title: In vitro inhibition of breast cancer spheroid-induced lymphendothelial defects resembling intravasation into the lymphatic vasculature by acetohexamide, isoxsuprine, nifedipin and proadifen.
abstract: BACKGROUND
  As metastasis is the prime cause of death from malignancies, there is vibrant interest to discover options for the management of the different mechanistic steps of tumour spreading. Some approved pharmaceuticals exhibit activities against diseases they have not been developed for. In order to discover such activities that might attenuate lymph node metastasis, we investigated 225 drugs, which are approved by the US Food and Drug Administration.
  
  
  METHODS
  A three-dimensional cell co-culture assay was utilised measuring tumour cell-induced disintegrations of the lymphendothelial wall through which tumour emboli can intravasate as a limiting step in lymph node metastasis of ductal breast cancer. The disintegrated areas in the lymphendothelial cell (LEC) monolayers were induced by 12(S)-HETE, which is secreted by MCF-7 tumour cell spheroids, and are called 'circular chemorepellent induced defects' (CCIDs). The putative mechanisms by which active drugs prevented the formation of entry gates were investigated by western blotting, NF-κB activity assay and by the determination of 12(S)-HETE synthesis.
  
  
  RESULTS
  Acetohexamide, nifedipin, isoxsuprine and proadifen dose dependently inhibited the formation of CCIDs in LEC monolayers and inhibited markers of epithelial-to-mesenchymal-transition and migration. The migration of LECs is a prerequisite of CCID formation, and these drugs either repressed paxillin levels or the activities of myosin light chain 2, or myosin-binding subunit of myosin phosphatase. Isoxsuprine inhibited all three migration markers, and isoxsuprine and acetohexamide suppressed the synthesis of 12(S)-HETE, whereas proadifen and nifedipin inhibited NF-κB activation. Both the signalling pathways independently cause CCID formation.
  
  
  CONCLUSIONS
  The targeting of different mechanisms was most likely the reason for synergistic effects of different drug combinations on the inhibition of CCID formation. Furthermore, the treatment with drug combinations allowed also a several-fold reduction in drug concentrations. These results encourage further screening of approved drugs and their in vivo testing.
authors.affiliation: Institute of Clinical Pathology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.
authors.forename: N
authors.initials: N
authors.lastname: Kretschy
authors.forename: M
authors.initials: M
authors.lastname: Teichmann
authors.forename: S
authors.initials: S
authors.lastname: Kopf
authors.forename: A G
authors.initials: AG
authors.lastname: Atanasov
authors.forename: P
authors.initials: P
authors.lastname: Saiko
authors.forename: C
authors.initials: C
authors.lastname: Vonach
authors.forename: K
authors.initials: K
authors.lastname: Viola
authors.forename: B
authors.initials: B
authors.lastname: Giessrigl
authors.forename: N
authors.initials: N
authors.lastname: Huttary
authors.forename: I
authors.initials: I
authors.lastname: Raab
authors.forename: S
authors.initials: S
authors.lastname: Krieger
authors.forename: W
authors.initials: W
authors.lastname: Jäger
authors.forename: T
authors.initials: T
authors.lastname: Szekeres
authors.forename: S M
authors.initials: SM
authors.lastname: Nijman
authors.forename: W
authors.initials: W
authors.lastname: Mikulits
authors.forename: V M
authors.initials: VM
authors.lastname: Dirsch
authors.forename: H
authors.initials: H
authors.lastname: Dolznig
authors.forename: M
authors.initials: M
authors.lastname: Grusch
authors.forename: G
authors.initials: G
authors.lastname: Krupitza
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000378:metabolism; D000092:Acetohexamide / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002448:Cell Adhesion / Q000187:drug effects; D002465:Cell Movement; D002633:Chemotaxis / Q000187:drug effects; D018920:Coculture Techniques; D004357:Drug Synergism; D004729:Endothelium, Lymphatic / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007556:Isoxsuprine / Q000494:pharmacology*; D008207:Lymphatic Metastasis; D042601:Lymphatic Vessels / Q000098:blood supply / Q000187:drug effects* / Q000473:pathology; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology*; D011335:Proadifen / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D018874:Spheroids, Cellular / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D007004:Hypoglycemic Agents; D016328:NF-kappa B; D012333:RNA, Messenger; D014665:Vasodilator Agents; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D011335:Proadifen; D009543:Nifedipine; D000092:Acetohexamide; D007556:Isoxsuprine