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N Auersperg

Publications and source records attributed to N Auersperg.

At least 91 records · Page 5Linked to original sources
PubMed1986

Cell-mediated co-action of transforming growth factors: incubation of type beta with normal rat kidney cells produces a soluble activity that prolongs the ruffling response to type alpha.

Intense, continuous ruffling is a characteristic of many transformed cells, but untransformed cells ruffle intensely only briefly after exposure to growth factors. We reported previously that cells of a normal rat kidney (NRK) cell line transformed by Kirsten murine sarcoma virus secrete their own ruffle-inducing agent(s) that cause sustained ruffling in either themselves or untransformed NRK cells. In the present study, we examined the roles of the transforming growth factors TGF-alpha and TGF-beta in the induction and maintenance of ruffling in untransformed NRK cells and observed the following: TGF-alpha caused a transient epidermal growth factor (EGF)-like response, which could be blocked by prior exposure of cells to EGF or by antiserum directed against the COOH-terminus of TGF-alpha. TGF-beta caused no ruffling and did not itself prolong TGF-alpha ruffling. A new, buffer-soluble (transferable) mediator activity produced by incubation of TGF-beta with NRK cells for 6-h extended the duration of maximal TGF-alpha-induced ruffling by several-fold. This study demonstrates that TGF-alpha alone causes an EGF-like, transient ruffling response, but neither TGF-alpha or TGF-beta alone, nor the two together, cause transformation-associated sustained ruffling. Rather, TGF-alpha acts in concert with a new, TGF-beta-dependent activity. This new activity appears to inhibit normal cellular off-regulation of TGF-alpha-induced ruffling. Inhibition of the cellular off-regulation of a growth factor response could play a key role in the unregulated growth associated with malignancy.

Animals↗
PubMed1986

Expression of viral p21ras during acquisition of a transformed phenotype by rat adrenal cortex cells infected with Kirsten murine sarcoma virus.

Rat adrenal cortex cells infected with Kirsten murine sarcoma virus acquire a transformed phenotype in a progressive fashion. The expression of the viral p21ras does not appear to correlate with the degree of transformation of the adrenocortical cells but rather is produced at similar levels as the culture becomes transformed. This indicates that the expression of an oncogenic form of p21ras is not of itself sufficient to completely transform rat adrenal cortex cells.

Adrenal Cortex↗
PubMed1986

Modulation by normal serum factors of Kirsten murine sarcoma virus-induced transformation in adult rat cells infected in early passage.

Adult rat adrenal cells, infected with Kirsten murine sarcoma virus in early passage, transform consistently in 10% fetal bovine serum (FBS)-supplemented medium. Substitution of 3% horse serum (HS) for FBS reverses early foci and delays transformation. The influence of the serum on DNA synthesis, anchorage dependence, tumorigenicity, and subcellular Mr 21,000 transforming protein (p21) distribution was followed from infection in passage 1 to complete transformation. In FBS, increased expression of p21 preceded other evidence of transformation. Subsequently, p21-positive cells transformed morphologically, but initially their growth parallelled that of coexisting untransformed cells. Foci formed at passages 5 to 10, and the cells became anchorage independent and tumorigenic at passages 10 to 20. As transformation in FBS progressed, p21 relocated from a diffuse distribution to sites of retraction from substrata and then to ruffles and lamellae on cellular processes. Early in transformation, HS-medium reduced proliferation of morphologically normal and morphologically transformed p21-positive cells. This effect was counteracted by the addition of FBS or the Mr 50,000 to 100,000 fraction of FBS. Fully transformed, tumorigenic cells grew rapidly in both sera but, if transferred from FBS to HS, became more anchorage and density dependent, and p21 relocated from cell processes to the cell bodies. In immortal lines, the substitution of HS for FBS accelerated rather than delayed the progression of Kirsten murine sarcoma virus-induced transformation. These results show that Kirsten murine sarcoma virus-induced transformation of adult presenescent cells is controlled by physiological factors to which immortal cells appear refractory. The changes in subcellular distribution of p21 during transformation parallel the expression of some, but not other, transformation parameters and suggest a possible association of p21 with increased membrane activity.

