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- Hagerling, Catharina, et al.
(author)
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WNT-5a-CKIalpha signaling promotes beta -catenin/E-cadherin complex formation and intercellular adhesion in human breast epithelial cells.
- 2009
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In: Journal of Biological Chemistry. - 1083-351X. ; 284, s. 10968-10979
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Journal article (peer-reviewed)abstract
- Wnt-5a is a non-transforming Wnt protein that is implicated in cell-polarity, adhesion and motility. We have previously shown that low expression of Wnt-5a is a predictor of shorter disease-free survival in human breast cancer. Here, we investigated whether ss-catenin/E-cadherin mediated cell-cell adhesion was affected by loss of Wnt-5a in breast carcinomas, thereby promoting a metastatic behavior of the tumor. We show that Wnt-5a stimulation of human breast epithelial cells leads to an increased Ca2+-dependent cell-cell adhesion. Furthermore, Wnt-5a/Casein Kinase Ia (CKIa)-specific Ser45-phosphorylation of ss-catenin is associated with an increased complex formation of ss-catenin/E-cadherin. Mutation of Ser45 decreases the ss-catenin/E-cadherin association. Also, the inhibitory effect of Wnt-5a on breast epithelial cell invasion is reduced upon mutation of ss-catenin-Ser45. The Wnt-5a-CKIa induced Ser45-phosphorylation does not lead to degradation of ss-catenin. Finally we show that human breast cancers lacking Wnt-5a protein have a significantly lower level of membrane-associated ss-catenin. Downregulation of Wnt-5a expression and subsequent reduction of membrane-associated ss-catenin in invasive breast cancer, can therefore contribute to a decreased cell-cell adhesion and increased motility resulting in a higher probability for metastatic disease.
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| 2. |
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| 3. |
- Leandersson, Karin, et al.
(author)
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Wnt-5a mRNA translation is suppressed by the Elav-like protein HuR in human breast epithelial cells.
- 2006
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In: Nucleic Acids Research. - : Oxford University Press (OUP). - 1362-4962 .- 0305-1048. ; 34:14, s. 3988-3999
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Journal article (peer-reviewed)abstract
- Wnt-5a is a non-transforming Wnt protein. Since Wnt-5a mRNA and protein levels differ within and between tumours, the potential of Wnt-5a as a prognostic factor has been debated. We have previously shown that the lack of Wnt-5a protein is a predictor of shorter disease-free survival in human breast cancer. Recently, however, we also showed that the breast tumours lacking Wnt-5a protein had a high or normal level of Wnt-5a mRNA that might explain the discrepancies in previous studies. We here report that Wnt-5a is regulated at the post-transcriptional level. The regulation was mediated by the Embryonic Lethal Abnormal Vision (ELAV)like protein HuR, which inhibited translation of Wnt-5a when bound to highly conserved AU-rich sequences in the 3'-untranslated region (3'-UTR) of the Wnt-5a mRNA molecule, as shown by both HA-tagged Wnt-5a- and Luciferase-Wnt-5a-3'-UTR reporter assays. The HuR-dependent inhibition of Wnt-5a was supported by the fact that active HuR is located in the cytoplasm in invasive human breast tumours and that hypoxia-induced activation of HuR inhibits translation of both Luciferase-Wnt5a-3'-UTR and endogenous Wnt-5a protein. We propose that the lack of Wnt-5a protein expression in invasive human breast tumours is caused by a HuR-mediated suppression of Wnt-5a mRNA translation..
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| 6. |
- Sitnicka Quinn, Ewa, et al.
(author)
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Critical role of FLT3 ligand in IL-7 receptor-independent T lymphopoiesis and regulation of lymphoid-primed multipotent progenitors
- 2007
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In: Blood. - Washington, DC : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 110:8, s. 2955-2964
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Journal article (peer-reviewed)abstract
- The molecular pathways regulating lymphoid priming, fate, and development of multipotent bone marrow (BM) stem/progenitor cells that continuously replace thymic progenitors remain largely unknown. Herein, we show that fms-like tyrosine kinase 3 (Flt3) ligand (Fl)-deficient mice have distinct reductions in the earliest thymic progenitors in fetal, postnatal, and adult thymus. A critical role of FL in thymopoiesis was particularly evident in the absence of interleukin-7 receptor alpha (IL-7Ralpha) signaling. Fl-/-Il-7r-/- mice have extensive reductions in fetal and postnatal thymic progenitors that result in a loss of active thymopoiesis in adult mice, demonstrating an indispensable role of FL in IL-7Ralpha-independent fetal and adult T lymphopoiesis. Moreover, we establish a unique and critical role of FL, distinct from that of IL-7Ralpha, in regulation of the earliest lineage-negative (Lin(-)) Lin(-)SCA1+KIT+ (LSK) FLT3(hi) lymphoid-primed multipotent progenitors in BM, demonstrating a key role of FLT3 signaling in regulating the very earliest stages of lymphoid progenitors.
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