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Biomedical subjects

N Auersperg

Publications and source records attributed to N Auersperg.

At least 55 records · Page 3Linked to original sources
PubMed1995

Influence of cell type on the steroidogenic potential and basal cyclic AMP levels of ras-oncogene-transformed rat cells.

Transformation with ras oncogenes causes loss, maintenance or modulation of differentiation, depending on the developmental history of the target cells. In the present study, we examined steps in signal transduction that may underlie some of this variation, using steroidogenic cells of adult rats as the model system. Steroidogenesis in normal cells is regulated by cyclic AMP and protein kinase A (the cAMP/PKA pathway). We showed previously that transformation with v-Ki-ras induces constitutive progesterone secretion in ovarian and adrenocortical cells that are normally steroidogenic (ovarian granulosa and adrenal glomerulosa cells) and also in developmentally related cells that are normally nonsteroidogenic (ovarian surface epithelium and adrenal capsular fibroblasts), but not in unrelated nonsteroidogenic cells, such as muscle fascia fibroblasts and peritoneal mesothelium. In the present study, basal cAMP levels in all transformed ovarian and adrenal cell-lines were increased over basal levels in normal cells, and of transformed muscle fascia and mesothelial cell-lines. As in normal cells, transformation-induced steroidogenesis was stimulated by cAMP and was PKA dependent. A comparison of malignancy-related characteristics showed that transformed cells from nonsteroidogenic organs were more tumorigenic in vivo and less sensitive to growth inhibition by cAMP in vitro than transformed ovarian and adrenocortical cells. The results show that the abnormal, constitutive steroidogenesis induced by the viral form of the Kirsten ras oncogene (v-Ki-ras) in certain cell types is associated with tissue-specific increases in basal cAMP levels. Thus, although the ras oncogenes function primarily through other signal transduction pathways, transformation with ras oncogenes alters PKA-mediated signal transduction in a manner that is developmentally determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Rapid ras-oncogene-mediated transformation maintains steroidogenic differentiation in adrenocortical parenchymal cells.

While its action as a transforming agent is well known, expression of the ras oncogene may also alter tissue-specific differentiation. We have been examining the relationship of transformation and differentiation in steroidogenic cells of the rat. Infection of adrenocortical zona glomerulosa (GLOM) cells with the v-Ki ras containing Kirsten murine sarcoma virus did not induce focus formation. Instead, diffuse cellular multilayers formed from which loosely adherent, refractile cells emerged. After selective passaging these refractile cells, designated KiGLOM, were morphologically transformed, had reduced serum requirements for growth, greatly increased saturation densities, and they rapidly formed tumours in immunosuppressed hosts. In addition, under conditions where normal cells were no longer steroidogenic (ie. after passaging), KiGLOM cells expressed the steroid-specific cholesterol side chain cleavage cytochrome P-450scc and they produced significant, albeit reduced, amounts of corticosterone in comparison with primary GLOM cultures. Additionally, trophic hormone treatment increased steroid production in Ki-GLOM cells and this increase was partially reversed by lovastatin, a pharmacological inhibitor of ras p21 function. Thus, after a morphological selection that removed normal neighbours, v-Ki ras infected cells transformed rapidly while remaining steroidogenic. These results, combined with previous reports of steroidogenic v-Ki ras transformed adrenocortical fibroblasts and ovarian granulosa cells suggest that the ability of the ras oncogene to co-opt signal transduction pathways associated with both growth and differentiation is a common feature of the steroidogenic phenotype.

Adrenal Cortex↗
PubMed1994

Reciprocal interactions between human ovarian surface epithelial cells and adjacent extracellular matrix.

