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PubMed1985

Growth factor production during multistage transformation of epithelium in vitro. I. Partial purification and characterisation of the factor(s) from a fully transformed epithelial cell line.

Transforming growth factor (TGF)-like activity is characterised from one of a series of salivary epithelial cell lines, CSG 211, chemically transformed in vitro. In this transformation system, we can demonstrate multiple stages in the acquisition of a malignant phenotype by normal diploid ductal epithelial cells from male mouse submandibular gland. The fully transformed, tumorigenic cell TGF-like activity in serum-free supernatants resembles no other well-characterised growth factor and has an apparent molecular weight (Mr) of 14 kd. There is also evidence of a higher Mr activity, which is separable by anion exchange chromatography. We show that the premalignant, nontumorigenic progenitor cells of this line do not produce demonstrable TGF-like activity and that this property is therefore acquired as CSG 211 cells become carcinoma producing.

Animals↗
PubMed1979

Cell-mediated immunity to Theileria-transformed cell lines.

In East and Central Africa the protozoan parasite Theileria parva causes a disease of cattle called East Coast fever (ECF). In Kenya alone between 60,000 and 85,000 cattle die from ECF every year. Infected animals can recover from ECF either naturally or after treatment with tetracyclines or menoctone and are subsequently able to resist challenge with the homologous strain of parasite. That this acquired resistance is due to cell-mediated rather than humoral immunity has been suspected but never decisively shown. A major difficulty in studying immunity to ECF has been the lack of inbred animals for studying Theileria-specific immunity in the absence of allogeneic histocompatibility barriers. We have avoided this problem by measuring cell-mediated immune responses in a syngeneic system in vitro. Unidirectional mixed lymphocyte cultures (MLC) were set up using bovine peripheral blood lymphocytes (PBL) as responder cells and autologous cell lines transformed in vitro by T. parva as stimulator cells. In these cultures, DNA synthesis was induced in PBL from both normal and Theileria-immune animals. However, cytotoxic lymphocytes were induced only in cultures containing responder lymphocytes from Theileria-immune cattle. The results show that Theileria-transformed cells express antigens which are recognized by effector cells and provide evidence that cell-mediated cytotoxic mechanisms function in immunity to ECF.

Animals↗
PubMed1992

The induction of IL-6 and gelatinase B by IL-1 in mouse cell lines transformed with bovine papillomavirus: decreased production in tumorigenic cells.

Six cell lines, that were cloned from murine C127 cells infected by bovine papillomavirus type 1 (BPV1), were found to differ in the degree of transformation in vitro and of tumorigenicity in vivo. In these cell lines the degree of tumorigenicity was inversely correlated with IL-6 induction by IL-1 beta. Whereas the parental C127 cell line produced 15-30 U/ml of IL-6 spontaneously, none of the transformed cell lines produced significant levels of IL-6 constitutively. On induction by human IL-1 beta the parental C127 cell line produced up to 300 U/ml of IL-6, whereas the fully transformed ID14 cell line failed to produce any. The less transformed cell lines produced lower yields of IL-1 beta-induced IL-6, dependent on their degrees of transformation and tumorigenicity. Gelatinase B (96 kDa), a matrix metalloproteinase inducible by IL-1 beta, was dose-dependently regulated in the parental C127 cell line and in the weakly transformed cell line Tlc. These data suggest that transformation processes by BPV1 generally impair IL-1-regulated gene transcription. This impairment seems not to be located at the IL-1 beta receptor level, since in all the cell lines studied the numbers and affinities of the IL-1 beta binding sites were found to be comparable. This impairment seems not to be mediated by transformation-induced inactivation of the protein kinase C pathway since phorbol 12-myristate 13-acetate (PMA) induced IL-6 production equally well in all C127 cell-derived clones. It is suggested that BPV1 transformation can change the expression of host genes that might play a functional role in tumor immune surveillance and tumorigenicity in vivo.

