Effect of human serum on the expression levels of the 5-aminolevulinate synthetase 1 protein in C3A hepatoma cells.

MORA, SANDRA; PARERA VICTORIA; OLIVERI, LEDA; ROSSETTI, MARIA VICTORIA; BUZALEH, ANA MARIA; GEREZ ESTHER

Virtual

Congreso; LXVI REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2021

Sociedad Argentina de Investigación Clínica

Studies carried out in our laboratory, in an in vitro model, demonstratedthat the presence of fetal bovine serum (FBS) in the culturemedium caused an increase in the amount of δ-aminolevulinatesynthetase (ALA-S1) protein, the first and regulatory enzyme ofthe heme pathway, due to an increase in protein translation. It hasalso been described that the addition of insulin influences markedlythe induction of ALA-S1 through the PI3K / Akt pathway. Therefore,in order to continue studying in vitro the effects obtained with FBSand to extend the research to human serum (Sh), it was decided toevaluate the effects of serum in cultures of the established line ofhuman hepatoma C3A.The cells were grown in low glucose DMEMmedium (5 mM) and without serum for 18 h. The cells were thentreated with different concentrations of Sh (1, 2.5, and 10%), with2% Sh inactivated (Shi) by heat or stripped with activated carbon(SHe) and 2% FBS. The addition of Sh caused a significant increasein ALA-S1 protein (100%) at all concentrations. Heat inactivation oractivated carbon treatment had no effect on the induction of ALAS1by Sh. However, the expression levels of ALA-S1 mRNA were significantlydecreased (30%). This result agrees with the observedincrease of the phosphorylation levels of Akt (Ser473), an enzymethat inactivates the transcription factor needed for the transcriptionof ALA-S1 mRNA. The phosphorylation levels of 4-EBP1 were 172%increased. When 4-EBP1 is phosphorylated, the protein synthesis isfavored, thus the obtained result would suggest that the increase inALA-S1 protein is due to a greater translation. These results herepresented constitute a significant contribution to the understandingof the molecular mechanisms that lead to changes in the expressionof ALA-S1. Moreover, the in vitro model used is adequate to furtherresearch the effect of Sh on ALA-S1.