The promoting molecular mechanism of alphafetoprotein on the growth of human hepatoma Bel7402 cell line  

作　　者：LiMS LiPF 等 

机构地区：[1]DepartmentofBiochemistyr,HainanMedicalCollege,Haikou571101,HainanProvince,China [2]DepartmentofBiochemistryandMolecularBiology,HealthScienceCenter,PekingUniversity,Beijing100083,China

出　　处：《World Journal of Gastroenterology》2002年第3期469-475,共7页世界胃肠病学杂志（英文版）

基　　金：National Natural Science Foundation of China,No.39760077

摘　　要：AIM: The goal of this study was to characterize the AFP receptor, its possible signal transduction pathway and its proliferative functions in human hepatoma cell line Bel 7402. METHODS: Cell proliferation enhanced by AFP was detected by MTT assay, 3H-thymidine incorporation and S-stage percentage of cell cycle analysis. With radioactive labeled 125I-AFP for receptor binding assay; cAMP accumulation, protein kinase A activity were detected by radioactive immunosorbent assay and the change of intracellular free calcium (Ca2+i) was monitored by scanning fluorescence intensity under TCS-NT confocal microscope. The expression of oncogenes N- ras, p 53, and p21( ras ) in the cultured cells in vitro were detected by Northern blotting and Western blotting respectively. RESULTS: It was demonstrated that AFP enhanced the proliferation of human hepatoma Bel 7402 cell in a dose dependent fashion as shown in MTT assay, (3)H-thymidine incorporation and S-phase percentage up to 2-fold. Two subtypes of AFP receptors were identified in the cells with Kds of 1.3 x 10(-9)mol.L(-1) and 9.9 x10(-8)mol. (-1)L respectively. Pretreatment of cells with AFP resulted in a significant increase (625%) in cAMP accumulation. The activity of protein kinase A activity were increased up to 37.5, 122.6, 73.7 and 61.2% at treatment time point 2, 6, 12 and 24 hours. The level of intracellular calcium were elevated after the treatment of alpha-fetoprotein and achieved to 204% at 4 min. The results also showed that AFP(20mg.L(-1)) could upregulate the expression of N- ras oncogenes and p 53 and p21( ras ) in Bel 7402 cells. In the later case,the alteration were 81.1%(12h) and 97.3%(12h) respectively compared with control. CONCLUSION: These results demonstrate that AFP is a potential growth factor to promote the proliferation of human hepatoma Bel 7402 cells. Its growth-regulatory effects are mediated by its specific plasma membrane receptors coupled with its transmembrane signaling transduction through the pathway of cAMP-PKA and intracellular calciumAIM: The goal of this study was to characterize the AlPreceptor, its possible signal transduction pathway and itsproliferative functions in human hepatoma cell line Bel 7402.METHODS: Cell proliferation enhanced by AFlP was detectedby MTT assay, 3H-thymidine incorporation and S-stsgepercentage of cell cycle analysis. With radioactive labeled 125 I-AFP for receptor binding assay; cAMP acctmuation, ProteinKinase A activity were detected by radioactive immunosorbentassay and the change of intracellular free calcium ([Ca2+ ], )was monitored by scanning fluorescence intensity under TCS-NT confocal microscope. The expression of oncxgenes N- ras,p53, and p21ras in the cultured cells in vitro were detected byNorthem blotting and Western blotting respectively.RESULTS: It was demonstrated that AFP enhanced theproliferation of human hepatoma Bel 7402 cell in a dosedependlent fashion asshown in MTT assay, 3H-thymidineincorporation and S-phase percentage up to 2-fold. Twosubtypes of AFP receptors were identified in the cells withKds of 1.3 x 10-9 mol. L-1 and 9.9 x 10-8 mol. L-1 respectively.Pretreatnent of cells with AFP resulted-in a significantincrease (625 %) in cAMP accumulation. The activity ofprotein kinase A activity were increased up to 37.5, 122.6,73.7 and 61.2 % at treatment time point 2, 6, 12 and 24hours. The level of intracellular calcium were elevated afterthe treatment of alpha-fetoprotsin and achieved to 204 % at 4min. The results also showed that AFP (20 mg. L-1 ) couldupregulate the expression of N-ras oncogenes and p53 andp21ras in Bel 7402 cells. In the later case, the alteration ware 81.1%(12 h) and 97.3 %(12 h) respectively compared with control.CONCLUSION: These results demonstrate that AFP is apotential growth factor to promote the proliferation of humanhepatoma Bel 7402 cells. Its growth-regulatory effects aremediated by its specific plasma membrane receptorscoupled with its transmembrane signaling transductionthrough the pathway of cAMP-PKA and intracellular calciumto regulate the expression of oncog

关 键 词：Calcium Carcinoma  Hepatocellular Cell Division Cyclic AMP Cyclic AMP-Dependent Protein Kinases Humans Liver Neoplasms Receptors  Peptide Research Support  Non-U.S. Gov't Signal Transduction Tumor Cells  Cultured ALPHA-FETOPROTEINS 

分 类 号：R735.7[医药卫生—肿瘤]