Zhao-Ru Dong

Ubiquitin‐specific protease 7 accelerates p14ARF degradation by deubiquitinating thyroid hormone receptor‐interacting protein 12 and promotes hepatocellular carcinoma progression

The prognosis for hepatocellular carcinoma (HCC) remains dismal in terms of overall survival (OS), and its molecular pathogenesis has not been completely defined. Here, we report that expression of deubiquitylase ubiquitin‐specific protease 7 (USP7) is higher in human HCC tissues than in matched peritumoral tissues. Ectopic USP7 expression promotes growth of HCC cells in vivo and in vitro. Mechanistically, USP7 overexpression fosters HCC cell growth by forming a complex with and stabilizing thyroid hormone receptor‐interacting protein 12 (TRIP12), which induces constitutive p14ARF ubiquitination. Clinically, USP7 overexpression is significantly correlated with a malignant phenotype, including larger tumor size, multiple tumor, poor differentiation, elevated alpha‐fetoprotein, and microvascular invasion. Moreover, overexpression of USP7 and/or TRIP12 correlates with shorter OS and higher cumulative recurrence rates of HCC. Conclusion: USP7 stabilizes TRIP12 by deubiquitination, thus constitutively inactivating p14ARF and promoting HCC progression. This represents a novel marker for predicting prognosis and a potential therapeutic target for HCC. (Hepatology 2015;61:1603‐1614)

BRD4 promotes tumor growth and epithelial-mesenchymal transition in hepatocellular carcinoma

Bromodomain and extraterminal domain (BET) proteins are epigenetic readers that play an important role in chromatin remodeling and transcriptional regulation. In this study, we found that BRD4, a BET family member, is significantly upregulated in hepatocellular carcinoma (HCC) tissues compared with adjacent normal tissues. Furthermore, the overexpression of BRD4 in cancer tissues was correlated with poor prognosis in HCC patients. Using shRNA-mediated knockdown of BRD4 or lentivirus-mediated overexpression of BRD4 in HCC cells, we further showed that BRD4 was involved in HCC cell growth and invasion in vitro. Forced expression of BRD4 was sufficient to induce epithelial-mesenchymal transition (EMT) phenotypes in HCC cells. Additionally, BRD4 shRNA significantly inhibited HCC cell proliferation in vivo. Collectively, our study confirmed that BRD4 expression is a valuable predictor of recurrence and survival in patients with HCC. BRD4 can be further used as a potential therapeutic target of HCC.

Comprehensive Multiple Molecular Profile of Epithelial Mesenchymal Transition in Intrahepatic Cholangiocarcinoma Patients

Background The aim of this study is to investigate the expression profile of multiple epithelial mesenchymal transition (EMT)-related molecules in intrahepatic cholangiocarcinoma (ICC) and the related prognostic significance. Methods Immunohistochemistry was performed to determine the expression of E-cadherin, Vimentin, Snail, slug and β-catenin in a tissue microarray consisting of tumor tissues of 140 ICC patients undergoing curative resection. The correlation between the expression of these molecules and the clinicopathological characteristics of ICC patients was analyzed, and their prognostic implication was evaluated. Results Reduced E-cadherin and increased Vimentin expression, the characteristic changes of EMT, identified in 55.0% and 55.7% of primary ICCs, respectively, were correlated with lymphatic metastasis and poorer overall survival (OS) and disease-free survival (DFS) of ICCs. The overexpression of snail and nonmembranous β-catenin, which are the major regulators of the EMT, were identified in 49.2% and 45.7% of primary ICCs, while little slug expression was detected in ICCs. Cytoplasmic/nuclear β-catenin did not significantly predict worse DFS and was not related with E-cadherin loss. The overexpression of snail predicted worse OS and DFS. Snail overexpression correlated with the down-regulation of E-cadherin and the up-regulation of Vimentin. Inhibition of snail in an ICC cell line decreased the expression of E-cadherin, enhanced the expression of Vimentin and impaired the invasion and migration ability of ICC cells. Conclusions These data support the hypothesis that EMT plays vital roles in ICC progression and suggest that snail but not slug and β-catenin plays a crucial role in the EMT induction of ICC.

Glucose-regulated phosphorylation of TET2 by AMPK reveals a pathway linking diabetes to cancer

