title: Aloe-emodin-mediated photodynamic therapy induces autophagy and apoptosis in human osteosarcoma cell line MG‑63 through the ROS/JNK signaling pathway.
abstract: The present study was carried out to investigate the effect and mechanisms of aloe‑emodin (AE)-mediated photodynamic therapy (AE-PDT) on the human osteosarcoma cell line MG-63. After treatment with AE-PDT, the human osteosarcoma cell line MG-63 was tested for levels of viability, autophagy, reactive oxygen species (ROS) and apoptosis and changes in cell morphology with the Cell Counting Kit-8 (CCK‑8), monodansylcadaverine (MDC) and Hoechst staining and transmission electron microscopy. The expression of proteins including LC-3, cleaved caspase-3, Beclin-1, Bcl-2, p-JNK, t-JNK and β-actin was examined with western blotting. AE-PDT significantly inhibited the viability of the MG-63 cells in an AE-concentration- and PDT energy density-dependent manner. Autophagy and apoptosis of MG-63 cells was substantially promoted in the AE-PDT group compared to the control group, the AE alone group and the light emitting diode (LED) alone group. Inhibition of autophagy by 3-methyladenine (3-MA) (5 mM) and chloroquine (CQ) (15 µM) significantly promoted the apoptosis rate and improved the sensitivity of the MG-63 cells to AE-PDT. AE-PDT was found to induce the expression of ROS and p-JNK. ROS scavenger, N-acetyl-L-cysteine (NAC, 5 mM), was able to hinder the autophagy, apoptosis and phosphorylation of JNK, and JNK inhibitor (SP600125, 10 µM) significantly inhibited the autophagy and apoptosis, and attenuated the sensitivity of MG63 cells to AE-PDT. In conclusion, AE-PDT induced the autophagy and apoptosis of human osteosarcoma cell line MG-63 through the activation of the ROS-JNK signaling pathway. Autophagy may play a protective role during the early stage following treatment of AE-PDT.
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China.
authors.forename: Pinghua
authors.initials: P
authors.lastname: Tu
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China.
authors.forename: Qiu
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China.
authors.forename: Yunsheng
authors.initials: Y
authors.lastname: Ou
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China.
authors.forename: Xing
authors.initials: X
authors.lastname: Du
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China.
authors.forename: Kaiting
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tao
authors.affiliation: Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China.
authors.forename: Hang
authors.initials: H
authors.lastname: Yin
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000873:Anthracenes / Q000494:pharmacology; D000880:Anthraquinones / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects*; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System; D012516:Osteosarcoma / Q000188:drug therapy* / Q000473:pathology; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000873:Anthracenes; D000880:Anthraquinones; D051017:Apoptosis Regulatory Proteins; D017319:Photosensitizing Agents; D017382:Reactive Oxygen Species; C432165:pyrazolanthrone; C518327:aloe emodin; D048031:JNK Mitogen-Activated Protein Kinases; D000111:Acetylcysteine