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Long noncoding RNA growth arrest‐specific 5 facilitates glioma cell sensitivity to cisplatin by suppressing excessive autophagy in an mTOR‐dependent manner
Author(s) -
Huo JunFeng,
Chen XiaoBing
Publication year - 2019
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.27900
Subject(s) - autophagy , gas5 , cisplatin , pi3k/akt/mtor pathway , gene knockdown , glioma , cancer research , cell growth , apoptosis , biology , long non coding rna , chemistry , microbiology and biotechnology , downregulation and upregulation , signal transduction , chemotherapy , biochemistry , genetics , gene
Malignant glioma is a severe type of brain tumor with a grim prognosis. The occurrence of resistance compromises the efficacy of chemotherapy for glioma. Long noncoding RNA growth arrest‐specific 5 (GAS5) has recently become an attractive target for cancer therapy by regulating cell growth, invasion, and migration. Nevertheless, its role in glioma chemoresistance remains elusive. In the current study, the expression of GAS5 was decreased in glioma cell lines, and lower levels of GAS5 were observed in U138 and LN18 glioma cells that had low sensitivity to cisplatin. Functional assay confirmed that knockdown of GAS5 enhanced cell resistance to cisplatin in U87 cells, which had a relatively high expression of GAS5. Conversely, elevation of GAS5 increased cell sensitivity to cisplatin in U138 cells that had a relatively low expression of GAS5. Mechanistically, cisplatin exposure evoked excessive autophagy concomitant with an increase in autophagy‐related LC3II expression and a decrease in autophagy substrate p62 expression, which was reversely muted after GAS5 overexpression. In addition, GAS5 restored cisplatin‐inhibited mammalian target of rapamycin (mTOR) activation. Preconditioning with mTOR antagonist rapamycin engendered not only mTOR inhibition but also abrogated GAS5‐mediated depression in cisplatin‐evoked autophagy. Notably, blocking the mTOR pathway also attenuated GAS5‐increased sensitivity to cisplatin in U138 cells. Cumulatively, these findings indicate that GAS5 may blunt the resistance of glioma cells to cisplatin by suppressing excessive autophagy through the activation of mTOR signaling, implying a promising therapeutic strategy against chemoresistance in glioma.