Zhen-Bin Ding

Association of Autophagy Defect with a Malignant Phenotype and Poor Prognosis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is an aggressive cancer with a poor prognosis. The role of autophagy and the prognostic value of autophagic genes are largely unknown in HCC. Here, we showed decreased expression of autophagic genes and their corresponding autophagic activity and increased expression of the antiapoptotic gene Bcl-xL in HCC cell lines compared with a normal hepatic cell line. We also found decreased expression of the autophagic gene Beclin 1 in 44 HCC tissue samples compared with adjacent nontumor tissues. In addition, we found that the most aggressive malignant HCC cell lines and HCC tissues with recurrent disease displayed much lower autophagic levels, especially when Bcl-xL was overexpressed. Interestingly, in a tissue microarray study consisting of 300 HCC patients who underwent curative resection, the expression of Beclin 1 was only significantly correlated with disease-free survival (DFS; P < 0.0001) and overall survival (OS; P < 0.0001) in the Bcl-xL(+) group. Multivariate and univariate analyses also revealed that Beclin 1 expression was an independent predictor for DFS and OS in Bcl-xL(+) patients. In addition, we found a significant correlation between Beclin 1 expression and tumor differentiation in Bcl-xL(+) but not in Bcl-xL(-) HCC patients. In conclusion, our data showed expression of autophagic genes and their corresponding autophagic activities were suppressed in HCC. The autophagy defects synergized with altered apoptotic activity might facilitate tumor malignant differentiation, which results in a more aggressive cancer cell phenotype and poor prognosis of HCC.

Role of overexpression of CD151 and/or c-Met in predicting prognosis of hepatocellular carcinoma†

It has been reported that tetraspanin CD151 acts as a promoter of metastasis in several tumors and plays an important role in c‐Met/hepatocyte growth factor signaling. However, the role of CD151 alone and coexpression of CD151/c‐Met in hepatocellular carcinoma (HCC) remains unclear. We found that expression of CD151 was positively related to metastatic potential of HCC cell lines, and modified cells with CD151high showed higher secretion of matrix metalloproteinase 9 and aggressiveness in vitro and higher metastatic ability in vivo. Furthermore, HCC patients with vascular invasion, large tumors, multiple tumors, high tumor‐node‐metastasis stage, and undifferentiated tumor were prone to have higher CD151 expression. The postoperative 3‐, 5‐, and 7‐year overall survival (OS) of patients in HCCs with CD151high were significantly lower than those in the CD151low group, and correspondingly cumulative recurrence rates in HCCs with CD151high were significantly higher than those in the CD151low group. Both CD151 and c‐Met were remarkably overexpressed in HCCs, compared with adjacent nontumorous and normal liver tissues. Pearson correlation analysis showed a slight correlation between CD151 and c‐Met in HCCs. Importantly, the 5‐ and 7‐year OS rates in CD151high/c‐Methigh patients were 50.5% and 37.8%, respectively, significantly lower than those of CD151low/c‐Metlow patients (63.9% and 54.6%, respectively). Five‐ and 7‐year cumulative recurrence rates in CD151high/c‐Methigh patients were 53.3% and 71.9%, respectively, markedly higher than those of CD151low/c‐Metlow patients (39.0% and 52.5%, respectively). Multivariate analysis revealed that CD151 and combination of CD151/c‐Met were independent prognostic indicators for OS and cumulative recurrence. Conclusion: CD151 is positively associated with invasiveness of HCC, and CD151 or combination of CD151/c‐Met is a novel marker in predicting the prognosis of HCC and a potential therapeutic target. (HEPATOLOGY 2008.)

Targeting autophagy enhances sorafenib lethality for hepatocellular carcinoma via ER stress-related apoptosis.

