Role of β-catenin signaling in the anti-invasive effect of the omega-3 fatty acid DHA in human melanoma cells.
BACKGROUND
We previously found that docosahexaenoic acid (DHA), a dietary polyunsaturated fatty acid present at high level in fatty fish, inhibited cell growth and induced differentiation of melanoma cells in vitro by increasing nuclear β-catenin content. An anti-neoplastic role of nuclear β-catenin was suggested in melanoma, and related to the presence in the melanocyte lineage of the microphtalmia transcription factor (MITF), which interferes with the transcription of β-catenin/TCF/LEF pro-invasive target genes.


OBJECTIVE
In the present work we investigated if DHA could inhibit the invasive potential of melanoma cells, and if this effect could be related to DHA-induced alterations of the Wnt/β-catenin signaling, including changes in MITF expression.


METHODS
WM115 and WM266-4 human melanoma, and B16-F10 murine melanoma cell lines were used. Cell invasion was evaluated by Wound Healing and Matrigel transwell assays. Protein expression was analyzed by Western Blotting and β-catenin phosphorylation by immunoprecipitation. The role of MITF in the anti-invasive effect of DHA was analyzed by siRNA gene silencing.


RESULTS
We found that DHA inhibited anchorage-independent cell growth, reduced their migration/invasion in vitro and down-regulated several Matrix Metalloproteinases (MMP: MMP-2, MT1-MMP and MMP-13), known to be involved in melanoma invasion. We related these effects to the β-catenin increased nuclear expression and PKA-dependent phosphorylation, as well as to the increased expression of MITF.


CONCLUSIONS
The data obtained further support the potential role of dietary DHA as suppressor of melanoma progression to invasive malignancy through its ability to enhance MITF expression and PKA-dependent nuclear β-catenin phosphorylation.
Institute of General Pathology, Università Cattolica del S. Cuore, Rome, Italy.
Simona
S
Serini
Department of Pharmacy, Health and Nutritional Sciences, Università della Calabria, Arcavacata di Rende, Cosenza, Italy.
Antonio
A
Zinzi
Instituto de Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, Brazil.
Renata
R
Ottes Vasconcelos
Institute of General Pathology, Università Cattolica del S. Cuore, Rome, Italy.
Elena
E
Fasano
Department of Pharmacy, Health and Nutritional Sciences, Università della Calabria, Arcavacata di Rende, Cosenza, Italy.
Maria Greca
MG
Riillo
Institute of Dermatology, Università Cattolica del S. Cuore, Rome, Italy; Research Center for Biotechnology Applied to Cosmetology, Università Cattolica del S. Cuore, Rome, Italy.
Leonardo
L
Celleno
Department of Pharmacy, Health and Nutritional Sciences, Università della Calabria, Arcavacata di Rende, Cosenza, Italy.
Sonia
S
Trombino
Department of Pharmacy, Health and Nutritional Sciences, Università della Calabria, Arcavacata di Rende, Cosenza, Italy.
Roberta
R
Cassano
Institute of General Pathology, Università Cattolica del S. Cuore, Rome, Italy; Research Center for Biotechnology Applied to Cosmetology, Università Cattolica del S. Cuore, Rome, Italy. Electronic address: g.calviello@unicatt.it.
Gabriella
G
Calviello
D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D004032:Diet; D004281:Docosahexaenoic Acids / Q000737:chemistry; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D006801:Humans; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D008545:Melanoma / Q000378:metabolism*; D008546:Melanoma, Experimental; D051379:Mice; D051739:Microphthalmia-Associated Transcription Factor / Q000378:metabolism; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D010766:Phosphorylation; D015398:Signal Transduction; D012878:Skin Neoplasms / Q000378:metabolism*; D051176:beta Catenin / Q000378:metabolism*; D000096142:Cutaneous Malignant Melanoma
D015525:Fatty Acids, Omega-3; C497234:MITF protein, human; D051739:Microphthalmia-Associated Transcription Factor; C497235:Mitf protein, mouse; D051176:beta Catenin; D004281:Docosahexaenoic Acids; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; C507081:Mmp13 protein, mouse; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C522362:Mmp2 protein, mouse; D053511:Matrix Metalloproteinase 14
Docosahexaenoic acid; Invasion; MITF; Melanoma; PKA; β-Catenin