Targeting MDM2-dependent serine metabolism as a therapeutic strategy for liposarcoma

Area of Science:

• Oncology
• Molecular Biology
• Metabolic Pathways

Background:

• Well-differentiated and dedifferentiated liposarcomas (LPSs) exhibit amplification of the MDM2 oncogene, a regulator of the p53 pathway.
• The precise mechanisms driving MDM2 overexpression and its impact on p53 in LPS remain unclear.
• MDM2's role in regulating cellular metabolism, independent of p53, is increasingly recognized.

Purpose of the Study:

• To investigate the p53-independent metabolic functions of MDM2 in liposarcoma.
• To explore the role of serine metabolism in liposarcoma growth.
• To evaluate therapeutic strategies targeting MDM2's metabolic functions.

Main Methods:

• Analysis of MDM2's interaction with chromatin in LPS cells.
• Assessment of serine metabolism pathways in LPS.
• Treatment of LPS cells and patient-derived xenografts with MDM2 inhibitors (Nutlin-3A, SP141) and serine synthesis inhibitors.
• Evaluation of tumor growth in vitro and in vivo.

Main Results:

• Chromatin-bound MDM2's metabolic functions are enhanced in LPS, driving addiction to serine metabolism for nucleotide synthesis and tumor growth.
• Nutlin-3A, an MDM2-p53 inhibitor, unexpectedly increased MDM2's chromatin recruitment and control over serine metabolism, potentially explaining its limited clinical efficacy.
• Inhibition of chromatin-bound MDM2 by SP141 or interference with serine synthesis significantly impaired LPS growth in vitro and in vivo.

Conclusions:

• Targeting MDM2's role in serine metabolism presents a promising therapeutic avenue for liposarcoma.
• The p53-independent functions of MDM2 in regulating metabolism are critical for LPS progression.
• SP141 and serine synthesis inhibition demonstrate potential as novel treatment strategies for liposarcoma.