Apolipoprotein A-I synthesis and secretion are increased in Hep G2 cells depleted of copper by cupruretic tetramine.
Two amine chelators, namely N,N'-bis(2-aminoethyl)-1,3-propanediamine-4 HCl (2,3,2-tetramine) and diamsar, were used at various levels to deplete copper (Cu) from cultured Hep G2 cells. For cells cultured at 0.63 mumol of Cu/L, maximal depletions were attained after 24 h of incubation with 10 mumol of either chelator/L, which resulted in an average significant depletion of 45% of cellular Cu. In addition, when cells were cultured continuously for four passages at 0.63 mumol Cu/L with 20 mumol of 2,3,2-tetramine/L, cellular Cu was significantly depleted more than 40% compared with controls. Furthermore, after two passages of 2,3,2-tetramine treatment, cells were pulsed for 10 min with [3H]leucine and chased up to 2 h. At the end of the pulse, the amount of [3H]leucine incorporated into apolipoprotein A-I was twofold greater (P < 0.05) in treated than in control cells. No difference was detected for the synthesis of apolipoprotein B and total protein. During the chase, the cellular depletion curves for apolipoprotein A-I, apolipoprotein B and total protein were not altered by 2,3,2-tetramine treatment. From 30 to 120 min of the chase, the amount of nascent apolipoprotein A-I degraded was small and not altered, but that secreted into the medium was 56% higher (P < 0.05) in the Cu-depleted than in the control cells.
Zhang
J J
JJ
Department of Nutritional Sciences, University of Arizona, Tucson 85721.
Wang
Y
Y
Lei
K Y
KY
D016632:Apolipoprotein A-I / Q000096:biosynthesis* / Q000378:metabolism; D001055:Apolipoproteins B / Q000096:biosynthesis / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology*; D003300:Copper / Q000032:analysis / Q000378:metabolism* / Q000502:physiology; D018197:Hepatoblastoma / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007930:Leucine / Q000378:metabolism; D008113:Liver Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D011073:Polyamines / Q000494:pharmacology*; D011233:Precipitin Tests; D014316:Tritium; D014407:Tumor Cells, Cultured
D016632:Apolipoprotein A-I; D001055:Apolipoproteins B; D002614:Chelating Agents; D011073:Polyamines; D014316:Tritium; C022177:2,3,2-tetramine; D003300:Copper; D007930:Leucine