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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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Expression of CEA and CEACAM6 in the CEABAC mouse colon.A) Images of fluorescence in situ hybridization (FITC-labeled CEA cDNA probes and DAPI-stained nuclei) show one nuclear spot (red arrow) for CEABAC10 and two for CEABAC20. Magnification: 1000×. B) Significant reduction visually of body size of CEABAC20 mice at 3 weeks of age. C) Immunoblots of colon protein extracts show a correlation between expression levels of CEA (detected with A20 mAb) and CEACAM6 (detected with 9A6 mAb) and CEABAC transgene copy numbers in the CEABAC mice (CEABAC2, CEABAC10 and CEABAC20). D) Immunohistochemical staining (brown staining) for human CEACAM (detected with RbαCEA) in 3 week-old mouse colons shows increasing expression levels of CEA/CEACAM6 correlated with the transgene copy number. The high expression level of CEA/CEACAM6 in the CEABAC20 mice was no longer restricted to the apical surface (red arrow points to apical surface staining; black arrows point to basolateral staining) and significant intracellular localization of CEA/CEACAM6 was also evident. E) Immunohistochemical staining (brown staining) for human CEACAM (detected with RbαCEA) in 3 month-old CEABAC20 mouse colons shows levels and patterns of CEA/CEACAM6 expression which are similar to those of human colorectal carcinomas at a similar stage of progression. WT denotes wild-type littermate.
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pone-0001353-g001: Expression of CEA and CEACAM6 in the CEABAC mouse colon.A) Images of fluorescence in situ hybridization (FITC-labeled CEA cDNA probes and DAPI-stained nuclei) show one nuclear spot (red arrow) for CEABAC10 and two for CEABAC20. Magnification: 1000×. B) Significant reduction visually of body size of CEABAC20 mice at 3 weeks of age. C) Immunoblots of colon protein extracts show a correlation between expression levels of CEA (detected with A20 mAb) and CEACAM6 (detected with 9A6 mAb) and CEABAC transgene copy numbers in the CEABAC mice (CEABAC2, CEABAC10 and CEABAC20). D) Immunohistochemical staining (brown staining) for human CEACAM (detected with RbαCEA) in 3 week-old mouse colons shows increasing expression levels of CEA/CEACAM6 correlated with the transgene copy number. The high expression level of CEA/CEACAM6 in the CEABAC20 mice was no longer restricted to the apical surface (red arrow points to apical surface staining; black arrows point to basolateral staining) and significant intracellular localization of CEA/CEACAM6 was also evident. E) Immunohistochemical staining (brown staining) for human CEACAM (detected with RbαCEA) in 3 month-old CEABAC20 mouse colons shows levels and patterns of CEA/CEACAM6 expression which are similar to those of human colorectal carcinomas at a similar stage of progression. WT denotes wild-type littermate.

Mentions: CEABAC2 and CEABAC10 transgenic mice are independent founders containing 2 and 10 head-to-tail copies, respectively, of the 187 kb genomic DNA insert of a BAC which includes the genes for human CEA, CEACAM6, CEACAM7 and CEACAM3 [30]. The tissue specific expression patterns for these genes have been documented previously [30] and are almost identical to those in humans [1]. CEABAC20 mice with 20 copies were obtained by mating CEABAC10 mice, which are heterozygous for the transgene. In situ hybridization with a fluorescein isothiocyanate (FITC)-labeled CEA cDNA probe of cell nuclei showed a single spot for CEABAC10 and two spots for CEABAC20 (Figure 1A), which is consistent with the previous molecular analysis of CEABAC10 indicating head-to-tail linkage of all copies into one complex [30]. The CEABAC20 mice could be immediately recognized in litters because of their significantly smaller size (Figure 1B), which could be attributed to impaired gastrointestinal function (see below).


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)

Expression of CEA and CEACAM6 in the CEABAC mouse colon.A) Images of fluorescence in situ hybridization (FITC-labeled CEA cDNA probes and DAPI-stained nuclei) show one nuclear spot (red arrow) for CEABAC10 and two for CEABAC20. Magnification: 1000×. B) Significant reduction visually of body size of CEABAC20 mice at 3 weeks of age. C) Immunoblots of colon protein extracts show a correlation between expression levels of CEA (detected with A20 mAb) and CEACAM6 (detected with 9A6 mAb) and CEABAC transgene copy numbers in the CEABAC mice (CEABAC2, CEABAC10 and CEABAC20). D) Immunohistochemical staining (brown staining) for human CEACAM (detected with RbαCEA) in 3 week-old mouse colons shows increasing expression levels of CEA/CEACAM6 correlated with the transgene copy number. The high expression level of CEA/CEACAM6 in the CEABAC20 mice was no longer restricted to the apical surface (red arrow points to apical surface staining; black arrows point to basolateral staining) and significant intracellular localization of CEA/CEACAM6 was also evident. E) Immunohistochemical staining (brown staining) for human CEACAM (detected with RbαCEA) in 3 month-old CEABAC20 mouse colons shows levels and patterns of CEA/CEACAM6 expression which are similar to those of human colorectal carcinomas at a similar stage of progression. WT denotes wild-type littermate.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2131779&req=5

pone-0001353-g001: Expression of CEA and CEACAM6 in the CEABAC mouse colon.A) Images of fluorescence in situ hybridization (FITC-labeled CEA cDNA probes and DAPI-stained nuclei) show one nuclear spot (red arrow) for CEABAC10 and two for CEABAC20. Magnification: 1000×. B) Significant reduction visually of body size of CEABAC20 mice at 3 weeks of age. C) Immunoblots of colon protein extracts show a correlation between expression levels of CEA (detected with A20 mAb) and CEACAM6 (detected with 9A6 mAb) and CEABAC transgene copy numbers in the CEABAC mice (CEABAC2, CEABAC10 and CEABAC20). D) Immunohistochemical staining (brown staining) for human CEACAM (detected with RbαCEA) in 3 week-old mouse colons shows increasing expression levels of CEA/CEACAM6 correlated with the transgene copy number. The high expression level of CEA/CEACAM6 in the CEABAC20 mice was no longer restricted to the apical surface (red arrow points to apical surface staining; black arrows point to basolateral staining) and significant intracellular localization of CEA/CEACAM6 was also evident. E) Immunohistochemical staining (brown staining) for human CEACAM (detected with RbαCEA) in 3 month-old CEABAC20 mouse colons shows levels and patterns of CEA/CEACAM6 expression which are similar to those of human colorectal carcinomas at a similar stage of progression. WT denotes wild-type littermate.
Mentions: CEABAC2 and CEABAC10 transgenic mice are independent founders containing 2 and 10 head-to-tail copies, respectively, of the 187 kb genomic DNA insert of a BAC which includes the genes for human CEA, CEACAM6, CEACAM7 and CEACAM3 [30]. The tissue specific expression patterns for these genes have been documented previously [30] and are almost identical to those in humans [1]. CEABAC20 mice with 20 copies were obtained by mating CEABAC10 mice, which are heterozygous for the transgene. In situ hybridization with a fluorescein isothiocyanate (FITC)-labeled CEA cDNA probe of cell nuclei showed a single spot for CEABAC10 and two spots for CEABAC20 (Figure 1A), which is consistent with the previous molecular analysis of CEABAC10 indicating head-to-tail linkage of all copies into one complex [30]. The CEABAC20 mice could be immediately recognized in litters because of their significantly smaller size (Figure 1B), which could be attributed to impaired gastrointestinal function (see below).

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