Adrenal Glands↗
PubMed1985

p21ras. Heterogeneous localization in transformed cells.

The cellular targets for the Kirsten murine sarcoma virus (KiMSV)-transforming protein, p21ras, are unknown. Other studies have indicated that the mature form of p21 is distributed diffusely on the cytoplasmic face of the plasma membrane. However, after fixation without buffer washes, indirect immunofluorescent staining of sparse cultures revealed a particularly well preserved cellular architecture and a strikingly heterogeneous subcellular distribution of p21 in transformed normal rat kidney (NRK) cells but not in their untransformed counterparts. The transformed cells included A KiMSV-transformed NRK line. NRK cells newly transformed with KiMSV. A temperature-sensitive (ts) KiMSV-transformed NRK line. An uninfected, spontaneously transformed NRK line in which p21 was neither phosphorylated nor overproduced. In the tsKNRK line p21 was abundant at both permissive and non-permissive temperatures; however, its distribution was heterogeneous at the permissive temperature only. Observation of this array of cells indicates that the transformation-associated p21 distribution does not require overexpression of the gene, nor phosphorylation of the protein, nor the viral oncogene. Furthermore, it is reversible in the tsKNRK cells, and so appears to be highly correlated with acquisition of a transformed morphology. Accumulations of p21 occurred preferentially in subcellular locations similar to those where ruffles were observed by phase contrast microscopy and lamellar and villous extensions were observed by scanning electron microscopy (SEM). Since enhanced ruffling is a morphological correlate of transformation in a variety of cells, the distribution of p21 observed here may relate to its function as a transforming molecule.

Cell Line↗
PubMed1985

Regulation of a ras-related protein during development of Dictyostelium discoideum.

Recent work has shown that DNA sequences related to the mammalian ras proto-oncogenes are highly conserved in eucaryotic evolution. A monoclonal antibody (Y13-259) to mammalian p21ras specifically precipitated a 23,000-molecular-weight protein (p23) from lysates of Dictyostelium discoideum amoebae. Tryptic peptide analysis indicated that D. discoideum p23 was closely related in its primary structure to mammalian p21ras. p23 was apparently derived by post-translational modification of a 24,000-molecular-weight primary gene product. The amount of p23 was highest in growing amoebae, but declined markedly with the onset of differentiation such that by fruiting body formation there was less than 10% of the amoeboid level. The rate of p23 synthesis dropped rapidly during aggregation, rose transiently during pseudoplasmodial formation, and then declined during the terminal stages of differentiation. There was, therefore, a strong correlation between the expression of the ras-related protein p23 and cell proliferation of D. discoideum.

Cell Differentiation↗
PubMed1985

A cell line, ROSE 199, derived from normal rat ovarian surface epithelium.

A cell line, ROSE 199, derived from rat ovarian surface epithelium (ROSE) formed papillary structures which resembled, histologically, serous papillary cystadenomas of borderline malignancy seen in the human ovary. Crowded cultures produced two layers of cells separated by a thick layer of collagen fibers. Such cultures shed viable cells into the growth medium, while no cells were shed by short-term ROSE cultures. The resemblance to ovarian tumors exhibited by ROSE 199 cells in culture, reinforces the hypothesis that the common epithelial tumors of the ovary are derived from the ovarian surface epithelium. ROSE 199 cells, while retaining their epithelial morphology and ultrastructural characteristics, express stromal activity such as abundant collagen production. Perhaps this ability to express epithelial and stromal behavior is a contributing factor to the ready neoplastic transformation of the ovarian surface epithelium.

Animals↗
PubMed1984

Human ovarian surface epithelium in primary culture.