The human ovarian surface epithelium (OSE), or ovarian mesothelium, is functionally complex as seen by its capacity to proliferate, migrate, and contribute to ovulation and ovulatory repair in response to cyclic hormonal and environmental changes. We wished to determine whether this phenotypic versatility is reflected in cell-extracellular matrix interactions in primary and low-passage culture. Comparisons of cultures maintained on different substrata revealed that these cells form cohesive monolayers on plastic, while fibrin clots enhance cell dispersion, and thus may provide a migratory cue. The cells invaded Matrigel as multicellular aggregates, while collagen gels mediated a morphologic epithelial-mesenchymal conversion. On plastic, the cells produced extracellular matrix components characteristic of epithelial basement membrane (laminin and collagen type IV), as well as stroma (collagen types I and III). In addition, ovarian surface epithelial cells secreted serine proteases and matrix metalloproteinases. The levels of chymotrypsin- and elastase-like proteases were dictated by the substratum: low levels were secreted by cells grown on plastic, intermediate levels on collagen gels and fibrin clots, and most protease was produced on Matrigel. The rate of cell proliferation varied with the substrata and was inversely related to protease secretion. Integrin expression was greatest on plastic and least on collagen gels where integrins were downregulated with time. alpha 6/beta 4 was absent from all cells while varying levels of alpha 2, alpha 3, alpha 5, beta 1, and vitronectin receptor were detected depending on the culture substratum employed. In low-passage cultures of human ovarian surface epithelial cells, then, cell shape, growth, protease production, and integrin expression are modulated by the extracellular matrix. The cells, in turn, alter extracellular matrix by synthesis, lysis, and physical remodeling, and express both stromal and epithelial characteristics. The broad repertoire of these functions may be related to their mesodermal origin, and may reflect the expression of a dual, epithelio-mesenchymal phenotype by relatively immature, uncommitted cells. The results demonstrate the great complexity and versatility of these interactions which render OSE cells capable of participating in numerous physiological and pathological processes.

Adult↗
PubMed1994

A line of rat ovarian surface epithelium provides a continuous source of complex extracellular matrix.

A spontaneously immortalized, yet non-tumorigenic rat ovarian surface epithelial (ROSE 199) cell line, deposits large amounts of extracellular matrix (ECM) in response to crowding. The characteristics and components of ROSE 199-derived cell-free ECM were compared after three different preparative techniques: treatment with 20 mM ammonium hydroxide, with 1% sodium deoxycholate, or by repeated freeze-thaws. The ECMs were analyzed by histochemistry, immunofluorescence, electron microscopy, and Western immunoblotting. Components of ROSE 199 ECM included laminin, fibronectin, and collagen types I and III. Even though ROSE 199 is an epithelial cell line, striated collagen fibers formed a major part of its matrix. Thus, ROSE 199 matrix consists of both basement membrane and stromal matrix components. This matrix supported the adhesion, spreading, and growth of several cell types without altering their morphology or growth pattern, and enhanced the attachment of some cell types that spread on plastic only with difficulty. Immunofluorescence, electron microscopy, and dry weight determinations indicated that a greater proportion of matrix was retained in preparations obtained by ammonium hydroxide or freeze thaw techniques than after sodium deoxycholate treatment. Ammonium hydroxide and freeze-thaw treated matrices were also superior to sodium deoxycholate preparations as evidenced by enhanced initial cellular adhesion and spreading compared to cells plated on plastic. Residual nuclear material did not seem to affect the biological activity of this matrix. ROSE 199 extracellular matrix provides a novel, complex substratum for cell culture and for studies of matrix functions and synthesis.

Actins↗
PubMed1994

Characterization of cultured human ovarian surface epithelial cells: phenotypic plasticity and premalignant changes.

