indinavir-sulfate and Liver-Neoplasms

HIV protease inhibitor treatment is associated with insulin resistance. We have recently demonstrated that the HIV protease inhibitor indinavir influences initial insulin signaling steps in HepG2 cells. Here we investigated in the same cell model whether indinavir alters insulin-stimulated glycogen synthesis. Since an altered phosphotyrosine phosphatase activity could represent a mechanism by which insulin signaling is influenced, we also assessed potential indinavir effects on protein tyrosine phosphatase activity directed against tyrosine phosphorylated insulin receptor substrate-1. HepG2 cells were incubated for 48 h without or with indinavir (100 micro mol/l). Subsequently, the insulin-stimulated incorporation of 14C-glucose into glycogen was measured. In indinavir-treated cells the insulin effect on glycogen synthesis was reduced by 30 +/- 4.5 %. Dephosphorylation of immobilized tyrosine-phosphorylated insulin-receptor substrate-1 by the cell extracts was determined using a microwell plate-based method, and indinavir treatment did not alter this dephosphorylation. In conclusion, our data suggest that indinavir affects insulin-stimulation of glycogen synthesis in liver cells, and this may be related to the previously observed alterations in insulin signaling. Direct effects of indinavir on the GLUT4 transport system, that have been suggested from data in other cell systems, are unlikely in HepG2 cells that express no or almost no GLUT4 transport system. Finally, our data do not support the hypothesis that indinavir alters insulin signaling by influencing protein tyrosine phosphatase activity directed against insulin receptor substrate-1.

Topics: Carcinoma, Hepatocellular; Glucose; Glycogen; HIV Protease Inhibitors; Humans; Hypoglycemic Agents; Indinavir; Insulin; Liver; Liver Neoplasms; Protein Tyrosine Phosphatases; Stimulation, Chemical; Tumor Cells, Cultured

Patients treated with human immunodeficiency virus-1 protease inhibitors often develop impaired glucose tolerance or diabetes, most likely due to an induction of insulin resistance. We therefore investigated whether the protease inhibitor indinavir alters insulin signalling.. We incubated HepG2 cells for 48 h without or with indinavir (100 micromol/l). Subsequently 125I-insulin binding to the cells and the effects of insulin stimulation on insulin-receptor substrate-1-phosphorylation, association of phosphatidylinositol 3-kinase with insulin-receptor substrate-1 and Akt-Thr308-phosphorylation were measured.. In cells not exposed to indinavir, insulin (100 nmol/l) led to rapid increases of insulin-receptor substrate-1-phosphorylation, association of phosphatidylinositol 3-kinase with insulin-receptor substrate-1 and Akt-phosphorylation during the first 75 s, followed by subsequent decreases. In indinavir-treated cells, these insulin-stimulated increases during the first 75 s were reduced by 30-60% and this was not associated with alterations in cell number or viability, insulin binding to the cells or cellular insulin-receptor substrate-1-content.. Effects of indinavir on initial insulin signalling could cause, or contribute to, the metabolic effects of human immunodeficiency virus-1 protease inhibitors.

Topics: Carcinoma, Hepatocellular; Cell Survival; HIV Protease; HIV Protease Inhibitors; Humans; Indinavir; Insulin; Insulin Receptor Substrate Proteins; Kinetics; Liver Neoplasms; Phosphoproteins; Phosphorylation; Receptor, Insulin; Signal Transduction; Tumor Cells, Cultured