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FOXO3a and Posttranslational Modifications Mediate Glucocorticoid Sensitivity in B-ALL
Francesca Consolaro1, Sadaf Ghaem-Maghami2, Roberta Bortolozzi3
1Department of Surgery and Cancer, Imperial College London, Imperial Centre for Translational and Experimental Medicine (ICTEM), London, United Kingdom. Dipartimento di Salute della Donna e del Bambino, Laboratorio di Oncoematologia, University of Padova, Padova, Italy.
Molecular Cancer Research : MCR
|September 18, 2015
Summary
FOXO3a is crucial for dexamethasone effectiveness in B-acute lymphoblastic leukemia (B-ALL). Its activation, involving specific phosphorylation and acetylation, drives cancer cell death and offers potential therapeutic targets for overcoming resistance.
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Signaling
Background:
- Glucocorticoids are standard treatments for B-acute lymphoblastic leukemia (B-ALL).
- The precise molecular mechanisms of glucocorticoid action and resistance in B-ALL remain incompletely understood.
- Identifying key regulators of drug response is critical for improving B-ALL therapy.
Purpose of the Study:
- To investigate the role of FOXO3a in mediating dexamethasone response in B-ALL.
- To elucidate the regulatory mechanisms, including posttranslational modifications, controlling FOXO3a activity.
- To explore the potential of FOXO3a as a therapeutic target for B-ALL treatment.
Main Methods:
- Cell culture of B-ALL cell lines (RS4;11, SUP-B15).
- Dexamethasone treatment and analysis of FOXO3a nuclear translocation.
- Western blotting to assess protein expression, phosphorylation, and acetylation.
- Investigation of signaling pathways including PI3K/Akt and p38/JNK.
Main Results:
- FOXO3a activation by dexamethasone leads to its nuclear translocation and induction of cell death targets (p27Kip1, Bim).
- Dexamethasone-induced FOXO3a activation is partly mediated by suppression of the PI3K/Akt pathway.
- FOXO3a activation is associated with specific phosphorylation (Ser-7) and acetylation (Lys-242/245), linked to p38/JNK and SIRT1/CBP/p300 activity, respectively.
Conclusions:
- FOXO3a is essential for dexamethasone-induced cytotoxicity in B-ALL.
- Specific posttranslational modifications of FOXO3a (phosphorylation and acetylation) are key regulators of its activation.
- Targeting FOXO3a and related pathways (e.g., sirtuins) presents a promising strategy to enhance dexamethasone efficacy and overcome resistance in B-ALL.
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