title: PAX3 is expressed in the stromal compartment of the developing kidney and in Wilms tumors with myogenic phenotype.
abstract: Wilms tumor (WT) is the most frequent renal neoplasm of childhood; a myogenic component is observed in 5% to 10% of tumors. We demonstrate for the first time that myogenic WTs are associated with expression of PAX3, a transcription factor known to specify myoblast cell fate during muscle development. In a panel of 20 WTs, PAX3 was identified in 13 of 13 tumor samples with myogenic histopathology but was absent in 7 of 7 tumors lacking a myogenic component. Furthermore, we show that PAX3 is expressed in the metanephric mesenchyme and stromal compartment of developing mouse kidney. Modulation of endogenous PAX3 expression in human embryonic kidney (HEK293) cells influenced cell migration in in vitro assays. Mutations of WT1 were consistently associated with PAX3 expression in WTs, and modulation of WT1 expression in HEK293 cells was inversely correlated with the level of endogenous PAX3 protein. We demonstrate abundant PAX3 and absence of PAX2 expression in a novel cell line (WitP3) isolated from the stromal portion of a WT bearing a homozygous deletion of the WT1 gene. We hypothesize that PAX3 sets stromal cell fate in developing kidney but is normally suppressed by WT1 during the mesenchyme-to-epithelium transition leading to nephrogenesis. Loss of WT1 permits aberrant PAX3 expression in a subset of WTs with myogenic phenotype.
authors.affiliation: Department of Experimental Medicine, McGill University, Montreal Children's Hospital Research Institute, 4060 Ste-Catherine west, Montreal, QC, Canada.
authors.forename: Pierre-Alain
authors.initials: PA
authors.lastname: Hueber
authors.forename: Ryuji
authors.initials: R
authors.lastname: Fukuzawa
authors.forename: Reyhan
authors.initials: R
authors.lastname: Elkares
authors.forename: Leelee
authors.initials: L
authors.lastname: Chu
authors.forename: Miriam
authors.initials: M
authors.lastname: Blumentkrantz
authors.forename: Shu-Jie
authors.initials: SJ
authors.lastname: He
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Anaka
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Reeve
authors.forename: Michael
authors.initials: M
authors.lastname: Eccles
authors.forename: Nada
authors.initials: N
authors.lastname: Jabado
authors.forename: Diana M
authors.initials: DM
authors.lastname: Iglesias
authors.forename: Paul R
authors.initials: PR
authors.lastname: Goodyer
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D005109:Extracellular Matrix / Q000378:metabolism; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000196:embryology / Q000378:metabolism*; D007680:Kidney Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism; D051379:Mice; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D010641:Phenotype; D016133:Polymerase Chain Reaction; D034741:RNA, Small Interfering; D009396:Wilms Tumor / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D000072041:PAX3 Transcription Factor; C489409:PAX3 protein, human; D051761:Paired Box Transcription Factors; D034741:RNA, Small Interfering