Diabetes is a complex metabolic syndrome that is characterized by prolonged high blood glucose levels and frequently associated with life-threatening complications1,2. Epidemiological studies have suggested that diabetes is also linked to an increased risk of cancer3–5. High glucose levels may be a prevailing factor that contributes to the link between diabetes and cancer, but little is known about the molecular basis of this link and how the high glucose state may drive genetic and/or epigenetic alterations that result in a cancer phenotype. Here we show that hyperglycaemic conditions have an adverse effect on the DNA 5-hydroxymethylome. We identify the tumour suppressor TET2 as a substrate of the AMP-activated kinase (AMPK), which phosphorylates TET2 at serine 99, thereby stabilizing the tumour suppressor. Increased glucose levels impede AMPK-mediated phosphorylation at serinexa099, which results in the destabilization of TET2 followed by dysregulation of both 5-hydroxymethylcytosine (5hmC) and the tumour suppressive function of TET2 in vitro and in vivo. Treatment with the anti-diabetic drug metformin protects AMPK-mediated phosphorylation of serinexa099, thereby increasing TET2 stability and 5hmC levels. These findings define a novel ‘phospho-switch’ that regulates TET2 stability and a regulatory pathway that links glucose and AMPK to TET2 and 5hmC, which connects diabetes to cancer. Our data also unravel an epigenetic pathway by which metformin mediates tumour suppression. Thus, this study presents a new model for how a pernicious environment can directly reprogram the epigenome towards an oncogenic state, offering a potential strategy for cancer prevention and treatment.Modulation of DNA 5-hydroxymethylcytosine by glucose reveals an AMPK–TET2–5hmC axis that links diabetes to cancer.

Role of 5-hydroxymethylcytosine level in diagnosis and prognosis prediction of intrahepatic cholangiocarcinoma

The loss of 5-hydroxymethylcytosine (5-hmC) has been identified as an epigenetic hallmark in several malignancies. However, its role in intrahepatic cholangiocarcinoma (ICC) is still unknown. Our study aims to investigate the level of 5-hmC in diagnosis and prognosis prediction of ICC. The 5-hmC levels were detected using dot blot, tissue microarray technique and immunohistochemical method, and the correlation between 5-hmC level and ICC clinicopathological parameters was analysed. Compared with matched liver tissues, most of ICC tissues presented with the loss of 5-hmC. Furthermore, the subgroups of cirrhotic and poor differentiation tissues showed the lowest level of 5-hmC. We found that 5-hmC level in non-elevated ICC patients was significantly related to lymph node metastasis and TNM stage and not related to vessel invasion, sex, age, HBV, cirrhosis or degree of differentiation. ICC patients with high TNM stage (stages III and IV) and lymph node metastases had significantly lower 5-hmC level than those with low TNM stage (stages I and II) and no lymph node metastases. Further analysis showed that low 5-hmC level is significantly correlated with worse overall survival (OS) and disease-free survival (DFS). Importantly, multivariate analysis indicated that 5-hmC level, tumour diameter, lymphatic metastasis and tumour differentiation could be used as independent prognostic factors for ICC. The loss of 5-hmC is implicated in the progression of ICC. Our results can contribute to the diagnostic ability and postoperative surveillance of ICC patients.

Up-regulation of 14-3-3ζ expression in intrahepatic cholangiocarcinoma and its clinical implications

The 14-3-3 proteins are highly conserved molecules that are involved in many vital biologic processes and are associated with the progression of cancer. The role of 14-3-3ζ, a dimeric isoform of 14-3-3, in intrahepatic cholangiocarcinoma (ICC) was investigated in this study. The expression of 14-3-3ζ in tumour samples from patients with ICC was examined by Western blot and immunohistochemistry, and the correlation between its expression and various clinicopathological features was determined. Then, the capacity for invasion, migration and proliferation as well as the expression of epithelial–mesenchymal transition (EMT)-related markers in ICC cells were assessed after 14-3-3ζ depletion. Finally, the prognostic significance of 14-3-3ζ in patients with ICC was further evaluated by Kaplan–Meier and Cox regression analyses. The expression of 14-3-3ζ was significantly higher in ICC tissues compared to peritumoural tissues. High expression of 14-3-3ζ positively correlated with lymphatic metastasis and tumour–node–metastasis (TNM) stage. The inhibition of 14-3-3ζ expression was able to impair the invasion, migration and proliferation of ICC cells in vitro. The expression of 14-3-3ζ was significantly correlated with the expression of the EMT-related markers snail and E-cadherin in ICC samples. Moreover, the down-regulation of 14-3-3ζ also decreased the phosphorylation of extracellular signal-regulated kinase (ERK) in ICC cells. Clinically, patients with ICC with high 14-3-3ζ expression demonstrated a poor prognosis in terms of a short overall survival and a high recurrence rate of the disease. A multivariate analysis revealed that 14-3-3ζ overexpression was an independent prognostic indicator for patients with ICC. 14-3-3ζ may enhance the invasive and proliferative capacity of tumour cells and thus prompt the progression of ICC via the activation of ERK signalling and the induction of EMT. The overexpression of 14-3-3ζ may be used as a prognostic biomarker and therapeutic target in patients with ICC.

UBAP2 negatively regulates the invasion of hepatocellular carcinoma cell by ubiquitinating and degradating Annexin A2

The ubiquitin-dependent proteasomal degradation of proteins controls signaling and cellular survival. In this study, we found that ubiquitin associated protein 2 (UBAP2) was significantly downregulated in hepatocellular carcinoma (HCC) tissues compared with adjacent normal tissues. Furthermore, higher expression of UBAP2 in cancer tissues was correlated with good prognosis in HCC patients. Knockdown of UBAP2 significantly enhanced the invasion and proliferation of HCC cells in vitro and promoted tumor growth in vivo, while enforced expression of UBAP2 impaired the aggressive ability and tumor growth of HCC cells. Mechanistically, UBAP2 formed a complex with Annexin A2 and promoted the degradation of Annexin A2 protein by ubiquitination, and then inhibited HCC progression. Collectively, UBAP2 appears as a novel marker for predicting prognosis and a therapeutic target for HCC.

