title: Selective inhibitors of nuclear export block pancreatic cancer cell proliferation and reduce tumor growth in mice.
abstract: OBJECTIVE
  Tumor-suppressor proteins are inactivated by many different mechanisms, including nuclear exclusion by chromosome region maintenance (CRM)-1. Increased tumor levels of CRM-1 have been correlated with poor prognosis of patients with pancreatic cancer, making it a therapeutic target. Selective inhibitors of nuclear export (SINEs) bind to CRM-1 to irreversibly inhibit its ability to export proteins; we investigated a new class of SINEs in pancreatic cancer cells.
  
  
  METHODS
  We studied the effects of SINE analogs in a panel of pancreatic cancer cell lines and nontransformed human pancreatic ductal epithelial cells using proliferation, apoptosis, immunoblot, co-immunoprecipitation, small inhibitor RNA, and fluorescence microscopy analyses. The effects of the SINEs also were investigated in mice with subcutaneous and orthotopic tumors.
  
  
  RESULTS
  SINEs (KPT-185, KPT-127, KPT-205, and KPT-227) inhibited proliferation and promoted apoptosis of pancreatic cancer cells, but did not affect human pancreatic ductal epithelial cells. The nuclei of cells incubated with KPT-185 accumulated tumor-suppressor proteins (p27, FOXO, p73, and prostate apoptosis response-4 [PAR-4]) and inhibited interactions between CRM-1 and these proteins. Mutations in the region of CRM-1 that bind to SINEs (Cys-528), or small inhibitor RNA knockdown of PAR-4, prevented the ability of KPT-185 to block proliferation and induce apoptosis of pancreatic cancer cells. Oral administration of KPT-330 to mice reduced growth of subcutaneous and orthotopic xenograft tumors without major toxicity. Analysis of tumor remnants showed that KPT-330 disrupted the interaction between CRM-1 and PAR-4, activated PAR-4 signaling, and reduced proliferation of tumor cells.
  
  
  CONCLUSIONS
  We identified SINEs that inhibit CRM-1 and promote nuclear accumulation of tumor-suppressor proteins in pancreatic cancer cells. Oral administration of the drug to mice reduces growth of xenograft tumors.
authors.affiliation: Department of Pathology, Wayne State University, Detroit, Michigan.
authors.forename: Asfar S
authors.initials: AS
authors.lastname: Azmi
authors.affiliation: Karyopharm Therapeutics, Natick, Massachusetts.
authors.forename: Amro
authors.initials: A
authors.lastname: Aboukameel
authors.affiliation: Department of Pathology, Wayne State University, Detroit, Michigan.
authors.forename: Bin
authors.initials: B
authors.lastname: Bao
authors.affiliation: Department of Pathology, Wayne State University, Detroit, Michigan.
authors.forename: Fazlul H
authors.initials: FH
authors.lastname: Sarkar
authors.affiliation: Karyopharm Therapeutics, Natick, Massachusetts.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Philip
authors.affiliation: Department of Oncology, Karmanos Cancer Institute, Detroit, Michigan.
authors.forename: Michael
authors.initials: M
authors.lastname: Kauffman
authors.affiliation: Department of Oncology, Karmanos Cancer Institute, Detroit, Michigan.
authors.forename: Sharon
authors.initials: S
authors.lastname: Shacham
authors.affiliation: Karyopharm Therapeutics, Natick, Massachusetts. Electronic address: mohammar@karmanos.org.
authors.forename: Ramzi M
authors.initials: RM
authors.lastname: Mohammad
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000502:physiology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D047468:Immunoprecipitation; D028884:Karyopherins / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D009374:Neoplasms, Experimental; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D012334:RNA, Neoplasm / Q000235:genetics; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D000097606:Exportin 1 Protein
chemical_list: D051017:Apoptosis Regulatory Proteins; D028884:Karyopherins; D012334:RNA, Neoplasm; D018160:Receptors, Cytoplasmic and Nuclear; D000097606:Exportin 1 Protein