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MUC1 regulates cyclin D1 gene expression through p120 catenin and β-catenin.

Liu X, Caffrey TC, Steele MM, Mohr A, Singh PK, Radhakrishnan P, Kelly DL, Wen Y, Hollingsworth MA - Oncogenesis (2014)

Bottom Line: We observed a significant enhancement in the activation of cyclin D1 promoter-reporter activity in poorly differentiated Panc1.MUC1F cells that overexpress recombinant MUC1 relative to Panc-1.NEO cells, which express very low levels of endogenous MUC1.Further, MUC1 affected subcellular localization of p120 catenin in association with one of the main effectors of P120 catenin, the transcriptional repressor Kaiso, supporting the hypothesis that p120 catenin relieved transcriptional repression by Kaiso.Our data show MUC1 enhances the activities of both β-catenin and p120 catenin.

View Article: PubMed Central - PubMed

Affiliation: Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA.

ABSTRACT
MUC1 interacts with β-catenin and p120 catenin to modulate WNT signaling. We investigated the effect of overexpressing MUC1 on the regulation of cyclin D1, a downstream target for the WNT/β-catenin signaling pathway, in two human pancreatic cancer cell lines, Panc-1 and S2-013. We observed a significant enhancement in the activation of cyclin D1 promoter-reporter activity in poorly differentiated Panc1.MUC1F cells that overexpress recombinant MUC1 relative to Panc-1.NEO cells, which express very low levels of endogenous MUC1. In stark contrast, cyclin D1 promoter activity was not affected in moderately differentiated S2-013.MUC1F cells that overexpressed recombinant MUC1 relative to S2-013.NEO cells that expressed low levels of endogenous MUC1. The S2-013 cell line was recently shown to be deficient in p120 catenin. MUC1 is known to interact with P120 catenin. We show here that re-expression of different isoforms of p120 catenin restored cyclin D1 promoter activity. Further, MUC1 affected subcellular localization of p120 catenin in association with one of the main effectors of P120 catenin, the transcriptional repressor Kaiso, supporting the hypothesis that p120 catenin relieved transcriptional repression by Kaiso. Thus, full activation of cyclin D1 promoter activity requires β-catenin activation of TCF-lef and stabilization of specific p120 catenin isoforms to relieve the repression of KAISO. Our data show MUC1 enhances the activities of both β-catenin and p120 catenin.

No MeSH data available.


Related in: MedlinePlus

Different p120 catenin isoforms associate with Kaiso. (a) Proximity ligation assay (PLA) was used to detect interactions between p120 catenin and Kaiso in S2-013 cells with re-expression of different p120 catenin isoforms with or without MUC1. The red dots indicate interactions between p120 catenin and Kaiso. Blue (4′-6-diamidino-2-phenylindole, DAPI) staining indicates nuclei. The green indicates α-tubulin. (b–d) Quantification of results from PLAs. Results were compiled from three independent experiments.
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fig5: Different p120 catenin isoforms associate with Kaiso. (a) Proximity ligation assay (PLA) was used to detect interactions between p120 catenin and Kaiso in S2-013 cells with re-expression of different p120 catenin isoforms with or without MUC1. The red dots indicate interactions between p120 catenin and Kaiso. Blue (4′-6-diamidino-2-phenylindole, DAPI) staining indicates nuclei. The green indicates α-tubulin. (b–d) Quantification of results from PLAs. Results were compiled from three independent experiments.

Mentions: We sought to investigate the mechanism by which p120 catenin was enhancing TCF/Lef activity on the cyclin D1 promoter. The transcriptional repressor Kaiso has been shown to bind to the cyclin D1 promoter and repress transcription in both a sequence-specific and methylation-dependent manner,31 and it has been reported that p120 catenin can bind to Kaiso and de-repress its effects on transcription.25, 26 We investigated the possibility that specific isoforms of p120 catenin physically associate with Kaiso and sought to establish the precise subcellular localization of these complexes, given that binding in different subcellular locales might be associated with different types of activities. Result from proximity ligation assays revealed that Kaiso was highly associated with p120 catenin 3A in the nucleus (Figure 5) with less seen in the cytoplasm. P120 catenin isoform1A showed moderate and equivalent levels of interaction with Kaiso in both the nucleus and cytoplasm (Figure 5). P120 catenin isoform 4A showed higher levels of interaction with Kaiso in the cytoplasm (Figure 5). These differences in localization may explain in part the observed effects of different isoforms on cyclin D1 promoter activity. The high levels of interaction of p120 catenin isoform 3A with Kaiso in the nucleus (Figure 5) together with the results of cyclin D1 promoter activity (Figure 4) suggest that this isoform may not relieve Kaiso repression, whereas sequestration of Kaiso in the cytoplasm by p120 catenin isoforms 1A and 4A may enable de-repression of Kasio at the cyclin D1 promoter.