Sorafenib, a potent multikinase inhibitor, has been recognized as the standard systemic treatment for patients with advanced hepatocellular carcinoma (HCC). However, the direct functional mechanism of tumor lethality mediated by sorafenib remains to be fully characterized, and the precise mechanisms of drug resistance are largely unknown. Here, we showed sorafenib induced both apoptosis and autophagy in human HCC cells through a mechanism that involved endoplasmic reticulum (ER) stress and was independent of the MEK1/2-ERK1/2 pathway. Upregulation of IRE1 signals from sorafenib-induced ER stress was critical for the induction of autophagy. Moreover, autophagy activation alleviated the ER stress-induced cell death. Inhibition of autophagy using either pharmacological inhibitors or essential autophagy gene knockdown enhanced cell death in sorafenib treated HCC cell lines. Critically, the combination of sorafenib with the autophagy inhibitor chloroquine produced more pronounced tumor suppression in HCC both in vivo and in vitro. These findings indicated that both ER stress and autophagy were involved in the cell death evoked by sorafenib in HCC cells. The combination of autophagy modulation and molecular targeted therapy is a promising therapeutic strategy in treatment of HCC.

Autophagy Activation in Hepatocellular Carcinoma Contributes to the Tolerance of Oxaliplatin via Reactive Oxygen Species Modulation

Purpose: Understanding the roles of mammalian autophagy in cancer highlights recent advances in the pharmacologic manipulation of autophagic pathways as a therapeutic strategy for cancer. However, autophagy status and corresponding functions in hepatocellular carcinoma (HCC) after therapeutic stress remain to be clarified. This study was to determine whether the autophagic machinery could be activated after chemotherapy and the contribution of autophagy to tolerance of oxaliplatin in HCC. Experimental Design: Autophagy activation and cell death induced by oxaliplatin were examined in two HCC cell lines as well as in vivo using an HCC model in nude mice. HCC tissue samples with or without locoregional chemotherapy before surgery were also examined by immunohistochemical and electron microscopic analysis. Results: Autophagy was functionally activated in HCC cell lines and xenografts after oxaliplatin treatment. Suppression of autophagy using either pharmacologic inhibitors or RNA interference of essential autophagy gene enhanced cell death induced by oxaliplatin in HCC cells. Generation of reactive oxygen species has an important role in the induction of cell death by oxaliplatin in combination with autophagy inhibitors. Critically, the combination of oxaliplatin with autophagy inhibitor chloroquine resulted in a more pronounced tumor suppression in HCC xenografts. Furthermore, autophagy-specific protein LC3 and autophagic autophagosome formation were induced to a significantly higher level in HCC specimens that had been subjected to locoregional chemotherapy. Conclusions: Autophagy activation under therapy stress contributes to HCC tumor cell survival. Targeting the autophagy pathway is a promising therapeutic strategy to enhance the effects of chemotherapy and improve clinical outcomes in HCC patients. Clin Cancer Res; 17(19); 6229–38. ©2011 AACR.

Metadherin promotes hepatocellular carcinoma metastasis through induction of Epithelial-Mesenchymal transition

Purpose: To investigate the expression of metadherin (MTDH) for its prognostic value in hepatocellular carcinoma (HCC) and its role in promoting HCC metastasis. Experimental Design: This study employed a tissue microarray containing samples from 323 HCC patients to examine the expression of MTDH and its correlation with other clinicopathologic characteristics. The role of MTDH in the regulation of HCC metastasis was investigated both in vitro and in vivo using short hairpin RNA (shRNA)–mediated downregulation of MTDH in HCC cell lines with various metastatic potentials. Results: The expression of MTDH was markedly higher in HCC tumors than in normal liver tissue. Particularly high MTDH expression was observed in tumors with microvascular invasion, pathologic satellites, poor differentiation, or tumor-node-metastasis stages II to III. Furthermore, the clinical outcome was consistently poorer for the MTDHhigh group than for the MTDHlow group in the 1-, 3-, and 5-year overall survival (OS) rates and in the 1-, 3-, 5-year cumulative recurrence rates. In a nude mice model, the shRNA-mediated downregulation of MTDH resulted in a reduced migratory capacity in HCC cell lines, as well as a reduction in pulmonary and abdominal metastasis. Furthermore, we found that the expression level of MTDH correlated with four epithelial–mesenchymal transition (EMT) markers. Knockdown of MTDH expression in HCC cell lines resulted in downregulation of N-cadherin and snail, upregulation of E-cadherin, and translocation of β-catenin. Conclusions: MTDH may promote HCC metastasis through the induction of EMT process and may be a candidate biomarker for prognosis as well as a target for therapy. Clin Cancer Res; 17(23); 7294–302. ©2011 AACR.

