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M S Steinberg

Publications and source records attributed to M S Steinberg.

At least 19 recordsLinked to original sources
PubMed1998

Dexamethasone up-regulates cadherin expression and cohesion of HT-1080 human fibrosarcoma cells.

The synthetic glucocorticoid dexamethasone markedly decreases the invasiveness of HT-1080 human fibrosarcoma cells. We show here that dexamethasone treatment of HT-1080 cell aggregates more than doubles their cohesivity from 3.9 to 9.7 dyne/cm. Western blot analysis shows a corresponding increase in cadherin expression. This was accompanied by an increase in the rate of calcium-dependent aggregation. Dexamethasone-treated aggregates spread to form a monolayer in Matrigel spreading assays, but the cells remained much more contiguous than their untreated counterparts. Invasion-suppression by dexamethasone may therefore be due, at least in part, to a previously unsuspected increase in cadherin-mediated cohesion.

Antineoplastic Agents, Hormonal↗
PubMed1998

Viscoelastic properties of living embryonic tissues: a quantitative study.

A number of properties of certain living embryonic tissues can be explained by considering them as liquids. Tissue fragments left in a shaker bath round up to form spherical aggregates, as do liquid drops. When cells comprising two distinct embryonic tissues are mixed, typically a nucleation-like process takes place, and one tissue sorts out from the other. The equilibrium configurations at the end of such sorting out phenomena have been interpreted in terms of tissue surface tensions arising from the adhesive interactions between individual cells. In the present study we go beyond these equilibrium properties and study the viscoelastic behavior of a number of living embryonic tissues. Using a specifically designed apparatus, spherical cell aggregates are mechanically compressed and their viscoelastic response is followed. A generalized Kelvin model of viscoelasticity accurately describes the measured relaxation curves for each of the four tissues studied. Quantitative results are obtained for the characteristic relaxation times and elastic and viscous parameters. Our analysis demonstrates that the cell aggregates studied here, when subjected to mechanical deformations, relax as elastic materials on short time scales and as viscous liquids on long time scales.

Animals↗
PubMed1997

Germ-layer surface tensions and "tissue affinities" in Rana pipiens gastrulae: quantitative measurements.

The morphogenetic properties causing germ-layer spreading and stratification in amphibian gastrulation were called "tissue affinities" by Holtfreter. The differential adhesion hypothesis (DAH) attributes such liquid-like tissue rearrangements to forces generated by intercellular adhesions within and between the migrating cell populations. This theory predicts that, among the primary germ layers, the cohesiveness of deep ectoderm should be the greatest, that of deep mesoderm should be intermediate, and that of deep endoderm should be the least. Also, the cohesiveness of differentiating neural ectoderm should increase after induction, causing it to internalize and segregate from epidermis. The DAH also explains why the cohesiveness of "liquid" tissues, whose cells are free to rearrange, should be measurable as tissue surface tensions. Using a specially designed tissue surface tensiometer, we demonstrate that (i) aggregates of Rana pipiens deep germ layers do possess liquid-like surface tensions, (ii) their surface tension values lie in precisely the sequence necessary to account for germ-layer stratification in vitro and in vivo, and (iii) the surface tension of deep ectoderm just underlain by the archenteron roof is twice that of not-yet-underlain deep ectoderm. These measurements provide direct, quantitative evidence that the "tissue affinities" governing germ-layer flow during early stages of vertebrate morphogenesis are reflected in tissue surface tensions.

Animals↗
PubMed1997

Measurement of tumor cell cohesion and suppression of invasion by E- or P-cadherin.

