Integrated Bioinformatics Analysis and Validation of the Prognostic Value of RBM10 Expression in Hepatocellular Carcinoma.

Background: RBM10's function in hepatocellular carcinoma (HCC) has rarely been addressed. We intend to explore the prognostic significance and therapeutic meaning of RBM10 in HCC in this study. Methods: Multiple common databases were integrated to analyze the expression status and prognostic meaning of RBM10 in HCC. The relationship between RBM10 mRNA level and clinical features was also assessed. Multiple enrichment analyses of the differentially expressed genes between RBM10 high- and low- transcription groups were constructed by using R software (version 4.0.2). A Search Tool for Retrieval of Interacting Genes database was used to construct the protein-protein interaction network between RBM10 and other proteins. A tumor immune estimation resource database was employed to identify the relationship between RBM10 expression and immune cell infiltrates. The prognostic value of RBM10 expression was validated in our HCC cohort by immunohistochemistry test. Results: The transcription of RBM10 mRNA was positively correlated with tumor histologic grade (p < 0.001), T classification (p < 0.001), and tumor stage (p < 0.001). High transcription of RBM10 in HCC predicted a dismal overall survival (p = 0.0037) and recurrence-free survival (p < 0.001). Kyoto Encyclopedia of Genes and Genomes, Gene Ontology, and Gene Set Enrichment Analysis all revealed that RBM10 was involved in the regulation of cell cycle, DNA replication, and immune-related pathways. Tumor immune estimation analysis revealed that RBM10 transcription was positively related to multiple immune cell infiltrates and the expressions of PD-1 and PD-L1. Conclusion: RBM10 was demonstrated to be a dismal prognostic factor and a potential biomarker for immune therapy in HCC in that it may be involved in the immune-related signaling pathways.

Distinct role of nuclear receptor corepressor 1 regulated de novo fatty acids synthesis in liver regeneration and hepatocarcinogenesis in mice.

It is urgent that the means to improve liver regeneration (LR) be found, while mitigating the concurrent risk of hepatocarcinogenesis (HCG). Nuclear receptor corepressor 1 (NCoR1) is a co-repressor of nuclear receptors, which regulates the expression level of metabolic genes; however, little is known about its potential contribution for LR and HCG. Here, we found that liver-specific NCoR1 knockout in mice (NCoR1Δhep ) dramatically enhances LR after partial hepatectomy and, surprisingly, blocks the process of diethylnitrosamine (DEN)-induced HCG. Both RNA-sequencing and metabolic assay results revealed improved expression of Fasn and Acc2 in NCoR1Δhep mice, suggesting the critical role of de novo fatty acid synthesis (FAS) in LR. Continual enhanced de novo FAS in NCoR1Δhep mice resulted in overwhelmed adenosine triphosphate ATP and nicotinamide adenine dinucleotide phosphate (NADPH) consumption and increased mitochondrial reactive oxygen species production, which subsequently attenuated HCG through inducing apoptosis of hepatocytes at an early stage after DEN administration. CONCLUSION: NCoR1 functions as a negative modulator for hepatic de novo FAS and mitochondria energy adaptation, playing distinct roles in regeneration or carcinogenesis. (Hepatology 2018;67:1071-1087).

Aldehyde dehydrogenase-2 (ALDH2) opposes hepatocellular carcinoma progression by regulating AMP-activated protein kinase signaling in mice.

Potential biomarkers that can be used to determine prognosis and perform targeted therapies are urgently needed to treat patients with hepatocellular carcinoma (HCC). To meet this need, we performed a screen to identify functional genes associated with hepatocellular carcinogenesis and its progression at the transcriptome and proteome levels. We identified aldehyde dedydrogenase-2 (ALDH2) as a gene of interest for further study. ALDH2 levels were significantly lower at the mRNA and protein level in tumor tissues than in normal tissues, and they were even lower in tissues that exhibited increased migratory capacity. A study of clinical associations showed that ALDH2 is correlated with survival and multiple migration-associated clinicopathological traits, including the presence of metastasis and portal vein tumor thrombus. The result of overexpressing or knocking down ALDH2 showed that this gene inhibited migration and invasion both in vivo and in vitro. We also found that ALDH2 altered the redox status of cells by regulating acetaldehyde levels and that it further activated the AMP-activated protein kinase (AMPK) signaling pathway. CONCLUSION: Decreased levels of ALDH2 may indicate a poor prognosis in HCC patients, while forcing the expression of ALDH2 in HCC cells inhibited their aggressive behavior in vitro and in mice largely by modulating the activity of the ALDH2-acetaldehyde-redox-AMPK axis. Therefore, identifying ALDH2 expression levels in HCC might be a useful strategy for classifying HCC patients and for developing potential therapeutic strategies that specifically target metastatic HCC. (Hepatology 2017;65:1628-1644).

