrested populations of all in vitro ages exhibited a greater sensitivity to UV and the reinitiation of proliferation was enhanced by post-UV incubation before stimulation. Ultraviolet light had no effect on life span regardless of in vitro cell age, culture state at the time of exposure, or the presence of a postirradiation period of arrest.

Cell Division↗
PubMed1989

High-frequency 1H NMR studies of the effects of growth factors and phorbol esters on normal Syrian hamster diploid fibroblast cells.

The nuclear magnetic resonance (NMR) parameters, spin-lattice (T1), and spin-spin (T2) relaxation time, are usually longer for neoplastic cells than for normal cells of the same cell type. This has generally been true at low NMR frequencies (less than or equal to 100 MHz) when comparisons have been made between normal and neoplastic cells that have both spent a short time in culture. We have previously demonstrated that although the T1 values of paired normal and neoplastic Syrian hamster (SH) fibroblastic cells in culture are not significantly different when measured at 300 MHz, the 300 MHz T2 values for the neoplastic cells are smaller than those of the normal cells. (Xin et al. (1986), Cell Biophysics 8, 213.) Since treatment of normal diploid cells with polypeptide growth factors or tumor promoters frequently results in reversible expression of neoplasia-associated phenotypes, T1 and T2 were obtained at 300 MHz for treated and untreated SH cells to see if these compounds could also produce smaller 300 MHz T2 values. Secondary culture SH fetal fibroblast cells were treated with epidermal growth factor (EGF), fibroblast growth factor (FGF), phorbol-12,13-didecanoate (PDD) and 4-alpha-phorbol-12,13-didecanoate (4 alpha PDD). Treatment with either growth factor resulted in smaller T2 values, but a statistically significant decrease was not observed for PDD or 4 alpha PDD. The observed reductions in T2 values were correlated with the morphological and growth-stimulatory effects of these compounds on the cells.

Animals↗
PubMed1982

Effect of 3'-methyl-4-dimethylaminoazobenzene in the induction of malignant transformation and of 8-azaguanine-resistant mutations and chromosomal aberrations in a diploid clone derived from normal rat liver cells in culture.

The effect of 3' methyl-4-dimethylaminoazobenzene (3'-Me-DAB) in the induction of malignant transformation and of 8-azaguanine-resistant mutations and chromosomal aberrations was studied in a diploid strain derived from normal rat liver cells. The cells were malignantly transformed by treatment with 3'-Me-DAB 1.7 micrograms/ml for 130 to 221 d or 1.7 micrograms/ml for 53 d followed by 24.9 micrograms/ml for 27 to 77 d. The untreated control cells did not transform spontaneously until the 232nd d in culture. Some properties of the 3'-Me-DAB-treated cells were compared to those of untreated control cells but no reliable marker for predicting the tumorigenic potential of the cells was found. The single addition of 3'-Me-DAB caused little induction of 8-azaguanine-resistant mutations and chromosomal aberrations to the cells. However, mutations and chromosomal aberrations were significantly induced by N-acetoxy-4-methylaminoazobenzene, an active metabolite of 4-dimethylaminoazobenzene or 3'-Me-DAB in the presence of liver microsomes.

Animals↗
PubMed1976

Fine structural and cytochemical studies of human diploid fibroblasts arrested in an essentially nonmitotic state.

