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Upregulation of plakophilin‐2 and its acquisition to adherens junctions identifies a novel molecular ensemble of cell–cell‐attachment characteristic for transformed mesenchymal cells
Author(s) -
Rickelt Steffen,
WinterSimanowski Stefanie,
Noffz Edeltraut,
Kuhn Caecilia,
Franke Werner Wilhelm
Publication year - 2009
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.24552
Subject(s) - adherens junction , plakoglobin , downregulation and upregulation , mesenchymal stem cell , microbiology and biotechnology , cadherin , biology , cell , cancer research , chemistry , catenin , wnt signaling pathway , signal transduction , biochemistry , gene
In contrast to the desmosome‐containing epithelial and carcinoma cells, normal and malignantly transformed cells derived from mesenchymal tissues and tumors are connected only by adherens junctions (AJs) containing N‐cadherins and/or cadherin‐11, anchored in a cytoplasmic plaque assembled by α‐ and β‐catenin, plakoglobin, proteins p120 and p0071. Here, we report that the AJs of many malignantly transformed cell lines are characterized by the additional presence of plakophilin‐2 (Pkp2), a protein hitherto known only as a major component of desmosomal plaques, i.e ., AJs of epithelia and carcinomatous cells. This massive acquisition of Pkp2 and its integration into AJ plaques of a large number of transformed cell lines is demonstrated with biochemical and immunolocalization techniques. Upregulation of Pkp2 and its integration into AJs has also been noted in some soft tissue tumors insitu and some highly proliferative colonies of cultured mesenchymal stem cells. As Pkp2 has recently been identified as a functionally important major regulatory organizer in AJs and related junctions in epithelial cells and cardiomyocytes, we hypothesize that the integration of Pkp2 into AJs of “soft tissue tumor” cells also can serve functions in the upregulation of proliferation, the promotion of malignant growth in general as well as the close‐packing of diverse kinds of cells and the metastatic behavior of such tumors. We propose to examine its presence in transformed mesenchymal cells and related tumors and to use it as an additional diagnostic criterion. © 2009 UICC