CD151 modulates expression of matrix metalloproteinase 9 and promotes neoangiogenesis and progression of hepatocellular carcinoma.

Tetraspanin CD151 is involved in several pathological activities associated with tumor progression, including neoangiogenesis. However, the role and molecular mechanism of CD151 in the neoangiogenesis of hepatocellular carcinoma (HCC) remain enigmatic. We found that the level of expression of matrix metalloproteinase 9 (MMP9) was positively associated with CD151 expression in HCC cells. We developed a zone‐by‐zone blockade and demonstrated that overexpression of CD151 in HCC cells facilitated MMP9 expression through a phosphatidylinositol‐3‐kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase 3β (GSK‐3β)/Snail signaling pathway. In contrast, down‐regulation of CD151 expression impaired the ability of HCC cells to form microvessels in vitro and reduced their in vivo metastatic potential. In a clinical setting, a significant correlation of the expression of CD151 with MMP9 expression and with microvessel density (MVD) was revealed by Pearson correlation analysis of HCC patients. The postoperative 3‐, 5‐, and 7‐year overall survival rates of HCC patients with CD151high/MMP9high/MVDhigh were significantly lower than those of the CD151low/MMP9low/MVDlow group or groups in which only one or two of CD151, MMP9, and MVD were highly expressed. Cumulative recurrence rates were also highest in HCC patients with CD151high/MMP9high/MVDhigh in comparison with the other groups. Multivariate Cox proportional hazards analysis showed that the concomitant overexpression of CD151, MMP9, and MVD was an independent marker for predicting poor prognosis of HCC. Conclusion: Overexpression of CD151 up‐regulated the expression of MMP9 through the PI3K/Akt/GSK‐3β/Snail pathway. CD151‐dependent neoangiogenesis appeared to promote the progression of HCC, and this suggests that CD151 may be useful as a high‐priority therapeutic target for antiangiogenesis in HCC. HEPATOLOGY 2010

CXCR6 Upregulation Contributes to a Proinflammatory Tumor Microenvironment That Drives Metastasis and Poor Patient Outcomes in Hepatocellular Carcinoma

CXC chemokines and their cognate receptors have been implicated widely in cancer pathogenesis. In this study, we report a critical causal relationship between CXCR6 expression and tumorigenesis in the setting of human hepatocellular carcinoma (HCC). Among the CXC chemokine receptors, only CXCR6 was detected in all the hepatoma cell lines studied. Moreover, in HCC tissue, CXCR6 expression was significantly higher than in noncancerous liver tissues. Reduction of CXCR6 or its ligand CXCL16 in cancer cells reduced cell invasion in vitro and tumor growth, angiogenesis, and metastases in vivo. Importantly, loss of CXCR6 led to reduced Gr-1+ neutrophil infiltration and decreased neoangiogenesis in hepatoma xenografts via inhibition of proinflammatory cytokine production. Clinically, high expression of CXCR6 was an independent predictor of increased recurrence and poor survival in HCCs. Human HCC samples expressing high levels of CXCR6 also contained an increased number of CD66b+ neutrophils and microvessels, and the combination of CXCR6 and neutrophils was a superior predictor of recurrence and survival than either marker used alone. Together, our findings suggest that elevated expression of CXCR6 promotes HCC invasiveness and a protumor inflammatory environment and is associated with poor patient outcome. These results support the concept that inhibition of the CXCR6-CXCL16 pathway may improve prognosis after HCC treatment.

Autophagy inhibition suppresses pulmonary metastasis of HCC in mice via impairing anoikis resistance and colonization of HCC cells.

