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Biomedical subjects

N Auersperg

Publications and source records attributed to N Auersperg.

At least 109 records · Page 6Linked to original sources
PubMed1981

Morphological and functional differentiation of Kirsten murine sarcoma virus-transformed rat adrenocortical cell lines.

This study was undertaken to examine relationships of the phenotype of malignant cells to target cell properties and to events early in the transformation process. Eighteen transformed lines were obtained by Kirsten murine sarcoma virus infection of cells from adrenal glands of rats ages 4 to 30 weeks, at first or second passages in culture. They were grown either as fibroblastic adrenocortical stem cells or as more differentiated epithelial cells, depending on culture conditions. Of 14 lines examined for their capacity to synthesize corticosteroids, 11 converted [14C]pregnenolone to progesterone, and one converted to deoxycorticosterone. In vivo, seven lines produced tumors resembling pleomorphic carcinomas, six lines grew as sarcomas, four grew as mixed tumors, and one line produced anaplastic tumors. Distinguishing features in culture of the carcinoma-producing lines were early onset and rapid progression of morphological transformation, a noncohesive epithelial cell form in some lines, lack of extracellular matrix, and, possibly, and origin in older animals. In contrast, sarcoma-producing cells were fibroblastic and cohesive, produced extracellular matrix, and transformed morphologically after longer and less well-defined periods in culture. The variation in histopathology was unrelated to the differentiation of the target cells and to the capacity of the transformed cells to synthesize corticosteroids. The results show that adrenocortical cells, transformed by Kirsten murine sarcoma virus after short-term culture, usually retain some functional differentiation and sometimes resemble human adrenocortical carcinomas histologically. The susceptibility of adrenocortical cells to Kirsten murine sarcoma virus raises the possibility that mesodermally derived epithelia in general may be target tissues for C-type sarcoma viruses.

Adrenal Cortex↗
PubMed1981

Transformation of cultured rat ovarian surface epithelial cells by Kirsten murine sarcoma virus.

A method is described for the culture of rat ovarian surface epithelial cells, i.e., the cellular component thought to be the source of most ovarian cancers. These cells in culture have a characteristic epithelial morphology which distinguishes them from other ovarian cell types. Cultured surface epithelial cells are histochemically positive for 17 beta-hydroxysteroid dehydrogenase and negative for delta 5-3 beta-hydroxysteroid dehydrogenase, the same as in cryostat sections of whole rat ovary. Ultrastructurally, cultured surface epithelial cells have basement membranes, microvilli, and apical intercellular junctions. Kirsten murine sarcoma virus was used to produce three transformed cell lines from pure first-passage cultures of these cells. These three lines retained 17 beta-hydroxysteroid dehydrogenase activity and showed slight delta-3 beta-hydroxysteroid dehydrogenase activity. Tumors resulting when these cells were injected s.c. or i.p. into immunosuppressed female rats were highly malignant, resembling histologically human ovarian endometrioid stromal sarcoma. This is the first demonstration of the susceptibility of ovarian surface epithelium to an oncogenic virus.

Animals↗
PubMed1980

The use of lanthanum for intracellular calcium measurements in cultured cells.

The Lanthanum method, used extensively to measure the intracellular Ca content ([Ca]i) of muscle, was adapted for cell culture using the carcinoma line C-4II. Reproducible values of [Ca]i were obtained by atomic absorption spectrophotometry after 30 min of rinsing of monolayer fragments with cold 10 mM LaCl3 in 160 mM Tris-HCl buffer, pH 7.4. [Ca]i values were not influenced by the extracellular Ca concentration, the size of the monolayer fragments or by several culture variables examined. [Ca]i levels were inversely proportional to cell density. The modified La method provides a relatively simple means for [Ca]i measurements and the estimation of net Ca fluxes in and out of cultured cells.

Calcium↗
PubMed1980

Calcium in epithelial cell contraction.

