title: Aldose reductase regulates growth factor-induced cyclooxygenase-2 expression and prostaglandin E2 production in human colon cancer cells.
abstract: Inhibition of prostaglandin E(2) (PGE(2)) and cyclooxygenase (COX)-2 by nonsteroidal anti-inflammatory drugs reduces the progression of colon cancer. Inhibition of aldose reductase (AR; EC. 1.1.1.21.) by sorbinil or by antisense ablation prevented fibroblast growth factor-induced and platelet-derived growth factor-induced up-regulation of PGE(2) synthesis in human colon cancer cells, Caco-2. AR besides reducing aldo-sugars efficiently reduces toxic lipid aldehydes and their conjugates with glutathione. Inhibition of AR prevented growth factor-induced COX-2 activity, protein, and mRNA and significantly decreased activation of nuclear factor-kappaB and protein kinase C (PKC) and phosphorylation of PKC-beta2 as well as progression of Caco-2 cell growth but had no effect on COX-1 activity. Cell cycle analysis suggests that inhibition of AR prevents growth factor-induced proliferation of Caco-2 cells at S phase. Treatment of Caco-2 cells with the most abundant and toxic lipid aldehyde 4-hydroxy-trans-2-nonenal (HNE) or its glutathione-conjugate [glutathionyl-HNE (GS-HNE)] or AR-catalyzed product of GS-HNE, glutathionyl-1,4-dihydroxynonane (GS-DHN), resulted in increased COX-2 expression and PGE(2) production. Inhibition of AR prevented HNE- or GS-HNE-induced but not GS-DHN-induced up-regulation of COX-2 and PGE(2). More importantly, in vivo studies showed that administration of AR-small interfering RNA (siRNA), but not control siRNA, to nude mice bearing SW480 human colon adenocarcinoma cells completely arrested tumor progression. Collectively, these observations suggest that AR is an obligatory mediator of growth factor-induced up-regulation of COX-2, PGE(2), and growth of Caco-2 cells, indicating that inhibition of AR may be a novel therapeutic approach in preventing the progression of colon cancer.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-0647, USA.
authors.forename: Ravinder
authors.initials: R
authors.lastname: Tammali
authors.forename: Kota V
authors.initials: KV
authors.lastname: Ramana
authors.forename: Sharad S
authors.initials: SS
authors.lastname: Singhal
authors.forename: Sanjay
authors.initials: S
authors.lastname: Awasthi
authors.forename: Satish K
authors.initials: SK
authors.lastname: Srivastava
mesh_terms: D000230:Adenocarcinoma / Q000201:enzymology / Q000473:pathology*; D000449:Aldehyde Reductase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D000447:Aldehydes / Q000494:pharmacology; D000818:Animals; D003110:Colonic Neoplasms / Q000201:enzymology / Q000473:pathology*; D051546:Cyclooxygenase 2 / Q000096:biosynthesis* / Q000235:genetics; D015232:Dinoprostone / Q000096:biosynthesis*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D005978:Glutathione / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D048289:Imidazolidines / Q000494:pharmacology; D051379:Mice; D008819:Mice, Nude; D016328:NF-kappa B / Q000378:metabolism; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D016196:S Phase / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D000447:Aldehydes; D048289:Imidazolidines; D016328:NF-kappa B; D009363:Neoplasm Proteins; D010982:Platelet-Derived Growth Factor; D034741:RNA, Small Interfering; C524061:glutathionyl 4-hydroxy-2-nonenal conjugate; C524062:glutathionyl-1,4-dihydroxynonane; C462359:tert-4-hydroxy-2-nonenal; D016222:Fibroblast Growth Factor 2; D000449:Aldehyde Reductase; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011493:Protein Kinase C; C026411:sorbinil; D005978:Glutathione; D015232:Dinoprostone