title: Overexpression of SDF-1 activates the NF-κB pathway to induce epithelial to mesenchymal transition and cancer stem cell-like phenotypes of breast cancer cells.
abstract: The formation of EMT and EMT-induced CSC-like phenotype is crucial for the metastasis of tumor cells. The stromal cell-derived factor-1 (SDF-1) is upregulated in various human carcinomas, which is closely associated with proliferation, migration, invasion and prognosis of malignancies. However, limited attention has been directed towards the effect of SDF-1 on epithelial to mesenchymal transition (EMT) or cancer stem cell (CSC)-like phenotype formation in breast cancer cells and the related mechanism. In the present study, we screened MCF-7 cells with low SDF-1 expression level for the purpose of evaluating whether SDF-1 is involved in EMT and CSC-like phenotype formation in MCF-7 cells. The pEGFP-N1-SDF-1 plasmid was transfected into MCF-7 cells, and the stably overexpressed SDF-1 in MCF-7 cells was confirmed by real-time PCR and western blot analysis. Colony formation assay, MTT, wound healing assay and Transwell invasion assay demonstrated that overexpression of SDF-1 significantly boosted the proliferation, migration and invasion of MCF-7 cells compared with parental (P<0.05). Flow cytometry analysis revealed a notable increase of CD44+/CD24- subpopulation in SDF-1 overexpressing MCF-7 cells (P<0.001), accompanied by the apparently elevated ALDH activity and the upregulation of the stem cell markers OCT-4, Nanog, and SOX2 compared with parental (P<0.01). Besides, western blot analysis and immunofluorescence assay observed the significant decreased expression of E-cadherin and enhanced expression of slug, fibronectin and vimentin in SDF-1 overexpressed MCF-7 cells in comparison with parental (P<0.01). Further study found that overexpression of SDF-1 induced the activation of NF-κB pathway in MCF-7 cells. Conversely, suppressing or silencing p65 expression by antagonist or RNA interference could remarkably increase the expression of E-cadherin in SDF-1 overexpressed MCF-7 cells (P<0.001). Overall, the above results indicated that overexpression of SDF-1 enhanced EMT by activating the NF-κB pathway of MCF-7 cells and further induced the formation of CSC-like phenotypes, ultimately promoting the proliferation and metastasis of MCF-7 cells. Therefore, SDF-1 may further be assessed as a potential target for gene therapy of breast cancer.
authors.affiliation: Department of Medical Ultrasonics, Hongqi Hospital of Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, P.R. China.
authors.forename: Lingxin
authors.initials: L
authors.lastname: Kong
authors.affiliation: Key Laboratory of Cancer Prevention and Treatment of Heilongjiang Province, Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, P.R. China.
authors.forename: Sufen
authors.initials: S
authors.lastname: Guo
authors.affiliation: Department of Medical Ultrasonics, Hongqi Hospital of Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, P.R. China.
authors.forename: Chunfeng
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Medical Ultrasonics, Hongqi Hospital of Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, P.R. China.
authors.forename: Yiling
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Medical Ultrasonics, Hongqi Hospital of Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, P.R. China.
authors.forename: Chong
authors.initials: C
authors.lastname: Feng
authors.affiliation: Department of Medical Ultrasonics, Hongqi Hospital of Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, P.R. China.
authors.forename: Yunshuang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Medical Ultrasonics, Hongqi Hospital of Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, P.R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Medical Ultrasonics, Hongqi Hospital of Mudanjiang Medical University, Mudanjiang, Heilongjiang 157011, P.R. China.
authors.forename: Caijuan
authors.initials: C
authors.lastname: Li
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D015703:Antigens, CD; D001943:Breast Neoplasms / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism; D002465:Cell Movement; D049109:Cell Proliferation; D054377:Chemokine CXCL12 / Q000378:metabolism*; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D015316:Genetic Therapy / Q000379:methods; D006801:Humans; D061986:MCF-7 Cells; D008856:Microscopy, Fluorescence; D016328:NF-kappa B / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D014411:Neoplastic Stem Cells / Q000166:cytology*; D010641:Phenotype; D060888:Real-Time Polymerase Chain Reaction; D014746:Vimentin / Q000378:metabolism; D014945:Wound Healing
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; C515255:CXCL12 protein, human; D015820:Cadherins; D054377:Chemokine CXCL12; D016328:NF-kappa B; D014746:Vimentin; D000444:Aldehyde Dehydrogenase