Silencing HOXD10 by promoter region hypermethylation activates ERK signaling in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma is the fifth most common malignancy and the third leading cause of cancer-related death worldwide. Dysregulation of HomeoboxD10 (HOXD10) was found to suppress or promote cancer progression in different cancer types. The function and regulation of HOXD10 remain unclear in human hepatocellular carcinoma (HCC).

METHODS: Primary HCC samples (117), normal liver tissue samples (15), and 13 HCC cell lines (SNU182, SNU449, HBXF344, SMMC7721, Huh7, HepG2, LM3, PLC/PRF/5, BEL7402, SNU387, SNU475, QGY7703, and Huh1) were included in this study. Methylation-specific PCR, flow cytometry, western blot, transwell, siRNA, and chromatin immunoprecipitation assays were employed.

RESULTS: HOXD10 was methylated in 76.9% (90/117) of human primary HCC samples. HOXD10 methylation was significantly associated with vessel cancerous embolus, tumor cell differentiation, and the 3-year overall survival rate (all P  < 0.05). The expression of HOXD10 was regulated by promoter region methylation. HOXD10 suppressed colony formation, cell proliferation, cell invasion and migration, and induced G2/M phase arrest and apoptosis in HCC cells. HOXD10 suppressed HCC cell xenograft growth in mice. HOXD10 suppresses HCC growth by inhibiting ERK signaling.

CONCLUSION: HOXD10 is frequently methylated in human HCC, and the expression of HOXD10 is regulated by promoter region methylation. HOXD10 suppresses HCC cell growth both in vitro and in vivo. HOXD10 suppresses human HCC by inhibiting ERK signaling.