Epigenetic inactivation of HOXD10 is associated with human colon cancer via inhibiting the RHOC/AKT/MAPK signaling pathway

BACKGROUND: To examine the influence of HOXD10 on the metabolism and growth of colon carcinoma cells by suppressing the RHOC/AKT/MAPK pathway. METHODS: Thirty-seven paired colon cancer and its adjacent samples from The Cancer Genome Atlas (TCGA) were analyzed. Chip Analysis Methylation Pipeline (ChAMP) analysis was employed for differential methylated points (DMPs) and the differential methylation regions (DMRs) screening. The HOXD10 mRNA expression and DNA methylation levels were detected by RT-PCR. The Cell proliferation, migration, invasion and apoptosis were respectively measured by MTT assay, transwell assay, wound healing assay and flow cytometry assay in carcinoma cell lines after treated with 5-aza-2′-deoxycytidine (5-Aza-dC) or transfected with HOXD10-expressing plasmid. The expression of HOXD10 and RHOC was revealed by immunohistochemistry in disparate differentiation colon carcinoma tissues, and the dephosphorylation of AKT and MAPK pathways were detected by RT-PCR and western blot. RESULTS: The bioinformatics analysis demonstrated that HOXD10 was hypermethylated and low-expressed in colorectal cancer tissues. The detection of RT-PCR indicated the similar results in colorectal cancer cell lines and tissues. The induction of demethylation was recovered by treatment with 5-Aza-dC and the HOXD10 in colorectal cancer cell lines was re-expressed by transfection with a HOXD10 expression vector. The demethylation or overexpression of HOXD10 suppressed proliferation, migration, invasion and promoted apoptosis in colorectal cancer cells. HXOD10 suppressed the tumor growth and detected an opposite trend of protein RHOC. AKT and MAPK pathways were notably inactivated after the dephosphorylation due to the overexpression of HOXD10. CONCLUSIONS: HOXD10 was suppressed in colon adenocarcinoma cells, which down-regulated RHOC/AKT/MAPK pathway to enhance colon cancer cells apoptosis and constrain the proliferation, migration and invasion.