Invasiveness of carcinomas was connected early to decreased cohesiveness and has more recently been associated with loss or decreased activity of E-cadherin. In the first thermodynamic measurements of cohesive intensities among malignant cells, we here find the cohesive intensities of Lewis lung carcinoma cells to fall within the range measured previously for cells from a series of noninvasive embryonic tissues. Thus, too-low cohesiveness is itself an insufficient explanation for invasiveness. Nevertheless, transfection-mediated cadherin expression sufficient to increase cohesiveness by as little as 26% suffices to greatly reduce invasion of aggregates of Lewis lung carcinoma cells into Matrigel. This property is not restricted to E-cadherin but is shared by P-cadherin. The same cadherin-transfected cells do not display this invasion suppression when plated sparsely, indicating that invasion-suppression activity of cadherins requires cell-cell contact. These facts are consistent with the invasion-suppression activity of cadherins resulting either from the physical restraint of increased cohesion per se or from another cadherin activity mediated through cell-cell contact.

Animals↗
PubMed1996

Adhesion in development: an historical overview.

My purpose here is to provide brief historical overviews of three related subjects conceptually fundamental to the broader subject of "cell adhesion in development." These subjects are (1) the evolution of our present understanding of how animal cells cohere; (2) the question of what principles underlie the ability of embryonic cell populations to organize themselves into anatomically correct structures; and (3) the ongoing effort to understand the origins of the "recognition specificity" evinced in the latter phenomenon. Because this review must be brief, it is not possible to mention all of the significant advances, many of which will be referenced in a recent more detailed review of this subject (Grunwald, 1991). For the same reason, the important work on cell adhesion in nonvertebrate systems is not included.

Animals↗
PubMed1996

Surface tensions of embryonic tissues predict their mutual envelopment behavior.

During embryonic development, certain tissues stream to their destinations by liquidlike spreading movements. According to the 'differential adhesion hypothesis', these movements are guided by cell-adhesion-generated tissue surface tensions (sigmas), operating in the same manner as surface tensions do in the mutual spreading behavior of immiscible liquids, among which the liquid of lower surface tension is always the one that spreads over its partner. In order to conduct a direct physical test of the 'differential adhesion hypothesis', we have measured the sigmas of aggregates of five chick embryonic tissues, using a parallel plate compression apparatus specifically designed for this purpose, and compared the measured values with these tissues' mutual spreading behaviors. We show that aggregates of each of these tissues behave for a time as elasticoviscous liquids with characteristic surface tension values. Chick embryonic limb bud mesoderm (sigma = 20.1 dyne/cm) is enveloped by pigmented epithelium (sigma = 12.6 dyne/cm) which, in turn, is enveloped by heart (sigma = 8.5 dyne/cm) which, in turn, is enveloped by liver (sigma = 4.6 dyne/cm) which, in turn, is enveloped by neural retina (sigma = 1.6 dyne/cm). Thus, as predicted, the tissues' surface tension values fall in the precise sequence required to account for their mutual envelopment behavior.

Animals↗
PubMed1996

Morphogenesis of the axolotl pronephric duct: a model system for the study of cell migration in vivo.

Pronephric duct (PND) morphogenesis is a critical early event in the development of the vertebrate excretory system. This structure is the exit channel for both pronephric and mesonephric filtrate, forms the ureteric bud of the metanephros and gives rise to the ductus deferens of the testis. In addition, the PND and ureteric bud epithelia induce terminal differentiation of the mesonephric and metanephric mesenchyme, respectively. Elongation of the PND in all vertebrates involves active cell migration of the primordium. In urodele embryos--unlike in some anuran, avian and mammalian embryos--elongation of the PND occurs solely by cell migration. In the axolotl embryo, the PND primordium segregates as an ovoid tissue mass from the anterodorsal flank mesoderm directly beneath somites 3-7. The primordium then extends caudally along the ventral border of the developing somites until it reaches the cloaca. The ease with which these embryos can be manipulated microsurgically makes the PND system ideal for the study of the mechanisms controlling cell migration in vivo. This review summarizes the progress that has been made in characterizing the environmental cues and the cell surface recognition systems that drive this tightly regulated migration event.

Ambystoma↗
PubMed1995

The epidermis is a source of directional information for the migrating pronephric duct in Ambystoma mexicanum embryos.