Metastasis is one of the main causes of poor prognosis for hepatocellular carcinoma (HCC), which has been linked to cell-death resistance. Autophagy is an important survival mechanism under conditions of cell stress. We hypothesized that autophagy may play a role in HCC metastasis due to its prosurvival effect. Highly metastatic HCC cell lines with stable autophagy inhibition were established via lentivirus-mediated silencing of BECN1 and ATG5 genes. Mouse models of pulmonary metastasis were then developed using the cells with or without autophagy inhibition. The analysis of lung metastasis by histopathological examination and small animal imaging showed that autophagy inhibition significantly decreased the incidence of pulmonary metastases in vivo. Further invasion, migration, detachment, lung colonization, and epithelial-mesenchymal transition (EMT) assays indicated that autophagy inhibition did not affect cell invasiveness, migration or EMT but attenuated the anoikis-resistance and lung colonization of HCC cells. Investigation of the molecular mechanisms underlying showed that the autophagy-inhibition-mediated anoikis-resistance attenuation was associated with the regulation of apoptotic signaling. As autophagy inhibition was shown to be able to suppress HCC metastasis, an autophagy-based HCC tissue-specific target therapy system (AFP-Cre/LoxP-shRNA) was constructed. In vitro and in vivo analyses showed that the system was able to efficiently inhibit autophagy of HCC cells and tissue in a tissue-specific manner. Further in vivo metastasis assay showed that intratumoral administration of the system could significantly suppress lung metastasis. Together, our findings suggest that autophagy may be involved in HCC metastasis through facilitating anoikis resistance and lung colonization of HCC cells. Autophagy-based HCC tissue-specific target therapy may be a new strategy for the management of HCC metastasis.

αB-crystallin complexes with 14-3-3ζ to induce epithelial-mesenchymal transition and resistance to sorafenib in hepatocellular carcinoma.

The overall survival of patients with hepatocellular carcinoma (HCC) remains poor, and the molecular pathogenesis remains incompletely defined in HCC. Here we report that increased expression of αB‐Crystallin in human HCC predicts poor survival and disease recurrence after surgery. Multivariate analysis identifies αB‐Crystallin expression as an independent predictor for postoperative recurrence and overall survival. We show that elevated expression of αB‐Crystallin promotes HCC progression in vivo and in vitro. We demonstrate that αB‐Crystallin overexpression fosters HCC progression by inducing epithelial‐mesenchymal transition (EMT) in HCC cells through activation of the extracellular‐regulated protein kinase (ERK) cascade, which can counteract the effect of sorafenib. αB‐Crystallin complexes with and elevates 14‐3‐3ζ protein, leading to up‐regulation of ERK1/2 activity. Moreover, overexpression of αB‐Crystallin in HCC cells induces EMT progression through an ERK1/2/Fra‐1/slug signaling pathway. Clinically, our data reveal that overexpression of both αB‐Crystallin and 14‐3‐3ζ correlates with the HCC poorest survival outcomes, and sorafenib response is impaired in patients with αB‐Crystallin overexpression. Conclusion: These data suggest that the αB‐Crystallin‐14‐3‐3ζ complex acts synergistically to promote HCC progression by constitutively activating ERK signaling. This study reveals αB‐Crystallin as a potential therapeutic target for HCC and a biomarker for predicting sorafenib treatment response. (HEPATOLOGY 2013)

Prognostic significance of Beclin 1-dependent apoptotic activity in hepatocellular carcinoma.

Autophagy is believed to be important in tumorigenesis and tumor progression. However, the role of autophagy in hepatocellular carcinoma (HCC), and especially the prognostic value of autophagic proteins, has not been investigated. Our studies described here show decreased basal expression of autophagic genes and their corresponding autophagic activity under conditions of starvation in HCC cell lines, and the autophagy defect correlated well with the highly malignant phenotype of HCC. In addition, in a tissue microarray study of HCC patients who underwent resection, the expression of the autophagy-related protein Beclin 1 was extremely low in tumors, where Beclin 1 could predict the prognosis of HCC patients only in a Bcl-XL-positive expression background. Based on our results, we propose that autophagy defects that synergize with altered apoptotic activity might facilitate tumor progression and poor prognosis of HCC, due to the fact that autophagy may interact with apoptosis in the regulation of HCC.