title: Modulation of insulin degrading enzyme activity and liver cell proliferation.
abstract: Diabetes mellitus type 2 (T2DM), insulin therapy, and hyperinsulinemia are independent risk factors of liver cancer. Recently, the use of a novel inhibitor of insulin degrading enzyme (IDE) was proposed as a new therapeutic strategy in T2DM. However, IDE inhibition might stimulate liver cell proliferation via increased intracellular insulin concentration. The aim of this study was to characterize effects of inhibition of IDE activity in HepG2 hepatoma cells and to analyze liver specific expression of IDE in subjects with T2DM. HepG2 cells were treated with 10 nM insulin for 24 h with or without inhibition of IDE activity using IDE RNAi, and cell transcriptome and proliferation rate were analyzed. Human liver samples (n = 22) were used for the gene expression profiling by microarrays. In HepG2 cells, IDE knockdown changed expression of genes involved in cell cycle and apoptosis pathways. Proliferation rate was lower in IDE knockdown cells than in controls. Microarray analysis revealed the decrease of hepatic IDE expression in subjects with T2DM accompanied by the downregulation of the p53-dependent genes FAS and CCNG2, but not by the upregulation of proliferation markers MKI67, MCM2 and PCNA. Similar results were found in the liver microarray dataset from GEO Profiles database. In conclusion, IDE expression is decreased in liver of subjects with T2DM which is accompanied by the dysregulation of p53 pathway. Prolonged use of IDE inhibitors for T2DM treatment should be carefully tested in animal studies regarding its potential effect on hepatic tumorigenesis.
authors.affiliation: a Department of Clinical Nutrition ; German Institute of Human Nutrition Potsdam-Rehbruecke ; Nuthetal , Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Pivovarova
authors.forename: Christian
authors.initials: C
authors.lastname: von Loeffelholz
authors.forename: Iryna
authors.initials: I
authors.lastname: Ilkavets
authors.forename: Carsten
authors.initials: C
authors.lastname: Sticht
authors.forename: Sergei
authors.initials: S
authors.lastname: Zhuk
authors.forename: Veronica
authors.initials: V
authors.lastname: Murahovschi
authors.forename: Sonja
authors.initials: S
authors.lastname: Lukowski
authors.forename: Stephanie
authors.initials: S
authors.lastname: Döcke
authors.forename: Jennifer
authors.initials: J
authors.lastname: Kriebel
authors.forename: Tonia
authors.initials: T
authors.lastname: de las Heras Gala
authors.forename: Anna
authors.initials: A
authors.lastname: Malashicheva
authors.forename: Anna
authors.initials: A
authors.lastname: Kostareva
authors.forename: Johan F
authors.initials: JF
authors.lastname: Lock
authors.forename: Martin
authors.initials: M
authors.lastname: Stockmann
authors.forename: Harald
authors.initials: H
authors.lastname: Grallert
authors.forename: Norbert
authors.initials: N
authors.lastname: Gretz
authors.forename: Steven
authors.initials: S
authors.lastname: Dooley
authors.forename: Andreas F H
authors.initials: AF
authors.lastname: Pfeiffer
authors.forename: Natalia
authors.initials: N
authors.lastname: Rudovich
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D015331:Cohort Studies; D056767:Cyclin G2 / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000473:pathology; D005260:Female; D020869:Gene Expression Profiling; D056945:Hep G2 Cells; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D007339:Insulysin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D019394:Ki-67 Antigen / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D064111:Minichromosome Maintenance Complex Component 2 / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D034622:RNA Interference; D059467:Transcriptome / Q000187:drug effects; D019014:fas Receptor / Q000378:metabolism
chemical_list: C101593:CCNG2 protein, human; D056767:Cyclin G2; C491901:FAS protein, human; D007328:Insulin; D019394:Ki-67 Antigen; D018809:Proliferating Cell Nuclear Antigen; D019014:fas Receptor; D007339:Insulysin; C084859:MCM2 protein, human; D064111:Minichromosome Maintenance Complex Component 2
keywords: CCNG2, Cyclin G2 gene, CDKN1A/P21, Cyclin-dependent kinase inhibitor 1A (p21, Cip1) gene; CDKN1B/P27, Cyclin-dependent kinase inhibitor 1B (p27, Kip1) gene; FAS, Fas cell surface death receptor gene; FBS, Fetal bovine serum; IDE, Insulin-degrading enzyme; MCM2, Minichromosome maintenance complex component 2 gene; MKI67, Marker of proliferation Ki-67 gene; NAFLD, Non-alcoholic fatty liver disease; NAS, Non-alcoholic fatty liver disease score; OGTT, Oral glucose tolerance test; PCNA, Proliferating cell nuclear antigen gene; SESN1, Sestrin 1 gene; T2DM, Type 2 diabetes mellitus.; TP53, Tumor protein p53 gene; TP53I3, Tumor protein p53 inducible protein 3 gene; hepatocellular carcinoma; insulin-degrading enzyme; non-alcoholic fatty liver disease; proliferation; qRT-PCR, Quantitative real-time PCR; type 2 diabetes mellitus