Wnt interaction and extracellular release of prominin-1/CD133 in human malignant melanoma cells.

Abstract

Prominin-1 (CD133) is the first identified gene of a novel class of pentaspan membrane glycoproteins. It is expressed by various epithelial and non-epithelial cells, and notably by stem and cancer stem cells. In non-cancerous cells such as neuro-epithelial and hematopoietic stem cells, prominin-1 is selectively concentrated in plasma membrane protrusions, and released into the extracellular milieu in association with small vesicles. Previously, we demonstrated that prominin-1 contributes to melanoma cells pro-metastatic properties and suggested that it may constitute a molecular target to prevent prominin-1-expressing melanomas from colonizing and growing in lymph nodes and distant organs. Here, we report that three distinct pools of prominin-1 co-exist in cultures of human FEMX-I metastatic melanoma. Morphologically, in addition to the plasma membrane localization, prominin-1 is found within the intracellular compartments, (e.g., Golgi apparatus) and in association with extracellular membrane vesicles. The latter prominin-1-positive structures appeared in three sizes (small, ≤40 nm; intermediates ~40-80 nm, and large, >80 nm). Functionally, the down-regulation of prominin-1 in FEMX-I cells resulted in a significant reduction of number of lipid droplets as observed by coherent anti-Stokes Raman scattering image analysis and Oil red O staining, and surprisingly in a decrease in the nuclear localization of beta-catenin, a surrogate marker of Wnt activation. Moreover, the T-cell factor/lymphoid enhancer factor (TCF/LEF) promoter activity was 2 to 4 times higher in parental than in prominin-1-knockdown cells. Collectively, our results point to Wnt signaling and/or release of prominin-1-containing membrane vesicles as mediators of the pro-metastatic activity of prominin-1 in FEMX-I melanoma.

• Authors: Germana Rappa, Javier Mercapide, Fabio Anzanello, Thuc T Le, Mary G Johlfs, Ronald R Fiscus, Michaela Wilsch-Bräuninger, Denis Corbeil, Aurelio Lorico
• Journal: Experimental cell research (Exp Cell Res) Vol. 319 Issue 6 Pg. 810-9 (Apr 01 2013) ISSN: 1090-2422 [Electronic] United States
• PMID: 23318676 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical References

• AC133 Antigen
• Antigens, CD
• Azo Compounds
• Biomarkers, Tumor
• CTNNB1 protein, human
• Glycoproteins
• Lipids
• PROM1 protein, human
• Peptides
• TCF Transcription Factors
• beta Catenin
• oil red O

Topics

• AC133 Antigen
• Antigens, CD (genetics, metabolism)
• Azo Compounds (metabolism)
• Biomarkers, Tumor (metabolism)
• Cell Adhesion
• Cell Line, Tumor
• Cell Membrane (metabolism, pathology)
• Cell Movement
• Cell Nucleus (genetics, metabolism)
• Gene Expression Regulation, Neoplastic
• Gene Knockdown Techniques
• Glycoproteins (genetics, metabolism)
• Golgi Apparatus (metabolism)
• Humans
• Immunohistochemistry
• Lipids (analysis)
• Melanoma (metabolism, pathology)
• Neoplasm Invasiveness (pathology)
• Peptides (genetics, metabolism)
• Promoter Regions, Genetic
• Protein Interaction Mapping
• Spectrum Analysis, Raman
• TCF Transcription Factors (genetics, metabolism)
• Transcription, Genetic
• Transfection
• Wnt Signaling Pathway
• beta Catenin (genetics, metabolism)