title: FZD7 has a critical role in cell proliferation in triple negative breast cancer.
abstract: Breast cancer is genetically and clinically heterogeneous. Triple negative breast cancer (TNBC) is a subtype of breast cancer that is usually associated with poor outcome and lack of benefit from targeted therapy. We used microarray analysis to perform a pathway analysis of TNBC compared with non-triple negative breast cancer (non-TNBC). Overexpression of several Wnt pathway genes, such as frizzled homolog 7 (FZD7), low density lipoprotein receptor-related protein 6 and transcription factor 7 (TCF7) was observed in TNBC, and we directed our focus to the Wnt pathway receptor, FZD7. To validate the function of FZD7, FZD7shRNA was used to knock down FZD7 expression. Notably, reduced cell proliferation and suppressed invasiveness and colony formation were observed in TNBC MDA-MB-231 and BT-20 cells. Study of the possible mechanism indicated that these effects occurred through silencing of the canonical Wnt signaling pathway, as evidenced by loss of nuclear accumulation of β-catenin and decreased transcriptional activity of TCF7. In vivo studies revealed that FZD7shRNA significantly suppressed tumor formation, through reduced cell proliferation, in mice bearing xenografts without FZD7 expression. Our findings suggest that FZD7-involved canonical Wnt signaling pathway is essential for tumorigenesis of TNBC, and thus, FZD7 shows promise as a biomarker and a potential therapeutic target for TNBC.
authors.affiliation: Department of Molecular Pharmacology, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA 91010, USA.
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.forename: X
authors.initials: X
authors.lastname: Wu
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: K
authors.initials: K
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Wu
authors.forename: Y-C
authors.initials: YC
authors.lastname: Yuan
authors.forename: X
authors.initials: X
authors.lastname: Deng
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: C C H
authors.initials: CC
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Lau
authors.forename: G
authors.initials: G
authors.lastname: Somlo
authors.forename: Y
authors.initials: Y
authors.lastname: Yen
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic / Q000378:metabolism; D005260:Female; D051157:Frizzled Receptors / Q000502:physiology*; D006801:Humans; D009376:Neoplasms, Hormone-Dependent; D040081:Protein Array Analysis; D015398:Signal Transduction; D015854:Up-Regulation; D060449:Wnt Signaling Pathway / Q000502:physiology
chemical_list: C115810:FZD7 protein, human; D051157:Frizzled Receptors