Interleukin-18 (IL-18) was recently reported to have a pro-tumor effect in various cancers. Increased IL-18 levels in the serum of cancer patients correlated with malignancy, and IL-18 acts a crucial factor for cell migration in gastric cancer and melanoma. Claudins, which are the most important tight junction proteins, are also linked with cancer progression and metastasis. However, the relationship between claudins and IL-18 is not well-understood. Here, we show that the migratory ability of MCF-7 cells was reduced when endogenous IL-18 expression was inhibited with IL-18 siRNA. Moreover, exogenous IL-18 enhanced breast cancer cell migration and suppressed the expression of the tight junction proteins claudin-1, claudin-3, claudin-4, and claudin-12 in MCF-7 cells. Knockdown of claudin-3, claudin-4, and claudin-12, but not claudin-1, increased breast cancer migration with maximal effects observed in claudin-12 siRNA-transfected cells. To investigate whether the mitogen-activated protein kinase (MAPK) signaling pathway is involved in IL-18-induced cell migration and claudin-12 expression, cells were pretreated with SB203580 (an inhibitor of p38 MAPK) or PD98059 (an inhibitor of ERK1/2) prior to the addition of IL-18. Although pretreatment of MCF-7 cells with SB203580 blocked both the enhanced cell migration and the decreased claudin-12 expression, PD98059 only blocked cell migration and did not affect claudin-12 expression. In addition, exogenous IL-18 induced rapid phosphorylation of p38 MAPK. These results suggest that IL-18 is an important factor inducing breast cancer cell migration through down-regulation of claudin-12 and activation of the p38 MAPK pathway.
|Number of pages
|Biochemical and biophysical research communications
|Published - 2015 Apr 10
Bibliographical noteFunding Information:
This work was supported by a Samsung Biomedical Research Institute grant ( SMO 1131631 ), by the Bio-Med Translational Research Center at Samsung Medical Center , by the Korea Science and Engineering Foundation (KOSEF) through the SRC program, and by the Korea Drug Development Fund (KDDF), which is funded by the Ministry of Science, ICT and Future Planning , the Ministry of Trade, Industry & Energy , and the Ministry of Health & Welfare of the Republic of Korea ( KDDF-201404-04 ).
© 2015 Elsevier Inc. All rights reserved.
- Breast cancer
- Interleukin-18 (IL-18)
- Tight junction
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology