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 2

ARHGEF9 is a validated target gene of CHD1L and induces Cdc42 activation.

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ARHGEF9 is a validated target gene of CHD1L and induces Cdc42 activation...
(A) EMSA was used to detect the interaction between CHD1L and ARHGEF9 double-stranded DNA probes. Lane 1, without NE; lane 2, with NE from GFP-7703-C4 cells and DIG-labeled probe; lane 3, with NE from GFP/CHD1L-7703-C3 cells and labeled probe; lane 4, same as lane 3 plus a 50-fold molar excess of unlabeled probe; lane 5, same as lane 3 plus excess unlabeled nonspecific probe. (B) ARHGEF9 expression was modulated by CHD1L. After transient transfection, relative expression of CHD1L and ARHGEF9 was detected in Vec-7703, CHD1L-7703, Vec-LO2, and CHD1L-LO2 cells by qPCR. 18S rRNA was used as an internal control. (C) Silencing CHD1L expression downregulated ARHGEF9 expression. PLC8024 cells were treated with siCHD1L or siGAPDH as a negative control. The fold changes in CHD1L, ARHGEF9, and GAPDH expression in siCHD1L- or siGAPDH-treated PLC8024 cells were detected by qPCR. (D) Compared with empty vector transfectants, ARHGEF9 expression was upregulated in QGY-7703 and LO-2 cells stably expressing CHD1L, as detected by RT-PCR. 18S rRNA was used an endogenous control. (E) Expression of CHD1L, Cdc42-GTP, and total Cdc42, detected by Western blot. Cdc42-GTP increased in CHD1L-7703 and CHD1L-LO2 cells. β-Actin was used as a loading control.