Activation of NF-κB by the RANKL/RANK system up-regulates snail and twist expressions and induces epithelial-to-mesenchymal transition in mammary tumor cell lines.

Abstract

BACKGROUND:

Increased motility and invasiveness of cancer cells are reminiscent of the epithelial-mesenchymal transition (EMT), which occurs during cancer progression and metastasis. Recent studies have indicated the expression of receptor activator of nuclear factor-κB (RANK) in various solid tumors, including breast cancer. Although activation of the RANK ligand (RANKL)/RANK system promotes cell migration, metastasis, and anchorage-independent growth of tumor-initiating cells, it remains to be investigated if RANKL induces EMT in breast cancer cells. In this study, we investigated whether RANKL induces EMT in normal breast mammary epithelial cells and breast cancer cells, and the mechanism underlying such induction.

METHODS:

Expression levels of vimentin, N-cadherin, E-cadherin, Snail, Slug, and Twist were examined by real-time polymerase chain reaction. Cell migration and invasion were assessed using Boyden chamber and invasion assays, respectively. The effects of RANKL on signal transduction molecules were determined by western blot analyses.

RESULTS:

We found that stimulation by RANKL altered the cell morphology to the mesenchymal phenotype in normal breast epithelial and breast cancer cells. In addition, RANKL increased the expression levels of vimentin, N-cadherin, Snail, and Twist and decreased the expression of E-cadherin. We also found that RANKL activated nuclear factor-κB (NF-κB), but not extracellular signal-regulated kinase 1/2, Akt, mammalian target of rapamycin, c-Jun N-terminal kinase, and signal transducer and activator of transcription 3. Moreover, dimethyl fumarate, a NF-κB inhibitor, inhibited RANKL-induced EMT, cell migration, and invasion, and upregulated the expressions of Snail, Twist, vimentin, and N-cadherin.

CONCLUSIONS:

The results indicate that RANKL induces EMT by activating the NF-κB pathway and enhancing Snail and Twist expression. These findings suggest that the RANKL/RANK system promotes tumor cell migration, invasion, and metastasis via the induction of EMT.

• Authors: Masanobu Tsubaki, Makiko Komai, Shin-Ichiro Fujimoto, Tatsuki Itoh, Motohiro Imano, Kotaro Sakamoto, Hirotaka Shimaoka, Tomoya Takeda, Naoki Ogawa, Kenji Mashimo, Daiichiro Fujiwara, Junji Mukai, Katsuhiko Sakaguchi, Takao Satou, Shozo Nishida
• Journal: Journal of experimental & clinical cancer research : CR (J Exp Clin Cancer Res) Vol. 32 Pg. 62 (Sep 05 2013) ISSN: 1756-9966 [Electronic] England
• PMID: 24011086 (Publication Type: Journal Article)

Chemical References

• NF-kappa B
• Nuclear Proteins
• RANK Ligand
• Receptor Activator of Nuclear Factor-kappa B
• SNAI1 protein, human
• Snail Family Transcription Factors
• TNFRSF11A protein, human
• TNFSF11 protein, human
• TWIST1 protein, human
• Transcription Factors
• Twist-Related Protein 1

Topics

• Animals
• Breast Neoplasms (genetics, metabolism, pathology)
• Cell Line, Tumor
• Cell Movement (physiology)
• Disease Models, Animal
• Disease Progression
• Epithelial-Mesenchymal Transition (physiology)
• Female
• Humans
• MCF-7 Cells
• NF-kappa B (genetics, metabolism)
• Neoplasm Invasiveness
• Nuclear Proteins (biosynthesis)
• RANK Ligand (metabolism)
• Receptor Activator of Nuclear Factor-kappa B (metabolism)
• Signal Transduction
• Snail Family Transcription Factors
• Transcription Factors (biosynthesis)
• Twist-Related Protein 1 (biosynthesis)
• Up-Regulation