BACKGROUND: The ovarian surface epithelium (OSE) is a modified mesothelium that gives rise to most human ovarian carcinomas. In culture, OSE cells tend to assume atypical morphologies that make it difficult to accurately identify normal OSE cells and to recognize pathologic changes. The present study was undertaken to improve the accuracy of OSE identification and to distinguish phenotypic variations of normal OSE cells from early (pre)neoplastic changes. EXPERIMENTAL DESIGN: The expression of epithelial and stromal markers was compared between OSE cultures in low passage, three simian virus 40-immortalized OSE lines (IOSE lines) and two ovarian carcinoma lines, using immunofluorescence microscopy, immunocytochemistry, and Western blots, with fibroblasts and vascular endothelial cells as controls. RESULTS: Whereas keratin remained a convenient and specific epithelial marker for normal OSE, it was not expressed by all cells, and it diminished with passages in culture. E-cadherin and desmoplakins were absent in cultured OSE, mucin was detected in few cells, and microvilli diminished within one to two passages. Laminin and collagen IV were uniformly expressed and stable with time but were also found in endothelial cells. In contrast to endothelial cells, OSE lacked Factor VIII and did not bind Ulex Europaeus Lectin. The three IOSE lines were more stable than OSE morphologically, and keratin was expressed consistently in 100%, 90%, and 0% of the cells, respectively. All IOSE cells produced laminin and collagen IV but lacked E-cadherin. Microvilli persisted in 50% of the cells in one IOSE line and were lacking in the others. The antibody to breast/ovarian carcinoma, 2G3, reacted with few OSE cells but with significantly more IOSE cells. All fibroblast markers tested (vimentin, collagen types I and III, and prolyl-4-hydroxylase) were expressed in OSE and IOSE cultures, concurrently with the epithelial markers. There was no consistent relationship between any of the markers and cell morphology. CONCLUSIONS: Cultured OSE is more accurately identified if the demonstration of keratin is supplemented by 2G3, laminin, or the lack of endothelial markers. The modulation to a fibroblast-like morphology by OSE cells may reflect the expression of their dual epithelio-mesenchymal phenotype rather than epithelio-mesenchymal conversion. Possible indicators of early neoplastic change in immortalized OSE cells include reduced morphologic plasticity and increased 2G3 binding.

Cadherins↗
PubMed1993

An in vitro model of ovarian epithelial carcinogenesis: changes in cell-cell communication and adhesion occurring during neoplastic progression.

To investigate the cellular mechanisms of ovarian epithelial carcinogenesis, a series of progressively transformed rat ovarian surface epithelial (ROSE) cell lines were developed and studied. Transfection of primary ROSE cells and an immortalized ROSE line (ROSE 199) with the pSV3neo plasmid (SV40 T-antigen) yielded transformed lines which retained epithelial morphology. In vivo selection of these pSV3neo cell populations resulted in further phenotypic transformation. Transfection of ROSE 199 with pSV2neo/c-H-rasEJ (rasEJp21) resulted in a malignant line which appeared fibroblast-like and formed invasive sarcomas both in athymic mice and in immunocompetent rats. Gap junctional intercellular communication (GJIC) and cell-cell adhesion were studied in this series of ROSE lines. Both c-H-rasEJ-transformation and in vivo selection resulted in a significant reduction of GJIC between adjoining cells and a transition of in vitro migration as continuous epithelial sheets to the dissociation of individual cells. This apparent shift in cell adhesiveness was associated with reduced expression of the E-cadherin adhesion molecule. Our data suggest that neoplastic progression of the ovarian surface epithelium may be associated with concomitant reductions in GJIC, E-cadherin expression and functional adhesiveness.

Animals↗
PubMed1993

Lack of inter-species reactivity between antigens and antibodies is overcome by protease treatment of western blots.