Epithelial morphogenesis in many organs involves asymmetric microfilament-mediated cellular contractions. Similar contractions, in terms of ultrastructure and cytochalasin B sensitivity, can be induced in the carcinoma cell line C-4II in culture. This line was used to compare total intracellular calcium levels ([Ca]i) in contracted monolayer fragments and in control cultures, and to determine whether epithelial cell contraction depends on influx of extracellular Ca. [Ca]i, defined as Ca not displaceable by lanthanum, was measured by atomic absorption spectrophotometry. Degrees of contraction were determined from shape changes of monolayer fragments. Detachment from the growth surface initiated cellular contractions and caused an immediate increase in [Ca]i, from 1.0 to 4.0-5.0 micrograms Ca/mg protein in early confluent cultures, and from 0.3 to 1.0-2.0 micrograms Ca/mg protein in crowded cultures. This increase was followed by a gradual decline in [Ca]i, though Ca levels remained higher than in controls and contraction progressed for 30 min. Contraction was inhibited completely by cold (7 degrees C) and by Ca-free medium, and in a dose-dependent manner by papaverine (2.5 x 10(-6) M-2.5 x 10(-4) M), lanthanum (1.0 x 10(-6) M-1.0 x 10(-4) M); and D-600 (1.0-2.0 x 10(-4) M). The Ca ionophore A23187 had no effect at 5.0 x 10(-6) M and was inhibitory at higher concentrations. The results provided direct evidence for increased [Ca]i in contracting epithelial cells, and suggest that Ca influx is required for such contraction to take place.

Calcimycin↗
PubMed1978

Effects of culture conditions on the growth and differentiation of transformed rat adrenocortical cells.

Normal rat adrenocortical cells grow in vitro in two states of differentiation, depending on culture conditions. Under one set of conditions, they proliferate and are fibroblast shaped, with some myoid cell characteristics and with limited steroidogenic activity. Under alternate conditions they do not replicate and are epithelial-like and similar to adrenocortical secretory cells structurally and steroidogenically. The effects of oncogenic transformation on these cellular responses to culture variables were examined by using the Kirsten murine sarcoma virus-transformed rat adrenocortical line TRA. Transformation eliminated the differential proliferative response of the cells to culture variables and resulted in similar growth rates and high cell densities under all conditions. Horse serum, conducive to epithelial-like growth of nontransformed cells, caused aggregation, whereas fetal calf serum, conducive to fibroblastic growth of untransformed cells, caused dispersed growth in TRA cultures. Variations in dissociation procedures had little effect on growth patterns. Most ultrastructural characteristics of myoid as well as adrenocoritcal differentiation were reduced in TRA cells, although basement membranes and extracellular matrix were produced, but under different conditions than in untransformed cultures. Like normal adrenocortical cells, TRA cells were capable of 20alpha-reduction and delta5-3-beta-dehydrogenation of [4-14C5pregnenolone but, in contrast to untransformed cells, they did not respond to variables in culture conditions by qualitative changes in pregnenolone metabolism, did not produce deoxycorticosterone or corticosterone, and secreted progesterone, a hormone not recovered from untransformed cultures. TRA cells showed no increase in steroidogenic differentiation in response to those culture environment factors that normally cause modulation of the fibroblast-shaped adrenocortical stem cells to more differentiated steroid-secreting cells.

Adrenal Cortex↗
PubMed1977

Transformation of cultured rat adrenocortical cells by Kirsten murine sarcoma virus (Ki-MSV).

