LncRNA-LINC00261 suppresses the progression of NSCLC cells through upregulating miR-19a-mediated Kruppel-like factor 2 (KLF2)

Zhan-Yu Li, Zi-Zi Li,  Jian-Hui Zhou, Zhi-Juan Zhong, Xiao-Jin Wang, Ling Zhong,  Wen-Ying Zhou

Abstract:

Long non-coding RNA LINC00261 (LINC00261) has been reported to be implicated in tumorigenesis, treatment, and prognosis in different cancers including non-small cell lung cancer cells (NSCLCs). However, its mechanisms have been poorly investigated in NSCLC. Expressions of LINC00261, miR-19a and Kruppel-like factor 2 (KLF2) were detected using RT-qPCR and western blotting. Cell viability, migration and invasion and apoptosis were detected by MTT assay, transwell assay, flow cytometry and the expressions of Bcl-2, Bax, and cleaved caspase 3 were analyzed by western blotting. Tumor growth in vivo was measured in a xenograft experiment. The target binding between miR-19a and LINC00161 or KLF2 was predicted on the miRcode or Targetscan website and confirmed by luciferase reporter assay. The results showed that LINC00261 was downregulated in NSCLC tumors and cell lines, and this downregulation was correlated with higher TNM stage, larger tumor size, lymph node metastasis, and poor prognosis. Functionally, the upregulation of LINC00261 could promote NSCLC cell apoptosis and inhibit cell viability, migration, and invasion in A549 and H1299 cells, as well as suppress tumor growth. Mechanically, LINC00261 positively regulated KLF2 expression in NSCLC tumors through sponging miR-19a. Expression of miR-19a was upregulated while KLF2 was downregulated in NSCLC tumors, and there existed a negative linear correlation between miR-19a and LINC00261 or KLF2. Rescue experiments demonstrated that both miR-19a upregulation and KLF2 downregulation could abolish the LINC00261 effect in A549 and H1299 cells. Collectively, the upregulation of LINC00261 suppressed NSCLC cell progression through upregulating miR-19a-mediated KLF2, suggesting LINC00261/miR-19a/KLF2 pathway could contribute to the initiation, development, and prognosis in NSCLC.