MUC1 regulates cyclin D1 gene expression through p120 catenin and β-catenin.

Liu X, Caffrey TC, Steele MM, Mohr A, Singh PK, Radhakrishnan P, Kelly DL, Wen Y, Hollingsworth MA - Oncogenesis (2014)

Different p120 catenin isoforms associate with Kaiso. (a) Proximity ligation assay (PLA) was used to detect interactions between p120 catenin and Kaiso in S2-013 cells with re-expression of different p120 catenin isoforms with or without MUC1. The red dots indicate interactions between p120 catenin and Kaiso. Blue (4′-6-diamidino-2-phenylindole, DAPI) staining indicates nuclei. The green indicates α-tubulin. (b–d) Quantification of results from PLAs. Results were compiled from three independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150213&req=5

fig5: Different p120 catenin isoforms associate with Kaiso. (a) Proximity ligation assay (PLA) was used to detect interactions between p120 catenin and Kaiso in S2-013 cells with re-expression of different p120 catenin isoforms with or without MUC1. The red dots indicate interactions between p120 catenin and Kaiso. Blue (4′-6-diamidino-2-phenylindole, DAPI) staining indicates nuclei. The green indicates α-tubulin. (b–d) Quantification of results from PLAs. Results were compiled from three independent experiments.
Mentions: We sought to investigate the mechanism by which p120 catenin was enhancing TCF/Lef activity on the cyclin D1 promoter. The transcriptional repressor Kaiso has been shown to bind to the cyclin D1 promoter and repress transcription in both a sequence-specific and methylation-dependent manner,31 and it has been reported that p120 catenin can bind to Kaiso and de-repress its effects on transcription.25, 26 We investigated the possibility that specific isoforms of p120 catenin physically associate with Kaiso and sought to establish the precise subcellular localization of these complexes, given that binding in different subcellular locales might be associated with different types of activities. Result from proximity ligation assays revealed that Kaiso was highly associated with p120 catenin 3A in the nucleus (Figure 5) with less seen in the cytoplasm. P120 catenin isoform1A showed moderate and equivalent levels of interaction with Kaiso in both the nucleus and cytoplasm (Figure 5). P120 catenin isoform 4A showed higher levels of interaction with Kaiso in the cytoplasm (Figure 5). These differences in localization may explain in part the observed effects of different isoforms on cyclin D1 promoter activity. The high levels of interaction of p120 catenin isoform 3A with Kaiso in the nucleus (Figure 5) together with the results of cyclin D1 promoter activity (Figure 4) suggest that this isoform may not relieve Kaiso repression, whereas sequestration of Kaiso in the cytoplasm by p120 catenin isoforms 1A and 4A may enable de-repression of Kasio at the cyclin D1 promoter.

Bottom Line: We observed a significant enhancement in the activation of cyclin D1 promoter-reporter activity in poorly differentiated Panc1.MUC1F cells that overexpress recombinant MUC1 relative to Panc-1.NEO cells, which express very low levels of endogenous MUC1.Further, MUC1 affected subcellular localization of p120 catenin in association with one of the main effectors of P120 catenin, the transcriptional repressor Kaiso, supporting the hypothesis that p120 catenin relieved transcriptional repression by Kaiso.Our data show MUC1 enhances the activities of both β-catenin and p120 catenin.

View Article: PubMed Central - PubMed

Affiliation: Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA.

ABSTRACT
MUC1 interacts with β-catenin and p120 catenin to modulate WNT signaling. We investigated the effect of overexpressing MUC1 on the regulation of cyclin D1, a downstream target for the WNT/β-catenin signaling pathway, in two human pancreatic cancer cell lines, Panc-1 and S2-013. We observed a significant enhancement in the activation of cyclin D1 promoter-reporter activity in poorly differentiated Panc1.MUC1F cells that overexpress recombinant MUC1 relative to Panc-1.NEO cells, which express very low levels of endogenous MUC1. In stark contrast, cyclin D1 promoter activity was not affected in moderately differentiated S2-013.MUC1F cells that overexpressed recombinant MUC1 relative to S2-013.NEO cells that expressed low levels of endogenous MUC1. The S2-013 cell line was recently shown to be deficient in p120 catenin. MUC1 is known to interact with P120 catenin. We show here that re-expression of different isoforms of p120 catenin restored cyclin D1 promoter activity. Further, MUC1 affected subcellular localization of p120 catenin in association with one of the main effectors of P120 catenin, the transcriptional repressor Kaiso, supporting the hypothesis that p120 catenin relieved transcriptional repression by Kaiso. Thus, full activation of cyclin D1 promoter activity requires β-catenin activation of TCF-lef and stabilization of specific p120 catenin isoforms to relieve the repression of KAISO. Our data show MUC1 enhances the activities of both β-catenin and p120 catenin.

No MeSH data available.


Related in: MedlinePlus