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Updated: Jan 29, 2026
Describing a Transcription Factor Dependent Regulation of the MicroRNA Transcriptome
Published on: June 15, 2016
MicroRNA-340-5p suppresses osteosarcoma development by down-regulating the Wnt/β-catenin signaling pathway via
1Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, China. dempseywell@163.com.
Objective:
To study the effects of miR-340-5p on the proliferation of osteosarcoma (OS) U2OS cells.
Patients And Methods:
miR-340-5p expression was measured by quantitative Real-time Polymerase Chain Reaction (qRT-PCR) in cancer tissues and paracancerous tissues from OS patients, and in OS cell line U2OS and normal osteoblast cell line hFOB1.19. The dual luciferase reporter vector was constructed to verify whether Signal transducers and activators of transcription 3 (STAT3) were a potential target gene of miR-340-5p. MiR-340-5p mimics/inhibitor was transfected into U2OS cells using liposomes, and transfection results were verified by qRT-PCR. Cell Counting Kit-8 (CCK-8) and Annexin V/PI were used to analyze the proliferation and apoptosis of transfected cells, respectively. Western Blot was used to detect STAT3 protein expression and Wnt/β-catenin pathway-related proteins after transfection. U2OS cells were injected into nude mice to observe the effects of over expression of miR-340-5p on tumor growth in vivo.
Results:
miR-340-5p gene expression in OS tissues and U2OS cells was significantly lower than that in paracancerous tissues and hFOB1.19 cells. miR-340-5p directly interacted with the 3'-untranslated region (3'-UTR) of STAT3 gene and negatively regulated its expression. The increase of miR-340-5p expression could significantly inhibit U2OS proliferation in vitro and induce apoptosis, and vice versa. STAT3, β-catenin, c-Myc, TCF-4, CyclinD1, and ROCK1 protein expression in U2OS cells was significantly decreased after miR-340-5p over-expression, and vice versa. MiR-340-5p over-expression in nude mice significantly decreased tumor size and weight.
Conclusions:
Low expression of miR-340-5p in OS and U2OS cells could inhibit the course of OS by negatively regulating Wnt/β-catenin signaling pathway through targeting STAT3 gene. Therefore, miR-340-5p might be a potential biomarker and target for the diagnosis and treatment of OS.
Insights
Low miR-340-5p expression promotes osteosarcoma (OS) growth by activating the STAT3/Wnt/β-catenin pathway. Restoring miR-340-5p inhibits OS cell proliferation and tumor growth, suggesting its potential as a therapeutic target.
Area of Science:
- Molecular Biology
- Oncology
- Biochemistry
Background:
- Osteosarcoma (OS) is a primary bone malignancy with a complex molecular landscape.
- MicroRNAs (miRNAs) play crucial roles in regulating gene expression and are implicated in various cancers, including OS.
Purpose of the Study:
- To investigate the role of miR-340-5p in the proliferation and apoptosis of osteosarcoma (OS) U2OS cells.
- To elucidate the molecular mechanism underlying miR-340-5p's function in OS, focusing on its interaction with STAT3 and the Wnt/β-catenin pathway.
Main Methods:
- Quantitative Real-time Polymerase Chain Reaction (qRT-PCR) to assess miR-340-5p expression in patient tissues and cell lines.
- Dual luciferase reporter assay to confirm STAT3 as a direct target of miR-340-5p.
- In vitro assays (CCK-8, Annexin V/PI) and in vivo xenograft models to evaluate the functional effects of miR-340-5p modulation on OS cell proliferation, apoptosis, and tumor growth.
Main Results:
- miR-340-5p expression was significantly downregulated in OS tissues and cells compared to normal counterparts.
- miR-340-5p directly targets and negatively regulates STAT3 expression.
- Overexpression of miR-340-5p suppressed U2OS cell proliferation, induced apoptosis, and inhibited tumor growth in vivo by downregulating STAT3 and downstream Wnt/β-catenin pathway components (β-catenin, c-Myc, CyclinD1).
Conclusions:
- Downregulation of miR-340-5p contributes to OS progression by promoting STAT3-mediated activation of the Wnt/β-catenin signaling pathway.
- miR-340-5p holds potential as a diagnostic biomarker and a therapeutic target for osteosarcoma.
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