title: A 3D in vitro model to explore the inter-conversion between epithelial and mesenchymal states during EMT and its reversion.
abstract: Epithelial-to-mesenchymal transitions (EMT) are strongly implicated in cancer dissemination. Intermediate states, arising from inter-conversion between epithelial (E) and mesenchymal (M) states, are characterized by phenotypic heterogeneity combining E and M features and increased plasticity. Hybrid EMT states are highly relevant in metastatic contexts, but have been largely neglected, partially due to the lack of physiologically-relevant 3D platforms to study them. Here we propose a new in vitro model, combining mammary E cells with a bioengineered 3D matrix, to explore phenotypic and functional properties of cells in transition between E and M states. Optimized alginate-based 3D matrices provided adequate 3D microenvironments, where normal epithelial morphogenesis was recapitulated, with formation of acini-like structures, similar to those found in native mammary tissue. TGFβ1-driven EMT in 3D could be successfully promoted, generating M-like cells. TGFβ1 removal resulted in phenotypic switching to an intermediate state (RE cells), a hybrid cell population expressing both E and M markers at gene/protein levels. RE cells exhibited increased proliferative/clonogenic activity, as compared to M cells, being able to form large colonies containing cells with front-back polarity, suggesting a more aggressive phenotype. Our 3D model provides a powerful tool to investigate the role of the microenvironment on metastable EMT stages.
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.
authors.forename: S J
authors.initials: SJ
authors.lastname: Bidarra
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.|Expression Regulation in Cancer Group, Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Oliveira
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.|Expression Regulation in Cancer Group, Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.
authors.forename: S
authors.initials: S
authors.lastname: Rocha
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.
authors.forename: D P
authors.initials: DP
authors.lastname: Saraiva
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.|Expression Regulation in Cancer Group, Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.|Department of Pathology and Oncology, Faculty of Medicine, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319 Porto, Portugal.
authors.forename: C
authors.initials: C
authors.lastname: Oliveira
authors.affiliation: i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.|INEB - Instituto de Engenharia Biomédica, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal.|Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
authors.forename: C C
authors.initials: CC
authors.lastname: Barrias
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000464:Alginates / Q000737:chemistry; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D018929:Cell Culture Techniques; D002460:Cell Line; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects* / Q000235:genetics; D005260:Female; D015870:Gene Expression; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D019394:Ki-67 Antigen / Q000235:genetics / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D062793:Occludin / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D018874:Spheroids, Cellular / Q000166:cytology* / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*
chemical_list: D000199:Actins; D000464:Alginates; D015415:Biomarkers; D015820:Cadherins; C000611838:Cdh1 protein, mouse; D006603:Hexuronic Acids; D019394:Ki-67 Antigen; C498355:Mki67 protein, mouse; D062793:Occludin; C568986:Ocln protein, mouse; D053773:Transforming Growth Factor beta1; D020723:Glucuronic Acid