title: Mitf regulation of Dia1 controls melanoma proliferation and invasiveness.
abstract: It is widely held that cells with metastatic properties such as invasiveness and expression of matrix metalloproteinases arise through the stepwise accumulation of genetic lesions arising from genetic instability and "clonal evolution." By contrast, we show here that in melanomas invasiveness can be regulated epigenetically by the microphthalmia-associated transcription factor, Mitf, via regulation of the DIAPH1 gene encoding the diaphanous-related formin Dia1 that promotes actin polymerization and coordinates the actin cytoskeleton and microtubule networks at the cell periphery. Low Mitf levels lead to down-regulation of Dia1, reorganization of the actin cytoskeleton, and increased ROCK-dependent invasiveness, whereas increased Mitf expression leads to decreased invasiveness. Significantly the regulation of Dia1 by Mitf also controls p27(Kip1)-degradation such that reduced Mitf levels lead to a p27(Kip1)-dependent G1 arrest. Thus Mitf, via regulation of Dia1, can both inhibit invasiveness and promote proliferation. The results imply variations in the repertoire of environmental cues that determine Mitf activity will dictate the differentiation, proliferative, and invasive/migratory potential of melanoma cells through a dynamic epigenetic mechanism.
authors.affiliation: Signalling and Development Laboratory, Marie Curie Research Institute, Oxted, Surrey, RH8 0TL, United Kingdom.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Carreira
authors.forename: Jane
authors.initials: J
authors.lastname: Goodall
authors.forename: Laurence
authors.initials: L
authors.lastname: Denat
authors.forename: Mercedes
authors.initials: M
authors.lastname: Rodriguez
authors.forename: Paolo
authors.initials: P
authors.lastname: Nuciforo
authors.forename: Keith S
authors.initials: KS
authors.lastname: Hoek
authors.forename: Alessandro
authors.initials: A
authors.lastname: Testori
authors.forename: Lionel
authors.initials: L
authors.lastname: Larue
authors.forename: Colin R
authors.initials: CR
authors.lastname: Goding
mesh_terms: D000199:Actins / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000235:genetics / Q000378:metabolism; D005260:Female; D000080865:Formins; D016193:G1 Phase; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D008545:Melanoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D014162:Transfection; D054460:rho-Associated Kinases
chemical_list: D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; C108962:DIAPH1 protein, human; D000080865:Formins; D047908:Intracellular Signaling Peptides and Proteins; D051739:Microphthalmia-Associated Transcription Factor; D050760:Cyclin-Dependent Kinase Inhibitor p27; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020778:Matrix Metalloproteinase 2