title: Expression of Slug is regulated by c-Myb and is required for invasion and bone marrow homing of cancer cells of different origin.
abstract: In metastatic cancer cells, the process of invasion is regulated by several transcription factors that induce changes required for migration and resistance to apoptosis. Slug (SNAI2, Snail2) is involved in epithelial mesenchymal transition in physiological and in pathological contexts. We show here that in embryonic kidney, colon carcinoma, chronic myeloid leukemia-blast crisis, and in neuroblastoma cells, expression of Slug is transcriptionally regulated by c-Myb via Myb binding sites in the 5'-flanking region and in the first intron of the slug gene. In embryonic kidney and neuroblastoma cells, c-Myb induced vimentin, fibronectin, and N-cadherin expression and membrane ruffling via actin polymerization consistent with the acquisition of a mesenchymal-like phenotype. Furthermore, down-regulation of endogenous c-Myb levels in colon carcinoma cells led to increased expression of E-cadherin and reduced levels of vimentin. Some of these changes are predominantly Slug-dependent as Slug silencing via RNA interference (RNAi) reverts the cells to a quasi-parental condition. Changes in gene expression and morphology induced by c-Myb-activated Slug correlated with increased ability to migrate (embryonic kidney) and to invade through a Matrigel membrane (embryonic kidney, colon carcinoma, neuroblastoma). c-Myb-dependent Slug expression was also essential for the homing of chronic myeloid leukemia K562 cells to the bone marrow. In summary, we show here that the proto-oncogene c-Myb controls Slug transcription in tumor cells of different origin. Such a regulatory pathway contributes to the acquisition of invasive properties that are important for the metastatic process.
authors.affiliation: Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Research Center Casaccia, Laboratory of Radiation Biology and Biomedicine, 00123 Rome, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Tanno
authors.forename: Fabiola
authors.initials: F
authors.lastname: Sesti
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cesi
authors.forename: Gianluca
authors.initials: G
authors.lastname: Bossi
authors.forename: Giovanna
authors.initials: G
authors.lastname: Ferrari-Amorotti
authors.forename: Rita
authors.initials: R
authors.lastname: Bussolari
authors.forename: Donatella
authors.initials: D
authors.lastname: Tirindelli
authors.forename: Bruno
authors.initials: B
authors.lastname: Calabretta
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Raschellà
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D015153:Blotting, Western; D001853:Bone Marrow / Q000473:pathology*; D002460:Cell Line; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D005047:Etoposide / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D007438:Introns / Q000235:genetics; D051379:Mice; D016513:Mice, SCID; D009362:Neoplasm Metastasis / Q000235:genetics / Q000503:physiopathology; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D000090063:Proto-Oncogene Mas; D020598:Proto-Oncogene Proteins c-myb / Q000235:genetics / Q000378:metabolism*; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D020598:Proto-Oncogene Proteins c-myb; C000604407:SNAI1 protein, human; C000604408:SNAI2 protein, human; C000604429:Snai1 protein, mouse; C000604449:Snai2 protein, mouse; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D005047:Etoposide