title: Gene expression profiles of human melanoma cells with different invasive potential reveal TSPAN8 as a novel mediator of invasion.
abstract: Metastatic melanoma requires early detection, being treatment resistant. However, the earliest events of melanoma metastasis, and especially of dermal invasion, remain ill defined.
  
  
  
  Gene expression profiles of two clonal subpopulations, selected from the same human melanoma cell line, but differing in ability to cross the dermal-epidermal junction in skin reconstructs, were compared by oligonucleotide microarray. Of 26 496 cDNA probes, 461 were differentially expressed (>2-fold; P< 0.001), only 71 genes being upregulated in invasive cells. Among them, TSPAN8, a tetraspanin not yet described in melanoma, was upregulated at mRNA and protein levels in melanoma cells from the invasive clone, as assessed by RT-PCR, flow cytometry and western blot analysis. Interestingly, TSPAN8 was the only tetraspanin in which overexpression correlated with invasive phenotype. Flow cytometry of well-defined melanoma cell lines confirmed that TSPAN8 was exclusively expressed by invasive, but not non-invasive melanoma cells or normal melanocytes. Immunohistochemistry revealed that TSPAN8 was expressed by melanoma cells in primary melanomas and metastases, but not epidermal cells in healthy skin. The functional role of TSPAN8 was demonstrated by silencing endogenous TSPAN8 with siRNA, reducing invasive outgrowth from tumour spheroids within matrigel without affecting cell proliferation or survival.
  
  
  
  TSPAN8 expression may enable melanoma cells to cross the cutaneous basement membrane, leading to dermal invasion and progression to metastasis. TSPAN8 could be a promising target in early detection and treatment of melanoma.
authors.affiliation: Université de Lyon, Lyon F-69003, France. odile.berthier-vergnes@univ-lyon1.fr
authors.forename: O
authors.initials: O
authors.lastname: Berthier-Vergnes
authors.forename: M
authors.initials: M
authors.lastname: El Kharbili
authors.forename: A
authors.initials: A
authors.lastname: de la Fouchardière
authors.forename: T
authors.initials: T
authors.lastname: Pointecouteau
authors.forename: P
authors.initials: P
authors.lastname: Verrando
authors.forename: A
authors.initials: A
authors.lastname: Wierinckx
authors.forename: J
authors.initials: J
authors.lastname: Lachuer
authors.forename: F
authors.initials: F
authors.lastname: Le Naour
authors.forename: J
authors.initials: J
authors.lastname: Lamartine
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D002465:Cell Movement; D049109:Cell Proliferation; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D006801:Humans; D007124:Immunoenzyme Techniques; D008207:Lymphatic Metastasis; D008544:Melanocytes / Q000378:metabolism; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D018874:Spheroids, Cellular / Q000378:metabolism / Q000473:pathology; D059470:Tetraspanins; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C065609:TSPAN8 protein, human; D059470:Tetraspanins