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Updated: Oct 25, 2025

A Syngeneic Orthotopic Osteosarcoma Sprague Dawley Rat Model with Amputation to Control Metastasis Rate
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MiR-449a Sponges Cyclin D1 Expression and Suppresses Phosphorylation of Retinoblastoma Protein against Osteosarcoma

Zhongzheng Sun1, Mengliang Gao2, Zhixiang Li1

  • 1Department of Orthopedics, PKUCare Luzhong Hospital, No. 65, Taigong Road, Linzi District, Zibo City, Shandong, China, 255440.

Critical Reviews in Eukaryotic Gene Expression
|August 9, 2021
PubMed

Insights

MicroRNA-449a (miR-449a) inhibits osteosarcoma cell growth by targeting cyclin D1, reducing pRb phosphorylation, and halting cell cycle progression. This suggests miR-449a as a potential therapeutic biomarker for osteosarcoma.

Area of Science:

  • Oncology
  • Molecular Biology
  • Biochemistry

Background:

  • MicroRNA-449a (miR-449a) exhibits tumor-regulatory functions across various cancers.
  • The specific role and mechanism of miR-449a in osteosarcoma remain incompletely understood.

Purpose of the Study:

  • To elucidate the underlying mechanism by which miR-449a regulates osteosarcoma cells.
  • To investigate the potential of miR-449a as a therapeutic biomarker for osteosarcoma.

Main Methods:

  • Quantitative real-time PCR (qRT-PCR), western blot, and immunofluorescence assays were used to assess gene and protein expression.
  • Dual-luciferase reporter assays confirmed miR-449a targets.
  • Cell viability, proliferation, and cell cycle progression were analyzed using CCK-8, colony formation, and flow cytometry assays.

Main Results:

  • Osteosarcoma tissues and cells showed suppressed miR-449a and pRb expression, alongside elevated cyclin D1 levels.
  • Cyclin D1 was identified as a direct target of miR-449a.
  • MiR-449a significantly inhibited osteosarcoma cell viability and proliferation by targeting cyclin D1, thereby reducing pRb phosphorylation and arresting the cell cycle.

Conclusions:

  • MiR-449a exerts an anticancer effect in osteosarcoma by directly targeting cyclin D1 and inhibiting pRb phosphorylation.
  • MiR-449a demonstrates potential as a novel diagnostic and therapeutic biomarker for osteosarcoma.

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