The analysis of proteins by Western blotting is frequently limited by the inability of antibodies to recognize antigenic epitopes in proteins of different species. In the present study, we investigated the influence of mild protease digestion on the reactivity of nitrocellulose-blotted proteins and microscopic sections with antibodies produced against analogous proteins of different species. The proteins were partially purified, electrophoresed and blotted by standard procedures. They were then incubated with either trypsin or pepsin, at concentrations ranging from 0.5 to 80 micrograms/mL, for different time periods prior to reaction with the first antibody. After incubation with the second antibody, the bands were visualized by chemiluminescence. The following antibody/antigen pairs produced no signal by conventional methods but resulted in the appropriate bands following protease treatment: (i) monoclonal antibody (Mab) to human keratin #18/rat keratin; (ii) Mab to starfish extracellular matrix/mouse laminin; (iii) rabbit antiserum to human platelet myosin II/ratfish nonmuscle myosin II. In the latter system, protease treatment also revealed previously hidden epitopes in microscopic sections. Appropriate controls demonstrated that the antibodies retained their specificity after the protease treatment of the preparations. Optimal conditions varied and had to be defined for each protein under study.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Growth of normal human ovarian surface epithelial cells in reduced-serum and serum-free media.

The human ovarian surface epithelium (OSE) is believed responsible for over 85% of ovarian cancers, yet little is known about the normal biology of these cells. To date, culture of OSE has only been reported in media with high serum supplements. We have developed two media, one with less than 1% of serum (OSEM-1) and the other comprised of highly purified and defined materials (OSEM-2), which allow us to study OSE under relatively defined conditions. By substituting 0.05% of Pedersen's fetuin for 15% fetal bovine serum (FBS) with Medium 199/MCDB105 basal medium, the cell numbers reached 50 to 60% of those in the presence of 15% FBS over 7 days. However, over several weeks, the total number of population doublings achieved were comparable to those in 15% FBS. Addition of insulin, transferrin, ethanolamine, lipoic acid, and phosphatidylcholine to the medium with Pedersen's fetuin (OSEM-1) enhanced growth up to 20% more than in their absence. Supplementation of M199/105 with highly purified (> 99%) fetuin, alpha 2-macroglobulin, and hydrocortisone resulted in a defined medium (OSEM-2) that permitted 1 to 2 doublings/7 days. In addition, cells maintained a more normal, epithelial-like morphology in culture for a longer period in the presence of Pedersen's or purified fetuin than in M199/105/15% FBS, thus increasing the number of morphologically normal cells available for experimentation. Addition of 0.05% Pedersen's fetuin to M199/105 in the presence of 6 to 8% FBS resulted in levels of growth equivalent to those in M199/105/15% FBS alone. We are now able to study the effects of various compounds on the growth and differentiation of OSE under defined conditions, and have reduced the requirement for FBS to produce large numbers of OSE cells.

Cell Count↗
PubMed1993

Secretion of bioactive interleukin-1, interleukin-6, and colony-stimulating factors by human ovarian surface epithelium.

The ovarian surface epithelium (OSE) takes part in the lysis and repair of the ovulatory site. It also forms invaginations and cysts that give rise to the majority of ovarian epithelial carcinomas. In the present study, we investigated the capacity of cultured human OSE to secrete cytokines that may contribute to the regulation of ovarian functions and may influence ovarian carcinogenesis. Bioassays, combined with antibody neutralization experiments, showed that OSE cells in short-term culture secrete bioactive interleukin-1 (IL-1), interleukin-6 (IL-6), macrophage colony-stimulating factor (CSF-1), granulocyte colony-stimulating factor (G-CSF), and limited granulocyte-macrophage colony-stimulating factor (GM-CSF). There was a tendency for these factors to be absent or secreted in reduced amounts in SV40-immortalized OSE lines and in two ovarian carcinoma lines. No IL-2, IL-3, or IL-4 was detected. The results show that normal OSE cells secrete factors that are known to have regulatory effects on follicular growth and differentiation, ovulation, and the distribution of intraovarian cells of the immune system. In addition, the results suggest that the secretion of cytokines by ovarian carcinomas represents the retention of normal precursor cell properties, rather than new characteristics acquired as a result of neoplastic progression.

Animals↗
PubMed1993

Mixed parenchymal-stromal populations of rat adrenocortical cells support the proliferation and differentiation of steroidogenic cells.

