HGF-MET signals via the MLL-ETS2 complex in hepatocellular carcinoma
Shugaku Takeda, Han Liu, Satoru Sasagawa, Yiyu Dong, Paul A. Trainor, Emily H. Cheng, James J. Hsieh
Shugaku Takeda, Han Liu, Satoru Sasagawa, Yiyu Dong, Paul A. Trainor, Emily H. Cheng, James J. Hsieh
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Research Article

HGF-MET signals via the MLL-ETS2 complex in hepatocellular carcinoma

Abstract

HGF signals through its cognate receptor, MET, to orchestrate diverse biological processes, including cell proliferation, cell fate specification, organogenesis, and epithelial-mesenchymal transition. Mixed-lineage leukemia (MLL), an epigenetic regulator, plays critical roles in cell fate, stem cell, and cell cycle decisions. Here, we describe a role for MLL in the HGF-MET signaling pathway. We found a shared phenotype among Mll–/–, Hgf–/–, and Met–/– mice with common cranial nerve XII (CNXII) outgrowth and myoblast migration defects. Phenotypic analysis demonstrated that MLL was required for HGF-induced invasion and metastatic growth of hepatocellular carcinoma cell lines. HGF-MET signaling resulted in the accumulation of ETS2, which interacted with MLL to transactivate MMP1 and MMP3. ChIP assays demonstrated that activation of the HGF-MET pathway resulted in increased occupancy of the MLL-ETS2 complex on MMP1 and MMP3 promoters, where MLL trimethylated histone H3 lysine 4 (H3K4), activating transcription. Our results present an epigenetic link between MLL and the HGF-MET signaling pathway, which may suggest new strategies for therapeutic intervention.

Authors

Shugaku Takeda, Han Liu, Satoru Sasagawa, Yiyu Dong, Paul A. Trainor, Emily H. Cheng, James J. Hsieh

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Figure 3

MLL is required for HGF-induced cell invasion.

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MLL is required for HGF-induced cell invasion. (A) siRNA-mediated knockd...
(A) siRNA-mediated knockdown of MLL (siMLL and siMLL #2) in HepG2 and HLE cells. Scrambled siRNA (siScr) was used as a control. Anti-MLL Western blot analyses demonstrated effective silencing of MLL. Protein levels of MET in HepG2 and HLE cells transfected with the indicated siRNA oligos were determined by anti-MET Ab. β-actin served as loading control. (B) Equivalent numbers of HepG2 cells (4 × 105) carrying the indicated siRNA oligos were cultured for 60 hours to determine their proliferation. (C) Cell invasion assay. HepG2 and HLE cells were transfected with the indicated siRNA oligos, seeded on Matrigel-coated transwells, and subjected to 20 and 50 ng/ml HGF, respectively, for 24 hours. Invaded cells were stained with crystal violet and Hoechst 33342. Data are mean ± SD from 5 independent fields of 3 independent experiments. *P < 0.05. Scale bars: 0.2 mm.