title: Increased p21-activated kinase-1 expression is associated with invasive potential in uveal melanoma.
abstract: Prognosis in patients with uveal melanoma is poor as approximately half of all tumors metastasize and currently there are no effective treatments for disseminated disease. Differences in invasiveness between uveal melanomas could therefore be of major significance regarding clinical outcome. To identify genes associated with invasive potential, we have used microarray expression profiling combined with phenotypic characterization of uveal melanoma and melanocyte cell lines to define a gene signature associated with cellular invasion. A panel of 14 uveal cell cultures was assessed using three assays of invasiveness: matrigel invasion chamber system, scratch wound closure and cell motility. We identified a set of 853 differentially expressed transcripts (Wilcoxon-Mann-Whitney test, P<0.01) that discriminated between samples with high or low invasive capacity based on a composite phenotype that takes into account behavior across all three assays. Of particular interest, expression of two members of the p21-activated kinase (PAK) family, PAK1 and PAK7, was elevated in the more invasive cultures. PAK1 has previously been shown to play a central role in regulating cell motility and invasiveness in other cell types, and increased expression has been observed in breast and colorectal carcinomas. Using small interfering RNA-mediated PAK1 knockdown, we showed up to a five-fold decrease in invasion through matrigel, indicating that elevated levels of PAK1 are associated with invasive potential in uveal melanoma. These data implicate PAK1 as a potential new target for therapy of these tumors.
authors.affiliation: Human Genetics Laboratory, Queensland Institute of Medical Research, Herston, Queensland, Australia. sandraP@qimr.edu.au
authors.forename: Sandra
authors.initials: S
authors.lastname: Pavey
authors.forename: Wieke
authors.initials: W
authors.lastname: Zuidervaart
authors.forename: Frans
authors.initials: F
authors.lastname: van Nieuwpoort
authors.forename: Leisl
authors.initials: L
authors.lastname: Packer
authors.forename: Martine
authors.initials: M
authors.lastname: Jager
authors.forename: Nelleke
authors.initials: N
authors.lastname: Gruis
authors.forename: Nicholas
authors.initials: N
authors.lastname: Hayward
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics; D002465:Cell Movement; D003094:Collagen / Q000378:metabolism; D004273:DNA, Neoplasm / Q000032:analysis; D004338:Drug Combinations; D020869:Gene Expression Profiling; D006801:Humans; D007797:Laminin / Q000378:metabolism; D008545:Melanoma / Q000201:enzymology / Q000235:genetics / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D011379:Prognosis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011509:Proteoglycans / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014604:Uveal Neoplasms / Q000201:enzymology / Q000235:genetics / Q000473:pathology*; D054462:p21-Activated Kinases
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D004338:Drug Combinations; D007797:Laminin; D009363:Neoplasm Proteins; D011509:Proteoglycans; C059485:matrigel; D003094:Collagen; C515903:PAK1 protein, human; D017346:Protein Serine-Threonine Kinases; D054462:p21-Activated Kinases