In the urodele Ambystoma mexicanum, the pronephric duct (PND) is formed from a coherent group of cells that migrate from the pronephros to the cloaca along a pathway immediately ventral to the developing somites. The guidance cues used by the migrating PND primordium to find the cloaca are a local property of the migration substratum, are temporally regulated, and are both polarized and oriented. Since the pronephric duct migrates between two tissues--the underlying lateral mesoderm and the overlying epidermis--we performed a study to identify the tissue(s) in which PND guidance cues originate. Through direct manipulation of the epidermis overlying the duct pathway, we show that the migrating PND reads epidermally derived cues (1) along the anterior-posterior axis that direct migration from anterior to posterior and (2) along the dorsal-ventral axis that constrain migration to the duct pathway. Heterochronic grafting experiments reveal that the ability to direct PND migration is a stable property of flank epidermis throughout the period of PND migration. Epidermal cues are, therefore, not responsible for the observed temporal restrictions on PND migration. Thus, the region of the embryo within which the advancing PND tip can migrate actually represents an area where two distinct but required sets of PND migration cues overlap. The epidermis overlying the duct pathway provides directional information; temporal restriction of duct migration is hypothesized to be a property of the flank mesoderm.

Ambystoma mexicanum↗
PubMed1994

Experimental specification of cell sorting, tissue spreading, and specific spatial patterning by quantitative differences in cadherin expression.

The sorting-out of embryonic cells from a cell mixture and the selective spreading of one cell population over the surface of another have been attributed to various causes. These include differentials in chemotaxis, in cellular adhesiveness, in cell surface contractility, in speed of cell movement, and in the timing of postulated changes in cellular adhesive and motile properties. One of us earlier predicted on mathematical grounds that two motile cell types differing only in the level of expression of a single cell adhesion system should not only segregate from one another but also arrange themselves with the less cohesive cells enveloping a core of the more cohesive ones. To test these predictions, we combined two populations of L cells transfected with P-cadherin cDNA and expressing this homophilic adhesion molecule in substantially differing amounts. When the two cell populations were intermixed, they segregated to approach a sphere-within-a-sphere configuration, the cell population expressing more P-cadherin forming islands which fused to become an internal "medulla." When the two cell populations were first formed into separate aggregates which were subsequently allowed to fuse, the cell population expressing more P-cadherin was enveloped by its partner, which formed an external "cortex." These observations confirm the early prediction and support the conclusion that both morphogenetic movements and the specific anatomical configurations to which they lead can be determined by particular sets of intercellular adhesive intensities, regardless of how these are generated and in the absence of differentials in other parameters.

Animals↗
PubMed1993

Three populations of migrating amphibian embryonic cells utilize different guidance cues.

Previous investigations designed to identify the molecule(s) governing the directed migration of the amphibian pronephric duct (PND) revealed a requirement for a glycosyl phosphatidylinositol (GPI)-linked cell surface molecule, possibly the ectoenzyme alkaline phosphatase (AP). Cranial neural crest cells (CNC) grafted to the flank migrate along the same pathways as the PND, suggesting that PND and CNC guidance systems might have a common molecular basis. Both PND and CNC migration pathways display AP. The present experiments demonstrate, however, that GPI-linked molecules on these pathways are not required for migration of either cell type. Because PND cells themselves express AP prominently but CNC cells do not, we asked whether the GPI-linked molecule required for PND migration resides on the PND cells themselves. Treatment of PND cells with phosphatidylinositol-specific phospholipase C, an enzyme that removes GPI-linked proteins, prevents their migration. Transplantation experiments show that although CNC cells are capable of following PND migration pathways, the converse is not the case. Extension of the transplantation experiments to include trunk neural crest (TNC) cells indicates that although CNC cells can follow PND guidance information on the flank, PND, CNC, and TNC cells all normally utilize different molecular cues to guide their migrations in situ.

Ambystoma↗
PubMed1991

An immunoelectron microscopic comparison of desmosomal constituents and hemidesmosomal ones originating from the same tissue of the same animal.

