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Updated: May 12, 2026
Analysis of Combinatorial miRNA Treatments to Regulate Cell Cycle and Angiogenesis
Published on: March 30, 2019
The tumor-suppressive miR-497-195 cluster targets multiple cell-cycle regulators in hepatocellular carcinoma
Mayuko Furuta1, Ken-ichi Kozaki, Kousuke Tanimoto
1Department of Molecular Cytogenetics, Medical Research Institute and School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan.
Abstract:
MicroRNAs (miRNAs) are key post-transcriptional regulators of gene expression and commonly deregulated in carcinogenesis. To explore functionally crucial tumor-suppressive (TS)-miRNAs in hepatocellular carcinoma (HCC), we performed integrative function- and expression-based screenings of TS-miRNAs in six HCC cell lines. The screenings identified seven miRNAs, which showed growth-suppressive activities through the overexpression of each miRNA and were endogenously downregulated in HCC cell lines. Further expression analyses using a large panel of HCC cell lines and primary tumors demonstrated four miRNAs, miR-101, -195, -378 and -497, as candidate TS-miRNAs frequently silenced in HCCs. Among them, two clustered miRNAs miR-195 and miR-497 showed significant growth-suppressive activity with induction of G1 arrest. Comprehensive exploration of their targets using Argonute2-immunoprecipitation-deep-sequencing (Ago2-IP-seq) and genome-wide expression profiling after their overexpression followed by pathway analysis, revealed a significant enrichment of cell cycle regulators. Among the candidates, we successfully identified CCNE1, CDC25A, CCND3, CDK4, and BTRC as direct targets for miR-497 and miR-195. Moreover, target genes frequently upregulated in HCC in a tumor-specific manner, such as CDK6, CCNE1, CDC25A and CDK4, showed an inverse correlation in the expression of miR-195 and miR-497, and their targets. These results suggest the molecular pathway regulating cell cycle progression to be integrally altered by downregulation of miR-195 and miR-497 expression, leading to the aberrant cell proliferation in hepatocarcinogenesis.
Insights
Tumor-suppressive microRNAs (miRNAs) like miR-195 and miR-497 are frequently silenced in hepatocellular carcinoma (HCC). Their downregulation disrupts cell cycle regulation, promoting tumor growth in HCC.
Area of Science:
- Oncology
- Molecular Biology
- Gene Regulation
Background:
- MicroRNAs (miRNAs) are critical post-transcriptional regulators of gene expression.
- Dysregulation of miRNAs is a common event in cancer development, including hepatocellular carcinoma (HCC).
- Identifying tumor-suppressive miRNAs (TS-miRNAs) is crucial for understanding HCC pathogenesis.
Purpose of the Study:
- To identify and functionally characterize TS-miRNAs that are downregulated in HCC.
- To investigate the role of specific TS-miRNAs in regulating cell cycle progression in HCC.
- To elucidate the molecular mechanisms by which these miRNAs suppress tumor growth.
Main Methods:
- Integrative function- and expression-based screening of TS-miRNAs in HCC cell lines.
- Overexpression of candidate miRNAs and assessment of growth-suppressive activities.
- Argonaute2-immunoprecipitation followed by deep sequencing (Ago2-IP-seq) to identify miRNA targets.
- Genome-wide expression profiling and pathway analysis.
Main Results:
- Seven miRNAs exhibited growth-suppressive activities and were downregulated in HCC cell lines.
- Four candidate TS-miRNAs (miR-101, -195, -378, -497) were frequently silenced in HCC.
- miR-195 and miR-497 demonstrated significant growth suppression by inducing G1 arrest.
- CCNE1, CDC25A, CCND3, CDK4, and BTRC were identified as direct targets of miR-497 and miR-195.
- Inverse correlation observed between miR-195/-497 expression and their target genes (e.g., CDK6, CCNE1, CDC25A, CDK4) in HCC tumors.
Conclusions:
- miR-195 and miR-497 function as potent tumor suppressors in HCC.
- Downregulation of miR-195 and miR-497 contributes to aberrant cell proliferation by dysregulating cell cycle regulators.
- These miRNAs represent potential therapeutic targets for HCC treatment.
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