Stabilization of E-cadherin adhesions by COX-2/GSK3β signaling is a targetable pathway in metastatic breast cancer
Kuppusamy Balamurugan, … , Shikha Sharan, Esta Sterneck
Kuppusamy Balamurugan, … , Shikha Sharan, Esta Sterneck
Published February 9, 2023
Citation Information: JCI Insight. 2023;8(6):e156057. https://doi.org/10.1172/jci.insight.156057.
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Research Article Cell biology Oncology

Stabilization of E-cadherin adhesions by COX-2/GSK3β signaling is a targetable pathway in metastatic breast cancer

Abstract

Metastatic progression of epithelial cancers can be associated with epithelial-mesenchymal transition (EMT) including transcriptional inhibition of E-cadherin (CDH1) expression. Recently, EM plasticity (EMP) and E-cadherin–mediated, cluster-based metastasis and treatment resistance have become more appreciated. However, the mechanisms that maintain E-cadherin expression in this context are less understood. Through studies of inflammatory breast cancer (IBC) and a 3D tumor cell “emboli” culture paradigm, we discovered that cyclooxygenase 2 (COX-2; PTGS2), a target gene of C/EBPδ (CEBPD), or its metabolite prostaglandin E2 (PGE2) promotes protein stability of E-cadherin, β-catenin, and p120 catenin through inhibition of GSK3β. The COX-2 inhibitor celecoxib downregulated E-cadherin complex proteins and caused cell death. Coexpression of E-cadherin and COX-2 was seen in breast cancer tissues from patients with poor outcome and, along with inhibitory GSK3β phosphorylation, in patient-derived xenografts (PDX) including triple negative breast cancer (TNBC).Celecoxib alone decreased E-cadherin protein expression within xenograft tumors, though CDH1 mRNA levels increased, and reduced circulating tumor cell (CTC) clusters. In combination with paclitaxel, celecoxib attenuated or regressed lung metastases. This study has uncovered a mechanism by which metastatic breast cancer cells can maintain E-cadherin–mediated cell-to-cell adhesions and cell survival, suggesting that some patients with COX-2+/E-cadherin+ breast cancer may benefit from targeting of the PGE2 signaling pathway.

Authors

Kuppusamy Balamurugan, Dipak K. Poria, Saadiya W. Sehareen, Savitri Krishnamurthy, Wei Tang, Lois McKennett, Veena Padmanaban, Kelli Czarra, Andrew J. Ewald, Naoto T. Ueno, Stefan Ambs, Shikha Sharan, Esta Sterneck

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Figure 4

The COX-2 inhibitor celecoxib downregulates E-cadherin protein in vivo and reduces SUM149 tumor growth and cluster CTCs.

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The COX-2 inhibitor celecoxib downregulates E-cadherin protein in vivo a...
(A) Western blot analysis of IBC-3 emboli established after 3 days of culture in 3D followed by treatment for the indicated times with 50 μM celecoxib (0 hours = 48 hours DMSO). (B) Images of representative IBC-3 emboli after 3 days of culture (0 hours) and the same emboli following another 72 hours with celecoxib and stained with propidium iodide (PI) to label dying cells as indicated (representative of 3 experiments; BF, bright-field). Scale bar: 400 μm. (C) Representative images of SUM149 cells cultured in 3D ± celecoxib for 72 hours and stained with PI (representative of 3 experiments; BF, bright-field). Scale bar: 400 μm. (D) Assessment of cell death by PI staining (top panel) and Western blot analysis (bottom panel) from SUM149 cells that were transfected with empty vector or E-cadherin–expressing plasmid followed by culture in 3D for 1 day and treated with celecoxib for additional 3 days (n = 3, mean ± SEM; *P < 0.05, **P < 0.01). (E) Western blot analysis (bottom panel) of SUM149 cells cultured on plastic (2D) or as emboli (3D) for 3 days followed by treatment with celecoxib for another 3 days, and quantification of E-cadherin from 5 independent experiments (n = 5; *P < 0.05, ***P < 0.001). (F and G) Western blot (F) and tumor volume (G) analysis of SUM149-GFP-Luc orthotopic tumors from mice fed control chow or celecoxib chow for 7 days starting at tumor volumes > 1,000 mm3 (n =14–15, paired or unpaired [indicated with #] 2-sided Wilcoxon rank-sum test). (H) CTC analysis of peripheral blood drawn from mice as in F and G (n =14–15, paired or unpaired [indicated with #] 2-sided Wilcoxon rank-sum test). (I and J) Western blot (I) and CDH1 mRNA (J) analysis of BCM-5471 PDX tumors from mice that were fed control chow or celecoxib chow for the indicated number of days (determined by study end points) starting when tumor volumes were 300–600 mm3 (n = 6–8; *P = 0.029 by unpaired 2-sided Wilcoxon rank-sum test).