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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

Inhibition of EC109 cell proliferation, migration and invasion by miR-218 and the increase in EC109 cell apoptosis induced by miR-218. (A) Expression of miR-218 measured by RT-qPCR in EC109 cells transfected with miR-218 mimics or miR-control. (B) MTT assay of relative EC109 cell viability at different time points (24, 48, 72 and 96 h) after transfection with miR-218 mimics or miR-control. (C) Effect of miR-218 on EC109 cell proliferation determined by EdU staining. Blue, Hoechst 33342 labeling of cell nuclei; red, EdU labeling of nuclei of proliferative cells. Quantitative data showed the percentage of EdU-positive cells (number of red vs. blue nuclei). (D) Effect of miR-218 overexpression on colony formation of EC109 cells. (E) Effect of miR-218 on migration of EC109 cells by wound healing assay. (F) Transwell invasion assay of EC109 cells treated with miR-218 mimics. (G) Effect of miR-218 on EC109 cell apoptosis determined by flow cytometry. Q2 + Q3 represent the total apoptotic rate. Data are presented as the means ± SD from 3 replicate samples. *P<0.05 and **P<0.01 vs. control.
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f2-ijmm-36-01-0093: Inhibition of EC109 cell proliferation, migration and invasion by miR-218 and the increase in EC109 cell apoptosis induced by miR-218. (A) Expression of miR-218 measured by RT-qPCR in EC109 cells transfected with miR-218 mimics or miR-control. (B) MTT assay of relative EC109 cell viability at different time points (24, 48, 72 and 96 h) after transfection with miR-218 mimics or miR-control. (C) Effect of miR-218 on EC109 cell proliferation determined by EdU staining. Blue, Hoechst 33342 labeling of cell nuclei; red, EdU labeling of nuclei of proliferative cells. Quantitative data showed the percentage of EdU-positive cells (number of red vs. blue nuclei). (D) Effect of miR-218 overexpression on colony formation of EC109 cells. (E) Effect of miR-218 on migration of EC109 cells by wound healing assay. (F) Transwell invasion assay of EC109 cells treated with miR-218 mimics. (G) Effect of miR-218 on EC109 cell apoptosis determined by flow cytometry. Q2 + Q3 represent the total apoptotic rate. Data are presented as the means ± SD from 3 replicate samples. *P<0.05 and **P<0.01 vs. control.

Mentions: Since the decreased expression of miR-218 was detected in the ESCC tissues and cell lines, we hypothesized that miR-218 acts as tumor suppressor gene and regulates tumor formation and development. We then investigated whether treatment with miR-218 exerts an inhibitory effect on the growth of ESCC cells. We found that miR-218 expression in the mimics-transfected group was significantly higher than that in the miR-control-transfected group (Fig. 2A). The corresponding cell growth curves indicated that the OD450 of the miR-218 group was significantly decreased on the fourth day post-transfection in the EC109 cells (Fig. 2B). In addition, we found that the extent of EdU staining was decreased in the EC109 cells transfected with the miR-218 mimics. EdU assay revealed that the number of EC109 cells was significantly decreased in the group transfected with miR-218 mimics (Fig. 2C). Moreover, colony formation assay also validated that transfection with miR-218 mimics was effective. The restoration of miR-218 expression markedly inhibited clonogenic cell growth, since transfection with miR-218 mimics led to the inhibition of colony formation compared to the miR-control-transfected group (P<0.01; Fig. 2D). These results indicate that miR-218 has the ability to effectively suppress ESCC cell growth.


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)

Inhibition of EC109 cell proliferation, migration and invasion by miR-218 and the increase in EC109 cell apoptosis induced by miR-218. (A) Expression of miR-218 measured by RT-qPCR in EC109 cells transfected with miR-218 mimics or miR-control. (B) MTT assay of relative EC109 cell viability at different time points (24, 48, 72 and 96 h) after transfection with miR-218 mimics or miR-control. (C) Effect of miR-218 on EC109 cell proliferation determined by EdU staining. Blue, Hoechst 33342 labeling of cell nuclei; red, EdU labeling of nuclei of proliferative cells. Quantitative data showed the percentage of EdU-positive cells (number of red vs. blue nuclei). (D) Effect of miR-218 overexpression on colony formation of EC109 cells. (E) Effect of miR-218 on migration of EC109 cells by wound healing assay. (F) Transwell invasion assay of EC109 cells treated with miR-218 mimics. (G) Effect of miR-218 on EC109 cell apoptosis determined by flow cytometry. Q2 + Q3 represent the total apoptotic rate. 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

f2-ijmm-36-01-0093: Inhibition of EC109 cell proliferation, migration and invasion by miR-218 and the increase in EC109 cell apoptosis induced by miR-218. (A) Expression of miR-218 measured by RT-qPCR in EC109 cells transfected with miR-218 mimics or miR-control. (B) MTT assay of relative EC109 cell viability at different time points (24, 48, 72 and 96 h) after transfection with miR-218 mimics or miR-control. (C) Effect of miR-218 on EC109 cell proliferation determined by EdU staining. Blue, Hoechst 33342 labeling of cell nuclei; red, EdU labeling of nuclei of proliferative cells. Quantitative data showed the percentage of EdU-positive cells (number of red vs. blue nuclei). (D) Effect of miR-218 overexpression on colony formation of EC109 cells. (E) Effect of miR-218 on migration of EC109 cells by wound healing assay. (F) Transwell invasion assay of EC109 cells treated with miR-218 mimics. (G) Effect of miR-218 on EC109 cell apoptosis determined by flow cytometry. Q2 + Q3 represent the total apoptotic rate. Data are presented as the means ± SD from 3 replicate samples. *P<0.05 and **P<0.01 vs. control.
Mentions: Since the decreased expression of miR-218 was detected in the ESCC tissues and cell lines, we hypothesized that miR-218 acts as tumor suppressor gene and regulates tumor formation and development. We then investigated whether treatment with miR-218 exerts an inhibitory effect on the growth of ESCC cells. We found that miR-218 expression in the mimics-transfected group was significantly higher than that in the miR-control-transfected group (Fig. 2A). The corresponding cell growth curves indicated that the OD450 of the miR-218 group was significantly decreased on the fourth day post-transfection in the EC109 cells (Fig. 2B). In addition, we found that the extent of EdU staining was decreased in the EC109 cells transfected with the miR-218 mimics. EdU assay revealed that the number of EC109 cells was significantly decreased in the group transfected with miR-218 mimics (Fig. 2C). Moreover, colony formation assay also validated that transfection with miR-218 mimics was effective. The restoration of miR-218 expression markedly inhibited clonogenic cell growth, since transfection with miR-218 mimics led to the inhibition of colony formation compared to the miR-control-transfected group (P<0.01; Fig. 2D). These results indicate that miR-218 has the ability to effectively suppress ESCC cell growth.

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