title: PDCD4 is a CSL associated protein with a transcription repressive function in cancer associated fibroblast activation.
abstract: The Notch/CSL pathway plays an important role in skin homeostasis and carcinogenesis. CSL, the key effector of canonical Notch signaling endowed with an intrinsic transcription repressive function, suppresses stromal fibroblast senescence and Cancer Associated Fibroblast (CAF) activation through direct down-modulation of key effector genes. Interacting proteins that participate with CSL in this context are as yet to be identified. We report here that Programmed Cell Death 4 (PDCD4), a nuclear/cytoplasmic shuttling protein with multiple functions, associates with CSL and plays a similar role in suppressing dermal fibroblast senescence and CAF activation. Like CSL, PDCD4 is down-regulated in stromal fibroblasts of premalignant skin actinic keratosis (AKs) lesions and squamous cell carcinoma (SCC). While devoid of intrinsic DNA binding capability, PDCD4 is present at CSL binding sites of CAF marker genes as well as canonical Notch/CSL targets and suppresses expression of these genes in a fibroblast-specific manner. Thus, we propose that PDCD4 is part of the CSL repressive complex involved in negative control of stromal fibroblasts conversion into CAFs.
authors.affiliation: Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, MA, USA.|Department of Dermatology, Harvard Medical School, Boston, MA, USA.
authors.forename: Seung-Hee
authors.initials: SH
authors.lastname: Jo
authors.affiliation: Department of Biochemistry, University of Lausanne, Epalinges, CH, Switzerland.
authors.forename: Dong Eun
authors.initials: DE
authors.lastname: Kim
authors.affiliation: Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, MA, USA.|Department of Dermatology, Harvard Medical School, Boston, MA, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Clocchiatti
authors.affiliation: Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, MA, USA.|Department of Biochemistry, University of Lausanne, Epalinges, CH, Switzerland.
authors.forename: G Paolo
authors.initials: GP
authors.lastname: Dotto
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D000072645:Cancer-Associated Fibroblasts / Q000276:immunology* / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D016922:Cellular Senescence; D015536:Down-Regulation; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein / Q000378:metabolism*; D055623:Keratosis, Actinic / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016513:Mice, SCID; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D023041:Xenograft Model Antitumor Assays
chemical_list: D051017:Apoptosis Regulatory Proteins; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; C114487:PDCD4 protein, human; C497570:RBPJ protein, human; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins
keywords: CAFs; Notch/CSL signaling; PDCD4; squamous cancer; transcription repression