scholarly journals Dissecting tumor cell invasion: epithelial cells acquire invasive properties after the loss of uvomorulin-mediated cell-cell adhesion.

1989 ◽  
Vol 108 (6) ◽  
pp. 2435-2447 ◽  
Author(s):  
J Behrens ◽  
M M Mareel ◽  
F M Van Roy ◽  
W Birchmeier

The generation of invasiveness in transformed cells represents an essential step of tumor progression. We show here, first, that nontransformed Madin-Darby canine kidney (MDCK) epithelial cells acquire invasive properties when intercellular adhesion is specifically inhibited by the addition of antibodies against the cell adhesion molecule uvomorulin; the separated cells then invade collagen gels and embryonal heart tissue. Second, MDCK cells transformed with Harvey and Moloney sarcoma viruses are constitutively invasive, and they were found not to express uvomorulin at their cell surface. These data suggest that the loss of adhesive function of uvomorulin (which is identical to E-cadherin and homologous to L-CAM) is a critical step in the promotion of epithelial cells to a more malignant, i.e., invasive, phenotype. Similar modulation of intercellular adhesion might also occur during invasion of carcinoma cells in vivo.

2006 ◽  
Vol 17 (8) ◽  
pp. 3345-3355 ◽  
Author(s):  
Maya Elbert ◽  
David Cohen ◽  
Anne Müsch

Mammalian Par1 is a family of serine/threonine kinases comprised of four homologous isoforms that have been associated with tumor suppression and differentiation of epithelial and neuronal cells, yet little is known about their cellular functions. In polarizing kidney epithelial (Madin-Darby canine kidney [MDCK]) cells, the Par1 isoform Par1b/MARK2/EMK1 promotes the E-cadherin–dependent compaction, columnarization, and cytoskeletal organization characteristic of differentiated columnar epithelia. Here, we identify two functions of Par1b that likely contribute to its role as a tumor suppressor in epithelial cells. 1) The kinase promotes cell–cell adhesion and resistance of E-cadherin to extraction by nonionic detergents, a measure for the association of the E-cadherin cytoplasmic domain with the actin cytoskeleton, which is critical for E-cadherin function. 2) Par1b attenuates the effect of Dishevelled (Dvl) expression, an inducer of wnt signaling that causes transformation of epithelial cells. Although Dvl is a known Par1 substrate in vitro, we determined, after mapping the PAR1b-phosphorylation sites in Dvl, that PAR1b did not antagonize Dvl signaling by phosphorylating the wnt-signaling molecule. Instead, our data suggest that both proteins function antagonistically to regulate the assembly of functional E-cadherin–dependent adhesion complexes.


1990 ◽  
Vol 1 (12) ◽  
pp. 921-936 ◽  
Author(s):  
M J van Zeijl ◽  
K S Matlin

The effects of microtubule perturbation on the transport of two different viral glycoproteins were examined in infected Madin-Darby canine kidney (MDCK) cells grown on both permeable and solid substrata. Quantitative biochemical analysis showed that the microtubule-depolymerizing drug nocodazole inhibited arrival of influenza hemagglutinin on the apical plasma membrane in MDCK cells grown on both substrata. In contrast, the microtubule-stabilizing drug taxol inhibited apical appearance of hemagglutinin only when MDCK cells were grown on permeable substrata. On the basis of hemagglutinin mobility on sodium dodecyl sulfate gels and its sensitivity to endo H, it was evident that nocodazole and taxol arrested hemagglutinin at different intracellular sites. Neither drug caused a significant increase in the amount of hemagglutinin detected on the basolateral plasma membrane domain. In addition, neither drug had any noticeable effect on the transport of the vesicular stomatitis virus (VSV)-G protein to the basolateral surface. These results shed light on previous conflicting reports using this model system and support the hypothesis that microtubules play a role in the delivery of membrane glycoproteins to the apical, but not the basolateral, domain of epithelial cells.


