title: Melanocyte transformation associated with substrate adhesion impediment.
abstract: Exclude experimental models of malignant transformation employ chemical and physical carcinogens or genetic manipulations to study tumor progression. In this work, different melanoma cell lines were established after submitting a nontumorigenic melanocyte lineage (melan-a) to sequential cycles of forced anchorage impediment. The great majority of these cells underwent anoikis when maintained in suspension. After one deadhesion cycle, phenotypic alterations were noticeable in the few surviving cells, which became more numerous and showed progressive alterations after each adhesion impediment step. No significant differences in cell surface expression of integrins were detected, but a clear electrophoretic migration shift, compatible with an altered glycosylation pattern, was observed for beta1 chain in transformed cell lines. In parallel, a progressive enrichment of tri- and tetra-antennary N-glycans was apparent, suggesting increased N-acetylglucosaminyltransferase V activity. Alterations both in proteoglycan glycosylation pattern and core protein expression were detected during the transformation process. In conclusion, this model corroborates the role of adhesion state as a promoting agent in transformation process and demonstrates that cell adhesion disturbances may act as carcinogenic stimuli, at least for a nontumorigenic immortalized melanocyte lineage. These findings have intriguing implications for in vivo carcinogenesis, suggesting that anchorage independence may precede, and contribute to, neoplastic conversion.
authors.affiliation: Laboratório de Biologia Molecular, Departamento de Neurologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Sueli M
authors.initials: SM
authors.lastname: Oba-Shinjo
authors.forename: Mariangela
authors.initials: M
authors.lastname: Correa
authors.forename: Tatiana I
authors.initials: TI
authors.lastname: Ricca
authors.forename: Fernanda
authors.initials: F
authors.lastname: Molognoni
authors.forename: Maria A
authors.initials: MA
authors.lastname: Pinhal
authors.forename: Izabel A
authors.initials: IA
authors.lastname: Neves
authors.forename: Sueli K
authors.initials: SK
authors.lastname: Marie
authors.forename: Lúcia O
authors.initials: LO
authors.lastname: Sampaio
authors.forename: Helena B
authors.initials: HB
authors.lastname: Nader
authors.forename: Roger
authors.initials: R
authors.lastname: Chammas
authors.forename: Miriam G
authors.initials: MG
authors.lastname: Jasiulionis
mesh_terms: D000818:Animals; D023102:Anoikis; D002448:Cell Adhesion; D002461:Cell Line, Transformed / Q000637:transplantation; D019070:Cell Lineage; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured / Q000166:cytology; D011508:Chondroitin Sulfate Proteoglycans / Q000096:biosynthesis / Q000235:genetics; D016895:Culture Media, Serum-Free; D058575:Decorin; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000235:genetics; D005260:Female; D005353:Fibronectins; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D005966:Glucuronidase / Q000096:biosynthesis / Q000235:genetics; D006025:Glycosaminoglycans / Q000032:analysis; D019812:Heparan Sulfate Proteoglycans / Q000096:biosynthesis / Q000235:genetics; D016023:Integrins / Q000378:metabolism; D007797:Laminin; D037181:Lectins, C-Type / Q000096:biosynthesis / Q000235:genetics; D008544:Melanocytes / Q000166:cytology* / Q000378:metabolism / Q000637:transplantation; D008546:Melanoma, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D010641:Phenotype; D011509:Proteoglycans / Q000096:biosynthesis / Q000235:genetics; D012334:RNA, Neoplasm / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053675:Versicans; D000099175:Heparanase
chemical_list: D011508:Chondroitin Sulfate Proteoglycans; D016895:Culture Media, Serum-Free; D058575:Decorin; D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D005966:Glucuronidase; D006025:Glycosaminoglycans; D019812:Heparan Sulfate Proteoglycans; D016023:Integrins; D007797:Laminin; D037181:Lectins, C-Type; D009363:Neoplasm Proteins; D011509:Proteoglycans; D012334:RNA, Neoplasm; D053675:Versicans; D000099175:Heparanase; C546879:Dcn protein, mouse; C508323:Vcan protein, mouse; C071927:perlecan