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Colorectal hyperplasia and dysplasia due to human carcinoembryonic antigen (CEA) family member expression in transgenic mice.

Chan CH, Camacho-Leal P, Stanners CP - PLoS ONE (2007)

Bottom Line: The colonocyte surface level of integrin alpha5 and the activation of AKT increased progressively with the expression levels of CEA/CEACAM6.Colonic crypts showed a progressive increase in colonocyte proliferation, an increase in crypt fission, and a strong inhibition of both differentiation and anoikis/apoptosis.All transgenic mice showed massively enlarged colons comprising a continuous mosaic of severe hyperplasia, dysplasia and serrated adenomatous morphology.

View Article: PubMed Central - PubMed

Affiliation: McGill Cancer Centre, Department of Biochemistry, McGill University, Montréal, Québec, Canada. carlos.chan@mcgill.ca

ABSTRACT
CEA and CEACAM6 are immunoglobulin family intercellular adhesion molecules that are up-regulated without structural mutations in approximately 70% of human cancers. Results in in vitro systems showing tumorigenic effects for these molecules suggest that this correlation could indicate an instrumental role in tumorigenesis. To test whether this applies in vivo, transgenic mice harboring 187 kb of the human genome containing four CEA family member genes including the CEA and CEACAM6 genes were created and their copy numbers increased by mating until colonocyte expression levels reached levels seen in human colorectal carcinomas. The colonocyte surface level of integrin alpha5 and the activation of AKT increased progressively with the expression levels of CEA/CEACAM6. Colonic crypts showed a progressive increase in colonocyte proliferation, an increase in crypt fission, and a strong inhibition of both differentiation and anoikis/apoptosis. All transgenic mice showed massively enlarged colons comprising a continuous mosaic of severe hyperplasia, dysplasia and serrated adenomatous morphology. These results suggest that up-regulated non-mutated adhesion molecules could have a significant instrumental role in human cancer.

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Cell surface expression of CEACAM and integrins on purified colonocytes.FACS profiles of WT (shaded area), CEABAC2 (dotted line) and CEABAC10 (solid line) purified colonocytes. A–B) FACS profiles of CEA detected by T84.66 mAb (A) and CEACAM6 detected by 9A6 mAb (B), show a higher cell surface expression of CEA and CEACAM6 in the CEABAC10 than CEABAC2 colonocytes, whereas wild-type (WT) colonocytes show only a background flurorescence. C) FACS profiles of integrin α5 detected by HMα5-1 mAb show increasing cell surface expression levels of integrin α5 with increasing CEA/CEACAM6 cell surface expression levels (A–B). D) FACS profiles of integrin α2 detected by HMalpha2 mAb show the same cell surface or even less expression levels of integrins α2.
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pone-0001353-g002: Cell surface expression of CEACAM and integrins on purified colonocytes.FACS profiles of WT (shaded area), CEABAC2 (dotted line) and CEABAC10 (solid line) purified colonocytes. A–B) FACS profiles of CEA detected by T84.66 mAb (A) and CEACAM6 detected by 9A6 mAb (B), show a higher cell surface expression of CEA and CEACAM6 in the CEABAC10 than CEABAC2 colonocytes, whereas wild-type (WT) colonocytes show only a background flurorescence. C) FACS profiles of integrin α5 detected by HMα5-1 mAb show increasing cell surface expression levels of integrin α5 with increasing CEA/CEACAM6 cell surface expression levels (A–B). D) FACS profiles of integrin α2 detected by HMalpha2 mAb show the same cell surface or even less expression levels of integrins α2.

Mentions: A case for a positive change in the activation state of integrin α5β1 as a result of CEA clustering was made from previous in vitro studies (see Introduction). Here, using purified colonocytes from the transgenic mice, it was not technically possible to measure their binding to fibronectin, the major ligand of integrin α5β1, as an indication of its activation state. However, the cell surface level of integrin α5 was higher in CEABAC2 than in WT colonocytes and even higher in CEABAC10 (Figure 2C). This finding correlated well with the cell surface levels of CEA and CEACAM6 in the CEABAC2 and CEABAC10 mice (Figures 2A and 2B). CEABAC20 colonocytes were not included in this part of the characterization because the extensive distortion of the crypt architecture (see below) rendered their isolation too difficult using the current method. The expression level of integrin α2 showed no such increase with CEA/CEACAM6 expression (Figure 2D) and integrin αv could not be detected (data not shown). These results suggest that integrin α5β1 signaling could be increased in colonocytes from CEABAC transgenic mice and in a CEA/CEACAM6 gene dose-dependent fashion.


