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MicroRNA-218 inhibits the proliferation and metastasis of esophageal squamous cell carcinoma cells by targeting BMI1.

Wang T, Chen T, Niu H, Li C, Xu C, Li Y, Huang R, Zhao J, Wu S - Int. J. Mol. Med. (2015)

Bottom Line: MicroRNAs (miRNAs or miRs) play a pivotal role in esophageal carcinogenesis either as oncogenes or as tumor suppressor genes.Furthermore, the decreased expression of miR-218 was found to be associated with an enhanced ESCC cell proliferation and metastasis.In the present study, our findings confirm miR-218 as a tumor suppressor and identify BMI1 as a novel target of miR-218 in ESCC.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China.

ABSTRACT
MicroRNAs (miRNAs or miRs) play a pivotal role in esophageal carcinogenesis either as oncogenes or as tumor suppressor genes. In the present study, we found that the expression level of miR-218 was significantly reduced in esophageal squamous cell carcinoma (ESCC) tissues and ESCC cell lines. Moreover, its expression was found to correlate with the clinicopathological stage of ESCC; miR-218 expression was lower in the stage III tissue samples than in the stage I and II tissue samples. Furthermore, the decreased expression of miR-218 was found to be associated with an enhanced ESCC cell proliferation and metastasis. Western blot analysis and luciferase reporter assay revealed that miR-218 decreased BMI1 expression by binding to the putative binding sites in its 3'-untranslated region (3'-UTR). The BMI1 mRNA expression levels were markedly increased and negatively correlated with the miR-218 expression level in the ESCC tissues. Functional analyses revealed that the restoration of miR-218 expression inhibited ESCC cell proliferation, migration and invasion and promoted apoptosis. The knockdown of BMI1 by siRNA showed the same phenocopy as the effect of miR-218 on ESCC cells, indicating that BMI1 was a major target of miR-218. In the present study, our findings confirm miR-218 as a tumor suppressor and identify BMI1 as a novel target of miR-218 in ESCC. Therefore, miR-218 may prove to be a useful biomarker for monitoring the initiation and development of ESCC, and may thus be an effective therapeutic target in ESCC.

No MeSH data available.


Related in: MedlinePlus

Effects of the downregulation of BMI1 expression on the phenotype of EC109 cells. (A) Determination of BMI1 protein levels by western blot analysis. EC109 cells were transfected with 25 nM BMI1-siRNA, 50 nM BMI1-siRNA or control oligo. GAPDH was used as a loading control. The relative values of BMI1 expression in the cells were calculated following normalization to GAPDH using ImageJ software. (B) MTT assay of EC109 cell growth at different time points (24, 48, 72 and 96 h) following transfection with BMI1-siRNA or control oligo. (C) Effect of BMI1 on EC109 cell proliferation determined by EdU staining. (D) Transwell invasion assay of EC109 cells transfected with BMI1-siRNA. (E) Effect of BMI1 on EC109 cell apoptosis determined by flow cytometry. Data are presented as the means ± SD from 3 replicate samples. *P<0.05 and **P<0.01 vs. control.
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f4-ijmm-36-01-0093: Effects of the downregulation of BMI1 expression on the phenotype of EC109 cells. (A) Determination of BMI1 protein levels by western blot analysis. EC109 cells were transfected with 25 nM BMI1-siRNA, 50 nM BMI1-siRNA or control oligo. GAPDH was used as a loading control. The relative values of BMI1 expression in the cells were calculated following normalization to GAPDH using ImageJ software. (B) MTT assay of EC109 cell growth at different time points (24, 48, 72 and 96 h) following transfection with BMI1-siRNA or control oligo. (C) Effect of BMI1 on EC109 cell proliferation determined by EdU staining. (D) Transwell invasion assay of EC109 cells transfected with BMI1-siRNA. (E) Effect of BMI1 on EC109 cell apoptosis determined by flow cytometry. Data are presented as the means ± SD from 3 replicate samples. *P<0.05 and **P<0.01 vs. control.

Mentions: To explore the effects of BMI1 on ESCC, we used BMI1-siRNA to knockdown BMI1 expression in the EC109 cells. The protein expression level of BMI1 was significantly reduced in the BMI1-siRNA-transfected EC109 cells compared with the siRNA-control-transfected EC109 cells (Fig. 4A). MTT assay revealed that the growth rate of EC109 cells transfected with BMI1-siRNA was significantly lower than that of the siRNA-control-transfected cells (Fig. 4B). In order to further elucidate the effects of BMI1-siRNA on cancer cell proliferation, we used EdU incorporation assay to determine the effects of BMI1 on ESCC cell proliferation. EdU assay revealed that cell number was significantly reduced in the BMI1-siRNA-transfected EC109 cells (Fig. 4C). Transwell assay revealed that BMI1 knockdown inhibited the invasion of ESCC cells (Fig. 4D). The number of apoptotic cells were significantly increased in the BMI1-siRNA-transfected EC109 cells compared with the siRNA-control-transfected cells (Fig. 4E).