The mechanisms which regulate adrenocortical steroidogenesis in differentiated parenchymal cells have been studied in great detail. However, the stem cells that are responsible for regeneration of the adult cortex have never been identified or isolated, and their characteristics are unknown. We have developed a tissue culture system that supports the simultaneous proliferation and differentiation of steroidogenic adrenocortical cells. Utilizing density gradient separation, a cell population composed of a mixture of stromal, endothelial and parenchymal cells (MIX) was isolated from the adult rat adrenal cortex. In primary culture, MIX populations formed high saturation density multilayers from which rounded cells emerged. These cells proliferated, contained lipid, and expressed the steroidogenic enzymes delta 5,3 beta-hydroxysteroid dehydrogenase and cholesterol side-chain cleavage cytochrome P-450scc. After selective passaging, rounded MIX-derived cells retained their steroidogenic potential, even in the absence of trophic hormone treatment. In contrast, parenchymal cells obtained from the zonae fasciculata (FASC) and glomerulosa (GLOM) respectively, formed homogeneous monolayers in primary culture, gradually de-differentiated, and no longer responded to trophic hormone treatment after passaging. Thus, primary MIX cultures provided a microenvironment that resulted in the production of adrenocortical cells with stem cell-like qualities. These cultures provide for the first time, a system for the identification of specific inducers that are responsible for both adrenocortical cytogenesis and its associated proliferation and steroidogenic differentiation.

Adrenal Cortex↗
PubMed1993

Comparison of the neutral red and methylene blue assays to study cell growth in culture.

The neutral red and methylene blue in vitro cytotoxicity assays were compared under a variety of conditions using normal human ovarian epithelial cells to determine whether either assay is superior for studying cell growth. The results were standardized against a DNA spectrofluorometric assay. Although the assays were equivalent in reflecting cell number, each has specific advantages: while neutral red discriminates between viable and dead cells, the methylene blue assay is more sensitive and easier to perform.

Cell Division↗
PubMed1992

Reversal of divergent differentiation by ras oncogene-mediated transformation.

In embryogenesis, ovarian surface epithelial cells and ovarian granulosa cells arise through divergent differentiation from a common mesenchymal precursor, the urogenital ridge. In the adult rat, ovarian surface epithelial cells are nonsteroidogenic and keratin positive, while ovarian granulosa cells are steroidogenic and keratin negative. In culture, Kirsten murine sarcoma virus-transformed, tumorigenic ovarian surface epithelial cells continued to express keratin but also became steroidogenic. Transformed ovarian granulosa cells remained steroidogenic but also acquired keratins. Mesodermally derived cells from other sources did not show these differentiation-related changes in response to transformation. The results suggest that v-ras oncogenes may cause the reversion of adult, developmentally related cells to the phenotype of a common, multipotential precursor. They also demonstrate the capacity of v-ras to either induce or reduce the same differentiated characteristic, depending on the developmental history of the target cells.

3-Hydroxysteroid Dehydrogenases↗
PubMed1992

Divergent differentiation of rat adrenocortical cells is associated with an interruption of angiotensin II-mediated signal transduction.

The zones of the adrenal cortex contain distinct populations of cells which share a common developmental origin and steroidogenic template. In the rat, zona glomerulosa cells respond to angiotensin II (Ang II) with increased steroidogenesis while zona fasciculata/reticularis cells do not. We have examined Ang II-mediated signal transduction in homogeneous cellular sub-populations derived from either the zona glomerulosa (GLOM) or the zona fasciculata (FASC). In both of these sub-populations Ang II treatment significantly increased the levels of 3H-labelled inositol phosphates as well as the total mass of inositol 1,4,5-triphosphate. In contrast, the two cell types exhibited very different Ang II-mediated changes in free intracellular calcium ([Ca2+]i). Ang II (10 nM), induced [Ca2+]i increases of > 50 nM in 90% of individual GLOM cells (53/58), but in only 28% of FASC cells (11/39). These [Ca2+]i responses occurred after a transient Ang II stimulation ( < 1 min), in the presence of verapamil and in the absence of extracellular calcium, indicating an intracellular release. In small groups of 10-30 cells, stimulation with 1, 10 and 100 nM Ang II induced [Ca2+]i increases of 78, 178 and 215 nM respectively in GLOM cultures compared to only 35, 64, and 65 nM in FASC cultures. Thapsigargin treatment, which releases intracellular calcium in an inositol phosphate independent manner, elicited [Ca2+]i increases in both populations. Importantly, a calcium ionophore induced elevation of [Ca2+]i increased steroidogenesis in both cell types. These results suggest that an interruption of the signaling cascade at the level of intracellular calcium release contributes to the lack of a steroidogenic response to Ang II by the FASC cells. Therefore, in the rat adrenal cortex, divergent differentiation of related cell types may involve alterations within signal transduction pathways distal to initial receptor-mediated events (i.e. inositol phosphate production) and proximal to downstream effector events (i.e. steroidogenesis).

