The switch from ER stress-induced apoptosis to autophagy via ROS-mediated JNK/p62 signals: A survival mechanism in methotrexate-resistant choriocarcinoma cells.
BACKGROUND
Human choriocarcinoma, a highly curable solid tumour, is exceptionally sensitive to methotrexate-based chemotherapy at the metastatic stage. The present study aimed to investigate the molecular basis for this resistance to methotrexate therapy occurs in some cases, and these patients subsequently die from progressive and advanced disease.


METHODS
The autophagy and apoptotic activity regulated by PERK/ATF4 axis in methotrexate-resistant JEG-3 and parental cells were evaluated with western blotting and chromatin immunoprecipitation (ChIP). The regulatory relationships among the reactive oxygen species (ROS), JNK/p62 axis, PERK/ATF4-mediated apoptosis and autophagy were assessed with western blotting, RT-PCR, fluorescence-activated cell sorting as well as ChIP.


RESULTS
The decreased apoptosis in methotrexate-resistant JEG-3 cells was observed with an up-regulation of protective autophagy, suggesting a switch from apoptosis to autophagy, which was regulated via the PERK/ATF4 pathway under condition of endoplasmic reticulum (ER) stress. Further experiments demonstrated that this cell death switch was regulated by ROS-mediated JNK/p62 pathway and subsequently lead to the resistance of choriocarcinoma cells to methotrexate treatment.


CONCLUSIONS
This study provides evidence to explain a survival mechanism of the switch from ER stress-induced apoptosis to autophagy via ROS-mediated JNK/p62 signals in methotrexate-resistant choriocarcinoma cells and may implicate the chemotherapy of methotrexate resistance in choriocarcinoma.
Technical Service Centre of Family Planning and Reproductive Health, National Research Institute for Family Planning, Beijing 100081, People׳s Republic of China.
Yun
Y
Shen
Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, People׳s Republic of China.
Junjun
J
Yang
Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, People׳s Republic of China.
Jing
J
Zhao
Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, People׳s Republic of China.
Changji
C
Xiao
National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100005, People׳s Republic of China. Electronic address: cmxu@ibms.pumc.edu.cn.
Caimin
C
Xu
Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, People׳s Republic of China. Electronic address: xiangy@pumch.cn.
Yang
Y
Xiang
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002822:Choriocarcinoma / Q000378:metabolism / Q000473:pathology*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008727:Methotrexate / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000071456:Sequestosome-1 Protein; D015398:Signal Transduction / Q000187:drug effects; D013329:Structure-Activity Relationship
D048868:Adaptor Proteins, Signal Transducing; D017382:Reactive Oxygen Species; C099718:SQSTM1 protein, human; D000071456:Sequestosome-1 Protein; D048031:JNK Mitogen-Activated Protein Kinases; D008727:Methotrexate
Apoptosis; Autophagy; Choriocarcinoma; Drug resistance; Endoplasmic reticulum; Methotrexate