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Updated: May 23, 2026
Genome-wide Screen for miRNA Targets Using the MISSION Target ID Library
Published on: April 6, 2012
MicroRNA-21 inhibits Serpini1, a gene with novel tumour suppressive effects in gastric cancer
Sumitaka Yamanaka1, Alexandru V Olaru, Fangmei An
1Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Background:
A thorough understanding of gastric cancer at the molecular level is urgently needed. One prominent oncogenic microRNA, miR-21, was previously reported to be upregulated in gastric cancer.
Methods:
We performed an unbiased search for downstream messenger RNA targets of miR-21, based on miR-21 dysregulation, by using human tissue specimens and the MKN28 human gastric carcinoma cell line. Molecular techniques include microRNA microarrays, cDNA microarrays, qRT-PCR for miR and mRNA expression, transfection of MKN28 with miR-21 inhibitor or Serpini1 followed by Western blotting, cell cycle analysis by flow cytometry and luciferase reporter assay.
Results:
This search identified Serpini1 as a putative miR-21 target. Luciferase assays demonstrated direct interaction between miR-21 and Serpini1 3'UTR. miR-21 and Serpini1 expression levels were inversely correlated in a subgroup of gastric cancers, suggesting a regulatory mechanism that included both of these molecules. Furthermore, Serpini1 induced growth retardation of MKN28 and induced vigorous G1/S arrest suggesting its potential tumour-suppressive function in the stomach.
Conclusion:
Taken together, these data suggest that in a subgroup of gastric cancers, miR-21 is upregulated, inducing downregulation of Serpini1, which in turn releases the G1-S transition checkpoint, with the end result being increased tumour growth.
Insights
In gastric cancer, elevated microRNA-21 (miR-21) downregulates Serpini1, promoting tumor growth by releasing cell cycle checkpoints. This identifies a key molecular mechanism in stomach cancer progression.
Area of Science:
- Molecular Oncology
- Cancer Genomics
Background:
- Gastric cancer requires deeper molecular understanding.
- MicroRNA-21 (miR-21) is a known oncogenic microRNA upregulated in gastric cancer.
Purpose of the Study:
- To identify downstream messenger RNA targets of miR-21 in gastric cancer.
- To elucidate the regulatory relationship between miR-21 and its targets.
Main Methods:
- Utilized human gastric carcinoma cell lines (MKN28) and tissue specimens.
- Employed microRNA and cDNA microarrays, qRT-PCR, Western blotting, flow cytometry, and luciferase reporter assays.
Main Results:
- Identified Serpini1 as a direct miR-21 target, confirmed by luciferase assays.
- Observed inverse correlation between miR-21 and Serpini1 expression in gastric cancers.
- Demonstrated Serpini1 induces growth retardation and G1/S arrest in MKN28 cells, indicating tumor-suppressive potential.
Conclusions:
- miR-21 upregulation in gastric cancer downregulates Serpini1.
- This downregulation releases the G1-S transition checkpoint, contributing to increased tumor growth.
- Serpini1 acts as a tumor suppressor in the stomach by inhibiting cell cycle progression.
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