Exp Mol Med.  2017 Feb;49(2):e295. 10.1038/emm.2016.148.

NF-κB signaling regulates cell-autonomous regulation of CXCL10 in breast cancer 4T1 cells

• Jin WJ
• Kim B
• Kim D
• Park Choo
• Kim HH
• Ha H
• Lee ZH

• KMID: 2375025
• DOI: http://doi.org/10.1038/emm.2016.148

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.

MeSH Terms

Animals
Breast Neoplasms*
Breast*
Cell Line
Cell Movement
Chemokine CXCL10
Coculture Techniques
Culture Media, Conditioned
Down-Regulation
Macrophages
Mice
Models, Animal
Neoplasm Metastasis
Osteoblasts
Osteoclasts
Chemokine CXCL10
Culture Media, Conditioned