Animals↗
PubMed1998

The DF-1 chicken fibroblast cell line: transformation induced by diverse oncogenes and cell death resulting from infection by avian leukosis viruses.

DF-1 is a continuous cell line of chicken embryo fibroblasts. The cells are free of endogenous sequences related to avian sarcoma and leukosis viruses and have normal fibroblastic morphology. DF-1 cells support the replication of avian retroviruses; diverse oncogenes induce foci of oncogenic transformation on monolayers of DF-1, and avian leukosis viruses of envelope subgroups B, D, and C induce cell death and form plaques. The new cell line will greatly facilitate studies on oncogenic transformation and cell killing by avian viruses.

Animals↗
PubMed1995

A genetic model for undifferentiated cell tumor formation: similar tumors formed by different cell lines transformed by the E1A oncogene.

The activation of oncogenes and the mutation/deletion of suppressor genes may be involved in tumor heterogeneity. In an attempt to study tumor heterogeneity, we transformed cell lines from epithelial (PAM 212), mesenchymal (NIH-3T3), or melanocytic origin (L-BIOBR) with the wild type E1a oncogene. To make the cell lines tumorigenic, cells were infected with Harvey sarcoma virus carrying the v-H-ras oncogene. The transformed cells were injected into nude mice and the tumors studied by optical and electron microscopy. The tumors formed by v-H-ras-transformed cells consisted of epitheliod melanomas, spindle cells sarcomas and poorly-differentiated carcinomas, depending on the cell of origin. In contrast, the tumors obtained from cells also carrying the E1a oncogene showed a predominant small and undifferentiated cell pattern regardless of the cell of origin. We conclude that the E1a oncogene products induce a negative control of differentiation, independent of the cell type, and that tumors formed by cells carrying the E1a oncogene display an undifferentiated cell pattern.

Adenovirus E1A Proteins↗
PubMed1986

Effects of mevinolin and mevalonate on cell growth in several transformed cell lines.

Studies were conducted to explore the effects of mevinolin, a competitive inhibitor of HMG CoA reductase, on the growth and morphology of normal and transformed murine fibroblasts. Mevinolin is known to block DNA synthesis and cell growth in a number of kinds of non-transformed cells. Eight cell lines were studied, including two normal fibroblast cell lines (C3H 10T 1/2 and NIH 3T3) and derivatives of these cell lines transformed by chemical carcinogens, X-irradiation or the H-ras oncogene. All of the eight cell lines displayed appreciable growth inhibition by 5 microM mevinolin and marked inhibition by 30 microM mevinolin. Mevinolin also induced a marked rounding in the morphology of all of the cell lines. These effects of mevinolin on cell growth and morphology were blocked or reversed by the addition of mevalonic acid. Thus, both normal and transformed cells require mevalonate, or an as yet unidentified metabolite of mevalonate for their growth, even though some transformed cells have become relatively autonomous of other growth factors. Whereas mevinolin acted primarily as a cytostatic agent for most of the cell lines studied, with the transformed cell line MCA/10T 1/2, which ordinarily grows to a very high cell density, prolonged exposure to mevinolin caused marked cytotoxicity. Thus mevinolin might be useful as an anti-tumor agent for specific tumors.

Animals↗
PubMed1977

The preferential cytotoxicity of reovirus for certain transformed cell lines.

The susceptibility of a variety of cell lines of different mammalian origin to cytotoxic (CT) induction by either ultraviolet light-irradiated reovirus type 2 (UVR2) or viable reovirus type 2 plus the protein synthesis inhibitor, cycloheximide, was examined. The following groups of cells were found to be susceptible to CT-induction: certain tumor cells and spontaneously transformed cell lines of human origin and certain virally and spontaneously transformed cell lines of murine origin. The following groups of cells were found to be resistant: normal human diploid cell lines, primary and continuous cell cultures of subhuman primates, primary mouse cells, normal rat kidney cells and baby hamster kidney cells. Susceptibility to CT-induction could not be related to the adsorption of virus to cells, nor to the capacity of the cell to support virus replication.

