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Role of PML in cell growth and the retinoic acid pathway
1Department of Human Genetics and Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, Sloan-Kettering Division, Graduate School of Medical Sciences, Cornell University, New York, NY 10021, USA.
Abstract:
The PML gene is fused to the retinoic acid receptor alpha (RARalpha) gene in chromosomal translocations associated with acute promyelocytic leukemia (APL). Ablation of murine PML protein by homologous recombination revealed that PML regulates hemopoietic differentiation and controls cell growth and tumorigenesis. PML function was essential for the tumor-growth-suppressive activity of retinoic acid (RA) and for its ability to induce terminal myeloid differentiation of precursor cells. PML was needed for the RA-dependent transactivation of the p21WAF1/CIP1 gene, which regulates cell cycle progression and cellular differentiation. These results indicate that PML is a critical component of the RA pathway and that disruption of its activity by the PML-RARalpha fusion protein may be important in APL pathogenesis.
Insights
The PML gene is crucial for myeloid differentiation and tumor suppression. Its disruption by the PML-RARalpha fusion protein is key in acute promyelocytic leukemia (APL) pathogenesis.
Area of Science:
- Molecular Biology
- Cancer Research
- Hematology
Background:
- Acute promyelocytic leukemia (APL) is characterized by PML-RARalpha fusion genes.
- The PML protein's role in normal hematopoiesis and tumor suppression is not fully understood.
Purpose of the Study:
- To investigate the function of the PML gene in hemopoietic differentiation and tumorigenesis.
- To determine PML's role in the anti-leukemic effects of retinoic acid (RA).
Main Methods:
- Homologous recombination was used to ablate the murine PML gene.
- The effects of PML ablation on hemopoietic differentiation, cell growth, and tumor development were analyzed.
- RA-dependent gene transactivation, including the p21WAF1/CIP1 gene, was assessed.
Main Results:
- PML ablation impaired hemopoietic differentiation and promoted uncontrolled cell growth and tumorigenesis.
- PML is essential for the tumor-suppressive and differentiation-inducing effects of RA.
- PML mediates RA-dependent transactivation of the p21WAF1/CIP1 gene.
Conclusions:
- PML is a critical regulator of hemopoietic differentiation and a tumor suppressor.
- PML is a key component of the retinoic acid signaling pathway.
- Disruption of PML function by the PML-RARalpha fusion protein is likely important in APL pathogenesis.