MicroRNA-338-3p suppresses cell proliferation and induces apoptosis of non-small-cell lung cancer by targeting sphingosine kinase 2

Guowei Zhang; Hao Zheng; Guojun Zhang; Ruirui Cheng; Chunya Lu; Yijie Guo; Guoqiang Zhao

doi:10.1186/s12935-017-0415-9

MicroRNA-338-3p suppresses cell proliferation and induces apoptosis of non-small-cell lung cancer by targeting sphingosine kinase 2

Cancer Cell Int. 2017 Apr 17:17:46. doi: 10.1186/s12935-017-0415-9. eCollection 2017.

Authors

Guowei Zhang^{1

2}, Hao Zheng³, Guojun Zhang¹, Ruirui Cheng¹, Chunya Lu¹, Yijie Guo⁴, Guoqiang Zhao³

Affiliations

¹ Department of Respiratory Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052 Henan People's Republic of China.
² Department of Respiratory Medicine, Henan Cancer Hospital, Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, 450008 Henan People's Republic of China.
³ School of Basic Medical Sciences, Zhengzhou University, No.100 Kexue Road, Zhengzhou, 450001 Henan People's Republic of China.
⁴ Zhengzhou Foreign Language School, High School (16) Class, Fengyang Road, Zhengzhou, 450001 Henan People's Republic of China.

Abstract

Background: Lung cancer is the major cause of cancer-related death worldwide, and 80% patients of lung cancer are non-small-cell lung cancer (NSCLC) cases. MicroRNAs are important gene regulators with critical roles in diverse biological processes, including tumorigenesis. Studies indicate that sphingosine kinase 2 (SphK2) promotes tumor progression in NSCLC, but how this occurs is unclear. Thus, we explored the effect of miR-338-3p targeting SphK2 on proliferation and apoptosis of NSCLC cells.

Methods: Expression of miR-338-3p and SphK2 in NSCLC A549 and H1299 cell lines was measured using qRT-PCR and Western blot. CCK-8 and colony formation assays were used to assess the effect of miR-338-3p on NSCLC cell line proliferation. Flow cytometry was used to study the effect of miR-338-3p on NSCLC apoptosis. Luciferase reporter assay and Western blot were used to confirm targeting of SphK2 by miR-338-3p. Finally, in vivo tumorigenesis studies were used to demonstrate subcutaneous tumor growth.

Results: miR-338-3p expression in 34 NSCLC clinical samples was downregulated and this was correlated with TNM stage. miR-338-3p significantly suppressed proliferation and induced apoptosis of NSCLC A549 and H1299 cells in vitro. SphK2 was a direct target of miR-338-3p. Overexpression of miR-338-3p significantly inhibited SphK2 expression and reduced luciferase reporter activity containing the SphK2 3'-untranslated region (3'-UTR) through the first binding site. SphK2 lacking 3'-UTR restored the effects of miR-338-3p on cell proliferation inhibition. miR-338-3p significantly inhibited tumorigenicity of NSCLC A549 and H1299 cells in a nude mouse xenograft model.

Conclusions: Collectively, miR-338-3p inhibited cell proliferation and induced apoptosis of NSCLC cells by targeting and down-regulating SphK2, and miR-338-3p could inhibit NSCLC cells A549 and H1299 growth in vivo, suggesting a potential mechanism of NSCLC progression. Therapeutically, miR-338-3p may serve as a potential target in the treatment of human lung cancer.

Keywords: Apoptosis; Cell proliferation; MicroRNA-338-3p; Non-small-cell lung carcinoma; Sphingosine kinase 2.