MicroRNA-218 inhibits the proliferation and metastasis of esophageal squamous cell carcinoma cells by targeting BMI1.

Wang T, Chen T, Niu H, Li C, Xu C, Li Y, Huang R, Zhao J, Wu S - Int. J. Mol. Med. (2015)

Effects of the downregulation of BMI1 expression on the phenotype of EC109 cells. (A) Determination of BMI1 protein levels by western blot analysis. EC109 cells were transfected with 25 nM BMI1-siRNA, 50 nM BMI1-siRNA or control oligo. GAPDH was used as a loading control. The relative values of BMI1 expression in the cells were calculated following normalization to GAPDH using ImageJ software. (B) MTT assay of EC109 cell growth at different time points (24, 48, 72 and 96 h) following transfection with BMI1-siRNA or control oligo. (C) Effect of BMI1 on EC109 cell proliferation determined by EdU staining. (D) Transwell invasion assay of EC109 cells transfected with BMI1-siRNA. (E) Effect of BMI1 on EC109 cell apoptosis determined by flow cytometry. Data are presented as the means ± SD from 3 replicate samples. *P<0.05 and **P<0.01 vs. control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494586&req=5

f4-ijmm-36-01-0093: Effects of the downregulation of BMI1 expression on the phenotype of EC109 cells. (A) Determination of BMI1 protein levels by western blot analysis. EC109 cells were transfected with 25 nM BMI1-siRNA, 50 nM BMI1-siRNA or control oligo. GAPDH was used as a loading control. The relative values of BMI1 expression in the cells were calculated following normalization to GAPDH using ImageJ software. (B) MTT assay of EC109 cell growth at different time points (24, 48, 72 and 96 h) following transfection with BMI1-siRNA or control oligo. (C) Effect of BMI1 on EC109 cell proliferation determined by EdU staining. (D) Transwell invasion assay of EC109 cells transfected with BMI1-siRNA. (E) Effect of BMI1 on EC109 cell apoptosis determined by flow cytometry. Data are presented as the means ± SD from 3 replicate samples. *P<0.05 and **P<0.01 vs. control.
Mentions: To explore the effects of BMI1 on ESCC, we used BMI1-siRNA to knockdown BMI1 expression in the EC109 cells. The protein expression level of BMI1 was significantly reduced in the BMI1-siRNA-transfected EC109 cells compared with the siRNA-control-transfected EC109 cells (Fig. 4A). MTT assay revealed that the growth rate of EC109 cells transfected with BMI1-siRNA was significantly lower than that of the siRNA-control-transfected cells (Fig. 4B). In order to further elucidate the effects of BMI1-siRNA on cancer cell proliferation, we used EdU incorporation assay to determine the effects of BMI1 on ESCC cell proliferation. EdU assay revealed that cell number was significantly reduced in the BMI1-siRNA-transfected EC109 cells (Fig. 4C). Transwell assay revealed that BMI1 knockdown inhibited the invasion of ESCC cells (Fig. 4D). The number of apoptotic cells were significantly increased in the BMI1-siRNA-transfected EC109 cells compared with the siRNA-control-transfected cells (Fig. 4E).

Bottom Line: MicroRNAs (miRNAs or miRs) play a pivotal role in esophageal carcinogenesis either as oncogenes or as tumor suppressor genes.Furthermore, the decreased expression of miR-218 was found to be associated with an enhanced ESCC cell proliferation and metastasis.In the present study, our findings confirm miR-218 as a tumor suppressor and identify BMI1 as a novel target of miR-218 in ESCC.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Medical College of Soochow University, Suzhou, Jiangsu 215123, P.R. China.

ABSTRACT
MicroRNAs (miRNAs or miRs) play a pivotal role in esophageal carcinogenesis either as oncogenes or as tumor suppressor genes. In the present study, we found that the expression level of miR-218 was significantly reduced in esophageal squamous cell carcinoma (ESCC) tissues and ESCC cell lines. Moreover, its expression was found to correlate with the clinicopathological stage of ESCC; miR-218 expression was lower in the stage III tissue samples than in the stage I and II tissue samples. Furthermore, the decreased expression of miR-218 was found to be associated with an enhanced ESCC cell proliferation and metastasis. Western blot analysis and luciferase reporter assay revealed that miR-218 decreased BMI1 expression by binding to the putative binding sites in its 3'-untranslated region (3'-UTR). The BMI1 mRNA expression levels were markedly increased and negatively correlated with the miR-218 expression level in the ESCC tissues. Functional analyses revealed that the restoration of miR-218 expression inhibited ESCC cell proliferation, migration and invasion and promoted apoptosis. The knockdown of BMI1 by siRNA showed the same phenocopy as the effect of miR-218 on ESCC cells, indicating that BMI1 was a major target of miR-218. In the present study, our findings confirm miR-218 as a tumor suppressor and identify BMI1 as a novel target of miR-218 in ESCC. Therefore, miR-218 may prove to be a useful biomarker for monitoring the initiation and development of ESCC, and may thus be an effective therapeutic target in ESCC.

No MeSH data available.


Related in: MedlinePlus