title: Amiloride sensitizes human pancreatic cancer cells to erlotinib in vitro through inhibition of the PI3K/AKT signaling pathway.
abstract: OBJECTIVE
  Blockade of EGFR by EGFR tyrosine kinase inhibitors such as erlotinib is insufficient for effective treatment of human pancreatic cancer due to independent activation of the Akt pathway, while amiloride, a potassium-sparing diuretic, has been found as a potential Akt inhibitor. The aim of this study was to investigate the anticancer effects of combined amiloride with erlotinib against human pancreatic cancer cells in vitro.
  
  
  METHODS
  Cell proliferation, colony formation, cell cycle and apoptosis were analyzed in 4 human pancreatic cancer cell lines Bxpc-3, PANC-1, Aspc-1 and CFPAC-1 treated with erlotinib or amiloride alone, or in their combination. The synergistic analysis for the effects of combinations of amiloride and erlotinib was performed using Chou-Talalay's combination index isobolographic method.
  
  
  RESULTS
  Amiloride (10, 30, and 100 μmol/L) concentration-dependently potentiated erlotinib-induced inhibition of cell proliferation and colony formation in the 4 pancreatic cancer cell lines. Isobolographic analysis confirmed that combinations of amiloride and erlotinib produced synergistic cytotoxic effects. Amiloride significantly potentiated erlotinib-induced G0/G1 cell-cycle arrest and apoptosis in Bxpc-3 and PANC-1 cells. Amiloride inhibited EGF-stimulated phorsphorylation of AKT, and significantly enhanced erlotinib-induced downregulation of phorsphorylation of EGFR, AKT, PI3K P85 and GSK 3β in Bxpc-3 and PANC-1 cells.
  
  
  CONCLUSIONS
  Amiloride sensitizes human pancreatic cancer cells to erlotinib in vitro through inhibition of the PI3K/AKT signaling pathway. Treatment of pancreatic cancer patients with combination of erlotinib and amiloride merits further investigation.
authors: Department of Clinical Pharmacy, School of Pharmacy, Fudan University, Shanghai 201203, China.
authors: Yuan-ting
authors: YT
authors: Zheng
authors: Department of Clinical Pharmacy, School of Pharmacy, Fudan University, Shanghai 201203, China.
authors: Hui-ying
authors: HY
authors: Yang
authors: Department of Clinical Pharmacy, School of Pharmacy, Fudan University, Shanghai 201203, China.
authors: Tao
authors: T
authors: Li
authors: Department of Clinical Pharmacy, School of Pharmacy, Fudan University, Shanghai 201203, China.
authors: Bei
authors: B
authors: Zhao
authors: Department of Clinical Pharmacy, School of Pharmacy, Fudan University, Shanghai 201203, China.
authors: Teng-fei
authors: TF
authors: Shao
authors: Department of Clinical Pharmacy, School of Pharmacy, Fudan University, Shanghai 201203, China.
authors: Xiao-qiang
authors: XQ
authors: Xiang
authors: Department of Clinical Pharmacy, School of Pharmacy, Fudan University, Shanghai 201203, China.
authors: Wei-min
authors: WM
authors: Cai
mesh_terms: D000584:Amiloride / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism; D000069347:Erlotinib Hydrochloride / Q000494:pharmacology*; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects; D006801:Humans; D058990:Molecular Targeted Therapy; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors* / Q000378:metabolism; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D013997:Time Factors
chemical_list: D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D000584:Amiloride; D000069347:Erlotinib Hydrochloride; D058539:Phosphatidylinositol 3-Kinase; C512478:EGFR protein, human; D066246:ErbB Receptors; D051057:Proto-Oncogene Proteins c-akt