Enhanced expression of long non-coding RNA NEAT1 is associated with the progression of gastric adenocarcinomas

Abstract

Background: Long non-coding RNAs (lncRNAs) are emerging as new players in the cancer. The aim of this study was to examine the abnormalities of NEAT1 (nuclear paraspeckle assembly transcript 1, also known as MENε/β) in gastric adenocarcinomas (GACs).

Methods: One hundred thirty-one GAC tissues and matched adjacent normal tissues (ANTs) were collected from patients who undergone surgery. Differences in of NEAT1 expression were examined via quantitative reverse transcriptase PCR (qRT-PCR). WST-1 assay and transwell assay were carried out in vitro to investigate the proliferation and migration of GAC cells with alteration in NEAT1 long non-coding RNA (lncRNA) expression.

Results: The expression levels of lncRNA NEAT1 were significantly elevated in GAC tissues (P<0.001) compared with ANTs. There was also a statistical difference in NEAT1 expression between early and advanced GACs (P=0.0111). GACs with lymph node metastasis (LNM) expressed higher levels of NEAT1 lncRNA compared with those without LNM (P=0.004). In the in vitro experiments, the proliferation but not migration of GAC cells was attenuated after NEAT1 knockdown by RNA interference.

Conclusions: Expression of NEAT1 lncRNA was enhanced in GACs; and NEAT1 may influence GAC progression by promoting tumor growth.

Fig. 1

Enhanced expression of NEAT1 lncRNA in GAC. Real-time PCR assay was carried out as described under the “Methods” section, and the results were obtained from indicated group of samples. a Scatter plot illustrated the relative expression of indicated lncRNAs as a ratio of lncRNA to β-actin mRNA in each sample. b Scatter plot illustrated the relative expression of NEAT1 as a ratio of GAC to ANT mRNA (GAC/ACTB: ANT/ACTB) in each sample

Fig. 2

Higher expression of NEAT1 in GAC with lymph node metastasis. a Scatter plot illustrated the relative expression of NEAT1 as a ratio of GAC to paired ANT in the GACs with or without lymph node metastasis. b Scatter plot illustrated the relative expression of NEAT1 as a ratio of GAC to paired ANT in the primary tumors and lymph node metastases

Fig. 3

Knockdown of NEAT1 lncRNA impairs growth of GAC cells in vitro. a Expression levels of NEAT1 lncRNA were examined by real-time PCR. b The expressions of NEAT1 mRNA in MGC803 cells transfected with pcDNA3-NEAT1 and control vector detected by RT-qPCR. c After treatment of lentiviruses expressing NEAT1 shRNA and control shRNAs, the expression levels of NEAT1 lncRNA were examined by real-time PCR. The relative expression of NEAT1 lncRNA (as the ratio of NEAT1 lncRNA to β-actin mRNA) is illustrated as a ratio to control (cells transfected with control shRNA). d WST-1 (Roche) assay measuring the activity of mitochondrial dehydrogenases was performed following the manufacturer’s instruction at 0-, 1-, 2-, 3-, and 4-day time points. Error bars represent the standard deviation of the mean. e Cell migration was determined using a transwell assay as described in the “Methods” section. Microscopic image of migrated MKN45 and AGS cells, cells transfected with nonsense strand or NEAT1 shRNA, respectively. Original magnification 200×. The diagrams of migrating cells from the different transfectants are also shown, which come from more than three independent experiments