title: Time course of apoptosis induced by photodynamic therapy with PsD007 in LT12 acute myeloid leukemia cells.
abstract: Apoptosis is one of the major mechanisms of photodynamic therapy (PDT) that leads to tumor degradation. Apoptosis-related genes and proteins function in a certain order and timing in the complex network of apoptosis. To further understanding of the apoptotic mechanism of PDT, this research examined the time course of apoptosis from PsD007 (a second-generation photosensitizer developed in China) induced PDT on the rat acute myeloid leukemia cell line LT12. MTT was used to detect the temporal dynamic of PDT killing effects and identified the "apoptotic window" of 2-24 h. Apoptosis showed a basal peak at 2 h, and the duration of apoptosis depended on PDT dose, which disappeared quickly at low concentrations but lasted to higher levels to 6 or 12 h at high concentrations as detected by flow cytometry. High-content imaging confirmed these results. An 84-gene apoptosis PCR array identified 15 genes with an expression level change of over twofold at 6 h post-PDT. Nine apoptosis-related genes showed changes in expression at 2-12 h after PDT. TNF family genes TNF and FASLG showed a maximal change of 3.47- and 4.42-fold from baseline. Key apoptosis proteins such as activated caspases showed strong up-regulation after PDT, with the expression peaks of cleaved caspase-7, caspase-9 and PARP at 4-6 h, and cleaved caspase-3 delayed to 6-12 h. Our findings help clarify the time course of apoptosis events in response to PDT treatment in a leukemia cell line and may help contribute to the clinical application of PDT in leukemia treatment.
authors: Laboratory of Laser Medicine, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences, Tianjin, 300192, China.
authors: Huijuan
authors: H
authors: Yin
authors: Cardiovascular Department, Tianjin First Central Hospital, Tianjin, 300192, China.
authors: Xuying
authors: X
authors: Ye
authors: Laboratory of Laser Medicine, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences, Tianjin, 300192, China.
authors: Qing
authors: Q
authors: Niu
authors: Biomedical Engineering College, Tianjin Medical University, Tianjin, 300070, China.
authors: Chao
authors: C
authors: Wang
authors: Laboratory of Laser Medicine, Institute of Biomedical Engineering, Chinese Academy of Medical Sciences, Tianjin, 300192, China. yingxinli2005@126.com.
authors: Yingxin
authors: Y
authors: Li
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D015870:Gene Expression / Q000187:drug effects; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy*; D010778:Photochemotherapy / Q000295:instrumentation / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D051381:Rats; D015854:Up-Regulation
chemical_list: D017319:Photosensitizing Agents; D053148:Caspase 3
keywords: Acute myeloid leukemia; Apoptosis; Caspases; Photodynamic therapy; Temporal dynamic