IBYME   02675
INSTITUTO DE BIOLOGIA Y MEDICINA EXPERIMENTAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
ROR1 CONTRIBUTES TO MELANOMA DEVELOPMENT AND PROGRESSION
Autor/es:
FERNANDEZ N; LORENZO D; BRAVO MS; LOPEZ BERGAMI, P
Lugar:
Egmond aan Zee
Reunión:
Congreso; EMBO Meeting - 30 Years of Wnt Signalling; 2012
Institución organizadora:
EMBO - European Molecular Biology Organization
Resumen:
Receptor tyrosine kinase-like orphan receptor 1 and 2 (ROR1 and ROR2) are a conserved family oftyrosine kinase receptors that play crucial roles in the development of various organs and tissues aswell as in human disease. They were originally cloned as orphan receptors but they are nowrecognized as bona-fide Wnt receptors. Although the functions of ROR1 and ROR2 are somewhatredundant during development, emerging evidence suggests they might play different roles in adultmammalian cells. It was demonstrated that ROR2 mediates noncanonical Wnt5a signaling and that itcan inhibit the β-catenin-TCF pathway. As a mediator of Wnt5a signaling, ROR2 was implicated inpolarized cell migration. In contrast to ROR2, ROR1 has been studied less rigorously. ROR1 isoverexpressed in chronic lymphocytic leukemia and confers a survival advantage to these cells.Consistent with this finding, a RNAi screen of human kinases identified ROR1 as a survival kinasein HeLa cells.We have determined (see another abstract presented at this conference) that ROR1 is overexpressedand active in melanoma consistent with Wnt5a overexpression and Dvl phosphorylation in thesecells. These findings prompted us to determine the role of ROR1 in proliferation, apoptosis, and othercellular process related to tumor growth. Transduction of melanoma cells with ROR1 shRNAdecreased proliferation (determined by MTT assay) in two melanoma cell lines expressing differentamounts of endogenous Wnt5a. ROR1 silencing significantly reduced the cell growth by 28% and26% compared to control cells in both A375 (after 5 days in culture) and Lu1205 (after 3 days inculture) cell lines (p<0.05). As demonstrated in B lymphocytes, silencing of ROR1 increased bothspontaneous and stress-induced apoptosis in Lu1205 and A375 melanoma cells as assessed byPI/Annexin V staining. ROR1 silencing also reduced anchorage-independent growth in soft agar.Twenty days after plating, A375 cells expressing shRNA for ROR1 gave rise to 95.3 +/- 21.4colonies whereas 203 +/- 42.5 colonies were observed in the control plate (seeded with A375 cellstransduced with a scramble shRNA). Interestingly, a reduction on the size of the colonies was alsoobserved in A375 melanoma cells expressing ROR1 shRNA. These data indicate that ROR1contributes to melanoma cell growth.To determine the role of ROR1 in cell adhesion we performed a Crystal Violet Adhesion Assay inA375 cells. After 30 min at 37oC, cells expressing ROR1 shRNA adhered less efficiently to the platethan control cells (DO590: 0,197 +/- 0,046 vs. 0,363 +/- 0,071 in control cells, p<0.01). These resultsindicate that ROR1 is implicated in cell adhesion as previously determined for Wnt5a and Dvl.Based on these evidences, we hypothesize that Wnt/ROR1 signaling play an important role inmelanoma progression by affecting cell growth, apoptosis and cell adhesion.