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Hyperactive mTOR induces neuroendocrine differentiation in prostate cancer cell with concurrent up‐regulation of IRF1
Author(s) -
Kanayama Mayuko,
Hayano Toshiya,
Koebis Michinori,
Maeda Tatsuya,
Tabe Yoko,
Horie Shigeo,
Aiba Atsu
Publication year - 2017
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.23425
Subject(s) - lncap , pi3k/akt/mtor pathway , irf1 , cancer research , prostate cancer , biology , mechanistic target of rapamycin , cell growth , rptor , transcription factor , medicine , microbiology and biotechnology , cancer , signal transduction , gene , genetics
Background Neuroendocrine‐differentiated prostate cancer (NEPCa) is refractory to androgen deprivation therapy and shows a poor prognosis. The underlying mechanisms responsible for neuroendocrine differentiation (NED) are yet to be clarified. In this study, we investigated the role of mammalian target of rapamycin (mTOR) in NEPCa. Methods We utilized a gain‐of‐function analysis by establishing a human PCa LNCaP stable line that expresses hyperactive mTOR (LNCaP‐mTOR). Then, we employed a comprehensive mass spectrometric analysis to identify a key transcription factor in LNCaP‐mTOR, followed by a loss‐of‐function analysis using CRISPR/Cas system. Results The activation of mTOR induced NED. We observed significant cell growth arrest in NED of LNCaP‐mTOR, which accompanied increased expression of p21 WAF1/CIP1 . A comprehensive mass spectrometric analysis identified interferon regulatory factor 1 (IRF1) as a key transcription factor in growth arrest of LNCaP‐mTOR. The disruption of IRF1 gene in LNCaP‐mTOR reversed cell growth arrest along with the suppression of its target p21 WAF1/CIP1 . These results indicate that the growth arrest in NED is at least in part dependent on IRF1 through the induction of p21 WAF1/CIP1 . Conclusions We identified active mTOR as a novel inducer of NED, and elucidated a mechanism underlying the malignant transformation of NEPCa by recapitulating NED in vitro.