2000 ◽  
Vol 11 (9) ◽  
pp. 3219-3232 ◽  
Author(s):  
Tetsuro Takeda ◽  
William Y. Go ◽  
Robert A. Orlando ◽  
Marilyn Gist Farquhar

Podocalyxin is a major membrane protein of the glomerular epithelium and is thought to be involved in maintenance of the architecture of the foot processes and filtration slits characteristic of this unique epithelium by virtue of its high negative charge. However, until now there has been no direct evidence for podocalyxin's function. Podocalyxin is a type 1 transmembrane sialoprotein with an N-terminal mucin-like domain. To assess its function, we cloned rat podocalyxin and examined the effects of its expression on the cell adhesion properties of stably transfected Chinese hamster ovary (CHO)-K1 and Madin-Darby canine kidney (MDCK) cells and inducible ecdysone receptor–expressing (EcR)-CHO cells. In a cell aggregation assay, CHO-K1 cells expressing high levels of podocalyxin showed complete inhibition of cell aggregation, and MDCK transfectants showed greatly reduced aggregation (∼60–80%) compared with parental cells. In EcR-CHO cells, the expression level of podocalyxin induced by increasing levels of ecdysone analogue correlated closely with the antiadhesion effect. The inhibitory effect of podocalyxin was reversed by treatment of the cells with Arthrobacter ureafacienssialidase, indicating that sialic acid is required for inhibition of cell adhesion. Overexpression of podocalyxin also affected transepithelial resistance and the distribution of junctional proteins in MDCK cells by an unknown mechanism that may involve interaction with the actin cytoskeleton. These results provide direct evidence that podocalyxin functions as an antiadhesin that maintains an open filtration pathway between neighboring foot processes in the glomerular epithelium by charge repulsion.


2004 ◽  
Vol 164 (5) ◽  
pp. 717-727 ◽  
Author(s):  
David Cohen ◽  
Patrick J. Brennwald ◽  
Enrique Rodriguez-Boulan ◽  
Anne Müsch

Epithelial differentiation involves the generation of luminal surfaces and of a noncentrosomal microtubule (MT) network aligned along the polarity axis. Columnar epithelia (e.g., kidney, intestine, and Madin-Darby canine kidney [MDCK] cells) generate apical lumina and orient MT vertically, whereas liver epithelial cells (hepatocytes and WIFB9 cells) generate lumina at cell–cell contact sites (bile canaliculi) and orient MTs horizontally. We report that knockdown or inhibition of the mammalian orthologue of Caenorhabditis elegans Par-1 (EMK1 and MARK2) during polarization of cultured MDCK and WIFB9 cells prevented development of their characteristic lumen and nonradial MT networks. Conversely, EMK1 overexpression induced the appearance of intercellular lumina and horizontal MT arrays in MDCK cells, making EMK1 the first known candidate to regulate the developmental branching decision between hepatic and columnar epithelial cells. Our experiments suggest that EMK1 primarily promotes reorganization of the MT network, consistent with the MT-regulating role of this gene product in other systems, which in turn controls lumen formation and position.


1996 ◽  
Vol 270 (1) ◽  
pp. C200-C207 ◽  
Author(s):  
E. D. Kwon ◽  
K. Zablocki ◽  
E. M. Peters ◽  
K. Y. Jung ◽  
A. Garcia-Perez ◽  
...  

The amount of glycerophosphocholine (GPC) in renal medullary cells in vivo and in cultured renal [Madin-Darby canine kidney (MDCK)] cells varies with extracellular NaCl and urea. We previously showed that this is largely due to modulation of GPC degradation catalyzed by GPC:choline phosphodiesterase (GPC: PDE). GPC also varies inversely with the levels of other compatible osmolytes, the accumulation of which is induced by high tonicity. We tested whether GPC:PDE activity and GPC degradation are affected by accumulation of compatible osmolytes other than GPC. We find that MDCK cell GPC content decreases when the cells take up betaine and/or inositol from the medium. The effect is considerably greater for cells in isosmotic or high-NaCl medium than in high-urea medium. This difference is associated with suppression of betaine and inositol accumulation with high urea. We then measured GPC:PDE activity with a novel chemiluminescent assay. Addition of inositol and/or betaine to the medium greatly increases GPC:PDE activity in cells in isosmotic or high-NaCl media, but the increase is much less in high-urea medium. The increases in GPC:PDE activity, associated with the presence of betaine, are accompanied by commensurate increases in absolute rates of endogenous GPC degradation by cells in isosmotic or high-NaCl medium. We found previously that, in MDCK cells incubated for 2 days in high-NaCl medium, the rate of GPC synthesis from phosphatidylcholine is increased, correlated with an increase in phospholipase activity. However, in the present experiments, betaine accumulation has no effect on phospholipase activity under those conditions and, thus, presumably does not affect GPC synthesis. Collectively, these data support the conclusion that betaine and/or inositol reduces GPC by increasing GPC degradation catalyzed by GPC:PDE. This mechanism enables GPC to be reciprocally regulated relative to other compatible osmolytes, thus maintaining an appropriate total osmolyte content.


