title: Cellular senescence and autophagy of myoepithelial cells are involved in the progression of in situ areas of carcinoma ex-pleomorphic adenoma to invasive carcinoma. An in vitro model.
abstract: During tumor invasion, benign myoepithelial cells of carcinoma ex-pleomorphic adenoma (CXPA) surround malignant epithelial cells and disappear. The mechanisms involved in the death and disappearance of these myoepithelial cells were investigated via analysis of the expression of regulatory proteins for apoptosis, autophagy and cellular senescence in an in situ in vitro model. Protein expression relating to apoptosis (Bax, Bcl-2, Survivin), autophagy (Beclin-1, LC3B) and cellular senescence (p21, p16) was evaluated using indirect immunofluorescence. β-galactosidase expression was assessed via histochemistry. Biopsies of CXPA (ex vivo) allowed immunhistochemical evaluation of p21 and p16, whilst LC3B, p21 and p16 protein expression was analyzed by western blotting. In the in vitro model, the myoepithelial cells were positive for LC3B (cytoplasm) and p21 (nucleus), whilst in vivo positivity for p21 and p16 was observed. In vitro, β-galactosidase activity increased in the myoepithelial cells over time. Western blotting analysis revealed an increased LC3B, p16 and p21 expression in the myoepithelial cells with previous contact with the malignant cells when compared with those without contact. The investigation of behavior of benign myoepithelial cells in ductal areas of CXAP revealed that the myoepithelial cells are involved in the autophagy-senescence phenotype that subsequently leads to their disappearance.
authors.affiliation: Department of Oral Pathology, São Leopoldo Mandic Institute and Research Center, Rua José Rocha Junqueira 13, Ponte Preta, 13045-755, Campinas, Brazil.
authors.forename: Carolina Amália Barcellos
authors.initials: CA
authors.lastname: Silva
authors.affiliation: Department of Oral Pathology, São Leopoldo Mandic Institute and Research Center, Rua José Rocha Junqueira 13, Ponte Preta, 13045-755, Campinas, Brazil.
authors.forename: Elizabeth Ferreira
authors.initials: EF
authors.lastname: Martinez
authors.affiliation: Department of Oral Pathology, São Leopoldo Mandic Institute and Research Center, Rua José Rocha Junqueira 13, Ponte Preta, 13045-755, Campinas, Brazil.
authors.forename: Ana Paula Dias
authors.initials: AP
authors.lastname: Demasi
authors.affiliation: Department of Pathology, State University of Campinas, Campinas, Brazil.
authors.forename: Albina
authors.initials: A
authors.lastname: Altemani
authors.affiliation: Department of Oral Pathology, São Leopoldo Mandic Institute and Research Center, Rua José Rocha Junqueira 13, Ponte Preta, 13045-755, Campinas, Brazil.
authors.forename: Jeruza Pinheiro
authors.initials: JP
authors.lastname: da Silveira Bossonaro
authors.affiliation: Department of Oral Pathology, São Leopoldo Mandic Institute and Research Center, Rua José Rocha Junqueira 13, Ponte Preta, 13045-755, Campinas, Brazil.
authors.forename: Ney Soares
authors.initials: NS
authors.lastname: Araújo
authors.affiliation: Department of Oral Pathology, São Leopoldo Mandic Institute and Research Center, Rua José Rocha Junqueira 13, Ponte Preta, 13045-755, Campinas, Brazil. vcaraujo@usp.br.
authors.forename: Vera Cavalcanti
authors.initials: VC
authors.lastname: de Araújo
keywords: Autophagy; Cellular Senescence; Myoepithelial Cells; Tumor Microenvironment