Low level of low-density lipoprotein receptor-related protein 1 predicts an unfavorable prognosis of hepatocellular carcinoma after curative resection.

BACKGROUND: Low-density lipoprotein receptor-related protein 1 (LRP1) is a multifunctional receptor involved in receptor-mediated endocytosis and cell signaling. The aim of this study was to elucidate the expression and mechanism of LRP1 in hepatocellular carcinoma (HCC). METHODS: LRP1 expression in 4 HCC cell lines and 40 HCC samples was detected. After interruption of LRP1 expression in a HCC cell line either with specific lentiviral-mediated shRNA LRP1 or in the presence of the LRP1-specific chaperone, receptor-associated protein (RAP), the role of LRP1 in the migration and invasion of HCC cells was assessed in vivo and in vitro, and the expression of matrix metalloproteinase (MMP) 9 in cells and the bioactivity of MMP9 in the supernatant were assayed. The expression and prognostic value of LRP1 were investigated in 327 HCC specimens. RESULTS: Low LRP1 expression was associated with poor HCC prognosis, with low expression independently related to shortened overall survival and increased tumor recurrence rate. Expression of LRP1 in non-recurrent HCC samples was significantly higher than that in early recurrent samples. LRP1 expression in HCC cell lines was inversely correlated with their metastatic potential. After inhibition of LRP1, low-metastatic SMCC-7721 cells showed enhanced migration and invasion and increased expression and bioactivity of MMP9. Correlation analysis showed a negative correlation between LRP1 and MMP9 expression in HCC patients. The prognostic value of LRP1 expression was validated in the independent data set. CONCLUSIONS: LRP1 modulated the level of MMP9 and low level of LRP1 expression was associated with aggressiveness and invasiveness in HCCs. LRP1 offered a possible strategy for tumor molecular therapy.

Profiling of the tetraspanin CD151 web and conspiracy of CD151/integrin ß1 complex in the progression of hepatocellular carcinoma.

Tetraspanin CD151 has been implicated in metastasis through forming complexes with different molecular partners. In this study, we mapped tetraspanin web proteins centered on CD151, in order to explore the role of CD151 complexes in the progression of hepatocellular carcinoma (HCC). Immunoprecipitation was used to isolate tetraspanin complexes from HCCLM3 cells using a CD151 antibody, and associated proteins were identified by mass spectrometry. The interaction of CD151 and its molecular partners, and their roles in invasiveness and metastasis of HCC cells were assayed through disruption of the CD151 network. Finally, the clinical implication of CD151 complexes in HCC patients was also examined. In this study, we identified 58 proteins, characterized the tetraspanin CD151 web, and chose integrin ß1 as a main partner to further investigate. When the CD151/integrin ß1 complex in HCC cells was disrupted, migration, invasiveness, secretion of matrix metalloproteinase 9, and metastasis were markedly influenced. However, both CD151 and integrin ß1 expression were untouched. HCC patients with high expression of CD151/integrin ß1 complex had the poorest prognosis of the whole cohort of patients. Together, our data show that CD151 acts as an important player in the progression of HCC in an integrin ß1-dependent manner.

CD151 amplifies signaling by integrin α6ß1 to PI3K and induces the epithelial-mesenchymal transition in HCC cells.

BACKGROUND & AIMS: Overexpression of CD151 is associated with poor prognosis for hepatocellular carcinoma (HCC), yet its role in pathogenesis is not known. METHODS: We analyzed the expression of the integrin subunit α6 by quantitative, real-time polymerase chain reaction and immunoblot analyses of 120 HCC tissue samples; its clinical significance was investigated using tissue microarray (TMAs) analysis of samples from 335 patients with HCC. Immunoprecipitation was used to assess the relationship between α6 and CD151. The molecular effects of high expression levels of α6 and CD151 in HCC cells were determined using RNA interference and pharmacologic approaches. RESULTS: Overexpression of α6 correlated with poor prognosis of patients with HCC; α6 formed a complex with endogenous CD151 in HCC cells. In cells that expressed high levels of α6 and CD151, laminin-5 promoted cell spreading by inducing the epithelial-mesenchymal transition (EMT); this effect was not observed in cells that expressed high levels of only α6 or CD151. Cells that expressed high levels of α6 and CD151 underwent the EMT in response to laminin-5, through hyperactivation of phosphatidylinositol-3-kinase (PI3K), primarily induced via the PI3K-protein kinase B (Akt)-Snail-phosphatase and tensin homolog feedback pathway. The EMT was reversed by PI3K inhibitors and antibodies against CD151 or α6 in vitro, and was delayed by specific interference with CD151 and α6 in vivo. CONCLUSIONS: High expression levels of CD151 and α6 promote invasiveness of HCC cells. Either of these proteins, or PI3K signaling, might be targets for therapeutics for subgroups of patients with HCC.

Overexpression of CD151 as an adverse marker for intrahepatic cholangiocarcinoma patients.

BACKGROUND: Previous studies have indicated that CD151, a hydrophobic protein, forms a functional complex with the proto-oncogene that encodes an N-methyl-N'-nitro-N-nitroso-guanidine (MET) protein (c-Met), and CD151 overexpression reportedly is involved in metastasis/invasion of several tumors. The objective of the current study was to investigate the expression and role of CD151 and/or c-Met in intrahepatic cholangiocarcinoma (ICC). METHODS: Sixty ICC tissues with matched nontumorous tissues and 20 normal liver tissues were used to analyze CD151 expression at the level of messenger RNA (mRNA) and protein. Then, the expression of CD151 in an ICC cell line was interrupted using a specific lentiviral-mediated small hairpin RNA (shRNA)-CD151, and the role of CD151 in the proliferation, metastasis, and invasion of ICC cells was assessed. The expression of CD151/c-Met was examined further by immunohistochemistry in a tissue microarray (TMA) that included 140 samples of ICC, and the prognostic role of CD151 and/or c-Met in ICC was evaluated in Kaplan-Meier and Cox regression analyses. RESULTS: The expression of CD151 in ICC tissues was much higher than that in nontumorous samples and normal liver; and, after the down-regulation of CD151, HCCC-9810 cells had decreased capability for metastasis/invasion in vitro. CD151 overexpression was correlated significantly with larger tumors, poor differentiation, multiple nodular, microvascular/bile duct invasion, and lymphatic metastasis (P<.05). The postoperative 2-year and 5-year overall survival (OS) rates for patients with low CD151 expression (<50% tumor staining) and/or low c-Met expression (<20% tumor staining) were higher than the rates for patients with high CD151 expression (≥50% tumor staining) and/or high c-Met expression (≥20% tumor staining). Multivariate analysis revealed that CD151 overexpression and c-Met overexpression were independent prognostic markers for ICC. CONCLUSIONS: Overexpression of CD151 was implicated in metastasis/invasion of ICC, and both CD151 overexpression and c-Met overexpression may be potential molecular therapeutic targets for ICC.

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

UNLABELLED: 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 3beta (GSK-3beta)/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 CD151(high)/MMP9(high)/MVD(high) were significantly lower than those of the CD151(low)/MMP9(low)/MVD(low) 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 CD151(high)/MMP9(high)/MVD(high) 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-3beta/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.