title: Sema6A and Mical1 control cell growth and survival of BRAFV600E human melanoma cells.
abstract: We used whole genome microarray analysis to identify potential candidate genes with differential expression in BRAFV600E vs NRASQ61R melanoma cells. We selected, for comparison, a peculiar model based on melanoma clones, isolated from a single tumor characterized by mutually exclusive expression of BRAFV600E and NRASQ61R in different cells. This effort led us to identify two genes, SEMA6A and MICAL1, highly expressed in BRAF-mutant vs NRAS-mutant clones. Real-time PCR, Western blot and immunohistochemistry confirmed preferential expression of Sema6A and Mical1 in BRAFV600E melanoma. Sema6A is a member of the semaphorin family, and it complexes with the plexins to regulate actin cytoskeleton, motility and cell proliferation. Silencing of Sema6A in BRAF-mutant cells caused cytoskeletal remodeling, and loss of stress fibers, that in turn induced cell death. Furthermore, Sema6A depletion caused loss of anchorage-independent growth, inhibition of chemotaxis and invasion. Forced Sema6A overexpression, in NRASQ61R clones, induced anchorage-independent growth, and a significant increase of invasiveness. Mical1, that links Sema/PlexinA signaling, is also a negative regulator of apoptosis. Indeed, Mical-1 depletion in BRAF mutant cells restored MST-1-dependent NDR phosphorylation and promoted a rapid and massive NDR-dependent apoptosis. Overall, our data suggest that Sema6A and Mical1 may represent new potential therapeutic targets in BRAFV600E melanoma.
authors.affiliation: Department of Experimental Oncology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Loria
authors.affiliation: Department of Experimental Oncology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Bon
authors.affiliation: Human Tumors Immunobiology Unit, Dept. of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Perotti
authors.affiliation: Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Gallo
authors.affiliation: Human Tumors Immunobiology Unit, Dept. of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Bersani
authors.affiliation: Human Tumors Immunobiology Unit, Dept. of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Baldassari
authors.affiliation: Department of Chemotherapy, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Porru
authors.affiliation: Department of Chemotherapy, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Leonetti
authors.affiliation: Department of Experimental Oncology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Selene
authors.initials: S
authors.lastname: Di Carlo
authors.affiliation: Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Visca
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy.
authors.forename: Maria Felice
authors.initials: MF
authors.lastname: Brizzi
authors.affiliation: Human Tumors Immunobiology Unit, Dept. of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Anichini
authors.affiliation: Human Tumors Immunobiology Unit, Dept. of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Mortarini
authors.affiliation: Department of Experimental Oncology, Regina Elena National Cancer Institute, Rome, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Falcioni
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D002470:Cell Survival; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling / Q000379:methods; D015972:Gene Expression Regulation, Neoplastic; D056726:Genetic Association Studies; D006801:Humans; D007150:Immunohistochemistry; D060588:LIM Domain Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008545:Melanoma / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D008819:Mice, Nude; D008840:Microfilament Proteins; D006899:Mixed Function Oxygenases; D009154:Mutation; D009361:Neoplasm Invasiveness; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010766:Phosphorylation; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D034622:RNA Interference; D060888:Real-Time Polymerase Chain Reaction; D039961:Semaphorins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D012878:Skin Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D014162:Transfection; D000096985:Calponins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D003598:Cytoskeletal Proteins; D060588:LIM Domain Proteins; D008840:Microfilament Proteins; D006899:Mixed Function Oxygenases; D009687:Nuclear Proteins; D048493:Proto-Oncogene Proteins B-raf; D039961:Semaphorins; C435745:HEMGN protein, human; C504201:SEMA6A protein, human; C455272:MICAL1 protein, human; D000096985:Calponins; C482119:BRAF protein, human