title: Targeting eukaryotic translation in mesothelioma cells with an eIF4E-specific antisense oligonucleotide.
abstract: BACKGROUND
  Aberrant cap-dependent translation is implicated in tumorigenesis in multiple tumor types including mesothelioma. In this study, disabling the eIF4F complex by targeting eIF4E with eIF4E-specific antisense oligonucleotide (4EASO) is assessed as a therapy for mesothelioma.
  
  
  METHODS
  Mesothelioma cells were transfected with 4EASO, designed to target eIF4E mRNA, or mismatch-ASO control. Cell survival was measured in mesothelioma treated with 4EASO alone or combined with either gemcitabine or pemetrexed. Levels of eIF4E, ODC, Bcl-2 and β-actin were assessed following treatment. Binding to a synthetic cap-analogue was used to study the strength of eIF4F complex activation following treatment.
  
  
  RESULTS
  eIF4E level and the formation of eIF4F cap-complex decreased in response to 4EASO, but not mismatch control ASO, resulting in cleavage of PARP indicating apoptosis. 4EASO treatment resulted in dose dependent decrease in eIF4E levels, which corresponded to cytotoxicity of mesothelioma cells. 4EASO resulted in decreased levels of eIF4E in non-malignant LP9 cells, but this did not correspond to increased cytotoxicity. Proteins thought to be regulated by cap-dependent translation, Bcl-2 and ODC, were decreased upon treatment with 4EASO. Combination therapy of 4EASO with pemetrexed or gemcitabine further reduced cell number.
  
  
  CONCLUSIONS
  4EASO is a novel drug that causes apoptosis and selectively reduces eIF4E levels, eIF4F complex formation, and proliferation of mesothelioma cells. eIF4E knockdown results in decreased expression of anti-apoptotic and pro-growth proteins and enhances chemosensitivity.
authors.affiliation: Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America.
authors.forename: Blake A
authors.initials: BA
authors.lastname: Jacobson
authors.forename: Saritha C
authors.initials: SC
authors.lastname: Thumma
authors.forename: Joseph
authors.initials: J
authors.lastname: Jay-Dixon
authors.forename: Manish R
authors.initials: MR
authors.lastname: Patel
authors.forename: K
authors.initials: K
authors.lastname: Dubear Kroening
authors.forename: Marian G
authors.initials: MG
authors.lastname: Kratzke
authors.forename: Ryan G
authors.initials: RG
authors.lastname: Etchison
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Konicek
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Graff
authors.forename: Robert A
authors.initials: RA
authors.lastname: Kratzke
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D002452:Cell Count; D045744:Cell Line, Tumor; D003841:Deoxycytidine / Q000031:analogs & derivatives / Q000494:pharmacology; D039561:Eukaryotic Initiation Factor-4E / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D039562:Eukaryotic Initiation Factor-4F / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005971:Glutamates / Q000494:pharmacology; D006147:Guanine / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D008654:Mesothelioma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D058990:Molecular Targeted Therapy; D016376:Oligonucleotides, Antisense / Q000235:genetics* / Q000378:metabolism; D009955:Ornithine Decarboxylase / Q000235:genetics / Q000378:metabolism; D000068437:Pemetrexed; D011065:Poly(ADP-ribose) Polymerases / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D014176:Protein Biosynthesis / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D000093542:Gemcitabine
chemical_list: D000199:Actins; D000970:Antineoplastic Agents; D039561:Eukaryotic Initiation Factor-4E; D039562:Eukaryotic Initiation Factor-4F; D005971:Glutamates; D016376:Oligonucleotides, Antisense; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D000068437:Pemetrexed; D003841:Deoxycytidine; D006147:Guanine; D011065:Poly(ADP-ribose) Polymerases; D009955:Ornithine Decarboxylase; D000093542:Gemcitabine