title: Nuclear cathepsin D enhances TRPS1 transcriptional repressor function to regulate cell cycle progression and transformation in human breast cancer cells.
abstract: The lysosomal protease cathepsin D (Cath-D) is overproduced in breast cancer cells (BCC) and supports tumor growth and metastasis formation. Here, we describe the mechanism whereby Cath-D is accumulated in the nucleus of ERα-positive (ER+) BCC. We identified TRPS1 (tricho-rhino-phalangeal-syndrome 1), a repressor of GATA-mediated transcription, and BAT3 (Scythe/BAG6), a nucleo-cytoplasmic shuttling chaperone protein, as new Cath-D-interacting nuclear proteins. Cath-D binds to BAT3 in ER+ BCC and they partially co-localize at the surface of lysosomes and in the nucleus. BAT3 silencing inhibits Cath-D accumulation in the nucleus, indicating that Cath-D nuclear targeting is controlled by BAT3. Fully mature Cath-D also binds to full-length TRPS1 and they co-localize in the nucleus of ER+ BCC where they are associated with chromatin. Using the LexA-VP16 fusion co-activator reporter assay, we then show that Cath-D acts as a transcriptional repressor, independently of its catalytic activity. Moreover, microarray analysis of BCC in which Cath-D and/or TRPS1 expression were silenced indicated that Cath-D enhances TRPS1-mediated repression of several TRPS1-regulated genes implicated in carcinogenesis, including PTHrP, a canonical TRPS1 gene target. In addition, co-silencing of TRPS1 and Cath-D in BCC affects the transcription of cell cycle, proliferation and transformation genes, and impairs cell cycle progression and soft agar colony formation. These findings indicate that Cath-D acts as a nuclear transcriptional cofactor of TRPS1 to regulate ER+ BCC proliferation and transformation in a non-proteolytic manner.
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Bach
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Danielle
authors.initials: D
authors.lastname: Derocq
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Laurent-Matha
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Montcourrier
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Salwa
authors.initials: S
authors.lastname: Sebti
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Béatrice
authors.initials: B
authors.lastname: Orsetti
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Theillet
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Gongora
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Pattingre
authors.affiliation: Universität zu Lübeck, Lübeck, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Ibing
authors.affiliation: Department of Pathology, CHU Nimes, Nimes, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Roger
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Laetitia K
authors.initials: LK
authors.lastname: Linares
authors.affiliation: Institute of Molecular Medicine and Cell Research, Albert-Ludwigs-University, Freiburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Reinheckel
authors.affiliation: Functional Genomic Plateform, Institut Gustave Roussy, Villejuif, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Meurice
authors.affiliation: Universität zu Lübeck, Lübeck, Germany.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Kaiser
authors.affiliation: INSERM U938, Molecular and Clinical Oncology, Paris 6 University Pierre et Marie Curie, Hôpital Saint-Antoine, Paris, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Gespach
authors.affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, France.|INSERM U1194, Montpellier, France.|Université de Montpellier, Montpellier, France.|Institut Régional du Cancer de Montpellier, Montpellier, France.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Liaudet-Coopman
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002402:Cathepsin D / Q000235:genetics* / Q000378:metabolism; D002453:Cell Cycle / Q000235:genetics*; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D015151:Immunoblotting; D061986:MCF-7 Cells; D008856:Microscopy, Fluorescence; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D044162:Parathyroid Hormone-Related Protein; D011485:Protein Binding; D034622:RNA Interference; D011960:Receptors, Estrogen / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques
chemical_list: C092009:BAG6 protein, human; D004268:DNA-Binding Proteins; D018832:Molecular Chaperones; D044162:Parathyroid Hormone-Related Protein; D011960:Receptors, Estrogen; D012097:Repressor Proteins; C108387:TRPS1 protein, human; D014157:Transcription Factors; D002402:Cathepsin D
keywords: BAT3; GATA-factor; PTHrP promoter; confocal microscopy; yeast-two hybrid