Generation and characterization of a tetraspanin CD151/integrin α6β1-binding domain competitively binding monoclonal antibody for inhibition of tumor progression in HCC

Our previous studies revealed that tetraspanin CD151 plays multiple roles in the progression of hepatocellular carcinoma (HCC) by forming a functional complex with integrin α6β1. Herein, we generated a monoclonal antibody (mAb) that dissociates the CD151/integrin α6β1 complex, and we evaluated its bioactivity in HCCs. A murine mAb, tetraspanin CD151 (IgG1, called CD151 mAb 9B), was successfully generated against the CD151-integrin α6β1 binding site of CD151 extracellular domains. Co-immunoprecipitation using CD151 mAb 9B followed by Western blotting detected a 28 kDa protein. Both immunofluorescent and immunohistochemical staining showed a good reactivity of CD151 mAb 9B in the plasma membrane and cytoplasm of HCC cells, as well as in liver cells. In vitro assays demonstrated that CD151 mAb 9B could inhibit neoangiogenesis and both the mobility and the invasiveness of HCC cells. An in vivo assay showed that CD151 mAb 9B inhibited tumor growth potential and HCC cells metastasis. We successfully produced a CD151 mAb 9B targeting the CD151/integrin α6β1-binding domain, which not only can displayed good reactivity to the CD151 antigen but also prevented tumor progression in HCC.

Preoperative Albumin-Bilirubin Score for Postoperative Solitary Hepatocellular Carcinoma within the Milan Criteria and Child-Pugh A Cirrhosis

Surgical resection remains the initial treatment of choice for the majority of early stage hepatocellular carcinoma (HCC) patients. Although the factors that influence the prognosis of postoperative HCC patients have been well elucidated, there are a limited number of simple, objective, and distinct methods for estimating survival for postoperative patients with solitary HCC within the Milan criteria and Child-Pugh (C-P) A cirrhosis. The Albumin-Bilirubin (ALBI) score is a new evidence-based approach to assess liver function. The ALBI score eliminates subjective variables, such as ascites and encephalopathy which are the requirements for the conventional C-P grading system. This study enrolled 654 patients to determine whether the ALBI score can predict the outcomes of postoperative solitary HCC patients within the Milan criteria and C-P A cirrhosis. Our results showed the ALBI score significantly influenced the overall survival and cumulative recurrence rates. Furthermore, the ALBI score was significantly related to the degree of liver cirrhosis and serum γ-glutamyl transpeptidase (GGT) concentration in solitary HCC cases within the Milan criteria and C-P A cirrhosis. Additionally, the combination of the ALBI score and serum GGT concentration contributed to the prognosis prediction in this cohort. In conclusion, we externally validated the ALBI grade as a novel biomarker to predict prognosis for solitary HCC within the Milan Criteria and C-P A cirrhosis.

Canonical Wnt Signaling Remodels Lipid Metabolism in Zebrafish Hepatocytes following Ras Oncogenic Insult

There is limited understanding of the effects of major oncogenic pathways and their combinatorial actions on lipid composition and transformation during hepatic tumorigenesis. Here, we report a negative correlation of Wnt/Myc activity with steatosis in human hepatocellular carcinoma (HCC) and perform in vivo functional studies using three conditional transgenic zebrafish models. Double-transgenic zebrafish larvae conditionally expressing human CTNNB1mt and zebrafish tcf7l2 or murine Myc together with krasv12 in hepatocytes led to severe hepatomegaly and significantly attenuated accumulation of lipid droplets and cell senescence triggered by krasv12 expression alone. UPLC-MS-based, nontargeted lipidomic profiling and transcriptome analyses revealed that Wnt/Myc activity promotes triacylglycerol to phospholipid transformation and increases unsaturated fatty acyl groups in phospholipids in a Ras-dependent manner. Small-scale screenings suggested that supplementation of certain free fatty acids (FA) or inhibition of FA desaturation significantly represses hepatic hyperplasia of double-transgenic larvae and proliferation of three human HCC cells with and without sorafenib. Together, our studies reveal novel Ras-dependent functions of Wnt signaling in remodeling the lipid metabolism of cancerous hepatocytes in zebrafish and identify the SCD inhibitor MK8245 as a candidate drug for therapeutic intervention.Significance: These findings identify FA desaturation as a significant downstream therapeutic target for antagonizing the combinatorial effects of Wnt and Ras signaling pathways in hepatocellular carcinoma.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/19/5548/F1.large.jpg Cancer Res; 78(19); 5548-60. ©2018 AACR.