title: Flurbiprofen benzyl nitrate (NBS-242) inhibits the growth of A-431 human epidermoid carcinoma cells and targets β-catenin.
abstract: BACKGROUND
  The Wnt/β-catenin/T cell factor (TCF) signaling pathway is important in the development of nonmelanoma skin cancers (NMSCs). Nitric-oxide-releasing nonsteroidal anti-inflammatory drugs (NO-NSAIDs) are chemopreventive agents consisting of a traditional NSAID attached to an NO-releasing moiety through a chemical spacer. Previously we showed that an aromatic spacer enhanced the potency of a particular NO-NSAID compared to an aliphatic spacer.
  
  
  METHODS
  We synthesized an NO-releasing NSAID with an aromatic spacer (flurbiprofen benzyl nitrate, NBS-242), and using the human skin cancer cell line A-431, we evaluated its effects on cell kinetics, Wnt/β-catenin, cyclin D1, and caspase-3.
  
  
  RESULTS
  NBS-242 inhibited the growth of A-431 cancer cells, being ~15-fold more potent than flurbiprofen and up to 5-fold more potent than NO-flurbiprofen with an aliphatic spacer, the half maximal inhibitory concentrations (IC50) for growth inhibition being 60 ± 4 μM, 320 ± 20 μM, and 880 ± 65 μM for NBS-242, NO-flurbiprofen, and flurbiprofen, respectively. This effect was associated with inhibition of proliferation, accumulation of cells in the G0/G1 phase of the cell cycle, and an increase in apoptotic cell population. NBS-242 cleaved β-catenin both in the cytoplasm and the nucleus of A-431 cells. NBS-242 activated caspase-3 whose activation was reflected in the cleavage of procaspase-3. To test the functional consequence of β-catenin cleavage, we determined the expression of cyclin D1, a Wnt-response gene. NBS-242 reduced cyclin D1 levels in a concentration dependent manner.
  
  
  CONCLUSIONS
  These findings establish a strong inhibitory effect of NBS-242 in A-431 human epidermoid carcinoma cells. NBS-242 modulates parameters that are important in determining cellular mass.
authors.affiliation: Department of Physiology, Pharmacology, and Neuroscience, Sophie Davis School of Biomedical Education, City University of New York Medical School, New York, NY, USA.
authors.forename: Niharika
authors.initials: N
authors.lastname: Nath
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Liu
authors.forename: Lloydine
authors.initials: L
authors.lastname: Jacobs
authors.forename: Khosrow
authors.initials: K
authors.lastname: Kashfi
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000473:pathology; D053148:Caspase 3 / Q000096:biosynthesis; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D005480:Flurbiprofen / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D009566:Nitrates / Q000494:pharmacology*; D009569:Nitric Oxide / Q000502:physiology; D060449:Wnt Signaling Pathway / Q000187:drug effects; D051176:beta Catenin / Q000037:antagonists & inhibitors*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D009566:Nitrates; D051176:beta Catenin; C584564:flurbiprofen benzyl nitrate; D009569:Nitric Oxide; D005480:Flurbiprofen; D053148:Caspase 3
keywords: chemoprevention; flurbiprofen; nitric oxide; skin cancer; β-catenin