Up-regulation of LINC00467 promotes the tumourigenesis in colorectal cancer

Abstract

Recent studies have reported that long non-coding RNAs (lncRNAs) are associated with the tumourigenesis of colorectal cancer (CRC); however, several of these are yet to be identified and characterised. In this study, we report a novel lncRNA, LINC00467, which was significantly up-regulated in CRC; we investigated its function and mechanism in CRC. Our study demonstrated that LINC00467 levels in 45 pairs of CRC tissues were higher than those in the corresponding normal colon mucosal tissues. We used the Gene Expression Omnibus (GEO) and Gene Expression Profiling Interactive Analysis (GEPIA) databases for the analysis and measurement of clinical samples, and observed that the CRC patients with high LINC00467 expression levels showed poor overall survival (OS) and recurrent-free survival (RFS) rates. Furthermore, following the short interfering RNA (siRNA) knockdown of LINC00467 in the CRC cell line, the results demonstrated that LINC00467 suppresses the proliferation, invasion and metastasis of CRC cells in vitro. Moreover, its molecular mechanism of LINC00467 decreased the expression of Cyclin D1, Cyclin A1, CDK2, CDK4 and Twist1 as well as enhanced the expression of E‑cadherin. Collectively, these findings suggest that LINC00467 may be crucial in the progression and development of CRC, and may serve as a potential therapeutic target for CRC patients.

Keywords: LINC00467, colorectal cancer, tumorigenesis, invasion; survival.

Figure 1

LINC00467 expression is up-regulated in CRC tissues and cell lines. (A) #GSE22598 (containing 17 pairs of CRC tissues and corresponding normal colorectal tissues) and (B) #GSE37364 (38 normal colon samples and 56 primary CRC samples) from the GEO database were used to analyse the expression of LINC00467. (C) LINC00467 is highly expressed in 45 pairs of CRC tissues compared with the corresponding normal colorectal tissues. (D) LINC00467 expression was significantly increased in the CRC cell lines (SW480, SW620, HT29 and HCT116) compared with NCM460, a normal colon mucosal cell line. (E and F) Nucleic and cytoplasmic RNA were analysed using qRT-PCR to detect the expression levels of LINC00467 in HT29 and SW480 cells. U6 was used as a nucleic RNA control; GAPDH and β-actin were used as cytoplasmic RNA controls. Data are presented as mean ± SEM. *p < 0.05 compared with control.

Figure 2

Relationship between LINC00467 expression and clinicopathological features. (A) Relative expression of LINC00467 in normal and metastatic human CRC tissues from the GEO database (#GSE50760, 18 metastasis CRC samples and adjacent non-metastatic samples) was studied. (B) The GEPIA database was used to analyse LINC00467 expression in the CRC samples (COAD stands for colon adenocarcinoma and READ for rectal adenocarcinoma). (C-D) GEPIA database was used to analyse the clinical impact of LINC00467 expression patterns on the CRC patients' RFS and OS (the TCGA CRC specimens were divided into two groups within the GEPIA database, group 1 = low LINC00467 expression, n = 218; group 2 = high LINC00467 expression, n = 218). *p < 0.05 compared with control.

Figure 3

Knockdown of LINC00467 expression impeded the proliferation of CRC cells. (A) The interference efficiency of siR-467 was verified in HT29 cells. HT29 cells were transfected with either si-NC or siR-467 (1#, 2#, 1+2#) for 48 h, and then, LINC00467 expression was analysed by qRT-PCR. After transfecting HT29 cells with si-NC or siR-467 for 48 h, the CCK8 assay (B) and flow cytometry (C) were used to detect the cell proliferative ability. Data are presented as mean ± SEM. *p < 0.05, **p < 0.01 compared with control.

Figure 4

Knockdown of LINC00467 expression impeded the invasiveness of CRC cells. The invasive ability of HT29 cells was detected using a Transwell Matrigel assay after transfecting with si-NC or siR-467 for 48 h. Data are presented as mean ± SEM. *p < 0.05 compared with control.

Figure 5

LINC00467 knockdown inhibits the proliferation and EMT markers expressed in CRC. After transfecting with si-NC or siR-467 for 48 h, the effect of LINC00467 on the protein and mRNA expressions of Cyclin D1, Cyclin A1, CDK2 and CDK4 (A-B) and of E‑cadherin and Twist1 (C-D) in HT29 cells were analysed by western blotting, densitometry and qRT-PCR. Data are presented as the mean ± SEM. *p < 0.05, **p < 0.01 compared with the control.