Animals↗
PubMed1983

Establishment and characterization of rat cell lines transformed by the left-end DNA fragments of adenovirus type 31.

A rat cell line, 3Y1, was transfected with the left-end DNA fragments of adenovirus (Ad) 31 DNA and transformed cell lines were established. A cell line 31BY4-1, which was induced by Ad31 BamHI-B (left-most 17.4% of the genome), showed typical transformation phenotypes, while cell lines 31GY1-2, 31GY2-5, and 31GY3-4, which were induced by Ad31 HindIII-G (left-most 6.7% of the genome), showed intermediate phenotypes between transformed and untransformed cells, with the following properties: (1) percent plating efficiencies in Eagle's minimum essential medium with 2% fetal calf serum and in soft-agar culture were extremely low, like those of 3Y1 cells; (2) they form tumors in newborn rats only after long latent periods. Southern blot hybridization revealed that, in all the transformed cell lines, viral DNA sequences were integrated at multiple loci in large-molecular-weight cell DNAs. Northern blot hybridization showed that viral mRNAs of early region 1A (E1A) and early region 1B (E1B) were both transcribed in 31BY4-1 cells as well as in KB cells early after infection with Ad31. On the other hand, E1B viral mRNA was present in a much lesser amount in 31GY cell lines, or was undetectable.

Adenoviridae↗
PubMed1980

Untransformed xeroderma pigmentosum cells are not hypersensitive to sister-chromatid exchange production by ethyl methanesulphonate--implications for the use of transformed cell lines and for the mechanism by which SCE arise.

A transformed cell line, XP12RO(SV40) has previously been found to be hypersensitive to several chemical mutagens including ethyl methanesulphonate, as judged by sister-chromatid exchange (SCE) formation. The hypersensitivity of this line has been confirmed for SCE formation and extended to cell survival. Measurements of SCE formation and survival show, however, that the hypersensitivity of the XP12RO(SV40) cell line is not typical of the primary strain (XP12RO) from which the transformed line was derived, nor it is typical of other primary strains also belonging to complementation group A (XP4LO, XP25RO). These results suggest that reports based on single cell lines must be viewed with caution and that the relationship between unexcised damage in DNA and SCE production is uncertain.

Cell Line↗
PubMed1995

Growth factor-independent expression of the gene encoding eukaryotic translation initiation factor 4E in transformed cell lines.

Activation of protein synthesis is necessary for the transition of cells from quiescence to proliferation, while withdrawal of growth factors leads to decrease in protein synthesis and transition of normal cells into the resting period. It is shown in this paper that serum growth factors are required for activation of expression of gene encoding translation initiation factor 4E (eIF-4E) in non-transformed NIH 3T3 and Rat-1 fibroblasts but this requirement is lost in C6 glioblastoma, A431 carcinoma and N-myc transformed Rat-1 cells. These data raise the possibility that neoplastic transformation leads to growth factor-independent expression of eIF-4E, thus facilitating continuous growth and replication of transformed cells.

3T3 Cells↗
PubMed1998

[Study of SV40-transformed cell lines from rat dorsolateral prostate--analysis of growth factors and their receptors in the epithelial cell line].