The ovarian surface epithelium (OSE) represents a minute fraction of the cell mass of the ovary but gives rise to over 80% of human ovarian carcinomas. No experimental models for the study of human OSE exist. To characterize OSE cells in culture, explants of ovarian surface from normal ovary of premenopausal women were grown on plastic, glass, and collagen gel in 25% fetal bovine serum/Waymouth's medium 752/1. About 25% of explants produced epithelial outgrowths. Morphologically, these outgrowths resembled OSE in vivo and endothelial and mesothelial cells in culture, but they differed from cultured ovarian stromal, granulosa, and luteal cells. Only OSE among ovarian cell types were intensely keratin positive by immunofluorescence. Keratin also distinguished OSE cells from the keratin-negative endothelial cells. Most but not all OSE colonies tested showed 17 beta-hydroxysteroid dehydrogenase (HSD) activity, which was absent in peritoneal mesothelial cells. Colonies from most patients were limited to a few millimetres and became stationary within a few weeks. Changes that accompanied cessation of growth included senescence, increased keratin content, or the formation of multicellular papillary aggregates. With time, OSE cells tended to assume a fibroblast-like morphology but remained keratin positive and continued to resemble OSE by scanning electron microscopy (SEM). Subcultured OSE cells persisted in a stationary keratin-positive form for many weeks. Throughout this study, all pavementlike epithelial outgrowths that were contiguous with an explant stained for keratin; thus, such colonies can be assumed to be OSE. Conversely, fibroblast-shaped cells may represent OSE as indicated by keratin content and SEM appearance. The methods presented here permit culture of normal human OSE under conditions in which the cells exhibit morphologic plasticity, variable 17 beta-HSD activity, and presence of keratin.

Cell Aggregation↗
PubMed1984

Development of serum independence in Kirsten murine sarcoma virus-infected rat adrenal cells.

Cells cultured from explants of adult rat adrenal cortex are spindle shaped and divide rapidly in media with 10-25% fetal bovine serum (FBS), but are epithelial-like and stationary in 3-6% horse serum (HS). Fully transformed Kirsten murine sarcoma virus (KiMSV)-infected cells lose this differential response to serum. To determine at what stage in the transformation process this loss occurs, cultures in passages 1-2 were infected with KiMSV, propagated for up to 30 weeks in FBS, and parallel cultures were transferred to HS prior to transformation, within 4 weeks after appearance of foci, or after complete transformation (exhibiting altered culture morphology, increased growth rate and tumorigenicity). In 7 lines grown in FBS, foci appeared 1-14 weeks post-infection and most cultures were completely transformed 1-3 weeks thereafter. Substitution of HS for FBS prior to focus formation caused partial reversion to epithelial-like morphology and reduction in growth rate. Transformation was delayed or prevented altogether, but could be elicited by addition of 1% FBS to HS. HS-substitution within 4 weeks after appearance of foci caused regression of foci, slowing of growth, and delays of complete transformation lasting up to 5 months. In three lines, HS effects on cell shape and on proliferation were dissociated, suggesting separate controls of these two parameters. HS-substitution after complete transformation did not reduce growth or reverse morphologic changes. The results indicate that, in some cases, transformation by acute oncogenic retroviruses is a multistep process involving epigenetic regulation, and that autonomy from environmental controls is acquired gradually by the infected cells. The results also demonstrate that acute transforming retroviruses can cause prolonged latent infections, the phenotypic expression of which depends on environmental factors.

Adrenal Cortex↗
PubMed1984

Distribution of 3 beta-hydroxysteroid dehydrogenase during development of the rat adrenal cortex and capsule.

