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Updated: Sep 10, 2025
Analysis of Combinatorial miRNA Treatments to Regulate Cell Cycle and Angiogenesis
Published on: March 30, 2019
MiR-145-5p arrests the cell cycle by modulating SMAD5/cyclin D1 to inhibit gastric cancer progression
Li Wang1,2, Jianghong Guo3, Caixia Lv4
1Department of Biochemistry and Molecular Biology, Shanxi Key Laboratory of Birth Effects and Cell Regeneration, MOE Key Laboratory of Coal Environmental Pathogenicity and Prevention, MOE Key Laboratory of Cellular Physiology, Shanxi Medical University, Taiyuan, China.
Purpose:
This study aimed to explore the dysregulation of miR-145-5p in gastric cancer (GC) and its effects on the proliferation and cell cycle of GC cells, exploring the potential regulatory mechanism of miR-145-5p in GC.
Methods:
In this study, the TCGA database combined with Microarray was used to detect differentially expressed microRNA (miRNA) in GC tissues and cells. Quantitative real-time (qRT)-PCR was used to further verify the expression of miR-145-5p in GC cells and the 41 pairs of GC tissues and adjacent tissues. A retrospective analysis was conducted on the correlation between miR-145-5p and the clinicopathological characteristics of patients with GC. The proliferation ability and cell cycle of AGS and MKN28 were detected by CCK-8, Edu and flow cytometry. The downstream target genes of miR-145-5p were screened by bioinformatics and further verified by the dual-luciferase reporter assay. Immunohistochemistry was used to detect the expression of SMAD5 in GC tissues. Western blot was used to detect cell cycle-related proteins that were regulated by siRNA SMAD5.
Results:
The expression of miR-145-5p was lower in GC tissues and cells compared with adjacent tissues and GES-1, and was related to the poor prognosis of patients with GC. Overexpression of miR-145-5p inhibited the proliferation of GC cells and blocked the cell cycle from G1 phase to S phase. MiR-145-5p targeted SMAD5 to inhibit the proliferation, and arrested the G1/S phase transition of GC cells. Mechanistically, SMAD5 siRNA significantly reduced CCND1 protein expression, Bioinformatics databases predicted that cyclin D1 was the transcription target gene of SMAD5. Moreover, the re-expression of cyclin D1 partially reversed the cell cycle arrest that was induced by SMAD5 depletion in GC cells.
Conclusion:
Taken together, these findings reveal a novel role of the miR-145-5p/SMAD5/cyclin D1 axis in modulating cell cycle progression and cell proliferation in GC, which may provide a prognostic biomarker for GC treatment.
Insights
This study found that miR-145-5p is downregulated in gastric cancer (GC), inhibiting cancer cell proliferation and cell cycle progression. The miR-145-5p/SMAD5/cyclin D1 axis offers a potential prognostic biomarker for GC treatment.
Area of Science:
- Molecular oncology
- Cancer biology
- Genetics and genomics
Background:
- Gastric cancer (GC) remains a significant global health challenge with complex underlying molecular mechanisms.
- Dysregulation of microRNAs (miRNAs) plays a crucial role in various cancers, including GC.
- Identifying novel molecular targets is essential for improving GC diagnosis and treatment strategies.
Purpose of the Study:
- To investigate the role and regulatory mechanism of miR-145-5p in gastric cancer.
- To determine the impact of miR-145-5p on GC cell proliferation and cell cycle.
- To explore the potential therapeutic and prognostic value of miR-145-5p in GC.
Main Methods:
- Utilized TCGA database and Microarray analysis to identify differentially expressed miRNAs in GC.
- Employed quantitative real-time PCR (qRT-PCR) to validate miR-145-5p expression in GC tissues and cells.
- Performed cell proliferation assays (CCK-8, Edu) and flow cytometry to assess cell cycle effects.
- Screened and verified downstream target genes of miR-145-5p using bioinformatics and dual-luciferase reporter assays.
- Investigated protein expression via immunohistochemistry and Western blot.
Main Results:
- miR-145-5p expression was significantly lower in GC tissues and cells compared to adjacent tissues.
- Reduced miR-145-5p expression correlated with poor prognosis in GC patients.
- Overexpression of miR-145-5p suppressed GC cell proliferation and induced G1/S phase cell cycle arrest.
- miR-145-5p directly targets SMAD5, inhibiting proliferation and arresting the G1/S phase transition.
- SMAD5 depletion reduced cyclin D1 expression, a key regulator of cell cycle progression.
Conclusions:
- The miR-145-5p/SMAD5/cyclin D1 axis is a critical regulator of cell cycle progression and proliferation in GC.
- miR-145-5p acts as a tumor suppressor in gastric cancer.
- This axis represents a promising novel prognostic biomarker and potential therapeutic target for GC treatment.
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