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MicroRNA‑20a promotes the proliferation and cell cycle of human osteosarcoma cells by suppressing early growth response 2 expression.

Zhuo W, Ge W, Meng G, Jia S, Zhou X, Liu J - Mol Med Rep (2015)

Bottom Line: It was determined that miR‑20a expression is markedly upregulated in OS tissues and cells compared with the matched adjacent normal tissues and h‑FOB human osteoblast cell lines.Data from luciferase reporter assays showed that miR‑20a directly binds to the 3'‑untranslated region (3'‑UTR) of EGR2 mRNA and represses expression at the transcriptional and translational levels.In conclusion, the data provide compelling evidence that miR‑20a functions as an onco‑miRNA, which is important in promoting cell proliferation in OS, and its oncogenic effect is mediated primarily through direct suppression of EGR2 expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopedics and Traumatology, Institute of Orthopedics and Traumatology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shanxi 710000, P.R. China.

ABSTRACT
MicroRNAs (miRNAs) are crucial in cancer development. However, the underlying mechanisms of miRNAs in osteosarcoma (OS) remain largely uncharacterized. The present study investigated the role of miR‑20a in OS cell proliferation. It was determined that miR‑20a expression is markedly upregulated in OS tissues and cells compared with the matched adjacent normal tissues and h‑FOB human osteoblast cell lines. Ectopic expression of miR‑20a promoted the proliferation and anchorage‑independent growth of OS cells, whereas inhibition of miR‑20a reduced this effect. Bioinformatics analysis further revealed early growth response 2 (EGR2), as a potential target of miR‑20a. Data from luciferase reporter assays showed that miR‑20a directly binds to the 3'‑untranslated region (3'‑UTR) of EGR2 mRNA and represses expression at the transcriptional and translational levels. In functional assays, miR‑20a promoted OS cell proliferation and the cell cycle, which could be suppressed by an inhibitor of miR‑20a. In conclusion, the data provide compelling evidence that miR‑20a functions as an onco‑miRNA, which is important in promoting cell proliferation in OS, and its oncogenic effect is mediated primarily through direct suppression of EGR2 expression.

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miR-20a suppresses EGR2 expression by directly targeting the EGR2 3′-UTR. (A) Predicted miR-20a target sequence in the 3′-UTR of EGR-2 (EGR-2–3′-UTR) and positions of mutated nucleotides in the 3′-UTR of EGR-2 (EGR-2–3′-UTR-mut). (B) Western blot analysis of EGR-2 expression in cells transfected with miR-20a or the miR-20a inhibitor. α-tubulin served as the loading control. (C) Luciferase reporter assay of the indicated cells transfected with the pGL3-EGR-2–3′-UTR reporter and miR-20a or miR-20a-in with oligonucleotides. *P<0.05, compared with NC. miR, microRNA; EGR2, early growth response 2; UTR, untranslated region; mut, mutant.
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f4-mmr-12-04-4989: miR-20a suppresses EGR2 expression by directly targeting the EGR2 3′-UTR. (A) Predicted miR-20a target sequence in the 3′-UTR of EGR-2 (EGR-2–3′-UTR) and positions of mutated nucleotides in the 3′-UTR of EGR-2 (EGR-2–3′-UTR-mut). (B) Western blot analysis of EGR-2 expression in cells transfected with miR-20a or the miR-20a inhibitor. α-tubulin served as the loading control. (C) Luciferase reporter assay of the indicated cells transfected with the pGL3-EGR-2–3′-UTR reporter and miR-20a or miR-20a-in with oligonucleotides. *P<0.05, compared with NC. miR, microRNA; EGR2, early growth response 2; UTR, untranslated region; mut, mutant.

Mentions: It is generally accepted that miRNAs regulate the expression of mRNAs by targeting the mRNA 3′UTR. Bioinformatics analysis revealed that EGR2, is a member of a multi-gene family encoding zinc finger proteins and is crucial in the regulation of cellular proliferation and the cell cycle, as a putative target of miR-20a (11–13). Therefore, EGR2 was selected as a target for further analysis (Fig. 4A).