Human diploid fibroblasts can be maintained in vitro in an arrested, essentially nonmitotic state for extended periods of time by reducing the serum concentration in the medium from 10 to 0.5%. Arrested cells can be induced to re-enter the proliferative state by subcultivation in medium containing 10% serum. Fine structure, acid phosphatase, cytochrome oxidase, and extracellular carbohydrates in arrested cells were examined and compared to cultures growing in 10% serum and to cells transferred to 10% serum after 21 days in 0.5% serum. Cells in 10% serum posessed a well-developed Golgi complex, extensive rough endoplasmic reticulum, mitochondria containing transverse cristae, and many free ribosomes in the cytoplasm. In arrested cells, Golgi complexes were rarely observed, the number of both free and membrane-bound ribosomes was reduced, the number of cristae per mitochondria was decreased and the amount of demonstrable cytochrome oxidase activity was diminished. There was an accumulation of intercellular carbohydrate components. After subcultivation with medium containing 10% serum, arrested cells regained the ultrastructural characteristics of cells continuously cultured at this serum level; however, the amount of intercellular carbohydrate remained elevated. These results indicate that distinct yet reversible changes occur in the subcellular morphology and organization of cells maintained in an essentially nonmitotic state. This arrested state may be a close approximation to the situation as it occurs in vivo in expanding cell populations.

Acid Phosphatase↗
PubMed1975

The recetor sites for complement (C3) on human diploid fibroblasts.

Sheep red cells, sensitized with 19S fraction of antiserum and subsequently treated with mouse serum as the source of complement (EAC), interact with human diploid fibroblasts (WI-38 cells) and form "Rosettes". Under a scanning electron microscope, EAC have not attached directly to the cell surface of fibroblasts, but to the fine processes or microvilli of the latter, as if there were fine bridges between EAC and the surface of fibroblasts. On the other hand, the attachment of sheep red cells washed in PBS (E) or sensitized with 19S fraction of antiserum (EA) to WI-38 cells was not observed. The pretreatment of WI-38 cells with mouse serum did not inhibit the interaction of WI-38 cells and EAC. No phagocytosis of EAC by WI-38 cells was observed in the 2 hrs incubation of both cells. From these results it is suspected that the interaction of WI-38 cells and EAC is immune adherence, and that WI-38 cells have the receptor site for complement, especially for C3, on the surface of cell membrane.

Animals↗
PubMed1984

On the formation of orientated protrusions in confrontation cultures of human diploid and tumor cells.

Wi38 cells (diploid human embryonic lung fibroblasts) were cultivated for 24 h on cover slips, following which HeLa cells (a monolayer and a suspension subline) were seeded on top of the fibroblasts. Some tumor cells lay on the glass between fibroblasts and by some means induced the Wi38 cells to form protrusions orientated towards the tumor cells. By statistical methods it has been shown that the outgrowth of these protrusions is a non-random process that is not restricted to either normal or the tumor cells. This contact behavior can only be explained by the assumption of an exchange of signals and a chemotactic mechanism must be assumed.

Cell Communication↗
PubMedDate not supplied

Molecular and cellular mechanisms of transformation of C3H/10T1/2 Cl 8 and diploid human fibroblasts by unique carcinogenic, nonmutagenic metal compounds. A review.

Work from our laboratory showed that carcinogenic metal salts of arsenic, nickel, and chromium induced morphological transformation of cultured C3H/10T1/2 Cl 8 (10T1/2) mouse embryo cells, and that many of the transformants grow in soft agarose and form tumors in nude mice. Concentrations of arsenic, nickel, and chromium compounds that induced morphological transformation did not induce mutation to ouabain resistance in 10T1/2 cells. This indicated that the mechanism of metal induced morphological transformation was likely not caused by induction of base substitution mutations, and in the case of lead chromate, likely not caused by frameshift or deletion mutations. In addition, we showed that carcinogenic arsenic, nickel, and chromium compounds, and MNNG, induced anchorage independence in diploid human fibroblasts. Anchorage-independent cell strains derived from anchorage-independent colonies were stable but did not form foci and eventually senesced, therefore, arsenic and nickel compounds and lead chromate induced stable anchorage independence as an isolated phenotype. Nickel compounds and lead chromate induced anchorage independence but not mutation to ouabain resistance or to 6-thioguanine resistance. Hence, the mechanism of induction of anchorage independence by these metal salts in human fibroblasts was likely not via induction of base substitution, frameshift, or deletion mutations that would be measured in these mutation assays.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