miR-320a suppresses colorectal cancer progression by targeting Rac1
Hongchao Zhao1, Taotao Dong, Houmin Zhou
1Shanghai Key Laboratory of Gastric Neoplasms, Department of General Surgery, Shanghai Institute of Digestive Surgery, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, People's Republic of China.
Abstract:
MicroRNAs (miRNAs) have emerged as critical epigenetic regulators involved in cancer progression. miR-320a has been identified to be a novel tumour suppressive miRNA in colorectal cancer (CRC). However, the detailed molecular mechanisms are not fully understood. Here, we reported that miR-320a inversely associated with CRC aggressiveness in both cell lines and clinical specimens. Functional studies demonstrated that miR-320a significantly decreased the capability of cell migration/invasion and induced G0/G1 growth arrest in vitro and in vivo. Furthermore, Rac1 was identified as one of the direct downstream targets of miR-320a and miR-320a specifically binds to the conserved 8-mer at position 1140-1147 of Rac1 3'-untranslated region to regulate Rac1 protein expression. Over-expression of miR-320a in SW620 cells inhibited Rac1 expression, whereas reduction of miR-320a by anti-miR-320a in SW480 cells enhanced Rac1 expression. Re-expression of Rac1 in the SW620/miR-320a cells restored the cell migration/invasion inhibited by miR-320a, whereas knockdown of Rac1 in the SW480/anti-miR-320a cells repressed these cellular functions elevated by anti-miR-320a. Conclusively, our results demonstrate that miR-320a functions as a tumour-suppressive miRNA through targeting Rac1 in CRC.
Insights
MicroRNAs (miRNAs) are key in cancer. miR-320a suppresses colorectal cancer (CRC) by targeting Rac1, inhibiting cell migration, invasion, and promoting growth arrest.
Area of Science:
- Molecular Biology
- Epigenetics
- Cancer Research
Background:
- MicroRNAs (miRNAs) are critical epigenetic regulators in cancer progression.
- miR-320a is a newly identified tumor-suppressive miRNA in colorectal cancer (CRC).
- The precise molecular mechanisms of miR-320a in CRC are not fully elucidated.
Purpose of the Study:
- To investigate the role and molecular mechanisms of miR-320a in colorectal cancer.
- To identify downstream targets of miR-320a involved in CRC progression.
- To evaluate the therapeutic potential of targeting the miR-320a/Rac1 axis in CRC.
Main Methods:
- Correlation analysis of miR-320a expression with CRC aggressiveness in cell lines and clinical specimens.
- In vitro and in vivo functional assays to assess the impact of miR-320a on cell migration, invasion, and growth.
- Luciferase reporter assays and Western blotting to validate Rac1 as a direct target of miR-320a.
- Rescue experiments involving re-expression of Rac1 or knockdown of Rac1.
Main Results:
- miR-320a expression inversely correlated with CRC aggressiveness.
- Overexpression of miR-320a inhibited cell migration, invasion, and induced G0/G1 growth arrest.
- Rac1 was identified as a direct downstream target of miR-320a, with miR-320a binding to the Rac1 3'-UTR.
- Modulation of miR-320a levels directly affected Rac1 protein expression.
- Restoration of Rac1 reversed the inhibitory effects of miR-320a on migration and invasion.
Conclusions:
- miR-320a acts as a tumor suppressor in colorectal cancer.
- The tumor-suppressive function of miR-320a is mediated through the direct targeting and downregulation of Rac1.
- Targeting the miR-320a/Rac1 pathway holds potential for CRC therapy.
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