ABSTRACT
BACKGROUND/AIMS: It was previously established that LAPTM4B-35 highly expressed in gallbladder carcinoma and being of clinicopathological and prognostic significances. However, expression of LAPTM4B gene in gallbladder carcinoma (GBC-SD), a gallbladder carcinoma cell line, and its role in invasive potential remain unclear. METHODOLOGY: Expression of LAPTM4B in GBC-SD cells was first detected. Plasmids, pcDNA3-AE (containing complete open reading frame of LAPTM4B) and Mock (pcDNA3), were transiently transfected into GBC-SD cells. Invasive phenotypes (migration and invasion) and relative molecules were then shown by transwell assay, crossing river test and Western blot analysis. RESULTS: Immunocytochemical staining revealed that LAPTM4B-35 positively expressed in cytoplasm of GBC-SD cells. But LAPTM4B-35 expression was obviously weaker in GBC-SD cells than that in BEL-7402 cells (positive control). Besides, cells transfected with pcDNA3-AE presented shorter crossing river time, less migrated and invaded cell numbers, compared with cells transfected with the Mock plasmid and parent cells. Finally, increased expressions of active uPA, MMP-9, pro MMP-2 and active MMP-2 were also observed in cells transfected with pcDNA3-AE. CONCLUSIONS: Our data suggested that LAPTM4B expressed in GBC-SD cells at a relatively low level. Forced overexpression of LAPTM4B increased invasive potential of GBC-SD cells, through modulating molecules associated with degradation of extracellular matrix.
Subject(s)
Gallbladder Neoplasms/genetics , Membrane Proteins/genetics , Oncogene Proteins/genetics , Blotting, Western , Cell Line, Tumor , Cell Movement , Dinucleoside Phosphates/metabolism , Extracellular Matrix/metabolism , Gallbladder Neoplasms/metabolism , Humans , Immunoenzyme Techniques , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/metabolism , Membrane Proteins/metabolism , Oncogene Proteins/metabolism , Open Reading Frames , Phenotype , Plasmids , Statistics, Nonparametric , Transfection , Tumor Cells, CulturedABSTRACT
PURPOSE: Lysosomal protein transmembrane 4 beta-35 (LAPTM4B-35) is a tetra-transmembrane glycoprotein that is abundantly localized on membrane-bound organelles including endosomes and lysosomes, and promotes cell proliferation and tumorigenesis through regulation of cell cycle and signaling pathways. The aim of the present study is to determine the potential clinical implications of LAPTM4B-35 expression in hepatocellular carcinoma (HCC). METHODS: Immunohistochemistry assay was used to determine the expression of LAPTM4B-35 protein in normal and HCC tissues from 71 patients. The correlations of LAPTM4B-35 expression with clinicopathological parameters, including gender, age, background liver, viral status, tumor size, portal vein invasion, histopathological differentiation, serum AFP level, TNM staging and recurrence of HCC were assessed by Chi-squared test. Patient survival and their differences were determined by Kaplan-Meier method and log-rank test. Cox regression (Proportional hazard model) was adopted for multivariate analysis of prognostic factors. RESULTS: LAPTM4B-35 immunoreactivity was negative or low in normal liver tissues, but high in HCC tissues (51/71, 71.8%). The overexpression of LAPTM4B-35 was significantly associated with recurrence, TNM staging and portal vein invasion of HCC. Patients with high LAPTM4B-35 expression had significantly poorer overall survival (OS) and disease-free survival (DFS) (both P < 0.001) when compared with patients with the low expression of LAPTM4B-35. On multivariate analysis, LAPTM4B-35 expression was found to be an independent prognostic factor for OS and DFS (P = 0.018 and P = 0.001, respectively). CONCLUSION: LAPTM4B-35 expression showed a strong association with the potencies of recurrence and metastasis and progression of HCC, and that may be applied as a novel marker for the prediction of recurrence and metastasis potency of HCC, and helpful for improving the diagnosis, prognosis and treatment of HCC.
Subject(s)
Biomarkers, Tumor/metabolism , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/secondary , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Membrane Proteins/metabolism , Neoplasm Recurrence, Local/metabolism , Oncogene Proteins/metabolism , Adult , Aged , Carcinoma, Hepatocellular/mortality , Carcinoma, Hepatocellular/surgery , Disease-Free Survival , Female , Gene Expression Regulation, Neoplastic , Hepatectomy , Humans , Immunohistochemistry , Liver Neoplasms/mortality , Liver Neoplasms/surgery , Male , Middle Aged , Neoplasm Staging , Predictive Value of Tests , Prognosis , Risk Factors , Survival Analysis , Up-RegulationABSTRACT
Argininosuccinate synthetase (ASS) has previously been proven to be reductively expressed in hepatocellular carcinoma (HCC) and various types of HCC cell lines. Arginine, the product of ASS, has been used as a target in HCC by recombinant human arginase or arginine deiminase, which is now in the phase II clinical trial stage. This study aimed to present the levels of ASS expression in HCCs and its correlation with clinicopathological features and prognosis of HCC patients. Immunohistochemical detection of ASS was performed on samples from 71 patients with HCC. Positive staining was found in 21 HCCs, with a score of 2, as well as in normal liver tissues. Reduced ASS staining was found in 70.4% (50/71) of HCC tissues, including 21 with a score of 0 and 29 with a score of 1. The staining score in cancer tissues was significantly associated with gender, background liver, histopathological differentiation, recurrence, TNM staging and portal vein invasion (P<0.05), but not with age, viral status, tumor size and serum α-fetoprotein level. Patients with a high ASS expression had significantly poorer overall and disease-free survival (P<0.001 and P<0.001, respectively). These data showed that ASS was reductively or negatively expressed in a large portion of HCC, and that ASS levels in HCCs correlated inversely with prognosis. In conclusion, a high expression of ASS may be a novel marker of poor prognosis of patients presenting with HCC.
