NRAGE promotes cell proliferation by stabilizing PCNA in a ubiquitin-proteasome pathway in esophageal carcinomas.
Neurotrophin receptor-interacting melanoma antigen-encoding gene homolog (NRAGE) is generally recognized as a tumor suppressor as it induces cell apoptosis and suppresses cell metastasis. However, it has recently been reported that NRAGE is overexpressed in lung cancer, melanoma and colon cancer, implicating a complicated role of NRAGE as we have expected. In the study, we aim to elucidate the functional roles and molecular mechanisms of NRAGE in esophageal carcinoma. We found that both NRAGE mRNA and protein were significantly overexpressed in esophageal tumor tissues. Consistently, both in vivo and in vitro analyses demonstrated that knockdown of NRAGE apparently inhibited cell growth, and cell cycle analysis further demonstrated that NRAGE knockdown cells were mainly arrested in G2M cell phase, accompanied with an apparent reduction of S phase. In the process of exploring molecular mechanisms, we found that either knockdown in vitro or knockout in vivo of NRAGE reduced proliferating cell nuclear antigen (PCNA) protein, expression of which could completely rescue the inhibited proliferation in NRAGE defective cells. Furthermore, NRAGE physically interacted with PCNA in esophageal cancer cells through DNA polymerase III subunit, and knockdown of NRAGE facilitated PCNA K48-linked polyubiquitination, leading PCNA to the proteasome-dependent degradation and a ubiquitin-specific protease USP10 was identified to be a key regulator in the process of K48 polyubiquitination in NRAGE-deleted cells. In conclusion, our study highlights a unique role of NRAGE and implies that NRAGE is likely to be an attractive oncotarget in developing novel genetic anticancer therapeutic strategies for esophageal squamous cell carcinomas.
Department of Clinical Laboratory Medicine, Tenth People's Hospital of Tongji University, Shanghai 200072, China, Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China, Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and The Central Laboratory, Tenth People's Hospital of Tongji University, Shanghai 200072, China.
Qingyuan
Q
Yang
Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China.
Chao
C
Ou
Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and.
Mei
M
Liu
The Central Laboratory, Tenth People's Hospital of Tongji University, Shanghai 200072, China.
Weifan
W
Xiao
Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and.
Chuanjun
C
Wen
Department of Clinical Laboratory Medicine, Tenth People's Hospital of Tongji University, Shanghai 200072, China, Department of Clinical Laboratory, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning 530021, China, Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, Nanjing 210023, China and The Central Laboratory, Tenth People's Hospital of Tongji University, Shanghai 200072, China Laboratorypan@yahoo.com.cn.
Fenyong
F
Sun
D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D015331:Cohort Studies; D004938:Esophageal Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D004947:Esophagus / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D008207:Lymphatic Metastasis; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D009367:Neoplasm Staging; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D059748:Proteolysis; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D046888:Tissue Array Analysis; D014407:Tumor Cells, Cultured; D043222:Ubiquitin Thiolesterase / Q000235:genetics / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
D000951:Antigens, Neoplasm; C120897:MAGED1 protein, human; D009363:Neoplasm Proteins; D018809:Proliferating Cell Nuclear Antigen; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C431363:USP10 protein, human; D014452:Ubiquitins; D043222:Ubiquitin Thiolesterase; D046988:Proteasome Endopeptidase Complex