title: Apoptosis of breast cancer cells induced by hypocrellin B under light-emitting diode irradiation.
abstract: OBJECTIVE
  Breast cancer is a common disease which threatens the life of women. To explore an alternative modality for combating breast cancer, a light-emitting diode (LED) that activates hypocrellin B was used in the present study to investigate apoptosis induction in breast cancer MDA-MB-231 cells.
  
  
  METHODS
  Photocytotoxicity was investigated 24h after photodynamic treatment of hypocrellin B using MTT reduction assay and light microscopy. Apoptosis was observed 6h after photodynamic treatment using flow cytometry with Annexin V/PI staining as well as fluorescent microscopy with Hoechst33258 staining. The ultrastructure of the treated cells was observed using transmission electron microscopy (TEM).
  
  
  RESULTS
  Hypocrellin B-induced photocytotoxicity in MDA-MB-231 cells exhibited a dose-dependent manner. The amount of MDA-MB-231 cells attached to the bottom of well decreased significantly after photodynamic treatment of hypocrellin B. Flow cytometry showed that the early and late apoptotic rate of MDA-MB-231 cells increased remarkably up to 17.46% and 32.80%, respectively, after treatment of LED-activated hypocrellin B. In addition, nuclear condensation, fragmentation and chromatin margination, and topical apoptotic body in the treated cells were observed by nuclear staining and TEM.
  
  
  CONCLUSIONS
  Photodynamic action of hypocrellin B irradiated by light-emitting diodes could significantly kill breast cancer cells and induce apoptotic cell death, which suggests LED-activated hypocrellin B is a promising strategy for combating breast cancer.
authors.affiliation: Department of Photodynamic and Sonodynamic Therapy, Second Affiliated Hospital, Chongqing Medical University, Chongqing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Xinshu
authors.initials: X
authors.lastname: Xia
authors.forename: Albert Wingnang
authors.initials: AW
authors.lastname: Leung
authors.forename: Junyan
authors.initials: J
authors.lastname: Xiang
authors.forename: Chuanshan
authors.initials: C
authors.lastname: Xu
mesh_terms: D017209:Apoptosis / Q000528:radiation effects*; D001943:Breast Neoplasms / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D028022:Low-Level Light Therapy / Q000379:methods*; D010569:Perylene / Q000031:analogs & derivatives* / Q000494:pharmacology; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011809:Quinones / Q000494:pharmacology*
chemical_list: D017319:Photosensitizing Agents; D011809:Quinones; D010569:Perylene; C064522:hypocrellin B