RRC ID 51685
Author Li W, Itou J, Tanaka S, Nishimura T, Sato F, Toi M.
Title A homeobox protein, NKX6.1, up-regulates interleukin-6 expression for cell growth in basal-like breast cancer cells.
Journal Exp Cell Res
Abstract Among breast cancer subtypes, basal-like breast cancer is particularly aggressive, and research on the molecules involved in its pathology might contribute to therapy. In this study, we found that expression of NKX6.1, a homeobox transcription factor, is higher in basal-like breast cancer than in other subtypes. In loss-of-function experiments on basal-like breast cancer cell lines, NKX6.1-depleted cells exhibited reduced cell growth. Because cytokine interleukin-6 (IL-6) is expressed in basal-like breast cancer, and increases cell growth, we analyzed expression levels of IL6, an IL-6 gene, and observed reduced IL6 expression in NKX6.1-depleted cells. In a reporter assay, IL6 promoter activity was reduced by loss of NKX6.1 function. A pull-down assay showed that NKX6.1 binds to the proximal region in IL6 promoter. These results indicate that NKX6.1 directly up-regulates IL6 expression. To investigate further, we established cells with forced expression of IL-6. We observed that exogenous IL-6 expression restored the reduced cell growth of NKX6.1-depleted cells. Furthermore, orthotopic xenografts showed that NKX6.1-depleted cells lost the capacity for tumor formation. We therefore conclude that NKX6.1 is a factor for IL-6-regulated growth and tumor formation in basal-like breast cancer. Our findings facilitate profound understanding of basal-like breast cancer, and the development of suitable therapy.
Volume 343(2)
Pages 177-189
Published 2016-5-1
DOI 10.1016/j.yexcr.2016.03.023
PII S0014-4827(16)30063-5
PMID 27032575
MeSH Animals Base Sequence Breast Neoplasms / genetics* Breast Neoplasms / pathology* Carcinogenesis / pathology Cell Line, Tumor Cell Proliferation Feedback, Physiological Female Gene Expression Regulation, Neoplastic* Homeodomain Proteins / metabolism* Humans Interleukin-6 / genetics* Interleukin-6 / metabolism Mice, Inbred NOD Mice, SCID Models, Biological Promoter Regions, Genetic Up-Regulation / genetics*
IF 3.383
Times Cited 4
Human and Animal Cells LoVo(RCB1639)