Adrenal Cortex↗
PubMed1992

Simian virus 40-transformed human ovarian surface epithelial cells escape normal growth controls but retain morphogenetic responses to extracellular matrix.

OBJECTIVE: We aimed to improve the availability of experimental models for the study of human ovarian surface epithelium. STUDY DESIGN: Low-passage cultures of human ovarian surface epithelium were transfected with SV40 large- T antigen and the resulting lines were characterized. RESULTS: Three immortalized lines were obtained. They formed epithelial monolayers resembling ovarian surface epithelium in serum-free medium, expressed large-T antigen and overexpressed p53, produced laminin, and were CA 125 negative. Two lines expressed keratin. On plastic surfaces, the growth rate and growth potential of immortalized ovarian surface epithelium were increased over the growth of ovarian surface epithelium, but on extracellular matrices their growth and morphologic features resembled ovarian surface epithelium. The lines were not tumorigenic in Nu/Nu mice. CONCLUSION: The immortalized ovarian surface epithelium lines resemble cells early in neoplastic progression and should be useful to study ovarian carcinogenesis.

Carcinogenicity Tests↗
PubMed1992

Human ovarian surface epithelial cells are capable of physically restructuring extracellular matrix.

OBJECTIVE: After ovulation the human ovarian surface epithelium proliferates at the wound edges, migrates over the ovulatory defect, and contributes to its repair primarily by the action of proteolytic enzymes and by the deposition of new matrix material. We examined the potential for human ovarian surface epithelial cells to physically remodel extracellular matrix in culture, similar to collagen gel lattice contraction by fibroblasts, a well-known culture model for wound repair, as an additional role of human ovarian surface epithelium in wound repair. STUDY DESIGN: Human ovarian surface epithelium cells from ovarian biopsies of 11 patients were grown in culture and plated onto a combination of collagen gel and rat ovarian surface epithelial-derived extracellular matrix. The degree of matrix contraction was measured as the percentage of the original culture diameter. RESULTS: Human ovarian surface epithelial cells surrounded and contracted the combination of matrices into a dense matrix organoid. The degree of organoid contraction was related to the number of human ovarian surface epithelial cells plated per organoid and to the inclusion of fibroblasts within the collagen gel but was not affected either by adding epidermal growth factor and hydrocortisone to the culture medium or by reducing the serum component of the medium. CONCLUSION: Human ovarian surface epithelial organoids may be useful for the study of normal and abnormal ovarian events such as ovulatory wound repair and cyst formation.

Adult↗
PubMed1992

Intermediate filaments in rat ovarian surface epithelial cells: changes with neoplastic progression in culture.