The molecular constituents of desmosomes and hemidesmosomes were compared by examining bovine muzzle epidermis under immunoelectron microscopy using a postembedding method, first with antibodies prepared to four desmosomal antigens (DP1/2, DP3, DG1, DG2/3), followed by protein A-gold (PAG) complexes. The four antibodies showed almost negative labeling at hemidesmosomes as compared with the labeling observed at the desmosomes in the same tissue. By counting the number of PAG particles/200 millimicrons at hemidesmosomes and desmosomes, the above qualitative observation was confirmed quantitatively. These results support a new concept which has recently been proposed by several researchers that hemidesmosomes and desmosomes are immunochemically distinct.

Animals↗
PubMed1989

Axolotl pronephric duct cell migration is sensitive to phosphatidylinositol-specific phospholipase C.

On the basis of its distribution pattern in embryos of the axolotl (Ambystoma mexicanum), we recently identified alkaline phosphatase as a molecule potentially involved in guiding the migration of the pronephric duct. Alkaline phosphatase is a cell surface protein anchored to cell membranes via a covalent linkage to a phosphatidylinositol glycan (PI-G). The enzyme phosphatidylinositol-specific phospholipase C (PIPLC) specifically releases from cell surfaces molecules anchored by the PI-G linkage. In order to test the possibility that a PI-G anchored protein is involved in directing pronephric duct cell migration, PIPLC was applied to axolotl embryos. The enzyme was introduced into embryos through the use of a novel slow-release bead material, hydrolysed polyacrylamide. PIPLC blocked pronephric duct cell migration without interfering with somite fissure formation, a concurrent, neighbouring morphogenetic cell rearrangement which occurs with little if any alkaline phosphatase present. In addition, alkaline phosphatase activity was markedly diminished in the vicinity of the implanted beads. These observations suggest that at least one protein anchored to the cell membrane by a PI-G linkage, possibly alkaline phosphatase, is involved in guiding or promoting pronephric duct cell migration.

Alkaline Phosphatase↗
PubMed1988

A molecular marker for cell guidance information in the axolotl embryo.

Previous studies from this laboratory suggested that the elongation of the pronephric duct (PND) in the axolotl Ambystoma mexicanum is directed by an adhesion gradient along the migrating cells' substratum. We have also shown that cranial neural crest (CNC) cells are able to follow the PND guidance information, for which these cells serve as useful probes (S.L. Zackson and M.S. Steinberg, (1986) Dev. Biol. 117, 342-353). These experiments allow the construction of a map of the cell guidance information. This map is presumed to reflect a molecular prepattern representing the distribution of a cell guidance associated molecule (CGAM) responsible for the ensuing pattern of cell migration. We refer to this proposal as the molecular prepattern hypothesis. In this paper we describe and identify a candidate CGAM displaying a localization pattern corresponding closely with our map of the PND/CNC guidance information on the embryonic flank. This candidate CGAM is also found to be abundant on the posterior neural tube, an embryonic region not previously explored for PND/CNC guidance information. The latter observation has provided the opportunity for an independent test of the correlation between the presence of this molecule in an embryonic region and the ability of that region to direct cell migration. We have found that grafted CNC cells do indeed migrate upon the strongly labeling posterior neural tube in preference to the neighboring poorly labeling presomitic mesoderm. We identify this candidate CGAM as the cell surface enzyme alkaline phosphatase. Possible roles for alkaline phosphatase in directing embryonic cell migrations are discussed.

Alkaline Phosphatase↗
PubMed1987

On the molecular organization, diversity and functions of desmosomal proteins.

