miR‑181b‑p53 negative feedback axis regulates osteosarcoma cell proliferation and invasion

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Osteosarcoma (OS) is a prevalent cancer in young adults with a high risk of metastasis.
• The p53 protein is a crucial tumor suppressor and prognostic marker in OS, frequently altered in approximately 50% of cases.
• MicroRNAs (miRNAs) play significant roles in cancer development, with specific miRNAs acting as oncomiRs or tumor suppressors.

Purpose of the Study:

• To investigate the regulatory relationship between miR-181b and p53 in osteosarcoma.
• To elucidate the functional impact of the miR-181b/p53 axis on OS cell proliferation and invasion.
• To explore the potential of targeting miR-181b for osteosarcoma treatment.

Main Methods:

• Quantitative analysis of miR-181b and p53 expression in OS tissues and cells.
• Luciferase reporter assays to confirm the targeting interactions between miR-181b and p53.
• Western blotting to assess protein level changes following miR-181b or p53 manipulation.
• In vitro cell proliferation and invasion assays.
• In vivo xenograft assays in mice.

Main Results:

• miR-181b was significantly upregulated, while p53 was downregulated in OS tissues and cells, exhibiting a negative correlation.
• p53 directly inhibited miR-181b transcription, and miR-181b suppressed p53 expression, establishing a negative feedback loop.
• miR-181b silencing increased p53 and epithelial-Cadherin, decreased Cyclin D1, and inhibited OS cell proliferation and invasion.
• p53 knockdown reversed these effects and attenuated the impact of miR-181b inhibition.
• In vivo studies confirmed the role of the miR-181b/p53 axis in promoting OS tumor growth.

Conclusions:

• A reciprocal negative feedback loop exists between miR-181b and p53 in osteosarcoma, regulating tumor cell proliferation and invasion.
• Targeting the aberrant upregulation of miR-181b presents a promising therapeutic strategy for osteosarcoma.