Two-week-old primary cultures of normal adult rat adrenal cortex were exposed to Kirsten murine sarcoma virus (KiMSV). Within a week, the adrenal cells, which are normally fusiform and aligned in parallel, became pleomorphic and piled up extensively. Saturation density increased from 5-10 x 10(4) to 5-10 x 10(5) cells/cm2, population doubling time during exponential growth decreased from 36-40 to 16h, acid production increased and the growth rate became independent of a reduction in serum concentration from 10% to 1%. Inoculation of 2 x 10(6) of these transformed cells into immuno-depressed rats produced rapidly growing tumors within 1 week. Histologically, the tumors were pleomorphic carcinomas with areas ranging from anaplasia to near-normal, highly differentiated adrenocortical tissue. In addition to histologic evidence of differentiation, metabolic studies using 14C-prognenolone showed that the transformed cells were capable of 20alpha reduction and delta5,3beta dehydrogenation, both characteristic of normal steroid-secreting tissues. The transformed adrenocortical cells produced infectious C-type virus as indicated by electron microscopy, 3H-uridine incorporation, and focus formation in NRK (normal rat kidney) cultures. The neutralization pattern of this virus resembled that of authentic Ki-MSV. The transformation of adrenocortical cells by K-MSV demonstrates the capacity of this agent to induce carcinomas in differentiated cells after short-term culture, and widens the range of tissues known to be susceptible to K-MSV to include a secretory epithelium of mesodermal origin.

Adrenal Cortex↗
PubMed1977

Chromosome analysis and alkaline phosphatase of C41, a cell line of human cervical origin distinct from HeLa.

The C41 cell line, which was derived from a human squamous carcinoma of the uterine cervix, has been characterized by analysis of quinacrine-banded metaphase chromosomes and study of alkaline phosphatase. C41 cells have a distinctive karyotype. They are hypodiploid, with a highly characteristic series of marker chromosomes, most of them derived by translocation or deletion. They contain no HeLa cell marker chromosomes, and the cell line shows no evidence of HeLa cell contamination. Nevertheless, the C41 and the HeLa cell line, both derived from cervix cancer, although of a different histological type, produce similar alkaline phosphatases. The enzyme is heat stable (placental type), is inhibited by L-phenylalanine, and responds to the inducing effects of prednisolone and/or hyperosmolality.

Alkaline Phosphatase↗
PubMed1976

Response to ACTH and dibutyryl cyclic AMP by enucleated adrenocortical tumor cells.

Y-1-L cells, a subline of the Y-1 functional murine adrenocortical tumor cell line, were enucleated with cytochalasin B and the response of these enucleated cells to ACTH and dibutyryl cyclic AMP (dbcAMP) was examined. Enucleated Y-1-L cells maintained a basal steroid output for at least 24 h and responded to either ACTH (10 mU/ml) or dbcAMP (1 mM) by a change from flat to rounded cell shape, and by increased steroidogenesis. The steroidogenic response of enucleated cells during the first 3 h after enucleation was highly significant and, though it decreased rapidly thereafter, it persisted to a limited degree for up to 12 h. On the other hand, the morphologic change could be induced even at 33 h after enucleation. The results of this study show that the nucleus is not required for the expression of the acute effects of ACTH or dbcAMP and that the cytoplasmic components necessary for cell 'rounding' and a steroidogenic response are stable for 36 h and 12 h, respectively.

Adrenal Cortex Neoplasms↗
PubMed1976

Effects of tissue culture environment on growth patterns and ultrastructure of poorly differentiated human cervical carcinomas.

Growth patterns and ultrastructure were compared between biopsy specimens and primary cultures of poorly differentiated carcinomas of the human uterine cervix. Though not obvious histologically, all carcinomas in vivo retained ultrastructural traits of squamous, glandular, or basal cell differentiation. Carcinomas with squamous traits grew as compact masses in vivo and formed cohesive colonies in vitro; tumors with basal and glandular traits infiltrated host tissues in a dispersed fashion, but their growth patterns in vitro were variable and unpredictable. The growth patterns of mixed carcinomas, in which squamous and glandular characteristics were evident in the same cells, generally resembled those of tumors with squamous traits. The levels of differentiation in vitro exceeded those found in vivo: Tonofilaments, desmosomes, and glycogen aggregations (squamous traits) as well as secretory vesicles, endoplasmic reticulum, and cilia (grandular traits) became more numerous and complex in culture. The direction of differentiation, expressed in vivo, usually persisted in vitro, through squamous traits appeared de novo or became more prominent when some of the tumors were explanted. The enhancement of differentiation by the culture environment indicated that the cervical carcinomas did not express their full potential to differentiate when growing in the natural host. The coexistence of squamous and glandular traits in the same cells and the capacity of tumors to shift from a glandular to a squamous differentiative pathway upon explantation support the concept that cervical carcinomas originate in bipotential cells, i.e, either reserve cells or metaplastic basal cells derived from the glandular epithelium.