1987 ◽  
Vol 104 (6) ◽  
pp. 1527-1537 ◽  
Author(s):  
W J Nelson ◽  
P J Veshnock

During growth of Madin-Darby canine kidney (MDCK) epithelial cells, there is a dramatic change in the stability, biophysical properties, and distribution of the membrane skeleton (fodrin) which coincides temporally and spatially with the development of the polarized distribution of the Na+, K+-ATPase, a marker protein of the basolateral domain of the plasma membrane. These changes occur maximally upon the formation of a continuous monolayer of cells, indicating that extensive cell-cell contact may play an important role in the organization of polarized MDCK cells (Nelson, W. J., and P. J. Veshnock, 1986, J. Cell Biol., 103:1751-1766). To directly analyze the role of cell-cell contact in these events, we have used an assay in which the organization of fodrin and membrane proteins is analyzed in confluent monolayers of MDCK cells in the absence or presence of cell-cell contact by adjusting the concentration Ca++ in the growth medium. Our results on the stability and solubility properties of fodrin reported here show directly that there is a positive correlation between cell-cell contact and increased stability and insolubility of fodrin. Furthermore, we show that fodrin can be recruited from an unstable pool of protein to a stable pool during induction of cell-cell contact; significantly, the stabilization of fodrin is not affected by the addition of cyclohexamide, indicating that proteins normally synthesized during the induction of cell-cell contact are not required. Together these results indicate that cell-cell contact may play an important role in the development of polarity in MDCK cells by initiating the formation of a stable, insoluble matrix of fodrin with preexisting (membrane) proteins at the cell periphery. This matrix may function subsequently to trap proteins targeted to the membrane, resulting in the maintenance of membrane domains.


1990 ◽  
Vol 110 (2) ◽  
pp. 349-357 ◽  
Author(s):  
W J Nelson ◽  
E M Shore ◽  
A Z Wang ◽  
R W Hammerton

Cell-cell contact is an important determinant in the formation of functionally distinct plasma membrane domains during the development of epithelial cell polarity. In cultures of Madin-Darby canine kidney (MDCK) epithelial cells, cell-cell contact induces the assembly and accumulation of the Na+,K+-ATPase and elements of the membrane-cytoskeleton (ankyrin and fodrin) at the regions of cell-cell contact. Epithelial cell-cell contact appears to be regulated by the cell adhesion molecule uvomorulin (E-cadherin) which also becomes localized at the lateral plasma membrane of polarized cells. We have sought to determine whether the colocalization of these proteins reflects direct molecular interactions which may play roles in coordinating cell-cell contact and the assembly of the basal-lateral domain of the plasma membrane. Recently, we identified a complex of proteins containing the Na+,K+-ATPase, ankyrin, and fodrin in extracts of whole MDCK cells (Nelson, W.J., and R. W. Hammerton. 1989. J. Cell Biol. 108:893-902). We have now examined cell extracts for protein complexes containing the cell adhesion molecule uvomorulin. Proteins were solubilized from whole MDCK cells and fractionated in sucrose gradients. The sedimentation profile of solubilized uvomorulin is well separated from the majority of cell surface proteins, suggesting that uvomorulin occurs in a protein complex. A distinct portion of uvomorulin (30%) cosediments with ankyrin and fodrin (approximately 10.5S). Further fractionation of cosedimenting proteins in nondenaturing polyacrylamide gels reveals a discrete band of proteins that binds antibodies specific for uvomorulin, Na+,K+-ATPase, ankyrin, and fodrin. Significantly, ankyrin and fodrin, but not Na+K+-ATPase, coimmunoprecipitate in a complex with uvomorulin using uvomorulin antibodies. This result indicates that separate complexes exist containing ankyrin and fodrin with either uvomorulin or Na+,K+-ATPase. These results are discussed in the context of the possible roles of uvomorulin-induced cell-cell contact in the assembly of the membrane-cytoskeleton and associated membrane proteins (e.g., Na+,K+-ATPase) at the contact zone and in the development of cell polarity.