BACKGROUND: We transformed primary cultured epithelial cells of the rat dorsolateral prostate by Simian Virus 40 (SV 40) and established a stable epithelial cell line (PESVH). To examine whether this cell line is available for the fundamental research of prostatic diseases, investigation on the growth factors and their receptors of this cell line was made. METHOD: The [3H]-thymidine uptake method was used to examine the influence for cell proliferation of epidermal growth factor (EGF), acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), keratinocyte growth factor (KGF), transforming growth factor (TGF)-alpha, TGF-beta 1 and androgens. The expression of mRNA for growth factors and their receptors was determined with Northern blot analysis. RESULT: DNA synthesis was increased to 2.1-fold of control by the addition of 100 ng/ml EFG. The addition of aFGF (100 ng/ml), bFGF (100 ng/ml) and TGF-alpha (100 ng/ml) tended to stimulate the DNA synthesis, but not significantly. The addition of KGF (0.1-100 ng/ml) did not influence on the DNA synthesis of PESVH. The addition of testosterone and 5 alpha-dihydrotestosterone (10(-10)-10(-6) M) did not influence on the DNA synthesis. Northern blot analysis showed expression of mRNA for TGF-alpha, TGF-beta 1, EGF receptor and TGF-beta receptor (type II) in PESVH cell. These expressions were not influenced by the addition of androgens. CONCLUSION: These findings suggested that PESVH cell could be used for one model of the androgen-independent prostatic cell.

Animals↗
PubMed2002

Growth factor-mediated altered expression and regulation of S-adenosylmethionine decarboxylase in a H-ras transformed cell line capable of malignant progression.

Mammalian S-adenosylmethionine decarboxylase (SAMDC) is a regulatory activity, which is involved in the biosynthesis of polyamines. The polyamines, namely putrescine, spermidine, and spermine, are essential for mammalian cell proliferation. SAMDC expression was examined in a H-ras transformed cell capable of metastasis formation. Serum stimulation of these cells resulted in increased SAMDC mRNA and enzyme activity expression. The effect of several physiologically relevant growth factors on SAMDC expression was also determined. SAMDC mRNA expression was increased in response to epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) stimulation but was unaffected by transforming growth factor beta(1) (TGF-beta(1)) and platelet derived growth factor (PDGF). Increased SAMDC enzyme activity occurred in response to exposure to EGF, bFGF, TGF-beta(1), and PDGF. The EGF and bFGF mediated alterations in SAMDC mRNA expression were apparently not due to alterations in the transcriptional apparatus but occurred partly through post-transcriptional mechanisms involving increased SAMDC message stability. EGF and bFGF were able both to cooperate with cycloheximide, an inhibitor of protein synthesis, to augment the expression of SAMDC mRNA. Furthermore, studies with NIH-3T3 fibroblasts transfected with either the normal basic fibroblast growth factor coding sequence that lacks a known secretory signal sequence or a chimeric bFGF sequence that targets the growth factor to the secretory pathway revealed that increased SAMDC expression occurred only in those cells which contained the chimeric bFGF sequence that targets the growth factor to the secretory pathway suggesting that the increase in expression of SAMDC occurs through an autocrine mechanism. Increased ornithine decarboxylase (ODC) expression was found to occur in both types of bFGF transfected cells suggesting that altered ODC expression in response to bFGF stimulation may occur through both autocrine and intracrine mechanisms. In addition, a correlation was found to exist between SAMDC expression and regulation in response to growth factor stimulation and malignant potential. This correlation supports the view that growth factor induced alterations in SAMDC expression, although not sufficient on their own to induce metastasis, are important in the promotion and establishment of events important to the phenotype expressed by H-ras transformed cells capable of malignant progression.

Adenosylmethionine Decarboxylase↗
PubMed1988

Characterization of transformed cell lines evolving from a normal C3H line.

The development of transformed cell lines evolving from an embryo fibroblastic C3H primary culture was followed before and after the ageing crisis using different techniques. By flow cytometry, alteration of subpopulations having different DNA content and altered metabolic activity was observed after the crisis, with the trend to assume a near tetraploid DNA index at higher passages. The fibrin clot retractile activity was lost in all cases during the ageing crisis, but the outcome did not present uniform values of growth characteristics or chromosome number and tumorigenicity appeared to be a nonstable property of the transformed cell lines.

Animals↗
PubMed1984

T cell growth factors from adult T cell leukemia virus-transformed cell lines.

