title: NF-κB signaling regulates cell-autonomous regulation of CXCL10 in breast cancer 4T1 cells.
abstract: The chemokine CXCL10 and its receptor CXCR3 play a role in breast cancer metastasis to bone and osteoclast activation. However, the mechanism of CXCL10/CXCR3-induced intracellular signaling has not been fully investigated. To evaluate CXCL10-induced cellular events in the mouse breast cancer cell line 4T1, we developed a new synthetic CXCR3 antagonist JN-2. In this study, we observed that secretion of CXCL10 in the supernatant of 4T1 cells was gradually increased during cell growth. JN-2 inhibited basal and CXCL10-induced CXCL10 expression and cell motility in 4T1 cells. Treatment of 4T1 cells with CXCL10 increased the expression of P65, a subunit of the NF-κB pathway, via activation of the NF-κB transcriptional activity. Ectopic overexpression of P65 increased CXCL10 secretion and blunted JN-2-induced suppression of CXCL10 secretion, whereas overexpression of IκBα suppressed CXCL10 secretion. These results indicate that the CXCL10/CXCR3 axis creates a positive feedback loop through the canonical NF-κB signaling pathway in 4T1 cells. In addition, treatment of osteoblasts with conditioned medium from JN-2-treated 4T1 cells inhibited the expression of RANKL, a crucial cytokine for osteoclast differentiation, which resulted in an inhibitory effect on osteoclast differentiation in the co-culture system of bone marrow-derived macrophages and osteoblasts. Direct intrafemoral injection of 4T1 cells induced severe bone destruction; however, this effect was suppressed by the CXCR3 antagonist via downregulation of P65 expression in an animal model. Collectively, these results suggest that the CXCL10/CXCR3-mediated NF-κB signaling pathway plays a role in the control of autonomous regulation of CXCL10 and malignant tumor properties in breast cancer 4T1 cells.
authors.affiliation: Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
authors.forename: Won Jong
authors.initials: WJ
authors.lastname: Jin
authors.affiliation: Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
authors.forename: Bongjun
authors.initials: B
authors.lastname: Kim
authors.affiliation: Division of Life and Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Darong
authors.initials: D
authors.lastname: Kim
authors.affiliation: Division of Life and Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Hea-Young
authors.initials: HY
authors.lastname: Park Choo
authors.affiliation: Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hong-Hee
authors.initials: HH
authors.lastname: Kim
authors.affiliation: Clinical Research Division, Korea Institute of Oriental Medicine, Daejeon, Republic of Korea.
authors.forename: Hyunil
authors.initials: H
authors.lastname: Ha
authors.affiliation: Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
authors.forename: Zang Hee
authors.initials: ZH
authors.lastname: Lee
mesh_terms: D000818:Animals; D001940:Breast / Q000276:immunology / Q000473:pathology; D001943:Breast Neoplasms / Q000276:immunology* / Q000473:pathology; D045744:Cell Line, Tumor; D054357:Chemokine CXCL10 / Q000032:analysis / Q000276:immunology*; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000032:analysis / Q000276:immunology*; D054367:Receptors, CXCR3 / Q000037:antagonists & inhibitors / Q000276:immunology; D015398:Signal Transduction
chemical_list: D054357:Chemokine CXCL10; C485433:Cxcl10 protein, mouse; C515188:Cxcr3 protein, mouse; D016328:NF-kappa B; D054367:Receptors, CXCR3