Colorectal hyperplasia and dysplasia due to human carcinoembryonic antigen (CEA) family member expression in transgenic mice.

Chan CH, Camacho-Leal P, Stanners CP - PLoS ONE (2007)

Cell surface expression of CEACAM and integrins on purified colonocytes.FACS profiles of WT (shaded area), CEABAC2 (dotted line) and CEABAC10 (solid line) purified colonocytes. A–B) FACS profiles of CEA detected by T84.66 mAb (A) and CEACAM6 detected by 9A6 mAb (B), show a higher cell surface expression of CEA and CEACAM6 in the CEABAC10 than CEABAC2 colonocytes, whereas wild-type (WT) colonocytes show only a background flurorescence. C) FACS profiles of integrin α5 detected by HMα5-1 mAb show increasing cell surface expression levels of integrin α5 with increasing CEA/CEACAM6 cell surface expression levels (A–B). D) FACS profiles of integrin α2 detected by HMalpha2 mAb show the same cell surface or even less expression levels of integrins α2.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2131779&req=5

pone-0001353-g002: Cell surface expression of CEACAM and integrins on purified colonocytes.FACS profiles of WT (shaded area), CEABAC2 (dotted line) and CEABAC10 (solid line) purified colonocytes. A–B) FACS profiles of CEA detected by T84.66 mAb (A) and CEACAM6 detected by 9A6 mAb (B), show a higher cell surface expression of CEA and CEACAM6 in the CEABAC10 than CEABAC2 colonocytes, whereas wild-type (WT) colonocytes show only a background flurorescence. C) FACS profiles of integrin α5 detected by HMα5-1 mAb show increasing cell surface expression levels of integrin α5 with increasing CEA/CEACAM6 cell surface expression levels (A–B). D) FACS profiles of integrin α2 detected by HMalpha2 mAb show the same cell surface or even less expression levels of integrins α2.
Mentions: A case for a positive change in the activation state of integrin α5β1 as a result of CEA clustering was made from previous in vitro studies (see Introduction). Here, using purified colonocytes from the transgenic mice, it was not technically possible to measure their binding to fibronectin, the major ligand of integrin α5β1, as an indication of its activation state. However, the cell surface level of integrin α5 was higher in CEABAC2 than in WT colonocytes and even higher in CEABAC10 (Figure 2C). This finding correlated well with the cell surface levels of CEA and CEACAM6 in the CEABAC2 and CEABAC10 mice (Figures 2A and 2B). CEABAC20 colonocytes were not included in this part of the characterization because the extensive distortion of the crypt architecture (see below) rendered their isolation too difficult using the current method. The expression level of integrin α2 showed no such increase with CEA/CEACAM6 expression (Figure 2D) and integrin αv could not be detected (data not shown). These results suggest that integrin α5β1 signaling could be increased in colonocytes from CEABAC transgenic mice and in a CEA/CEACAM6 gene dose-dependent fashion.

Bottom Line: The colonocyte surface level of integrin alpha5 and the activation of AKT increased progressively with the expression levels of CEA/CEACAM6.Colonic crypts showed a progressive increase in colonocyte proliferation, an increase in crypt fission, and a strong inhibition of both differentiation and anoikis/apoptosis.All transgenic mice showed massively enlarged colons comprising a continuous mosaic of severe hyperplasia, dysplasia and serrated adenomatous morphology.

View Article: PubMed Central - PubMed

Affiliation: McGill Cancer Centre, Department of Biochemistry, McGill University, Montréal, Québec, Canada. carlos.chan@mcgill.ca

ABSTRACT
CEA and CEACAM6 are immunoglobulin family intercellular adhesion molecules that are up-regulated without structural mutations in approximately 70% of human cancers. Results in in vitro systems showing tumorigenic effects for these molecules suggest that this correlation could indicate an instrumental role in tumorigenesis. To test whether this applies in vivo, transgenic mice harboring 187 kb of the human genome containing four CEA family member genes including the CEA and CEACAM6 genes were created and their copy numbers increased by mating until colonocyte expression levels reached levels seen in human colorectal carcinomas. The colonocyte surface level of integrin alpha5 and the activation of AKT increased progressively with the expression levels of CEA/CEACAM6. Colonic crypts showed a progressive increase in colonocyte proliferation, an increase in crypt fission, and a strong inhibition of both differentiation and anoikis/apoptosis. All transgenic mice showed massively enlarged colons comprising a continuous mosaic of severe hyperplasia, dysplasia and serrated adenomatous morphology. These results suggest that up-regulated non-mutated adhesion molecules could have a significant instrumental role in human cancer.

Show MeSH
Related in: MedlinePlus