Adenocarcinoma↗
PubMed1976

Steroidogenic pathways and trophic response to adrenocorticotrophin of cultured adrenocortical cells in different states of differentiation.

Adrenocortical cells obtained from adult rats were propagated in monolayer culture. Depending on culture conditions, they grew either as lipid-containing epithelial-like cells with a high level of steroid production, or as fibroblast-like cells with a low level of steroid production. The major fluorogenic steroid secreted by both morphologic forms of adrenal cortical cell was corticosterone as determined by chromatography and acid fluorometry. Basal fluorogenic steroid production per 10(6) cells over 24 h was: epithelial-like cells, 5.0-mug; fibroblast-like cells, 0-014 mug. Stimulation with ACTH for 5 days increased fluorogenic steroid production and induced morphologic changes in both adrenal cell forms. ACTH stimulation of fluorogenic steroid production by both cell forms reached a maximum after 3 days, then dropped to a refractory state after 5 days. With maximal ACTH stimulation, production increased 25-fold in fibroblast-like cells and five-fold in epithelial-like cells. The latter rate of corticosterone production is similar, per cell, to ACTH-stimulated adrenal glands in vivo. Progressive morphologic changes were observed with ACTH stimulation: epithelial-like cells retracted from the substratum and lost lipid inclusions; fibroblast-like cells became more epithelial-like. Both adrenal cell types formed intermediates from [4-(14)C] pregnenolone including pregn-5-ene-3 phi, 20 alpha-diol and 20 alpha-hydroxy-pregn-4-en-3-one. Control cultures of muscle fascia fibroblasts did not produce corticosterone or intermediates from [4-(14)C[ pregnenolone and did not respond to ACTH functionally or morphologically.

Adrenal Cortex↗
PubMed1974

Structural and functional heterogeneity of the surface of rat leukemia cells.

Rat leukemia cells IRC 741 in suspension culture form single cytoplasmic protrusions by which the cells preferentially adhere to one another. The induction and/or maintenance of these protrusions is sensitive to changes in intercellular contact, pH, temperature, and nutritional conditions. The protrusions are stable, rigid structures which take part in intercellular adhesion but not in adhesion to substrata. Movement on substrata occurs by means of ruffling membranes formed on the main cell body. This asymmetry in cellular form and function is associated with specialized cell surface regions. Ultrastructurally, the cell surface over the protrusions lacks microvilli, and is covered with a 3,000-4,000-A thick cell coat consisting of 200-500-A electron-dense particles in an amorphous matrix. In contrast, the surface over the main cell body has microvilli and a 200-A wide cell coat which lacks particles. The extracellular particles overlying the protrusions have electron-lucent cores, are protease- and pepsin-resistant, and do not stain with colloidal iron, while the matrix in which they are embedded is sensitive to proteolytic enzymes and contains acidic moieties. The negative surface charge density over the protrusions is higher than that over the main cell body, as shown by the orientation of the cells in an electric field. The unexpected observation that a region of higher charge density is one of increased intercellular adhesiveness might be explained, in part, by the rigidity of the protrusions and by the very small radius of curvature of the overlying extracellular particles. The protrusions permit the observation of discrete regions, differing in charge density, on the surface of living leukemia cells.

Animals↗