After a brief review of epithelial cell junctions, the authors describe a series of observations and experiments directed toward elucidating the molecular organization and functions of the proteins of desmosomes (maculae adherentes). Their immunofluorescence observations reveal differences between the proteins of junctional complex and other desmosomes of the same cells. Quantitative immuno-localization studies are described using protein A-colloidal gold markers and a series of monospecific, polyclonal antibodies directed against cytokeratins and four desmosomal protein families. It is shown that desmoplakin III (about 81 kDa) is restricted to the desmosomal cytoplasmic plaque, which possesses outer and inner dense zones. Desmoplakins I/II (about 240 kDa and 210 kDa) extend across the same range and beyond into the intermediate filament-rich cytoplasm. Two glycoprotein families, desmoglein I (DGI; about 150 kDa) and desmoglein II (DGII; about 97-118 kDa), extend from the desmosomal midline (or beyond) across the desmoglea (intercellular space), through the plasma membrane and across both layers of the plaque, terminating near its cytoplasmic border. Cytokeratins do not extend into the desmosome. With new procedures utilizing guanidine HCl for preparing and fractionating desmosomal proteins, DGII has been purified to homogeneity. DGII, DGI and a third protein are all shown to bind Ca2+, which is known to promote desmosome assembly.

Animals↗
PubMed1987

Chemotaxis or adhesion gradient? Pronephric duct elongation does not depend on distant sources of guidance information.

Previously published experimental studies have led to conflicting interpretations concerning the mechanism guiding pronephric duct elongation in the urodele embryo. Although most studies have led to the conclusion that duct migration is directed by an adhesion gradient (haptotaxis), one set of experiments has been interpreted as supporting chemotactic guidance. We have resolved this conflict by conducting grafting experiments in Ambystoma embryos which distinguish between these two possible mechanisms of cell guidance. Our results provide an alternative explanation for the observations originally interpreted as supporting chemotaxis and add further evidence for adhesive guidance.

Ambystoma↗
PubMed1986

Purification of desmoglein II: a method for the preparation and fractionation of desmosomal components.

We have developed rapid and efficient methods for the isolation of desmosomes and the fractionation of their components. These methods involve the use of 6 M guanidine HCl to isolate the desmosomes from bovine epidermis, followed by hydroxyapatite column chromatography in the presence of SDS to fractionate the desmosomal components. All of the desmoplakins and desmogleins were purified at least partially by these procedures, and desmoglein II was purified to apparent homogeneity. We expect these procedures to facilitate a detailed biochemical analysis of the molecular components of desmosomes. In addition, these methods may be applicable to the purification of other plasma membrane domains involved in cell adhesion.

Amino Acids↗
PubMed1986

A monoclonal antibody to the desmosomal glycoprotein desmoglein I binds the same polypeptide as human autoantibodies in pemphigus foliaceus.

Recent studies have demonstrated that antibodies from about half of patients with pemphigus foliaceus (PF) bind to a 160 kd polypeptide ("PF antigen") in sodium dodecyl sulfate (SDS) extracts of normal human epidermis. Desmoglein (DG) I, a glycoprotein enriched in desmosomal cores, is approximately the same m.w. as PF antigen. To demonstrate that PF autoantibodies bind to DG I, we used a monoclonal IgG antibody (MmDGI-1) that was raised against bovine muzzle desmosomal cores, and that specifically binds DG I. Double immunofluorescence labeling was performed on the same section of normal human skin with PF antibodies, detected by fluorescein-conjugated goat anti-human IgG, and MmDGI-1, detected by rhodamine-conjugated goat anti-mouse IgG. The pattern of reactivity with both antibodies was identical. Immunoblotting studies on proteins extracted from normal human epidermis and separated by SDS-polyacrylamide gel electrophoresis demonstrated that PF antibodies and MmDGI-1 bound co-migrating polypeptide bands of approximate m.w. 160,000. To confirm that these were identical polypeptides, we performed immunoblots of these epidermal extracts that were separated by two-dimensional gel electrophoreses (isoelectric focusing followed by SDS-PAGE). PF antibodies and MmDGI-1 bound identical spots with pI approximately 5.4 to 5.7 and m.w. approximately 160,000. These studies demonstrate that autoantibodies from certain patients with PF, a disorder of cell adhesion, bind to DG I, a desmosomal core glycoprotein.

Antibodies, Monoclonal↗