title: Bleomycin induces endothelial mesenchymal transition through activation of mTOR pathway: a possible mechanism contributing to the sclerotherapy of venous malformations.
abstract: OBJECTIVE
  Bleomycin (BLM), one of the most common sclerosants, is often used to treat venous malformations (VMs). The present study was designed to investigate whether endothelial mesenchymal transition (EndoMT) contributes to the therapeutic effects of BLM.
  
  
  METHODS
  Endothelial and mesenchymal markers of HUVECs were measured by immunofluorescence, real-time quantitative PCR and Western blot analysis. Cell migration and tube formation assays were performed to evaluate endothelial cell function. Slug small-interfering RNA and specific inhibitors [Z-VAD-FMK for pan caspases, rapamycin for mammalian target of rapamycin (mTOR)] were used to investigate the mechanism.
  
  
  RESULTS
  Long term (48 h or longer) treatment with BLM (0.1 mU·mL(-1) ) induced EndoMT in HUVECs, as manifested by a reduction in the expression of vascular endothelial-cadherin and an up-regulation in the expression of α-smooth muscle actin and fibroblast specific protein-1, as well as activation of the transcription factor Slug. The size and protein content of the transformed cells were increased. BLM also enhanced the migration of HUVECs but diminished their tube formation. By employing rapamycin, we demonstrated that activation of the mTOR pathway is involved in BLM-induced EndoMT in HUVECs.
  
  
  CONCLUSIONS
  Our results show that a Slug-dependent EndoMT process is involved in BLM-induced therapeutic effects on endothelial cells and, more importantly, indicate the potential role of this process in the sclerotherapy of VMs.
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China; Department of Oral & Maxillofacial - Head & Neck Oncology, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Jian-Gang
authors.initials: JG
authors.lastname: Ren
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Zhao
mesh_terms: D001761:Bleomycin / Q000494:pharmacology* / Q000627:therapeutic use; D002465:Cell Movement / Q000187:drug effects; D054338:Cell Transdifferentiation / Q000187:drug effects*; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012597:Sclerosing Solutions / Q000494:pharmacology* / Q000627:therapeutic use; D015911:Sclerotherapy; D020123:Sirolimus / Q000494:pharmacology; D000071250:Snail Family Transcription Factors; D058570:TOR Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014652:Vascular Diseases / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D014680:Veins / Q000473:pathology
chemical_list: C000604407:SNAI1 protein, human; D012597:Sclerosing Solutions; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D001761:Bleomycin; C546842:MTOR protein, human; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus
keywords: Slug; bleomycin; endothelial mesenchymal transition; mTOR; venous malformation