title: Stat5 promotes homotypic adhesion and inhibits invasive characteristics of human breast cancer cells.
abstract: Signal transducer and activator of transcription-5 (Stat5) mediates prolactin (PRL)-induced differentiation and growth of breast epithelial cells. We have recently identified active Stat5 as a tumor marker of favorable prognosis in human breast cancer, and determined that Stat5 activation is lost during metastatic progression. Here we provide novel evidence for an invasion-suppressive role of Stat5 in human breast cancer. Activation of Stat5 by PRL in human breast cancer lines was associated with increased surface levels of the invasion-suppressive adhesion molecule E-cadherin in vitro and in xenotransplant tumors in vivo. Inducible E-cadherin was blocked by dominant-negative (Dn) Stat5 or Dn-Jak2, but not by Dn-Stat3. Further experimental data indicated a role of Stat5 as a coordinate regulator of additional invasion-related characteristics of human breast cancer cells, including cell surface association of beta-catenin, homotypic cell clustering, invasion through Matrigel, cell migration, and matrix metalloproteinase activity. A role of Stat5 as a suppressor of breast cancer invasion and metastatic progression provides a biological mechanism to explain the favorable prognosis associated with active Stat5 in human breast cancer.
authors.affiliation: Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, NRB E504, 3970 Reservoir Rd NW, Washington, DC 20057-1469, USA.
authors.forename: Ahmed S
authors.initials: AS
authors.lastname: Sultan
authors.forename: Jianwu
authors.initials: J
authors.lastname: Xie
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: LeBaron
authors.forename: Erica L
authors.initials: EL
authors.lastname: Ealley
authors.forename: Marja T
authors.initials: MT
authors.lastname: Nevalainen
authors.forename: Hallgeir
authors.initials: H
authors.lastname: Rui
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000473:pathology; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D005260:Female; D006801:Humans; D051379:Mice; D008894:Milk Proteins / Q000235:genetics; D009361:Neoplasm Invasiveness / Q000517:prevention & control*; D009362:Neoplasm Metastasis; D011379:Prognosis; D011388:Prolactin / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000378:metabolism; D050799:STAT5 Transcription Factor; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D025521:Tumor Suppressor Proteins; D051176:beta Catenin
chemical_list: C495270:CTNNB1 protein, human; C495267:CTNNB1 protein, mouse; D015820:Cadherins; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D008894:Milk Proteins; D011994:Recombinant Proteins; D050799:STAT5 Transcription Factor; C494092:STAT5A protein, human; D015534:Trans-Activators; D025521:Tumor Suppressor Proteins; D051176:beta Catenin; D011388:Prolactin