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 CD151 high 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 CD151 high were significantly lower than those in the CD151 low group, and correspondingly cumulative recurrence rates in HCCs with CD151 high were significantly higher than those in the CD151 low 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 CD151 high /c-Met high patients were 50.5% and 37.8%, respectively, significantly lower than those of CD151 low /c-Met low patients (63.9% and 54.6%, respectively). Five-and 7-year cumulative recurrence rates in CD151 high /c-Met high patients were 53.3% and 71.9%, respectively, markedly higher than those of CD151 low / c-Met low 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 2009;49:491-503.)

To facilitate the identification of candidate molecular biomarkers that are linked to the pathogenesis of hepatocellular carcinoma (HCC), we investigated protein-expression profiles of 146 tissue specimens including 67 pairs of tumors and adjacent non-tumors resected from HCC patients as well as 12 normal livers by 2-DE. Among the 1800 spots displayed in the liver proteome, a total of 90 protein species were found to be significantly different between the three groups (P < 0.05). Three of the top candidate markers up-regulated in HCC, with high receiver operating characteristic (ROC) curves, were identified by MS/MS analysis and belonged to the chaperone members: heat-shock protein (Hsp)27, Hsp70 and glucose-regulated protein (GRP)78. Over-expression of these chaperone proteins in HCC tissues was confirmed by Western blotting and immunohistochemistry. In correlation with clinico-pathological parameters, expression of Hsp27 was linked to alpha-fetoprotein level (P = 0.007) whereas up-regulation of GRP78 was associated with tumor venous infiltration (P = 0.035). No significant association of Hsp70 with any pathologic features was observed. The present HCC proteome analysis revealed that in response to the stressful cancerous microenvironment, tumor cells strived to increase the expression of chaperone proteins for cyto-protective function and to enhance tumor growth and metastasis.

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 p14 ARF 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 p14 ARF and promoting HCC progression. This represents a novel marker for predicting prognosis and a potential therapeutic target for HCC. (HEPATOLOGY 2015;61:1603-1614 H epatocellular carcinoma (HCC) ranks as the fifth-most common cancer and the third cause of cancer-related mortality worldwide, mainly owing to its high rate of metastasis and recurrence.1 The recent identification of several oncogenes and tumor-suppressor genes has significantly deepened the understanding of the invasion and metastasis of HCC. 2 However, the effects of tumor progressionrelated genes often depend on the level of their protein products as well as their post-translational Abbreviations: 2D-LC-MS/MS, two-dimensional liquid chromatography coupled with tandem mass