ABSTRACT
<p><b>OBJECTIVES</b>To unravel the molecular mechanism of proliferation inhibition induced by transfection of pemt2-cDNA into rat CBRH-7919 hepatoma cells.</p><p><b>METHODS</b>We started with the highly expressed PEMT2 clone. Cell culture and Western blotting techniques were used to examine the expression of cyclinD1/CDK4, cyclinE/CDK2, phospho-Rb, caspase-3, c-jun and caveolins.</p><p><b>RESULTS</b>Our results showed that CDK4, CDK2, phospho-Rb and c-jun were down regulated in the pemt2 highly expressed cell clone. The high expression clone of pemt2-transfected cells also showed over expression of caspase-3.</p><p><b>CONCLUSION</b>The reductions of proliferation and apoptosis of pemt2 transfected cells could be related to the G1 phase arrest induced by down-regulation of the cell cycle-associated proteins.</p>
Subject(s)
Animals , Rats , Apoptosis , Physiology , Caspase 3 , Genetics , Cyclin-Dependent Kinase 2 , Genetics , Cyclin-Dependent Kinase 4 , Genetics , Cyclin-Dependent Kinases , Genetics , Down-Regulation , Liver Neoplasms, Experimental , Genetics , Metabolism , Phosphatidylethanolamine N-Methyltransferase , Genetics , Metabolism , Transfection , Tumor Cells, CulturedABSTRACT
<p><b>OBJECTIVES</b>To explore the mechanism of CBRH-7919 cell proliferation inhibition by transfecting phosphatidylethanolamine N-methyltransferase 2 gene (PEMT2).</p><p><b>METHODS</b>The effects of PEMT2 transfection on phosphorylation and translocation from cytosol to plasma membrane of PLC gamma 1 in cells were studied using SDS-PAGE and Western blot techniques. The phosphorylation and activity of c-Met were determined.</p><p><b>RESULTS</b>After transfection of pemt2, the PLC gamma 1 and phosphorylated PLC gamma 1 conjugated with plasma membrane were decreased by 45% and 27% of that of control cells respectively, and the phosphorylated c-Met was decreased to 32% of that of control cells.</p><p><b>CONCLUSION</b>Transfection of phosphatidylethanolamine N-methyltransferase 2 gene can inhibit the phosphorylation and translocation from cytosol to plasma membrane of PLC gamma 1 in cells. At the same time, the autophosphorylation of c-Met was decreased, which suggests that transfection of phosphatidylethanolamine N-methyltransferase 2 gene can downregulate the c-Met/PLC gamma 1 signaling pathway in CBRH-7919 cells.</p>
Subject(s)
Animals , Rats , Cell Line, Tumor , Cell Movement , Cell Proliferation , Liver Neoplasms, Experimental , Phosphatidylethanolamine N-Methyltransferase , Genetics , Metabolism , Phospholipase C gamma , Genetics , Metabolism , Phosphorylation , Proto-Oncogene Proteins c-met , Metabolism , TransfectionABSTRACT
<p><b>OBJECTIVE</b>To explore the mechanism of cell proliferation inhibition by transfecting phosphatidylethanolamine N-methyltransferase 2 gene (PEMT2).</p><p><b>METHODS</b>The expression and translocation of different isoforms of protein kinase C (PKC) in cells were observed with immunocytochemistry and Western blot techniques. The content of diacylglycerol (DAG) was analyzed with high performance thin layer chromatography (HPTLC) technique.</p><p><b>RESULTS</b>Transfection of PEMT2 can inhibit the expression of cPKC alpha, but obviously promotes the expression and translocation from cytosol to plasma membrane of cPKC beta2. At the same time, the content of DAG was decreased in the transfected cells. Expression and translocation of other PKC isoforms were not changed by PEMT2 transfection.</p><p><b>CONCLUSION</b>Effects of overexpression of PEMT2 on the expression and translocation of different PKC isoforms might be related to the mechanism of cell proliferation inhibition and apoptosis induced by transfecting PEMT2.</p>