RESUMO
BACKGROUND:Combination of biological and optical technique is used to study the molecular mechanism of cell proliferation and apoptosis, which has become the study hotspot in the filed of bioengineering.OBJECTIVE: The goal of this study was to study the molecular mechanism of XAP-induced apoptosis in single living human lung adenocarcinoma (ASTC-a-1) cells by using confocal fluorescence microscopy imaging and fluorescence resonance energy transfer (FRET) techniques.DESIGN: A controlled observation.SETTING: Institute of Laser Life Science (Key Laboratory of Education Department), South China Normal University.MARERIALS: This experiment was carried out in the Institute of Laser Life Science (Key Laboratory of Education Ministry), South China Normal University between October 2006 and March 2007. Human lung adenocarcinoma (ASTC-a-1) cells were cultured in our laboratory. Xiaoaiping (XAP) parenteral solution was purchased from Tonghua Shenyuan Pharmaceutical Co.,Ltd (No. Z20025869), and G418 was purchased from Huamei Biological Company. SCAT3 was provided by Professor Masayuki Miura. Auto microplate reader (infinite M200, Tecan,Austria)and mitochondrial location fluorescent probe (Mitertracker Red)was purchased from Molecular Probe Company.METHODS: ① The inhibition of XAP at different doses to ASTC-a-1 cell viability was detected by CCK-8. ② Dynamical change of caspase 3-induced by XAP was detected by confocal fluorescence microscopy imaging and fluorescence resonance energy transfer (FRET) techniques. ③The fluorescence emission spectrum of SCAT3 was detected by confocal fluorescence microscopy imaging at different time points after XAP treatment.MAIN OUTCOME MEASURES: ①Cell viability after XAP treatment. ② Dynamic change of fluorescence resonance energy transfer efficiency of SCAT3 detected after XAP treatment. ③ Dynamical change of mitochondrial morphology after XAP treatment.RESULTS: ①XAP inhibited the viability of tumor cells dose-dependently. ② XAP induced the activation of intracellular caspase 3. ③Some mitochondria became dot, and some were cracked after XAP treatment.CONCLUSION: XAP can induce the apoptosis of ASTC-a-1, and caspase 3 is involved in the regulation course.