title: Slug (SNAI2) down-regulation by RNA interference facilitates apoptosis and inhibits invasive growth in neuroblastoma preclinical models.
abstract: OBJECTIVE
  We assessed the relevance of Slug (SNAI2) for apoptosis resistance and invasion potential of neuroblastoma cells in vitro and in vivo.
  
  
  METHODS
  We evaluated the effect of imatinib mesylate on invasion and analyzed the genes modulated by imatinib mesylate treatment in neuroblastoma cells. Slug expression, inhibited by imatinib mesylate treatment, was knocked down in neuroblastoma cells by RNA interference, and the effects on invasion and apoptosis were evaluated in vitro. A pseudometastatic model of neuroblastoma in severe combined immunodeficient mice was used to assess the effects of Slug silencing alone or in combination with imatinib mesylate treatment on metastasis development.
  
  
  RESULTS
  Microarray analysis revealed that several genes, including Slug, were down-regulated by imatinib mesylate. Slug expression was detectable in 8 of 10 human neuroblastoma cell lines. Two Slug-expressing cell lines were infected with a vector encoding a microRNA to Slug mRNA. Infected cells with reduced levels of Slug were tested for the expression of apoptosis-related genes (p53, Bax, and Bcl-2) identified previously as Slug targets. Bcl-2 was down-regulated in Slug-interfered cells. Slug down-regulation increased sensitivity to apoptosis induced by imatinib mesylate, etoposide, or doxorubicin. Invasion of Slug-silenced cells was reduced in vitro. Animals injected with Slug-silenced cells had fewer tumors than controls and the inhibition of tumor growth was even higher in animals treated with imatinib mesylate.
  
  
  CONCLUSIONS
  Slug down-regulation facilitates apoptosis induced by proapoptotic drugs in neuroblastoma cells and decreases their invasion capability in vitro and in vivo. Slug inhibition, possibly combined with imatinib mesylate, may represent a novel strategy for treatment of metastatic neuroblastoma.
authors.affiliation: Section of Toxicology and Biomedical Sciences, ENEA Research Center Casaccia, Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Vitali
authors.forename: Camillo
authors.initials: C
authors.lastname: Mancini
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cesi
authors.forename: Barbara
authors.initials: B
authors.lastname: Tanno
authors.forename: Mariateresa
authors.initials: M
authors.lastname: Mancuso
authors.forename: Gianluca
authors.initials: G
authors.lastname: Bossi
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Robert V
authors.initials: RV
authors.lastname: Martinez
authors.forename: Bruno
authors.initials: B
authors.lastname: Calabretta
authors.forename: Carlo
authors.initials: C
authors.lastname: Dominici
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Raschellà
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D001549:Benzamides; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015536:Down-Regulation; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D000068877:Imatinib Mesylate; D051379:Mice; D009361:Neoplasm Invasiveness; D009447:Neuroblastoma / Q000188:drug therapy / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010879:Piperazines / Q000494:pharmacology; D011743:Pyrimidines / Q000494:pharmacology; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; C000604407:SNAI1 protein, human; C000604408:SNAI2 protein, human; C000604449:Snai2 protein, mouse; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D000068877:Imatinib Mesylate