title: Measuring dynamics of caspase-3 activity in living cells using FRET technique during apoptosis induced by high fluence low-power laser irradiation.
abstract: OBJECTIVE
  Low-power laser irradiation (LPLI) has been used for therapies such as curing spinal cord injury, healing wound etc. Yet, the mechanism of LPLI remains unclear. In order to determine the effects of high fluence LPLI on cell growth and caspase-3 activity, we have measured the dynamics of caspase-3 activity during cell apoptosis induced by high fluence LPLI treatment.
  
  
  METHODS
  He-Ne laser was used to irradiate human lung adenocarcinoma cells (ASTC-a-1). Cell Counting Kit-8 was used for cytotoxicity assay. A fluorescent microscope was used to perform fluorescence resonance energy transfer (FRET) imaging. A luminescence spectrometer was used to acquire the fluorescent emission spectrum. Statistical analysis was performed with Student's paired t-test.
  
  
  RESULTS
  Cytotoxicity assay showed that when light irradiation fluence exceeded 60 J/cm2, LPLI treatment induced ASTC-a-1 cell apoptosis in a fluence-dependent manner. FRET imaging and spectrofluorometric analysis demonstrated that caspase-3 was activated during high fluence LPLI-induced cell apoptosis.
  
  
  CONCLUSIONS
  Using FRET technique, we have reported that high fluence LPLI can induce human lung adenocarcinoma cells (ASTC-a-1) apoptosis. The activation of caspase-3 plays an important role in the apoptotic process.
authors.affiliation: Institute of Laser Life Science, South China Normal University, Guangzhou 510631, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Tong-Sheng
authors.initials: TS
authors.lastname: Chen
authors.forename: Da
authors.initials: D
authors.lastname: Xing
authors.forename: Jin-Jun
authors.initials: JJ
authors.lastname: Wang
authors.forename: Yun-Xia
authors.initials: YX
authors.lastname: Wu
mesh_terms: D000230:Adenocarcinoma; D017209:Apoptosis / Q000502:physiology* / Q000528:radiation effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism* / Q000528:radiation effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000502:physiology / Q000528:radiation effects; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D028022:Low-Level Light Therapy; D008175:Lung Neoplasms
chemical_list: C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases