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Published on: March 30, 2019
Negative regulation of CDC42 expression and cell cycle progression by miR-29a in breast cancer
Mingliang Zhang1, Wei Guo2, Jun Qian2
1Department of Breast Surgery, The First Affiliated Hospital of AnHui Medical University, AnHui province, 230032 China; Department of Oncology Surgery, The First Affiliated Hospital of BengBu Medical College, AnHui province, 233000 China.
Objective:
The inhibitory role of microRNA-29a (miR-29a) has been assessed in breast cancer cells. Herein, we analyze the underlying mechanisms of its role in cell cycle progression in breast cancer cells.
Methods:
We applied real-time polymerase chain reaction (PCR) to detect the expression of miR-29 in breast cancer cell lines. Then one of the cell lines, MDA-MB-453, was transfected with mimics of miR-29a. The cell cycle was analyzed by fluorescence-activated cell sorting after staining the cells with propidium iodide. Real-time PCR, luciferase assay and western blot were used together to verify the regulation of the predicted target, cell division cycle 42 (CDC42) by miR-29a.
Results:
MiR-29s were decreased in our selected mammary cell lines, among which miR-29a was the dominant isoform. Overexpression of miR-29a caused cell cycle arrest at the G0/G1 phase. We further found that miR-29a could target the expression of CDC42, which is a small GTPase associated with cell cycle progression.
Conclusion:
We suggest that miR-29a exerts its tumor suppressor role in breast cancer cells partially by arresting the cell cycle through negative regulation of CDC42.
Insights
MicroRNA-29a (miR-29a) acts as a tumor suppressor in breast cancer by halting cell cycle progression. This study reveals miR-29a inhibits cell division cycle 42 (CDC42) to achieve this effect.
Area of Science:
- Molecular Biology
- Cancer Research
- Genetics
Background:
- MicroRNAs (miRNAs) play crucial roles in regulating gene expression.
- Dysregulation of miRNAs is implicated in various cancers, including breast cancer.
- The specific role of microRNA-29a (miR-29a) in breast cancer cell cycle progression requires further elucidation.
Purpose of the Study:
- To investigate the inhibitory role of miR-29a in breast cancer.
- To elucidate the mechanisms by which miR-29a influences breast cancer cell cycle progression.
- To identify potential targets of miR-29a involved in cell cycle regulation.
Main Methods:
- Real-time polymerase chain reaction (PCR) to quantify miR-29 expression in breast cancer cell lines.
- Transfection of MDA-MB-453 cells with miR-29a mimics for overexpression studies.
- Flow cytometry analysis of cell cycle distribution after propidium iodide staining.
- Luciferase assay and Western blot to validate the regulatory relationship between miR-29a and its target, cell division cycle 42 (CDC42).
Main Results:
- Expression levels of miR-29s were found to be decreased in selected breast cancer cell lines, with miR-29a being the predominant isoform.
- Overexpression of miR-29a led to cell cycle arrest at the G0/G1 phase.
- miR-29a was confirmed to directly target and downregulate the expression of CDC42, a key regulator of cell cycle progression.
Conclusions:
- miR-29a functions as a tumor suppressor in breast cancer cells.
- The tumor-suppressive activity of miR-29a is partly mediated by inducing cell cycle arrest.
- Negative regulation of CDC42 by miR-29a is a key mechanism underlying its effect on the breast cancer cell cycle.
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