title: The role of Beclin 1 in SDT-induced apoptosis and autophagy in human leukemia cells.
abstract: OBJECTIVE
  To prove the occurrence of autophagy after treatment by protoporphyrin IX (PpIX)-mediated sonodynamic therapy (SDT) of human chronic myelogenous leukemia K562 cells as well as its relationship with apoptosis.
  
  
  METHODS
  The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenylter-trazolium bromide tetrazolium (MTT) assay was adopted to examine cytotoxicity of different treatments. Nuclear morphology changes were observed under a fluorescence microscopy with 4'-6-Diamidino-2-Phenylindole (DAPI) staining. Western blotting was used to analyze the expression of caspase-3, Beclin 1 (BECN 1) and the conversion of LC3- phosphatidylethanolamine conjugate/a cytosolic form of LC3 (LC3 II/I). Fluorescence microscope was used to identify the formation of autophagic vacuoles (AVO) during autophagy.
  
  
  RESULTS
  Under optimal conditions, SDT was shown to induce autophagy in K562 cells, which caused the up-regulation of Beclin-1 and the formation of AVO. In addition, pre-treatment of cancer cells with Beclin 1-targeted short hairpin RNA (Beclin 1 shRNA) was shown to reduce the level of LC3-II accumulation and staining with punctate spots of monodansylcadaverine (MDC) staining. Besides, the cytotoxic effect of SDT was significantly increased by Beclin 1 shRNA. Furthermore, studies showed a marked effect on the apoptosis of cells by Beclin 1 shRNA to sonodamage with increased DAPI staining and caspase-3 cleavage.
  
  
  CONCLUSIONS
  These results demonstrated that SDT significantly induced autophagy of K562 cells, probably to protect the K562 cells from sonodamage.
authors.affiliation: Key Laboratory of Medicinal Resources and Natural Pharmaceutical Chemistry, Ministry of Education, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University , Xi'an, Shaanxi , China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Su
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Wang
authors.forename: Quanhong
authors.initials: Q
authors.lastname: Liu
authors.forename: Pan
authors.initials: P
authors.lastname: Wang
authors.forename: Chuanshan
authors.initials: C
authors.lastname: Xu
authors.forename: Albert Wingnang
authors.initials: AW
authors.lastname: Leung
mesh_terms: D017209:Apoptosis / Q000235:genetics; D051017:Apoptosis Regulatory Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D001343:Autophagy / Q000235:genetics; D000071186:Beclin-1; D053148:Caspase 3 / Q000378:metabolism; D005456:Fluorescent Dyes; D055785:Gene Knockdown Techniques; D006801:Humans; D007211:Indoles; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011524:Protoporphyrins / Q000627:therapeutic use; D034741:RNA, Small Interfering / Q000235:genetics; D014464:Ultrasonic Therapy / Q000379:methods*; D014617:Vacuoles / Q000473:pathology
chemical_list: D051017:Apoptosis Regulatory Proteins; C491997:BECN1 protein, human; D000071186:Beclin-1; D005456:Fluorescent Dyes; D007211:Indoles; D008565:Membrane Proteins; D017319:Photosensitizing Agents; D011524:Protoporphyrins; D034741:RNA, Small Interfering; C007293:DAPI; C028025:protoporphyrin IX; C505407:CASP3 protein, human; D053148:Caspase 3
keywords: Beclin 1 shRNA; Sonodynamic therapy; apoptosis; autophagy; human leukemia K562 cells