title: Modulation of pancreatic cancer chemoresistance by inhibition of TAK1.
abstract: BACKGROUND
  TGF-β-activated kinase-1 (TAK1), a mitogen-activated protein kinase kinase kinase, functions in the activation of nuclear factor κB (NF-κB) and activator protein-1, which can suppress proapoptotic signaling pathways and thus promote resistance to chemotherapeutic drugs. However, it is not known if inhibition of TAK1 is effective in reducing chemoresistance to therapeutic drugs against pancreatic cancer.
  
  
  METHODS
  NF-κB activity was measured by luciferase reporter assay in human pancreatic cancer cell lines AsPc-1, PANC-1, and MDAPanc-28, in which TAK1 expression was silenced by small hairpin RNA. TAK1 kinase activity was targeted in AsPc-1, PANC-1, MDAPanc-28, and Colo357FG cells with exposure to increasing doses of a selective small-molecule inhibitor, LYTAK1, for 24 hours. To test the effect of LYTAK1 in combination with chemotherapeutic agents, AsPc-1, PANC-1, MDAPanc-28 cells, and control cells were treated with increasing doses of oxaliplatin, SN-38, or gemcitabine in combination with LYTAK1. In vivo activity of oral LYTAK1 was evaluated in an orthotopic nude mouse model (n = 40, 5 per group) with luciferase-expressing AsPc-1 pancreatic cancer cells. The results of in vitro proliferation were analyzed for statistical significance of differences by nonlinear regression analysis; differences in mouse survival were determined using a log-rank test. All statistical tests were two-sided.
  
  
  RESULTS
  AsPc-1 and MDAPanc-28 TAK1 knockdown cells had a statistically significantly lower NF-κB activity than did their respective control cell lines (relative luciferase activity: AsPc-1, mean = 0.18, 95% confidence interval [CI] = 0.10 to 0.27; control, mean = 3.06, 95% CI = 2.31 to 3.80; MDAPanc-28, mean = 0.30, 95% CI = 0.13 to 0.46; control, mean = 4.53, 95% CI = 3.43 to 5.63; both P < .001). TAK1 inhibitor LYTAK1 had potent in vitro cytotoxic activity in AsPc-1, PANC-1, MDAPanc-28, and Colo357FG cells, with IC(50) between 5 and 40 nM. LYTAK1 also potentiated the cytotoxicity of chemotherapeutic agents oxaliplatin, SN-38, and gemcitabine in AsPc-1, PANC-1, and MDAPanc-28 cells compared with control cells (P < .001). In nude mice, oral administration of LYTAK1 plus gemcitabine statistically significantly reduced tumor burden (gemcitabine vs gemcitabine plus LYTAK1, P = .03) and prolonged survival duration (median survival: gemcitabine, 82 days vs gemcitabine plus LYTAK1, 122 days; hazard ratio = 0.334, 95% CI = 0.027 to 0.826, P = .029).
  
  
  CONCLUSIONS
  The results of this study suggest that genetic silencing or inhibition of TAK1 kinase activity in vivo is a potential therapeutic approach to reversal of the intrinsic chemoresistance of pancreatic cancer.
authors: Experimental Pharmacology Unit, Istituto Nazionale per lo studio e la cura dei Tumori-Fondazione G. Pascale, Naples, Italy. d.melisi@istitutotumori.na.it
authors: Davide
authors: D
authors: Melisi
authors: Qianghua
authors: Q
authors: Xia
authors: Genni
authors: G
authors: Paradiso
authors: Jianhua
authors: J
authors: Ling
authors: Tania
authors: T
authors: Moccia
authors: Carmine
authors: C
authors: Carbone
authors: Alfredo
authors: A
authors: Budillon
authors: James L
authors: JL
authors: Abbruzzese
authors: Paul J
authors: PJ
authors: Chiao
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000201:enzymology / Q000378:metabolism*; D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000494:pharmacology*; D015153:Blotting, Western; D002166:Camptothecin / Q000031:analogs & derivatives / Q000494:pharmacology; D045744:Cell Line, Tumor; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D004334:Drug Administration Schedule; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D024202:Electrophoretic Mobility Shift Assay; D020868:Gene Silencing; D006801:Humans; D000077146:Irinotecan; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics; D051379:Mice; D008819:Mice, Nude; D016328:NF-kappa B / Q000378:metabolism*; D009944:Organoplatinum Compounds / Q000494:pharmacology; D000077150:Oxaliplatin; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000378:metabolism; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays; D000093542:Gemcitabine; D000099151:MAP Kinase Kinase Kinase 7
chemical_list: D002166:Camptothecin; D003841:Deoxycytidine; D000077146:Irinotecan; D020930:MAP Kinase Kinase Kinases; D016328:NF-kappa B; D009944:Organoplatinum Compounds; D000077150:Oxaliplatin; D016212:Transforming Growth Factor beta; D000093542:Gemcitabine; D000099151:MAP Kinase Kinase Kinase 7