Fibroblasts of the adult adrenal cortex are considered to be nonsteroidogenic connective-tissue cells. However, it has been reported that in response to regenerative stimuli, adrenocorticotropic hormone (ACTH), and transformation to malignancy, these cells acquire characteristics of parenchymal cells, which includes delta 5, 3 beta-hydroxysteroid-dehydrogenase (delta 5, 3 beta-HSD) activity. To determine whether such delta 5, 3 beta-HSD activity in adult adrenocortical fibroblasts was due to the activation or augmentation of gene expression normally occurring during embryogenesis, a histochemical study of adrenocortical development, with particular attention to the connective-tissue capsule, was undertaken. Cryostat sections of rat embryos, from 14-days postconception (PC) to birth, and of adrenal glands 1-8, 44 and 90 days after birth were tested histochemically for delta 5, 3 beta-HSD. The same or adjacent sections were stained for PAS-positive material and reticulin, and with hematoxylin and eosin. delta 5, 3 beta-HSD activity overlapped with fibroblast-like cells and with extracellular connective-tissue components in the periphery of the glands from day-17 PC onward. delta 5, 3 beta-HSD activity over the capsule diminished shortly after birth and was absent in the adult. Appropriate controls showed that the staining within the capsule was specific and not an artifact. 3 beta-HSD activity in the capsule was more intensive when dehydroepiandrosterone (DHEA) was replaced by etiocholan-3 beta-ol-17-one (ETIO) as the steroid substrate. Furthermore, the spatial distribution of 3 beta-HSD activity in the cortex differed depending on the substrate used, and the distribution patterns changed with developmental age. (ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxysteroid Dehydrogenases↗
PubMed1983

Ascorbic acid accumulation by cultured rat adrenocortical cells.

The influence of adrenocorticotrophin (ACTH) on radiolabeled ascorbic acid (AA) accumulation by adrenocortical cells was examined in primary cultures of collagenase dissociated glands from adult male rats. The cells were ACTH responsive by morphological and steroidogenic criteria. After 5 d in AA-free medium, cells pretreated with 100 mU/ml ACTH for 3 d took up two to three times more AA over a 2 h period than did untreated controls (4.0 to 10.0 nmol versus 1.7 to 3.4 nmol AA/micrograms DNA). In contrast, ACTH administered on Day 6 concurrently with AA inhibited AA accumulation compared to cultures exposed to AA alone. This acute inhibitory effect of ACTH was in the order of 30% in cultures pretreated with ACTH for 3 d but was not significant (7%) without ACTH pretreatment. The results show that ACTH has distinct long term stimulatory and acute inhibitory effects on AA accumulation by adrenocortical cells and suggest that both maximal AA accumulation and the responsiveness to acute inhibition of AA accumulation by ACTH may depend on the maintenance of the differentiated state of the adrenal cortex.

Adrenal Cortex↗
PubMed1983

Autoradiographic investigation of estrogen binding in cultured rat ovarian surface epithelial cells.

Autoradiographic evidence presented that the cultured rat ovarian surface epithelium exhibits estrogen receptor-like activity. Two autoradiographic techniques were used; one involved live cells that were labeled and freeze-dried, and the other the labeling of ethanol-fixed cells. Autoradiograms were prepared by dipping cells grown on plastic cover slips in liquid nuclear track emulsion. Exposure times were 1 to 4 weeks. Experiments using a pulse-chase technique in live cells and steroid competition tests in fixed and live cells gave evidence for translocation of tritiated estradiol from cytoplasm to nucleus in live cells and for a component of estrogen-specific binding in live and fixed cells. The techniques presented here for the investigation of estrogen receptors in cultured cells require little tissue, are simple, and relatively quick. Reports based on biochemical analyses of tissue homogenates claim the presence of estrogen receptors in human ovarian carcinomas of surface epithelial origin and in rat ovarian surface epithelium. The results of this study add further evidence that the ovarian surface epithelium has estrogen receptor activity and should be considered an estrogen target tissue.

Animals↗
PubMed1983

Effect of calcium deprivation on the proliferation and ultrastructure of cultured human carcinoma cells.

