DEAD-box helicase DP103 defines metastatic potential of human breast cancers
Eun Myoung Shin, … , Alan Prem Kumar, Vinay Tergaonkar
Eun Myoung Shin, … , Alan Prem Kumar, Vinay Tergaonkar
Published August 1, 2014
Citation Information: J Clin Invest. 2014;124(9):3807-3824. https://doi.org/10.1172/JCI73451.
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Research Article Oncology

DEAD-box helicase DP103 defines metastatic potential of human breast cancers

Abstract

Despite advancement in breast cancer treatment, 30% of patients with early breast cancers experience relapse with distant metastasis. It is a challenge to identify patients at risk for relapse; therefore, the identification of markers and therapeutic targets for metastatic breast cancers is imperative. Here, we identified DP103 as a biomarker and metastasis-driving oncogene in human breast cancers and determined that DP103 elevates matrix metallopeptidase 9 (MMP9) levels, which are associated with metastasis and invasion through activation of NF-κB. In turn, NF-κB signaling positively activated DP103 expression. Furthermore, DP103 enhanced TGF-β–activated kinase-1 (TAK1) phosphorylation of NF-κB–activating IκB kinase 2 (IKK2), leading to increased NF-κB activity. Reduction of DP103 expression in invasive breast cancer cells reduced phosphorylation of IKK2, abrogated NF-κB–mediated MMP9 expression, and impeded metastasis in a murine xenograft model. In breast cancer patient tissues, elevated levels of DP103 correlated with enhanced MMP9, reduced overall survival, and reduced survival after relapse. Together, these data indicate that a positive DP103/NF-κB feedback loop promotes constitutive NF-κB activation in invasive breast cancers and activation of this pathway is linked to cancer progression and the acquisition of chemotherapy resistance. Furthermore, our results suggest that DP103 has potential as a therapeutic target for breast cancer treatment.

Authors

Eun Myoung Shin, Hui Sin Hay, Moon Hee Lee, Jen Nee Goh, Tuan Zea Tan, Yin Ping Sen, See Wee Lim, Einas M. Yousef, Hooi Tin Ong, Aye Aye Thike, Xiangjun Kong, Zhengsheng Wu, Earnest Mendoz, Wei Sun, Manuel Salto-Tellez, Chwee Teck Lim, Peter E. Lobie, Yoon Pin Lim, Celestial T. Yap, Qi Zeng, Gautam Sethi, Martin B. Lee, Patrick Tan, Boon Cher Goh, Lance D. Miller, Jean Paul Thiery, Tao Zhu, Louis Gaboury, Puay Hoon Tan, Kam Man Hui, George Wai-Cheong Yip, Shigeki Miyamoto, Alan Prem Kumar, Vinay Tergaonkar

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Figure 6

DP103 regulates NF-κB in response to multiple stimuli.

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DP103 regulates NF-κB in response to multiple stimuli. (A) MDA-MB-231 ce...
(A) MDA-MB-231 cells transfected with either control siRNA or siDP103. Cells untreated (UT) or treated as indicated. Extracts analyzed with EMSA (top) and Western blotting (bottom). White separating lines between different stimuli. (B and C) MDA-MB-231 cells transfected with control siRNA or siDP103. Lysates of cells untreated or treated with TNF-α (B) or CPT (C), tested by EMSA. (D) BT549 cells transfected as in C and stimulated with TNF-α. RNA analyzed for mRNA expression of NF-κB target genes. *P < 0.05; **P < 0.01; ***P < 0.001. (E) MCF10A cells treated with TNF-α or LPS. (F) MCF10A cells either untreated or treated with inhibitors for IKK2, MEK1/2, JNK, p38, or PI3K, then stimulated with LPS. (G) White arrowheads indicate putative NF-κB–binding sites on DP103 promoter. (H) Nuclear proteins from MDA-MB-231 cells either untreated or treated with CPT tested by EMSA. Unlabeled DP103 probe as cold or IgG, p65, or p50 was used. (I) Nuclear proteins from MDA-MB-231 cells untreated or treated with TNF-α tested by EMSA using NF-κB consensus (lanes 1–3) or DP103 probe (lanes 4–6). Unlabeled NF-κB consensus cold probe added to lanes 3 and 6. (J) Cells transfected either with siRNA control or siDP103. Lysates immunoprecipitated with NEMO antibody and kinase assay performed as previously described (36). (K) BT549 cells transfected either with control siRNA or siDP103 as indicated and immunoblotted. Fold difference in protein DNA binding indicated in EMSA for A–C and for protein expression changes in E, F, J, and K.