title: The HIV protease inhibitor ritonavir synergizes with butyrate for induction of apoptotic cell death and mediates expression of heme oxygenase-1 in DLD-1 colon carcinoma cells.
abstract: The protease inhibitor ritonavir is an integral part of current antiretroviral therapy targeting human immunodeficiency virus. Recent studies demonstrate that ritonavir induces apoptotic cell death with high efficiency in lymphoblastoid cell lines. Moreover, ritonavir can suppress activation of the transcription factor nuclear factor-kappaB and is an inhibitor of interleukin-1beta and tumor necrosis factor-alpha production in peripheral blood mononuclear cells. Thus, ritonavir appears to have anti-inflammatory properties. In the present study, we investigated in DLD-1 colon carcinoma cell effects of ritonavir on apoptotic cell death and expression of heme oxygenase-1 (HO-1), an anti-inflammatory enzyme that may be critically involved in the modulation of colonic inflammation. Compared to unstimulated control, ritonavir resulted in a moderate increase in the rate of apoptotic cell death as observed after 20 h of incubation. Notably, ritonavir potently synergized with the short-chain fatty acid butyrate for induction of caspase-3-dependent apoptosis in DLD-1 cells. Ritonavir enhanced mRNA and protein expression of HO-1 in DLD-1 cells. Ritonavir-induced HO-1 protein was suppressed by SB203580 or SB202190 and preceded by immediate upregulation of cellular c-Fos and c-Jun protein levels. This process was associated with induction of activator protein-1 as detected by electrophoretic mobility shift analysis. The present data suggest that ritonavir has the potential to curb colon carcinogenesis by reducing cell growth via mechanisms that include apoptosis and by simultaneously modulating colonic inflammation via induction of anti-inflammatory HO-1.
authors.affiliation: Pharmazentrum frankfurt (ZAFES), University Hospital, Johann Wolfgang Goethe-Universität Frankfurt am Main, Theodor-Stern Kai 7, Haus 75A, Frankfurt am Main D-60590, Germany. H.Muehl@em.uni-frankfurt.de
authors.forename: Heiko
authors.initials: H
authors.lastname: Mühl
authors.forename: Jens
authors.initials: J
authors.lastname: Paulukat
authors.forename: Sonja
authors.initials: S
authors.lastname: Höfler
authors.forename: Markus
authors.initials: M
authors.lastname: Hellmuth
authors.forename: Rochus
authors.initials: R
authors.lastname: Franzen
authors.forename: Josef
authors.initials: J
authors.lastname: Pfeilschifter
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D002087:Butyrates / Q000494:pharmacology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000139:chemically induced* / Q000201:enzymology; D004247:DNA / Q000378:metabolism; D053938:DNA Fragmentation; D004357:Drug Synergism; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000096:biosynthesis / Q000235:genetics; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis* / Q000235:genetics; D051547:Heme Oxygenase-1; D006801:Humans; D015151:Immunoblotting; D008565:Membrane Proteins; D023282:Nuclease Protection Assays; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019438:Ritonavir / Q000494:pharmacology*
chemical_list: D002087:Butyrates; D017320:HIV Protease Inhibitors; D008565:Membrane Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D004247:DNA; C496541:HMOX1 protein, human; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D019438:Ritonavir