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Updated: May 30, 2026
Assessing Cell Cycle Progression of Neural Stem and Progenitor Cells in the Mouse Developing Brain after Genotoxic Stress
Published on: May 7, 2014
Cyclin D1 and cdk4 mediate development of neurologically destructive oligodendroglioma
Daniel Ciznadija1, Yuhui Liu, Stephanie M Pyonteck
1Program in Molecular Biology, Memorial Sloan-Kettering Cancer Center, New York, New York, USA.
Abstract:
Although the molecular changes that characterize gliomas have been studied, the pathogenesis of tumor development remains unclear. p21 contributes to gliomagenesis by stabilizing cyclin D1-cdk4 kinase complexes, suggesting that cyclin D1 and cdk4 may also be required for glial tumor development. In this study, we used a mouse model to attempt to confirm this hypothesis, finding that cyclin D1 and cdk4 played active roles in not only the tumor but also the tumor microenvironment. Loss of cdk4 blocked tumor development, but loss of cyclin D1 did not prevent gliomas from developing. Instead, loss of cyclin D1 impeded progression to higher stages of malignancy. Enforcing expression of cyclin D1 was insufficient to correct the progression defect observed in cyclin D1-deficient animals. In contrast, restoration of cdk4 in the cdk4-deficient animals restored cell proliferation and tumor formation, although at lower tumor grades. Notably, the failure of tumors in the cyclin D1- and cdk4-deficient animals to progress to higher grades was correlated with a failure to fully activate microglia in the tumor microenvironment. Moreover, when platelet-derived growth factor-transformed glial cells were engrafted orthotopically into the mice, the tumors that formed progressed to high grades in wild-type mice but not cyclin D1-deficient animals. Together, our findings establish that the cyclin D1-cdk4 axis is not only critical in glial tumor cells but also in stromal-derived cells in the surrounding tumor microenvironment that are vital to sustain tumor outgrowth.
Insights
The cyclin D1-cdk4 axis is crucial for glioma development and progression. This axis impacts both tumor cells and the surrounding microenvironment, affecting tumor growth and malignancy.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Research
Background:
- Glioma pathogenesis remains unclear despite known molecular changes.
- p21 stabilizes cyclin D1-cdk4 complexes, implicating them in gliomagenesis.
- The role of cyclin D1 and cdk4 in glial tumor development requires further investigation.
Purpose of the Study:
- To investigate the roles of cyclin D1 and cdk4 in glioma development and progression using a mouse model.
- To determine the involvement of the cyclin D1-cdk4 axis in both tumor cells and the tumor microenvironment.
- To elucidate the impact of cyclin D1 and cdk4 on glial tumor malignancy and microglial activation.
Main Methods:
- Utilized a mouse model to study glioma development.
- Assessed the effects of cyclin D1 and cdk4 loss and restoration on tumor formation and progression.
- Examined microglial activation in the tumor microenvironment.
- Engrafted platelet-derived growth factor-transformed glial cells orthotopically into mice.
Main Results:
- Loss of cdk4 blocked tumor development, while loss of cyclin D1 impeded progression to higher malignancy grades.
- Restoration of cdk4 restored proliferation and tumor formation, albeit at lower grades.
- Failure of tumor progression in cyclin D1- and cdk4-deficient mice correlated with impaired microglial activation.
- Tumors formed from engrafted cells progressed to high grades in wild-type mice but not in cyclin D1-deficient animals.
Conclusions:
- The cyclin D1-cdk4 axis is critical for both glial tumor cells and stromal cells within the tumor microenvironment.
- This axis is vital for sustaining tumor outgrowth and progression to higher malignancy grades.
- Targeting the cyclin D1-cdk4 axis may offer therapeutic strategies for glioma treatment by impacting tumor cells and their microenvironment.
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