title: Isoform-specific function of calpains in cell adhesion disruption: studies in postlactational mammary gland and breast cancer.
abstract: Cleavage of adhesion proteins is the first step for physiological clearance of undesired cells during postlactational regression of the mammary gland, but also for cell migration in pathological states such as breast cancer. The intracellular Ca(2+)-dependent proteases, calpains (CAPNs), are known to cleave adhesion proteins. The isoform-specific function of CAPN1 and CAPN2 was explored and compared in two models of cell adhesion disruption: mice mammary gland during weaning-induced involution and breast cancer cell lines according to tumor subtype classification. In both models, E-cadherin, β-catenin, p-120, and talin-1 were cleaved as assessed by western blot analysis. Both CAPNs were able to cleave adhesion proteins from lactating mammary gland in vitro Nevertheless, CAPN2 was the only isoform found to co-localize with E-cadherin in cell junctions at the peak of lactation. CAPN2/E-cadherin in vivo interaction, analyzed by proximity ligation assay, was dramatically increased during involution. Calpain inhibitor administration prevented the cytosolic accumulation of truncated E-cadherin cleaved by CAPN2. Conversely, in breast cancer cells, CAPN2 was restricted to the nuclear compartment. The isoform-specific expression of CAPNs and CAPN activity was dependent on the breast cancer subtype. However, CAPN1 and CAPN2 knockdown cells showed that cleavage of adhesion proteins and cell migration was mediated by CAPN1, independently of the breast cancer cell line used. Data presented here suggest that the subcellular distribution of CAPN1 and CAPN2 is a major issue in target-substrate recognition; therefore, it determines the isoform-specific role of CAPNs during disruption of cell adhesion in either a physiological or a pathological context.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Valencia, Avda. Blasco Ibañez, 15, Valencia 46010, Spain Fundación Investigación Hospital Clínico - INCLIVA, Avda. Blasco Ibañez, 15, Valencia 46010, Spain.
authors.forename: Lucía
authors.initials: L
authors.lastname: Rodríguez-Fernández
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Valencia, Avda. Blasco Ibañez, 15, Valencia 46010, Spain.
authors.forename: Iván
authors.initials: I
authors.lastname: Ferrer-Vicens
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Valencia, Avda. Blasco Ibañez, 15, Valencia 46010, Spain.
authors.forename: Concha
authors.initials: C
authors.lastname: García
authors.affiliation: Fundación Investigación Hospital Clínico - INCLIVA, Avda. Blasco Ibañez, 15, Valencia 46010, Spain.
authors.forename: Sara S
authors.initials: SS
authors.lastname: Oltra
authors.affiliation: Fundación Investigación Hospital Clínico - INCLIVA, Avda. Blasco Ibañez, 15, Valencia 46010, Spain Departamento de Anatomia y Embriologia Humana, Facultad de Medicina, Universidad de Valencia, Valencia, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: Zaragozá
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Valencia, Avda. Blasco Ibañez, 15, Valencia 46010, Spain Fundación Investigación Hospital Clínico - INCLIVA, Avda. Blasco Ibañez, 15, Valencia 46010, Spain.
authors.forename: Juan R
authors.initials: JR
authors.lastname: Viña
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Valencia, Avda. Blasco Ibañez, 15, Valencia 46010, Spain Fundación Investigación Hospital Clínico - INCLIVA, Avda. Blasco Ibañez, 15, Valencia 46010, Spain.
authors.forename: Elena R
authors.initials: ER
authors.lastname: García-Trevijano
mesh_terms: D000818:Animals; D001940:Breast / Q000502:physiology*; D001943:Breast Neoplasms / Q000503:physiopathology*; D002154:Calpain / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology*; D005260:Female; D006801:Humans; D007774:Lactation; D051379:Mice
chemical_list: D002154:Calpain
keywords: E-cadherin-cleavage; calpains; cell adhesion; cell migration; mammary gland involution; subcellular distribution