title: Multiple kinase pathways involved in the different de novo sensitivity of pancreatic cancer cell lines to 17-AAG.
abstract: BACKGROUND
  17-Allylamino-17-demethoxygeldanamycin (17-AAG) specifically targets heat shock protein (HSP)90 and inhibits its chaperoning functions for multiple kinases involved in cancer cell growth and survival. To select responsive patients, the molecular mechanisms underlying the sensitivity of cancer cells to 17-AAG must be elucidated.
  
  
  METHODS
  We used cytotoxicity assays and Western blotting to explore the effects of 17-AAG and sorafenib on cell survival and expression of multiple kinases in the pancreatic cancer cell lines AsPC-1 and Panc-1. Gene cloning and transfection, siRNA silencing, and immunohistochemistry were used to evaluate the effects of mutant p53 protein on 17-AAG sensitivity.
  
  
  RESULTS
  AsPC-1 and Panc-1 responded differently to 17-AAG, with half maximal inhibitory concentration (IC(50)) values of 0.12 and 3.18 μM, respectively. Comparable expression of HSP90, HSP70, and HSP27 was induced by 17-AAG in AsPC-1 and Panc-1 cells. P-glycoprotein and mutant p53 did not affect 17-AAG sensitivity in these cell lines. Multiple kinases are more sensitive to HSP90 inhibition in AsPC-1 than in Panc-1 cells. After 17-AAG treatment, p-Bad (S112) decreased in AsPC-1 cells and increased in Panc-1 cells. Sorafenib markedly increased p-Akt, p-ERK1/2, p-GSK-3β, and p-S6 in both cell lines. Accordingly, 17-AAG and sorafenib acted antagonistically in AsPC-1 and Panc-1 cells, except at high concentrations in AsPC-1 cells.
  
  
  CONCLUSIONS
  Differential inhibition of multiple kinases is responsible for the different de novo sensitivity of AsPC-1 and Panc-1 cells to HSP90 inhibition. P-glycoprotein and mutant p53 protein did not play a role in the sensitivity of pancreatic cancer cells to 17-AAG.
authors.affiliation: Department of Surgical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: Heping
authors.initials: H
authors.lastname: Liu
authors.forename: Ti
authors.initials: T
authors.lastname: Zhang
authors.forename: Rong
authors.initials: R
authors.lastname: Chen
authors.forename: David J
authors.initials: DJ
authors.lastname: McConkey
authors.forename: John F
authors.initials: JF
authors.lastname: Ward
authors.forename: Steven A
authors.initials: SA
authors.lastname: Curley
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D001557:Benzenesulfonates / Q000494:pharmacology; D016227:Benzoquinones / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors*; D006801:Humans; D047029:Lactams, Macrocyclic / Q000494:pharmacology*; D009154:Mutation / Q000235:genetics; D009536:Niacinamide / Q000031:analogs & derivatives; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D010671:Phenylurea Compounds; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011494:Protein Kinases / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*; D000077157:Sorafenib; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D001557:Benzenesulfonates; D016227:Benzoquinones; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D010671:Phenylurea Compounds; D047428:Protein Kinase Inhibitors; D011725:Pyridines; D034741:RNA, Small Interfering; D016159:Tumor Suppressor Protein p53; D009536:Niacinamide; C112765:tanespimycin; D000077157:Sorafenib; D011494:Protein Kinases