CYP3A5 Functions as a Tumor Suppressor in Hepatocellular Carcinoma by Regulating mTORC2/Akt Signaling.

CYP3A5 is a cytochrome P450 protein that functions in the liver metabolism of many carcinogens and cancer drugs. However, it has not been thought to directly affect cancer progression. In this study, we challenge this perspective by demonstrating that CYP3A5 is downregulated in many hepatocellular carcinomas (HCC), where it has an important role as a tumor suppressor that antagonizes the malignant phenotype. CYP3A5 was downregulated in multiple cohorts of human HCC examined. Lower CYP3A5 levels were associated with more aggressive vascular invasion, poor differentiation, shorter time to disease recurrence after treatment, and worse overall patient survival. Mechanistic investigations showed that CYP3A5 overexpression limited MMP2/9 function and suppressed HCC migration and invasion in vitro and in vivo by inhibiting AKT signaling. Notably, AKT phosphorylation at Ser473 was inhibited in CYP3A5-overexpressing HCC cells, an event requiring mTORC2 but not Rictor/mTOR complex formation. CYP3A5-induced ROS accumulation was found to be a critical upstream regulator of mTORC2 activity, consistent with evidence of reduced GSH redox activity in most clinical HCC specimens with reduced metastatic capacity. Taken together, our results defined CYP3A5 as a suppressor of HCC pathogenesis and metastasis with potential utility a prognostic biomarker.

MUC15 inhibits dimerization of EGFR and PI3K-AKT signaling and is associated with aggressive hepatocellular carcinomas in patients.

BACKGROUND & AIMS: Aberrant expression of MUC15 correlates with development of colorectal adenocarcinoma, and MUC15 has been reported to prevent trophoblast invasion of human placenta. However, little is known about the role of MUC15 in pathogenesis of hepatocellular carcinoma (HCC). METHODS: We analyzed HCC samples and matched nontumor liver tissues (controls) collected from 313 patients who underwent hepatectomy in Shanghai, China, from January 2006 through September 2009. Levels of messenger RNAs and proteins were determined by immunohistochemical, quantitative reverse transcription polymerase chain reaction, and immunoblot analyses. Statistical analyses were used to associate levels of MUC15 with tumor features and patient outcomes. RESULTS: Levels of MUC15 messenger RNA and protein were reduced in a greater percentage of HCC samples than control tissues. Tumors with reduced levels of MUC15 were more likely to have aggressive characteristics (eg, high levels of α-fetoprotein, vascular invasion, lack of encapsulation, and poor differentiation) than those with low levels. Patients whose tumors had reduced levels of MUC15 had shorter overall survival times (24 months vs 46 months for patients with tumors with high levels of MUC15) and time to disease recurrence. Stable expression of MUC15 in HCC cell lines (SMMC-7721 and HCC-LM3) reduced their proliferation and invasive features in vitro, and ability to form metastatic tumors in mice. MUC15 reduced transcription of the matrix metalloproteinases 2 and 7 increased expression of tissue inhibitor of metalloproteinase-2, which required phosphoinositide 3-kinase-v-akt murine thymoma viral oncogene homolog signaling. Physical interaction between MUC15 and epidermal growth factor receptor led to its relocation and degradation within early endosomes and was required for inactivation of phosphoinositide 3-kinase-v-akt murine thymoma viral oncogene homolog signaling. CONCLUSIONS: Reduced levels of MUC15 in HCCs are associated with shorter survival times of patients and reduced time to disease recurrence. Expression of MUC15 in HCC cells reduces their aggressive behavior in vitro and in mice by inducing dimerization of epidermal growth factor receptor and decreasing phosphoinositide 3-kinase signaling via v-akt murine thymoma viral oncogene homolog.