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Research article
PLEKHA7, an apical adherens junction protein, suppresses inflammatory breast cancer in the context of high E-cadherin and p120-catenin expression.
Panos Z Anastasiadis
Mayo Clinic Cancer Center
Corresponding Author
ORCiD: https://orcid.org/0000-0003-4436-9435
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: Inflammatory breast cancer is a highly aggressive form of breast cancer that robustly forms clusters of tumor emboli in dermal lymphatics and readily metastasizes. Inflammatory breast cancers express high levels of E-cadherin, the major protein of adherens junctions, which may enhance the ability of tumor cells to form such clusters and contribute to metastasis. Seemingly contradictory, E-cadherin has both tumor-suppressing and tumor-promoting roles in cancer; previous studies suggest that this depends on the balance between apical and basolateral cadherin-catenin complexes.
Methods: In the present study, we use immunohistochemistry of inflammatory breast cancer patient samples and biochemical analysis of cell lines to determine the expression of PLEKHA7, an apical adherens junction protein. We use viral transduction to ectopically express PLEKHA7 in the SUM149 inflammatory breast cancer cell line. The effect of PLEKHA7 on the aggressiveness of inflammatory breast cancer in 2D, 3D and in-vivo were examined.
Results: We determined that PLEKHA7 was deregulated in inflammatory breast cancer, demonstrating improper localization or lost expression in a strong majority of patient samples and very low expression in cell line models. We found that re-expressing PLEKHA7 is sufficient to suppress proliferation, anchorage independent growth, spheroid viability, and tumor growth in-vivo. We also observed a negative-selection pressure within the xenograft tumors to lose PLEKHA7 function or expression.
Conclusions: The data indicate that PLEKHA7 is frequently deregulated and acts as a suppressor of inflammatory breast cancer. They also suggest that the resulting imbalance between apical and basolateral cadherin-catenin complexes contributes to growth, survival and emboli-forming capacities of inflammatory breast cancer.
Keywords
Inflammatory breast cancer, PLEKHA7, adherens junction, cadherin-catenin complexes
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This is a list of supplementary files associated with this preprint. Click to download.
- SupplementalTable1.xlsx
Supplemental Table 1 (.xlsx): Table of IBC Patient Tumors characterized for PLEKHA7 expression and localization. This table includes raw characterization of PLEKHA7 expression and localization in 47 IBC patient samples, which was performed by an independent pathologist. The table also includes the breakdown of cellular morphology and nuclear pleomorphism in the IBC patient tumors.
- SupplementalFigure1.pdf
Supplemental Figure 1 (.pdf): Tumor patterns observed in IBC patient samples. A) Example of H&E from IBC tumor demonstrating solid cellular pattern. B) Example of H&E from IBC tumor demonstrating glandular cellular pattern. Scale bar represents 100μm.
- SupplementalFigure2.pdf
Supplemental Figure 2 (.pdf): Effects of PLEKHA7 re-expression in SUM149 cell growth in 2D culture. A) A representative graph displaying cell growth over time, as measured by the MTT cell metabolic assay, between SUM149 LZRS ms neo (control) and SUM149 LZRS PLEKHA7 cells cultured in 2D.
- SupplementalFigure3.pdf
Supplemental Figure 3 (.pdf): Expression of Cyclin-D1, Snail, and c-Myc in xenograft tumors. A) Fraction of Cyclin-D1 positive cells from SUM149 LZRS ms neo (control) or SUM149 LZRS PLEKHA7 xenografts at the 8-week end-point. B) Fraction of Snail positive cells from SUM149 LZRS ms neo or SUM149 LZRS PLEKHA7 xenografts at 8-weeks. C) Fraction of c-Myc positive cells from SUM149 LZRS ms neo or SUM149 LZRS PLEKHA7 xenografts at 8-weeks. n=6 for control group, n= 8 for PLEKHA7 group.
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Research article
PLEKHA7, an apical adherens junction protein, suppresses inflammatory breast cancer in the context of high E-cadherin and p120-catenin expression.
Panos Z Anastasiadis
Mayo Clinic Cancer Center
Corresponding Author
ORCiD: https://orcid.org/0000-0003-4436-9435
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 12 Aug, 2020
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: Inflammatory breast cancer is a highly aggressive form of breast cancer that robustly forms clusters of tumor emboli in dermal lymphatics and readily metastasizes. Inflammatory breast cancers express high levels of E-cadherin, the major protein of adherens junctions, which may enhance the ability of tumor cells to form such clusters and contribute to metastasis. Seemingly contradictory, E-cadherin has both tumor-suppressing and tumor-promoting roles in cancer; previous studies suggest that this depends on the balance between apical and basolateral cadherin-catenin complexes.
Methods: In the present study, we use immunohistochemistry of inflammatory breast cancer patient samples and biochemical analysis of cell lines to determine the expression of PLEKHA7, an apical adherens junction protein. We use viral transduction to ectopically express PLEKHA7 in the SUM149 inflammatory breast cancer cell line. The effect of PLEKHA7 on the aggressiveness of inflammatory breast cancer in 2D, 3D and in-vivo were examined.
Results: We determined that PLEKHA7 was deregulated in inflammatory breast cancer, demonstrating improper localization or lost expression in a strong majority of patient samples and very low expression in cell line models. We found that re-expressing PLEKHA7 is sufficient to suppress proliferation, anchorage independent growth, spheroid viability, and tumor growth in-vivo. We also observed a negative-selection pressure within the xenograft tumors to lose PLEKHA7 function or expression.
Conclusions: The data indicate that PLEKHA7 is frequently deregulated and acts as a suppressor of inflammatory breast cancer. They also suggest that the resulting imbalance between apical and basolateral cadherin-catenin complexes contributes to growth, survival and emboli-forming capacities of inflammatory breast cancer.
Figure 1
Figure 2
Figure 3
Figure 4