Interrelationships between neoplastic progression and the expression of intermediate filaments were examined in primary cultures, immortal lines, and Kirsten murine sarcoma virus (KiMSV) transformed lines of rat ovarian surface epithelial (ROSE) cells. Immunofluorescence microscopy revealed abundant keratin filaments in all cells of primary cultures. In immortal, nontumorigenic lines, keratin filaments were detected in fewer cells, in smaller numbers, and in microscopically altered forms. The percentage of keratin-positive cells ranged from 4 to 54%. Its expression was inversely proportional to cell density. Keratin expression was similar in the two immortal lines, although one had retained a monolayered epithelial growth pattern resembling primary cultures, while in the other the growth pattern of the cells was more atypical. The two KiMSV-transformed lines were previously shown to produce tumors in vivo that resemble human ovarian endometrioid stromal sarcomas. In spite of this histologic appearance, the proportion of keratin-positive cells in these cells was increased over the immortal lines. Keratin expression was unrelated to cell density, and keratin in most virally transformed cells was limited to few, fine filaments. In thymidine-labelled immortal and virus-transformed cultures stained for keratin, no correlation was found between keratin expression and proliferative activity. The keratin profiles of primary and immortal cultures were identical on Western blots, with subtypes ranging from 52 to 66 kDa. The two virally transformed lines lacked some of the subtypes. Vimentin networks were faint or absent in primary cultures. In the immortal and the virus-transformed lines, neoplastic progression was associated with increasing vimentin expression but with no changes in filament morphology and distribution. The results show that the abnormalities in intermediate filament expression that accompany immortalization do not preclude the retention of a normal epithelial morphology and growth pattern in this cell type. Furthermore, the number of intermediate filaments and their intracellular distribution appear to be altered at an earlier stage in neoplastic progression than those mechanisms that select for specific keratin subtypes, or those that respond to regulation by cell density. Finally, the presence of keratin in the KiMSV-transformed lines examined in this study supports the hypothesis that human ovarian stromal sarcomas can arise in the OSE.

Animals↗
PubMed1992

Divergence in patterns of invasion among subpopulations derived from a human carcinoma clone: roles of intercellular contacts and of cell-substratum adhesion.

In tumor progression, populations of cancer cells with different patterns of growth and invasion arise within the same tissue and within individual neoplasms. We tested the hypothesis that, even in histologically undifferentiated carcinomas, such diversity may be influenced by differentiation-dependent adhesive mechanisms. We used as prototypes two cell lines that originated in the same clone of a poorly differentiated cervical carcinoma, but express strikingly different phenotypes. Cells of line C-4I express select characteristics of the spinous stage of stratified squamous epithelial differentiation while cells of line C-4II resemble basal cells. C-4I cells form rapidly expanding compact tumors in vivo and multilayered cohesive colonies in culture, while C-4II cells form slow-growing infiltrating tumors in vivo and dispersed, monolayered colonies in culture. In suspension culture which prevented any cell-substratum interactions, C-4I cells formed aggregates that were significantly larger and more compact than those formed by C-4II. Thus, greater intercellular adhesion between the 'spinous' C-4I cells contributed significantly to the phenotypic divergence of the lines. Upon disruption of intercellular adhesion with the glutamine analogue 6-diazo-4-oxo-norleucine (DON), C-4I cultures on plastic and in suspension assumed forms resembling C-4II. On plastic, single 'basal' C-4II cells adhered more rapidly and migrated more slowly than C-4I cells, in keeping with the capacity of C-4II, but not C-4I, to secrete fibronectin (FN) substrata. However, on exogenous FN matrices, migration and cell dispersion were accelerated in both lines. Both lines expressed similar integrin profiles. Thus, the lines had diverged in extracellular matrix production, but not in the receptors for extracellular matrix components. The properties of the C-4 lines mimic those of specific cell types in normal stratified squamous epithelia, where intercellular adhesion increases but FN secretion diminishes with progression from the basal to the spinous stage of differentiation. Our results demonstrate a direct influence of differentiation-associated adhesive mechanisms on growth patterns and suggest that similar mechanisms may be responsible for variations in invasiveness among neoplastic clonal subpopulations. An awareness of these correlations may help to interpret the modes of local invasion by poorly differentiated carcinomas in terms of specific, well-defined cell properties.

Carcinoma↗