MicroRNA‑20a promotes the proliferation and cell cycle of human osteosarcoma cells by suppressing early growth response 2 expression.

Zhuo W, Ge W, Meng G, Jia S, Zhou X, Liu J - Mol Med Rep (2015)

miR-20a suppresses EGR2 expression by directly targeting the EGR2 3′-UTR. (A) Predicted miR-20a target sequence in the 3′-UTR of EGR-2 (EGR-2–3′-UTR) and positions of mutated nucleotides in the 3′-UTR of EGR-2 (EGR-2–3′-UTR-mut). (B) Western blot analysis of EGR-2 expression in cells transfected with miR-20a or the miR-20a inhibitor. α-tubulin served as the loading control. (C) Luciferase reporter assay of the indicated cells transfected with the pGL3-EGR-2–3′-UTR reporter and miR-20a or miR-20a-in with oligonucleotides. *P<0.05, compared with NC. miR, microRNA; EGR2, early growth response 2; UTR, untranslated region; mut, mutant.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581803&req=5

f4-mmr-12-04-4989: miR-20a suppresses EGR2 expression by directly targeting the EGR2 3′-UTR. (A) Predicted miR-20a target sequence in the 3′-UTR of EGR-2 (EGR-2–3′-UTR) and positions of mutated nucleotides in the 3′-UTR of EGR-2 (EGR-2–3′-UTR-mut). (B) Western blot analysis of EGR-2 expression in cells transfected with miR-20a or the miR-20a inhibitor. α-tubulin served as the loading control. (C) Luciferase reporter assay of the indicated cells transfected with the pGL3-EGR-2–3′-UTR reporter and miR-20a or miR-20a-in with oligonucleotides. *P<0.05, compared with NC. miR, microRNA; EGR2, early growth response 2; UTR, untranslated region; mut, mutant.
Mentions: It is generally accepted that miRNAs regulate the expression of mRNAs by targeting the mRNA 3′UTR. Bioinformatics analysis revealed that EGR2, is a member of a multi-gene family encoding zinc finger proteins and is crucial in the regulation of cellular proliferation and the cell cycle, as a putative target of miR-20a (11–13). Therefore, EGR2 was selected as a target for further analysis (Fig. 4A).

Bottom Line: It was determined that miR‑20a expression is markedly upregulated in OS tissues and cells compared with the matched adjacent normal tissues and h‑FOB human osteoblast cell lines.Data from luciferase reporter assays showed that miR‑20a directly binds to the 3'‑untranslated region (3'‑UTR) of EGR2 mRNA and represses expression at the transcriptional and translational levels.In conclusion, the data provide compelling evidence that miR‑20a functions as an onco‑miRNA, which is important in promoting cell proliferation in OS, and its oncogenic effect is mediated primarily through direct suppression of EGR2 expression.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopedics and Traumatology, Institute of Orthopedics and Traumatology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shanxi 710000, P.R. China.

ABSTRACT
MicroRNAs (miRNAs) are crucial in cancer development. However, the underlying mechanisms of miRNAs in osteosarcoma (OS) remain largely uncharacterized. The present study investigated the role of miR‑20a in OS cell proliferation. It was determined that miR‑20a expression is markedly upregulated in OS tissues and cells compared with the matched adjacent normal tissues and h‑FOB human osteoblast cell lines. Ectopic expression of miR‑20a promoted the proliferation and anchorage‑independent growth of OS cells, whereas inhibition of miR‑20a reduced this effect. Bioinformatics analysis further revealed early growth response 2 (EGR2), as a potential target of miR‑20a. Data from luciferase reporter assays showed that miR‑20a directly binds to the 3'‑untranslated region (3'‑UTR) of EGR2 mRNA and represses expression at the transcriptional and translational levels. In functional assays, miR‑20a promoted OS cell proliferation and the cell cycle, which could be suppressed by an inhibitor of miR‑20a. In conclusion, the data provide compelling evidence that miR‑20a functions as an onco‑miRNA, which is important in promoting cell proliferation in OS, and its oncogenic effect is mediated primarily through direct suppression of EGR2 expression.

Show MeSH
Related in: MedlinePlus