title: Regulation of p53, nuclear factor kappaB and cyclooxygenase-2 expression by bromelain through targeting mitogen-activated protein kinase pathway in mouse skin.
abstract: Bromelain is a pharmacologically active compound, present in stems and immature fruits of pineapples (Ananas cosmosus), which has been shown to have anti-edematous, anti-inflammatory, anti-thrombotic and anti-metastatic properties. In the present study, antitumorigenic activity of bromelain was recorded in 7,12-dimethylbenz(a)anthracene (DMBA)-initiated and 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted 2-stage mouse skin model. Results showed that bromelain application delayed the onset of tumorigenesis and reduced the cumulative number of tumors, tumor volume and the average number of tumors/mouse. To establish a cause and effect relationship, we targeted the proteins involved in the cell death pathway. Bromelain treatment resulted in upregulation of p53 and Bax and subsequent activation of caspase 3 and caspase 9 with concomitant decrease in antiapoptotic protein Bcl-2 in mouse skin. Since persistent induction of cyclooxygenase-2 (Cox-2) is frequently implicated in tumorigenesis and is regulated by nuclear factor-kappa B (NF-kappaB), we also investigated the effect of bromelain on Cox-2 and NF-kappaB expression. Results showed that bromelain application significantly inhibited Cox-2 and inactivated NF-kappaB by blocking phosphorylation and subsequent degradation of IkappaBalpha. In addition, bromelain treatment attenuated DMBA-TPA-induced phosphorylation of extracellular signal-regulated protein kinase (ERK1/2), mitogen-activated protein kinase (MAPK) and Akt. Taken together, we conclude that bromelain induces apoptosis-related proteins along with inhibition of NF-kappaB-driven Cox-2 expression by blocking the MAPK and Akt/protein kinase B signaling in DMBA-TPA-induced mouse skin tumors, which may account for its anti-tumorigenic effects.
authors: Proteomics Laboratory, Industrial Toxicology Research Centre, P.O. Box 80, M.G. Marg, Lucknow 226001, India.
authors: Neetu
authors: N
authors: Kalra
authors: Kulpreet
authors: K
authors: Bhui
authors: Preeti
authors: P
authors: Roy
authors: Smita
authors: S
authors: Srivastava
authors: Jasmine
authors: J
authors: George
authors: Sahdeo
authors: S
authors: Prasad
authors: Yogeshwer
authors: Y
authors: Shukla
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001963:Bromelains / Q000494:pharmacology*; D051546:Cyclooxygenase 2 / Q000032:analysis*; D005260:Female; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D051379:Mice; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D012867:Skin / Q000187:drug effects*; D012878:Skin Neoplasms / Q000188:drug therapy / Q000473:pathology; D013755:Tetradecanoylphorbol Acetate; D016159:Tumor Suppressor Protein p53 / Q000032:analysis*
chemical_list: D000970:Antineoplastic Agents; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D015127:9,10-Dimethyl-1,2-benzanthracene; D001963:Bromelains; D051546:Cyclooxygenase 2; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D013755:Tetradecanoylphorbol Acetate