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Reversion of the malignant phenotype of human breast cells in three-dimensional culture and in vivo by integrin blocking antibodies.

Weaver VM, Petersen OW, Wang F, Larabell CA, Briand P, Damsky C, Bissell MJ - J. Cell Biol. (1997)

Bottom Line: A stimulatory beta1-integrin antibody proved to be ineffective.The observed phenotypes were reversible when the cells were disassociated and the antibodies removed.Our results illustrate that the extracellular matrix and its receptors dictate the phenotype of mammary epithelial cells, and thus in this model system the tissue phenotype is dominant over the cellular genotype.

View Article: PubMed Central - PubMed

Affiliation: Ernest Orlando Lawrence Berkeley National Laboratory, California 94720, USA.

ABSTRACT
In a recently developed human breast cancer model, treatment of tumor cells in a 3-dimensional culture with inhibitory beta1-integrin antibody or its Fab fragments led to a striking morphological and functional reversion to a normal phenotype. A stimulatory beta1-integrin antibody proved to be ineffective. The newly formed reverted acini re-assembled a basement membrane and re-established E-cadherin-catenin complexes, and re-organized their cytoskeletons. At the same time they downregulated cyclin D1, upregulated p21(cip,wat-1), and stopped growing. Tumor cells treated with the same antibody and injected into nude mice had significantly reduced number and size of tumors in nude mice. The tissue distribution of other integrins was also normalized, suggesting the existence of intimate interactions between the different integrin pathways as well as adherens junctions. On the other hand, nonmalignant cells when treated with either alpha6 or beta4 function altering antibodies continued to grow, and had disorganized colony morphologies resembling the untreated tumor colonies. This shows a significant role of the alpha6/beta4 heterodimer in directing polarity and tissue structure. The observed phenotypes were reversible when the cells were disassociated and the antibodies removed. Our results illustrate that the extracellular matrix and its receptors dictate the phenotype of mammary epithelial cells, and thus in this model system the tissue phenotype is dominant over the cellular genotype.

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Phenotypic reversion as opposed to selection. Phase contrast micrographs of T4-2 cells grown in the presence of anti–β1-integrin  function blocking antibody (T4 β1), mock antibody (nonspecific IgG's) (T4-2 IgG) or no antibodies (T4-2) viewed directly inside EHS:  Despite two rounds of treatment, these antibody reverted cells were able to resume their original tumorigenic phenotypes when cultured in the absence of antibody. All cultures were analyzed after 10–12 d inside EHS. Bar, 50 μm.
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Figure 6: Phenotypic reversion as opposed to selection. Phase contrast micrographs of T4-2 cells grown in the presence of anti–β1-integrin function blocking antibody (T4 β1), mock antibody (nonspecific IgG's) (T4-2 IgG) or no antibodies (T4-2) viewed directly inside EHS: Despite two rounds of treatment, these antibody reverted cells were able to resume their original tumorigenic phenotypes when cultured in the absence of antibody. All cultures were analyzed after 10–12 d inside EHS. Bar, 50 μm.

Mentions: To distinguish between a reversible, microenvironmentally induced change as opposed to selection of possible nonmalignant contaminants or genetically altered mutants, we undertook a series of “reversion rescue” studies. Despite two rounds of reversion, rescue, monolayer propagation, and reculturing in 3-D, these cells were able to resume their original tumorigenic phenotypes when cultured in the absence of antibody (Fig. 6).


Reversion of the malignant phenotype of human breast cells in three-dimensional culture and in vivo by integrin blocking antibodies.

Weaver VM, Petersen OW, Wang F, Larabell CA, Briand P, Damsky C, Bissell MJ - J. Cell Biol. (1997)

Phenotypic reversion as opposed to selection. Phase contrast micrographs of T4-2 cells grown in the presence of anti–β1-integrin  function blocking antibody (T4 β1), mock antibody (nonspecific IgG's) (T4-2 IgG) or no antibodies (T4-2) viewed directly inside EHS:  Despite two rounds of treatment, these antibody reverted cells were able to resume their original tumorigenic phenotypes when cultured in the absence of antibody. All cultures were analyzed after 10–12 d inside EHS. Bar, 50 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2139858&req=5

Figure 6: Phenotypic reversion as opposed to selection. Phase contrast micrographs of T4-2 cells grown in the presence of anti–β1-integrin function blocking antibody (T4 β1), mock antibody (nonspecific IgG's) (T4-2 IgG) or no antibodies (T4-2) viewed directly inside EHS: Despite two rounds of treatment, these antibody reverted cells were able to resume their original tumorigenic phenotypes when cultured in the absence of antibody. All cultures were analyzed after 10–12 d inside EHS. Bar, 50 μm.
Mentions: To distinguish between a reversible, microenvironmentally induced change as opposed to selection of possible nonmalignant contaminants or genetically altered mutants, we undertook a series of “reversion rescue” studies. Despite two rounds of reversion, rescue, monolayer propagation, and reculturing in 3-D, these cells were able to resume their original tumorigenic phenotypes when cultured in the absence of antibody (Fig. 6).

Bottom Line: A stimulatory beta1-integrin antibody proved to be ineffective.The observed phenotypes were reversible when the cells were disassociated and the antibodies removed.Our results illustrate that the extracellular matrix and its receptors dictate the phenotype of mammary epithelial cells, and thus in this model system the tissue phenotype is dominant over the cellular genotype.

View Article: PubMed Central - PubMed

Affiliation: Ernest Orlando Lawrence Berkeley National Laboratory, California 94720, USA.

ABSTRACT
In a recently developed human breast cancer model, treatment of tumor cells in a 3-dimensional culture with inhibitory beta1-integrin antibody or its Fab fragments led to a striking morphological and functional reversion to a normal phenotype. A stimulatory beta1-integrin antibody proved to be ineffective. The newly formed reverted acini re-assembled a basement membrane and re-established E-cadherin-catenin complexes, and re-organized their cytoskeletons. At the same time they downregulated cyclin D1, upregulated p21(cip,wat-1), and stopped growing. Tumor cells treated with the same antibody and injected into nude mice had significantly reduced number and size of tumors in nude mice. The tissue distribution of other integrins was also normalized, suggesting the existence of intimate interactions between the different integrin pathways as well as adherens junctions. On the other hand, nonmalignant cells when treated with either alpha6 or beta4 function altering antibodies continued to grow, and had disorganized colony morphologies resembling the untreated tumor colonies. This shows a significant role of the alpha6/beta4 heterodimer in directing polarity and tissue structure. The observed phenotypes were reversible when the cells were disassociated and the antibodies removed. Our results illustrate that the extracellular matrix and its receptors dictate the phenotype of mammary epithelial cells, and thus in this model system the tissue phenotype is dominant over the cellular genotype.

Show MeSH
Related in: MedlinePlus