Tristetraprolin inhibits autophagy in cultured lung cancer cells the nuclear factor-κB pathway.
10.12122/j.issn.1673-4254.2019.03.09
- Author:
Xiaoya DENG
1
;
Qinli LUO
1
;
Fei DONG
1
;
Li XU
1
;
Xiaokui TANG
1
Author Information
1. Department of Respiratory and Critical Care Medicine, First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
- Publication Type:Journal Article
- Keywords:
Beclin1;
autophagy;
nuclear factor-κB;
tristetraprolin
- MeSH:
Autophagy;
Cell Line;
Humans;
Lung Neoplasms;
NF-kappa B;
Signal Transduction;
Tristetraprolin
- From:
Journal of Southern Medical University
2019;39(3):313-319
- CountryChina
- Language:Chinese
-
Abstract:
OBJECTIVE:To explore the expression of the RNA-binding protein tristetraprolin in lung adenocarcinoma cells and its molecular mechanism for inhibiting autophagy.
METHODS:Quantitative real-time PCR and Western blotting were performed to detect the expression of autophagy-related genes (including Beclin1, LC3-Ⅱ/LC3-Ⅰ and SQSTM1/p62) in cultured lung adenocarcinoma cells at 24, 48 and 72 h after transient transfection with a tristetraprolin-overexpressing plasmid and the empty plasmid. The effects of transfection with the tristetraprolin-overexpressing plasmid and empty plasmids in the presence or absence of tumor necrosis factor- (TNF-) on the expressions of nuclear factor-κB (NF-κB) p65, c-rel, and p50 were examined in lung adenocarcinoma cells using immunofluorescence assay and Western blotting. The cells were also transfected with the IκBα-mut plasmid and the tristetraprolin-overexpressing plasmid, either alone or in combination, and the changes in the expressions of tristetraprolin and autophagy-related genes were detected using RT-qPCR and Western blotting.
RESULTS:The expressions of tristetraprolin were significantly reduced at both the mRNA and protein levels in lung adenocarcinoma cells ( < 0.001). Overexpression of tristetraprolin in the cells significantly lowered the expressions of autophagy-related genes Beclin1 and the ratio of LC3-Ⅱ/LC3-Ⅰ at the mRNA and protein levels ( < 0.001), obviously lowered the expressions of NF-κB p65 and c-rel, and almost totally blocked the nuclear translocation of NF-κB p65 and c-rel ( < 0.05); the expression of p50, however, did not undergo significant changes in response to tristetraprolin overexpression ( > 0.05). The inhibitory effect of tristetraprolin overexpression on autophagy was abrogated by transfection of the cells with IκBα-mut plasmid, which blocked the NF-κB signaling pathway. Co-transfection of the cells with IκBα-mut also attenuated the inhibitory effect of tristetraprolin overexpression on Beclin1 and the LC3-Ⅱ/LC3-Ⅰ ratio at both the mRNA and protein levels ( < 0.05).
CONCLUSIONS:The expression of tristetraprolin is low in lung adenocarcinoma cells. Tristetraprolin overexpression causes inhibition of autophagy in lung adenocarcinoma cells possibly by blocking NF-κB p65 and c-rel nuclear translocation.
