Overexpression of long non-coding RNA H19 is associated with unfavorable prognosis in patients with colorectal cancer and increased proliferation and migration in colon cancer cells

Abstract

Long non-coding RNA-imprinted maternally expressed transcript (non-protein coding) (H19) has been previously identified to be involved in the development of a number of types of cancer. However, the function of H19 in the pathogenesis of colorectal cancer remains unclear. The expression level of H19 in colorectal tumor tissues, and the association between H19 expression and clinicopathological variables and prognosis was investigated in the present study. In addition, the effect of H19 overexpression on viability, migration and epithelial-mesenchymal transition (EMT) of colon cancer cells was investigated in HCT-116 and SW-480 cells. The results of the present study suggest that overexpression of H19 is associated with decreased recurrence-free survival and overall survival rates in patients with colorectal cancer, and increased viability and migration in colon cancer cells. The induction of the EMT process may be an underlying molecular mechanism associated with the H19-induced increased metastasis potential of colon cancer cells.

Keywords: H19; colorectal cancer; epithelial-mesenchymal transition; metastasis; overall survival; recurrence-free survival.

Figure 1.

H19 expression in rectal tumor tissues is significantly increased, compared with adjacent normal tissues. The means of the two groups were compared using Wilcoxon signed-rank test (**P<0.01 vs. normal). qPCR, quantitative polymerase chain reaction; H19, long non-coding RNA-imprinted maternally expressed transcript.

Figure 2.

Kaplan-Meier estimator analysis of (A) RFS and (B) OS rates, according to H19 expression. Statistical analysis by log-rank test, P<0.01. RFS, recurrence-free survival; OS, overall survival; H19, long non-coding RNA-imprinted maternally expressed transcript.

Figure 3.

Effect of H19 overexpression on viability, migration and expression level of endothelial-mesenchymal transition-associated proteins. (A) Expression level of H19 determined using the quantitative polymerase chain reaction 3 days after transfection with H19-expressing plasmid or control plasmid, in HCT-116 and SW-480 cells. Cells transfected with H19-expressing plasmid exhibited a markedly increased expression level of H19, compared with cells transfected with the control plasmid (vector). (B) Cells were transfected with the H19 expressing plasmid or the control plasmid for 24 h and incubated for 5 days, followed by MTT assays. The viability level of cells overexpressing H19 is markedly increased, compared with cells transfected with the control plasmid (vector). (C) Migratory capacity of cells overexpressing H19 was markedly increased compared with cells transfected with the control plasmid (vector). (D) Expression levels of E-cadherin, vimentin and Snail were determined in HCT-116 and SW-480 cells 72 h after transfection with H19 or control plasmid. All experiments were performed in triplicate and repeated 3 times. Results are presented as the mean ± standard error of the mean (n=3) (**P<0.01 vs. control). GAPDH was used as a loading control. H19, long non-coding RNA-imprinted maternally expressed transcript; E-cadherin, epithelial cadherin.

Figure 4.

Expression of F-actin was increased in cells transfected with H19-expressing plasmid, compared with cells transfected with the control plasmid (vector). SW-480 cells cultured on slides were transfected with H19-expressing plasmid or control plasmid for 72 h before cells were fixed, and immunofluorescence of F-actin and nucleus was performed. F-actin, filamentous actin; H19, long non-coding RNA-imprinted maternally expressed transcript.