1999 ◽  
Vol 10 (1) ◽  
pp. 179-195 ◽  
Author(s):  
Frederik Vilhardt ◽  
Morten Nielsen ◽  
Kirsten Sandvig ◽  
Bo van Deurs

Accumulated data indicate that endocytosis of the glycosylphosphatidyl-inositol-anchored protein urokinase plasminogen activator receptor (uPAR) depends on binding of the ligand uPA:plasminogen activator inhibitor-1 (PAI-1) and subsequent interaction with internalization receptors of the low-density lipoprotein receptor family, which are internalized through clathrin-coated pits. This interaction is inhibited by receptor-associated protein (RAP). We show that uPAR with bound uPA:PAI-1 is capable of entering cells in a clathrin-independent process. First, HeLaK44A cells expressing mutant dynamin efficiently internalized uPA:PAI-1 under conditions in which transferrin endocytosis was blocked. Second, in polarized Madin–Darby canine kidney (MDCK) cells, which expressed human uPAR apically, the low basal rate of uPAR ligand endocytosis, which could not be inhibited by RAP, was increased by forskolin or phorbol ester (phorbol 12-myristate 13-acetate), which selectively up-regulate clathrin-independent endocytosis from the apical domain of epithelial cells. Third, in subconfluent nonpolarized MDCK cells, endocytosis of uPA:PAI-1 was only decreased marginally by RAP. At the ultrastructural level uPAR was largely excluded from clathrin-coated pits in these cells and localized in invaginated caveolae only in the presence of cross-linking antibodies. Interestingly, a larger fraction of uPAR in nonpolarized relative to polarized MDCK cells was insoluble in Triton X-100 at 0°C, and by surface labeling with biotin we also show that internalized uPAR was mainly detergent insoluble, suggesting a correlation between association with detergent-resistant membrane microdomains and higher degree of clathrin-independent endocytosis. Furthermore, by cryoimmunogold labeling we show that 5–10% of internalized uPAR in nonpolarized, but not polarized, MDCK cells is targeted to lysosomes by a mechanism that is regulated by ligand occupancy.


2007 ◽  
Vol 18 (6) ◽  
pp. 2203-2215 ◽  
Author(s):  
David Cohen ◽  
Yuan Tian ◽  
Anne Müsch

Kidney-derived Madin Darby canine kidney (MDCK) cells form lumina at their apices, and target luminal proteins to an intracellular vacuolar apical compartment (VAC) when prevented from polarizing. Hepatocytes, by contrast, organize their luminal surfaces (the bile canaliculi; BC) between their lateral membranes, and, when nonpolarized, they display an intracellular luminal compartment that is distinct from the VACs of MDCK cells. Overexpression of the serine/threonine kinase Par1b/EMK1/MARK2 induces BC-like lateral lumina and a hepatic-type intracellular luminal compartment in MDCK cells, suggesting a role for Par1b in the branching decision between kidney- and hepatic-type epithelial phenotypes. Here, we report that Par1b promotes lateral lumen polarity in MDCK cells independently of Ca2+-mediated cell–cell adhesion by inhibiting myosin II in a rho kinase-dependent manner. Polarization was inhibited by E-cadherin depletion but promoted by an adhesion-defective E-cadherin mutant. By contrast, apical surface formation in control MDCK cells required Ca2+-dependent cell–cell adhesion, but it occurred in the absence of E-cadherin. We propose that E-cadherin, when in an adhesion-incompetent state at the lateral domain, serves as targeting patch for the establishment of lateral luminal surfaces. E-cadherin depletion also reverted the hepatic-type intracellular luminal compartment in Par1b-MDCK cells to VACs characteristic of control MDCK cells, indicating a novel link between E-cadherin and luminal protein targeting.


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