Some characteristics of T cell growth factors derived from adult T cell leukemia virus (ATLV)-transformed cell lines, MT 1 and MT 2 were analyzed. MT 1 cells release significant interleukin 2 (IL 2) activity into the culture medium, which showed the same elution pattern of gel filtration and isoelectric focusing of IL 2 from lectin-stimulated normal human lymphocytes. This activity was also detected in the cell extract of MT 1. In contrast, MT 2 cell line did not produce IL 2 activity, but non-IL 2 type growth factor was observed. The significance of these factors from MT cell lines is discussed from the viewpoint of 'autokine' in ATLV-transformed cells.

Adult↗
PubMed2001

Clonal chromosomal aberrations accompanied by strong telomerase activity in immortalization of human B-lymphoblastoid cell lines transformed by Epstein-Barr virus.

Human B-lymphoblastoid cell lines transformed by Epstein-Barr (EBV-LCLs) are considered to be immortalized, although most of them show a normal diploid karyotype. Recently, we and others have shown that only part of EBV-LCLs is immortalized by developing strong telomerase activity that stabilizes the telomeres. In this study, we investigated the change in karyotypes during immortalization. All the eight immortalized cell lines developed clonal chromosomal aberrations accompanied by the development of strong telomerase activity. Interestingly, abnormal chromosomes were not shared among the immortalized cell lines. These results strongly suggest that chromosomal rearrangements and induction of strong telomerase activity are two events that take place in parallel in the process of immortalization of EBV-LCLs, and indicate that EBV-LCLs are clearly divided into two distinct groups, pre-immortal cell lines mostly with a normal diploid karyotype and post-immortal cell lines with a clonally abnormal karyotype.

B-Lymphocytes↗
PubMed1977

In vitro traits of adenovirus-transformed cell lines and their relevance to tumorigenicity in nude mice.

Six independently isolated adenovirus 2-transformed rat cell lines and one adenovirus 5-transformed human cell line have been examined in vitro for serum growth requirements, saturation density, anchorage-independent growth, proteolytic enzyme activity and the presence of LETS glycoprotein and T antigen. This series of adenovirus-transformed cell lines exhibits an oncogeni spectrum ranging from being tumorigenic in immunocompetent rats through to nontumorigenic in adult nude mice. The relevance of the in vitro findings to growth potential in vivo is discussed.

Adenoviruses, Human↗
PubMed1985

Loss of epidermal growth factor receptors and release of transforming growth factors do not correlate with sarcoma virus-transformation in clonally-related NIH/3T3-derived cell lines.

Transformation of NIH/3T3 cells by Kirsten murine sarcoma virus (MSV) caused a dramatic reduction in the number of cell-surface receptors for epidermal growth factor (EGF). However, the number of EGF receptors remained at a very low level in a non-tumourigenic revertant cell line isolated from the virus-transformed cells, indicating that an increase in EGF receptors is not a requirement for the phenotypic reversion of Kirsten MSV-transformed 3T3 cells. Serum-free conditioned medium from normal and virus-transformed cell lines contained similar amounts of cell growth-promoting activity as assayed by the ability to stimulate DNA synthesis in quiescent Swiss 3T3 cell cultures. However, the concentrated conditioned medium from these cell lines showed no evidence of beta-transforming growth factor (TGF) activity as assayed by promotion of anchorage-independent growth of untransformed normal rat kidney (NRK) fibroblasts in agarose. The cellular release of alpha-TGF activity was assayed by measuring the ability of concentrated conditioned medium to inhibit the binding of 125I-EGF to Swiss 3T3 cells. Conditioned medium protein from the virus-transformed cell line inhibited 125I-EGF binding but only to the same extent as conditioned medium protein prepared from the untransformed cell line. The alpha-TGF secretion by these cell lines was estimated to be 30-45-fold lower than the level of alpha-TGF released by a well-characterized alpha-TGF-producing cell line (3B11). These results suggest that the induction of TGF release is not a necessary event in the transformation of NIH/3T3 cells by Kirsten MSV.

Animals↗