LINC00488 stimulates the progression of esophageal cancer by targeting microRNA-485-5p

Abstract

Esophageal cancer is the eighth most prevalent malignancy in the world and China has a high incidence of esophageal cancer. Previous studies have identified that LINC00488 is an oncogene; however, its role in esophageal cancer remains unclear. The present study detected the expression and biological functions of LINC00488 in the progression of esophageal cancer. LINC00488 levels in 45 esophageal cancer and matched paracancerous tissues were detected. The association between LINC00488 level, clinical indexes and overall survival rate of patients with esophageal cancer was analyzed. Using Cell Counting Kit-8, Transwell and wound healing assays, the influence of LINC00488 on the biological functions of OE19 and OE33 cells were assessed. The target gene of LINC00488, microRNA-485-5p (miRNA-485-5p), was predicted using bioinformatics databases. In addition, the role of miRNA-485-5p in the progression of esophageal cancer was evaluated using rescue experiments. LINC00488 was upregulated in esophageal cancer tissues and cell lines. A high level of LINC00488 was associated with lymphatic and distant metastasis and poor prognosis in patients with esophageal cancer. Silencing LINC00488 attenuated the viability, migration and wound healing of OE19 and OE33 cells. miRNA-485-5p was downregulated in esophageal cancer and low expression levels predicted a poor prognosis in these patients. In addition, miRNA-485-5p level was negatively correlated with that of LINC00488. Rescue experiments showed that knockdown of miRNA-485-5p reversed the attenuated proliferation and migration of esophageal cancer cells with LINC00488-knockdown. In conclusion, LINC00488 aggravated the malignant progression of esophageal cancer by targeting miRNA-485-5p.

Keywords: LINC00488; esophageal cancer; malignant progression; microRNA-485-5p.

Figure 1.

Upregulated LINC00488 in esophageal cancer predicts poor prognosis. LINC00488 level in (A) esophageal cancer tissues and adjacent normal tissues, (B) 16 paired esophageal cancer tissues and paracancerous tissues and (C) in HEEC, TE-1, EC-109, OE19 and OE33 cells. (D) Kaplan-Meier curves for survival in patients with esophageal cancer with low and high LINC00488 expression. Data are expressed as mean ± SD. *P<0.05, **P<0.01 and ***P<0.001 vs. respective control. HEEC, human esophageal epithelial cells.

Figure 2.

Knockdown of LINC00488 suppresses proliferation and migration. (A) Transfection efficacy of sh-LINC00488-1, sh-LINC00488-2 or sh-LINC00488-3 in OE19 and OE33 cells. (B) Viability in OE19 and OE33 cells transfected with sh-NC or sh-LINC00488-1. (C) Migratory cell number in OE19 and OE33 cells transfected with sh-NC or sh-LINC00488-1. (D) Wound closure in OE19 and OE33 cells transfected with sh-NC or sh-LINC00488-1. Data are expressed as mean ± SD. *P<0.05 and **P<0.01 vs. sh-NC. sh, short hairpin; NC, negative control.

Figure 3.

Low miR-485-5p expression in esophageal cancer tissues and cell lines. (A) Potential targets of LINC00488 predicted using miRDB, TargetScan and StarBase. (B) Relative levels of the five predicted targets (miR-485-5p, miR-10a, −200c, −22 and −141) in OE19 cells transfected with sh-NC or sh-LINC00488-1. miR-485-5p level in (C) esophageal cancer tissues and adjacent normal tissues and (D) HEEC, TE-1, EC-109, OE19 and OE33 cells. (E) Pearson's correlation analysis showed a negative correlation between expression levels of miR-485-5p and LINC00488. (F) Kaplan-Meier analysis showed significantly worse prognosis in patients with esophageal cancer with lower levels of miRNA-485-5p. (G) Bioinformatics analysis and luciferase reporter gene experiment confirmed the binding between miRNA-485-5p and LINC00488. Data are expressed as mean ± SD. *P<0.05, **P<0.01, ***P<0.001 vs. respective control. miR, microRNA; WT, wild-type; MUT, mutant; UTR, untranslated region.

Figure 4.

LINC00488 regulates esophageal cancer cells by targeting miR-485-5p. OE19 and OE33 cells were transfected with sh-NC+NC inhibitor, sh-LINC00488-1+NC inhibitor and sh-LINC00488-1+ miR-485-5p inhibitor. (A) miR-485-5p level. (B) Cell proliferation rate. (C) Migratory cell number (scale bar, 500 µm). (D) Wound closure percentage (scale bar, 500 µm). Data are expressed as mean ± SD. *P<0.05, ^#P<0.01. miR, microRNA; sh, short hairpin; NC, negative control.