Down-regulation of long non-coding RNA DUXAP8 suppresses proliferation, metastasis and EMT by modulating miR-498 through TRIM44-mediated AKT/mTOR pathway in non-small-cell lung cancer

X. Ji, R. Tao, L.-Y. Sun, X.-L. Xu, W. Ling

Department of Respiratory and Critical Care Medicine, Lin Yi People’s Hospital, Lin Yi, Shandong, China. ycknpi@163.com

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• Oncology

OBJECTIVE:  The long non-coding RNA double homeobox A pseudogene 8 (DUXAP8) was reported to be involved in the initiation and development of multiple cancers. However, the detailed biological role of DUXAP8 in non-small-cell lung cancer (NSCLC) remains unclear. Herein, we aimed to explore the biological function and molecular mechanism of DUXAP8 in NSCLC.

PATIENTS AND METHODS: The levels of DUXAP8, microRNA-498 (miR-498) and tripartite motif-44 (TRIM44) were detected by Quantitative Real-time polymerase chain reaction (qRT-PCR). The cell proliferation, migration and invasion were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and transwell assays. Protein expression levels were detected by Western blot. The target relationships among DUXAP8, miR-498 and TRIM44 were predicted by starBase2.0 and confirmed using luciferase reporter and RNA pull-down assays. To detect the role of DUXAP8 in vivo, tumor xenografts were created.

RESULTS: DUXAP8 and TRIM44 were upregulated in NSCLC tissues and cell lines, while miR-498 was downregulated. Functionally, knockdown of DUXAP8 could repress proliferation, migration, invasion, Epithelial-Mesenchymal Transition (EMT) and phosphorylation of AKT/mTOR in NSCLC cells. This inhibition could be restored by inhibiting miR-498 or overexpressing TRIM44. Furthermore, we also observed a positive correlation between DUXAP8 and TRIM44 expression, while the expressions of miR-498 and DUXAP8, as well as miR-498 and TRIM44, were negatively correlated in NSCLC tissues. Importantly, DUXAP8 could regulate the expression of TRIM44 via miR-498. Moreover, knockdown of DUXAP8 notably decreased the xenograft tumor volume, weight and number of metastatic nodules in vivo.

CONCLUSIONS: Our results identified that LncRNA DUXAP8 could regulate cell proliferation, metastasis and EMT in NSCLC cells by inhibiting miR-498 through the activation of TRIM44-mediated AKT/mTOR pathway.

 

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