CHD1L promotes hepatocellular carcinoma progression and metastasis in mice and is associated with these processes in human patients
Leilei Chen, … , Yan Li, Xin-Yuan Guan
Leilei Chen, … , Yan Li, Xin-Yuan Guan
Published March 24, 2010
Citation Information: J Clin Invest. 2010;120(4):1178-1191. https://doi.org/10.1172/JCI40665.
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Research Article

CHD1L promotes hepatocellular carcinoma progression and metastasis in mice and is associated with these processes in human patients

Abstract

Chromodomain helicase/ATPase DNA binding protein 1–like gene (CHD1L) is a recently identified oncogene localized at 1q21, a frequently amplified region in hepatocellular carcinoma (HCC). To explore its oncogenic mechanisms, we set out to identify CHD1L-regulated genes using a chromatin immunoprecipitation–based (ChIP-based) cloning strategy in a human HCC cell line. We then further characterized 1 identified gene, ARHGEF9, which encodes a specific guanine nucleotide exchange factor (GEF) for the Rho small GTPase Cdc42. Overexpression of ARHGEF9 was detected in approximately half the human HCC samples analyzed and positively correlated with CHD1L overexpression. In vitro and in vivo functional studies in mice showed that CHD1L contributed to tumor cell migration, invasion, and metastasis by increasing cell motility and inducing filopodia formation and epithelial-mesenchymal transition (EMT) via ARHGEF9-mediated Cdc42 activation. Silencing ARHGEF9 expression by RNAi effectively abolished the invasive and metastatic abilities of CHD1L in mice. Furthermore, investigation of clinical HCC specimens showed that CHD1L and ARHGEF9 were markedly overexpressed in metastatic HCC tissue compared with healthy tissue. Increased expression of CHD1L was often observed at the invasive front of HCC tumors and correlated with venous infiltration, microsatellite tumor nodule formation, and poor disease-free survival. These findings suggest that CHD1L-ARHGEF9-Cdc42-EMT might be a novel pathway involved in HCC progression and metastasis.

Authors

Leilei Chen, Tim Hon Man Chan, Yun-Fei Yuan, Liang Hu, Jun Huang, Stephanie Ma, Jian Wang, Sui-Sui Dong, Kwan Ho Tang, Dan Xie, Yan Li, Xin-Yuan Guan

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Figure 3

CHD1L induces filopodia formation, EMT, and cell migration and invasion.

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CHD1L induces filopodia formation, EMT, and cell migration and invasion....
(A) Representative images of cell morphology in Vec-LO2, CHD1L-LO2, Vec-7703, and CHD1L-7703 cells. (B) Redistribution of actin filaments to filopodia-like structures in CHD1L-7703 cells (arrows). The cells were stained for F-actin and counterstained with DAPI to visualize the nuclei. (C) Expression of epithelial markers (E-cadherin, α-catenin, and β-catenin) and mesenchymal markers (fibronectin, N-cadherin, vimentin, and α-SMA), compared between Vec-7703 and CHD1L-7703 cells by Western blot. (D) Double IF staining of E-cadherin and β-catenin was performed in Vec-7703 and CHD1L-7703 cells. Arrows denote the regions shown at higher magnification in the insets. (E) Fibronectin and vimentin in Vec-7703 and CHD1L-7703 cells were compared by IF staining; nuclei were counterstained with DAPI. (F) Cell migration rates of Vec-7703, CHD1L-7703, Vec-LO2, and CHD1L-LO2 cells were compared via wound healing assays. Microscopic observation was recorded at 0, 24, and 36 hours after scratching the surface of a confluent layer of cells. (G) Invasion rates of Vec-7703, CHD1L-7703, Vec-LO2, and CHD1L-LO2 cells. Number of cells that invaded through the Matrigel was counted in 10 fields under the ×20 objective lens. Original magnification, ×200 (A); ×400 (B, D, and E); ×1,000 (D, insets); ×100 (F).