title: CX3CL1 increases invasiveness and metastasis by promoting epithelial-to-mesenchymal transition through the TACE/TGF-α/EGFR pathway in hypoxic androgen-independent prostate cancer cells.
abstract: Epithelial-to-mesenchymal transition (EMT) endows cancer cells with enhanced invasive and metastatic potential during cancer progression. Fractalkine, also known as chemokine (C-X3-C motif) ligand 1 (CX3CL1), the only member recognized so far that belongs to the CX3C chemokine subfamily, was reported to participate in the molecular events that regulate cell adhesion, migration and survival of human prostate cancer cells. However, the relationship between CX3CL1 and EMT remains unknown. We treated DU145 and PC-3 cells with CX3CL1 under hypoxic conditions. The migration and invasion abilities of DU145 and PC-3 cells were detected by Transwell assays. Induction of EMT was verified by morphological changes in the DU145 and PC-3 cells and analysis of protein expression of EMT markers such as E-cadherin and vimentin. To identify the involved signaling pathway in CX3CL1-induced EMT, activation of epidermal growth factor receptor (EGFR) was measured using western blot analysis, and Slug expression was detected with or without an EGFR inhibitor prior to CX3CL1 treatment. Concentrations of soluble and total TGF-α in the CX3CL‑treated DU145 cells were detected by ELISA. Additionally, we determined the involvement of the TACE/TGF-α/EGFR pathway in CX3CL1‑induced EMT using RNA interference and specific inhibitors. CX3CL1 increased the migration and invasiveness of the DU145 and PC-3 cells, and resulted in characteristic alterations of EMT. Our results demonstrated that TACE/TGF-α/EGFR pathway activation and subsequent upregulation of Slug expression were responsible for CX3CL1‑induced EMT, and contributed to the migration and inva-sion of prostate cancer cells. Inhibition of TACE/TGF-α/EGFR signaling reversed EMT and led to reduced migration and invasion abilities of the prostate cancer cells. We provide initial evidence that CX3CL1 exposure resulted in EMT occurrence and enhancement of cell migration and invasion through a mechanism involving activation of TACE/TGF-α/EGFR signaling. These findings revealed that CX3CL1 may serve as a new target for the treatment of prostate cancer.
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Jiebing
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Lijie
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Rongjun
authors.initials: R
authors.lastname: Cui
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Dong
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Ultrasonography, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Xiulan
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Yujia
authors.initials: Y
authors.lastname: Pan
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Yandan
authors.initials: Y
authors.lastname: Du
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Yu
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000502:physiology*; D000072198:ADAM17 Protein; D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology*; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D002465:Cell Movement; D054428:Chemokine CX3CL1 / Q000502:physiology*; D058750:Epithelial-Mesenchymal Transition / Q000502:physiology*; D066246:ErbB Receptors / Q000502:physiology*; D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology*; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D016211:Transforming Growth Factor alpha / Q000502:physiology*; D015854:Up-Regulation
chemical_list: C515538:CX3CL1 protein, human; D054428:Chemokine CX3CL1; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering; C000604407:SNAI1 protein, human; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D016211:Transforming Growth Factor alpha; C512478:EGFR protein, human; D066246:ErbB Receptors; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human