ABSTRACT
The metabolic switch from oxidative phosphorylation to glycolysis is required for tumorigenesis in order to provide cancer cells with energy and substrates of biosynthesis. Therefore, it is important to elucidate mechanisms controlling the cancer metabolic switch. MTR4 is a RNA helicase associated with a nuclear exosome that plays key roles in RNA processing and surveillance. We demonstrate that MTR4 is frequently overexpressed in hepatocellular carcinoma (HCC) and is an independent diagnostic marker predicting the poor prognosis of HCC patients. MTR4 drives cancer metabolism by ensuring correct alternative splicing of pre-mRNAs of critical glycolytic genes such as GLUT1 and PKM2. c-Myc binds to the promoter of the MTR4 gene and is important for MTR4 expression in HCC cells, indicating that MTR4 is a mediator of the functions of c-Myc in cancer metabolism. These findings reveal important roles of MTR4 in the cancer metabolic switch and present MTR4 as a promising therapeutic target for treating HCC.
Subject(s)
Alternative Splicing , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , RNA Helicases/genetics , Aged , Animals , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/mortality , Carrier Proteins/genetics , Carrier Proteins/metabolism , Female , Gene Expression Regulation, Neoplastic , Genes, myc , Glucose Transporter Type 1/genetics , Glucose Transporter Type 1/metabolism , Glycolysis/physiology , Heterogeneous-Nuclear Ribonucleoproteins/genetics , Heterogeneous-Nuclear Ribonucleoproteins/metabolism , Humans , Liver Neoplasms/genetics , Liver Neoplasms/metabolism , Liver Neoplasms/mortality , Male , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice, SCID , Middle Aged , Polypyrimidine Tract-Binding Protein/genetics , Polypyrimidine Tract-Binding Protein/metabolism , Promoter Regions, Genetic , RNA Helicases/metabolism , Thyroid Hormones/genetics , Thyroid Hormones/metabolism , Thyroid Hormone-Binding ProteinsABSTRACT
OBJECTIVE: To investigate the expression of Wnt5b in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) tissues and its correlation with the clinicopathological parameters. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical staining were employed to measure Wnt5b mRNA and protein expressions in two groups of HBV-related HCC patients (100 cases in each) selected from a cohort of 289 cases with HBV-related HCC using simple random sampling method. The correlation of Wnt5b expression with the clinicopathological parameters and the prognosis of HCC patients was analyzed. RESULTS: Wnt5b mRNA expression was significantly higher in HCC tissues than that of adjacent noncancerous tissues in 65.0% (65/100) of the cases, and the positivity rate of Wnt5b protein was significantly higher in HCC tissues than that of adjacent noncancerous tissues (58.0% vs 22.0%, P<0.05). Wnt5b expression was significantly correlated with the tumor size (P<0.05), tumor number (P<0.01, only at the protein level), tumor differentiation (P<0.01, only at the protein level), TNM stage (P<0.05), BCLC stage (P<0.05), metastasis (P<0.05) and recurrence (P<0.01). The patients with up-regulated Wnt5b mRNA and protein had a shorter relapse-free survival (P<0.01). CONCLUSION: s Up-regulated Wnt5b might contribute to the progression of HBV-related HCC and predicts a poor prognosis.
ABSTRACT
Hepatocellular carcinoma is the most common histological type of primary liver cancer, which represents the second leading cause of cancer-related mortality. MiR-126 was reported to be downregulated in hepatocellular carcinoma tissues, compared with its levels in noncancerous tissues. However, baseline miR-126 expression levels in hepatitis B virus-related hepatocellular carcinoma patients who did not undergo pre-operational treatment remains unknown since hepatitis B virus infection and pre-operational transcatheter arterial chemoembolization were shown to upregulate miR-126 expression. Here, we demonstrated that miR-126 is generally downregulated in a homogeneous population of pre-operational treatment-naïve hepatitis B virus-related hepatocellular carcinoma patients (84.0%, 84/100), and its expression is significantly associated with pre-operational alpha-fetoprotein levels ( p < 0.05), microvascular invasion ( p < 0.05), tumor metastasis ( p < 0.05), as well as early recurrence (12 months after surgery; p < 0.01). Furthermore, the results of our study revealed that miR-126 is negatively correlated with ADAM9 expression in hepatitis B virus-related hepatocellular carcinoma patients. Overexpression of miR-126 was shown to attenuate ADAM9 expression in hepatocellular carcinoma cells, which subsequently inhibits cell migration and invasion in vitro. In addition, Cox proportional hazards regression model analysis showed that ADAM9 levels, tumor number, microvascular invasion, and tumor metastasis rate represent independent prognostic factors for shorter recurrence-free survival. In conclusion, we demonstrated that the loss of tumor suppressor miR-126 in hepatitis B virus-related hepatocellular carcinoma cells contributes to the development of metastases through the upregulated expression of its target gene, ADAM9. MiR-126-ADAM9 pathway-based therapeutic targeting may represent a novel approach for the inhibition of hepatitis B virus-related hepatocellular carcinoma metastases.
