LncRNA FOXD3-AS1 promoted chemo-resistance of NSCLC cells via directly acting on miR-127-3p/MDM2 axis

Zhaolong Zeng; Guofang Zhao; Huangkai Zhu; Liangqin Nie; Lifeng He; Jiangtao Liu; Rui Li; Shuai Xiao; Gang Hua

doi:10.1186/s12935-020-01402-9

LncRNA FOXD3-AS1 promoted chemo-resistance of NSCLC cells via directly acting on miR-127-3p/MDM2 axis

Cancer Cell Int. 2020 Jul 29:20:350. doi: 10.1186/s12935-020-01402-9. eCollection 2020.

Authors

Zhaolong Zeng^#^{1

2}, Guofang Zhao^#^{1

2}, Huangkai Zhu^#³, Liangqin Nie⁴, Lifeng He¹, Jiangtao Liu⁵, Rui Li¹, Shuai Xiao¹, Gang Hua¹

Affiliations

¹ Department of Thoracic Surgery, Hwamei Hospital, University of Chinese Academy of Sciences, No. 41 Northwest Street, Haishu District, Ningbo City, 315000 Zhejiang Province China.
² Department of Thoracic Surgery, Ningbo Institute of Life and Health Industry, University of Chinese Academy of Sciences, Ningbo, Zhejiang Province, China.
³ School of Medicine, Ningbo University, Ningbo, Zhejiang Province, China.
⁴ Department of Radiology, Hwamei Hospital, University of Chinese Academy of Sciences, Ningbo, Zhejiang Province, China.
⁵ Department of Spinal Surgery, Hwamei Hospital, University of Chinese Academy of Sciences, Ningbo, Zhejiang Province, China.

^# Contributed equally.

Abstract

Background: This study aims to investigate the mechanism underlying the high level of long non-coding RNA FOXD3-AS1 in cisplatin-resistant NSCLC cells.

Methods: Cisplatin-resistant cells were generated from A549 cells. CCK-8 were used to evaluate cell proliferation. The FOXD3-AS1, miR-127-3p, MDM2 and MRP1 mRNA expression levels were confirmed by qRT-PCR. Protein levels of MDM2 and MRP1 were determined by western blot assay. Luciferase reporter and RNA pull-down assays were evaluated the relationship between miR-127-3p and FOXD3-AS1/MDM2. In vivo tumor growth was evaluated in a xenograft nude mice model.

Results: FOXD3-AS1 was up-regulated in cisplatin-resistant NSCLC cells (A549/DDP and H1299/DDP cells) in comparison with their parental cell lines. Overexpression of FOXD3-AS1 promoted cisplatin-resistance in A549 and H1299 cells; while FOXD3-AS1 knockdown sensitized A549/DDP and H1299/DDP cells to cisplatin treatment. FOXD3-AS1 regulated miR-127-3p expression by acting as a competing endogenous RNA, and miR-127-3p repressed MDM2 expression via targeting the 3'UTR. MiR-127-3p overexpression and MDM2 knockdown both increased the chemo-sensitivity in A549/DDP cells; while miR-127-3p knockdown and MDM2 overexpression both promoted chemoresistance in A549 cells. Further rescue experiments revealed that miR-127-3p knockdown or MDM2 overexpression counteracted the suppressive effects of FOXD3-AS1 knockdown on chemo-resistance and MRP1 expression in A549/DDP cells. In vivo studies showed that FOXD3-AS1 knockdown potentiated the antitumor effects of cisplatin treatment. Inspection of clinical samples showed the upregulation of FOXD3-AS1 and MDM2, and down-regulation of miR-127-3p in NSCLC tissues compared to normal adjacent tissues.

Conclusion: In conclusion, our results suggest that LncRNA FOXD3-AS1 promotes chemo-resistance of NSCLC cells via directly acting on miR-127-3p/MDM2 axis. Our findings may provide novel perspectives for the treatment of NSCLC in patients resistant to chemotherapy.

Keywords: Chemo-resistance; Cisplatin; FOXD3-AS1; MDM2; NSCLC; miR-127-3p.