ERK inhibitor U0126 enhanced SDT-induced cytotoxicity of human leukemia U937 cells.
This study was to investigate the cell killing effect of chlorin-e6 (Ce6) mediated sonodynamic therapy (SDT) on human leukemia U937 cells and explore the role of ERK signal pathway in the process. The ultrastructure changes of U937 cells induced by ultrasonic irradiation were evaluated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The viability of cells was evaluated by viacount assay. Apoptosis was analyzed using ﬂow cytometer as well as ﬂuorescence microscopy with 4'-6-diamidino-2-phenylindole (DAPI) staining. Western blotting was used to analyze the expression of mitogen-activated protein kinase (MAPK). Intracellular reactive oxygen species (ROS) and mitochondria membrane potential (MMP) levels were also analyzed by ﬂow cytometer after exposure. Our experiments showed that several distinct sonochemical effects were found after Ce6-mediated SDT treatment. Western blotting analysis indicated that the MAPK were activated. Especially, pre-treatment with ERK inhibitor U0126 could additionally enhance SDT-induced cell viability loss, early- and late-apoptotic rate, chromatin condensation, DNA fragmentation and caspase-3 activation. Besides, a mass of ROS accumulation and a conspicuous loss of mitochondrial membrane potential were detected in U937 cells. These ﬁndings suggested ERK signal pathway may deliver a survival signal which counteracts SDT-induced cell death, while combination with U0126 could significantly potentiate the SDT-induced cytotoxic effect in U937 cells.
College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, China. wangpan@snnu.edu.cn.
Xiaomin
X
Su
Xiaobing
X
Wang
Kun
K
Zhang
Shuang
S
Yang
Qin
Q
Xue
Pan
P
Wang
Quanhong
Q
Liu
D017209:Apoptosis; D002070:Butadienes / Q000008:administration & dosage*; D053148:Caspase 3 / Q000378:metabolism; D002470:Cell Survival; D002735:Chlorophyllides; D002843:Chromatin / Q000737:chemistry; D053938:DNA Fragmentation; D004354:Drug Screening Assays, Antitumor; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008564:Membrane Potentials; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009570:Nitriles / Q000008:administration & dosage*; D011166:Porphyrins / Q000008:administration & dosage*; D011838:Radiation-Sensitizing Agents / Q000008:administration & dosage; D017382:Reactive Oxygen Species; D020298:U937 Cells; D014465:Ultrasonics
D002070:Butadienes; D002735:Chlorophyllides; D002843:Chromatin; D004791:Enzyme Inhibitors; D009570:Nitriles; D011166:Porphyrins; D011838:Radiation-Sensitizing Agents; D017382:Reactive Oxygen Species; C113580:U 0126; C062985:phytochlorin; D048049:Extracellular Signal-Regulated MAP Kinases; C505407:CASP3 protein, human; D053148:Caspase 3