The ability of cells to proliferate in the presence of low extracellular calcium levels has been proposed as a marker for malignancy. To further evaluate this marker, the effects of extracellular calcium deprivation on proliferation and morphology in culture were examined in eight tumorigenic lines derived from human cancers. With calcium reduced from 1.8 mM (HCM) to 0.02 mM (LCM), the colony-forming ability remained unchanged in five lines, increased in line SK-BR-3, decreased partially in line C-4II, and was reduced to the level of nontumorigenic cells (by approximately 90%) in line C-4I. This atypical response of C-4I could not be accounted for by the presence of a subpopulation of nontumorigenic cells. In contrast to nontumorigenic cell, sparsely seeded C-4I cells adapted to growth in LCM with time. Like nontumorigenic cells, C-4I cells grew efficiently in LCM if seeded at high densities, suggesting that conditioned medium compensated for calcium depletion. The four tumorigenic lines with the least organized growth patterns in HCM changed least in shape, intercellular associations, cell surface, and cytofilaments upon exposure to LCM. Line C-4I, which in HCM expressed characteristics of stratified squamous epithelium, underwent the most drastic changes, including a redistribution of tonofilaments from the peripheral cytoplasm and contact regions to a perinuclear position. The results support the concept that most tumorigenic lines have reduced calcium requirements for proliferation. Exceptions, as illustrated by the limited colony-forming ability in LCM of the C-4I cells, may be related to the retention of a requirement for growth factors.

Calcium↗
PubMed1982

Proliferation in low calcium medium as a marker for malignancy: an apparent exception among human carcinoma cells.

The proliferative capacity of 2 human carcinoma cell lines, C-4I and C-4II which have a reduced ability to form colonies in low calcium (0.02 mM) medium, was compared with that of other tumor cells (C-33) which were characteristically calcium-independent, and with non-tumorigenic cells. In low calcium medium the C-4 lines continued to incorporate [3H]thymidine but few cells reached metaphase. Under the same conditions DNA synthesis of non-tumorigenic cells was reduced, while C-33 cells proliferated as efficiently as in standard medium. These results indicate the possibility of multiple sites for proliferation arrest in low calcium medium, and the necessity to follow-up colony-forming assays with [3H]thymidine incorporation tests when proliferation in low calcium medium is used as a marker for malignancy.

Calcium↗
PubMed1982

Detection of circulating tumour-associated antigens in serum of women with cervical neoplasia. Use of rabbit antiserum to a continuous cancer cell line (C-4111).

Hyperimmune rabbit sera to partially purified human cervical cancer tissue antigen (CaCxTAA) and to human cervical cancer culture cell line antigens (C-4II-TAA) were used to demonstrate circulating tumour-associated antigens (C-TAA) in the sera of women with cervical neoplasia. Rabbit anti-CaCx serum detected C-TAA in 80% of the 60 sera from women with invasive cancer, cancer in situ and severe dysplasia and the rabbit anti-C-4II serum detected 67% of these cases. Negative reactions were obtained in over 95% of the 154 control sera with either rabbit serum. These results suggest that, in view of the difficulty of obtaining large specimens of cervical cancer tissues for the development of immunodiagnostic procedures, the use of a cervical cancer cell line, such as C-4II, appears desirable. Such cell lines would also be advantageous for studies aimed at providing further support for the association between genital herpes simplex virus infection and human cervical cancer.

Animals↗
PubMed1981

Epidermal growth factors enhances viral transformation of granulosa cells.

Kirsten sarcoma virus produced a low incidence of transient morphological transformation in primary cultures of rat ovarian granulosa cells. In the presence of epidermal growth factor, the incidence of transient transformation increased severalfold and two continuous cell lines were established. Epidermal growth factor, a naturally occurring polypeptide hormone, appears to act here as a tumor promoter in the retrovirus-induced transformation of a mesodermally derived epithelium.

Animals↗