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Updated: Jul 4, 2026

Induction of Mesenchymal-Epithelial Transitions in Sarcoma Cells
Published on: April 7, 2017
Enhanced MDM2 Oncoprotein Expression in Soft Tissue Sarcoma: Several Possible Regulatory Mechanisms
R E Pollock1, A Lang, A K El-Naggar
1Department of Surgical Oncology MD Anderson Cancer Center 1515 Holcombe Blvd, Box 106 University of Texas Houston TX 77030 USA.
MDM2 oncoprotein over-production in soft tissue sarcoma is linked to DNA amplification and may involve post-transcriptional regulation, impacting cell cycle arrest and DNA repair. Therapeutic strategies targeting MDM2 over-production show promise.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- MDM2 oncogene protein product can promote tumorigenesis by inhibiting p53 tumor suppressor-mediated cell cycle arrest.
- MDM2 DNA amplification is common in human sarcoma, but its link to oncoprotein over-production and functional significance in soft tissue sarcoma is unclear.
Purpose of the Study:
- To investigate the mechanisms linking MDM2 DNA amplification to MDM2 oncoprotein over-production in soft tissue sarcoma.
- To assess the functional significance of MDM2 oncoprotein over-production in soft tissue sarcoma.
Main Methods:
- Assembled a soft tissue sarcoma tissue bank with autologous normal tissues.
- Analyzed DNA and RNA for MDM2 DNA amplification (Southern blots) and mRNA over-expression (Northern blots).
- Examined MDM2 protein levels using Western blots and assessed p53 DNA and mRNA expression.
Main Results:
- MDM2 DNA amplification was detected in 10 of 30 soft tissue sarcomas.
- MDM2 oncoprotein over-production was observed, correlating with DNA amplification and mRNA over-expression in some cases.
- Post-transcriptional regulation was suggested in cases with normal MDM2 mRNA but elevated MDM2 protein, impacting cell cycle arrest.
Conclusions:
- Multiple mechanisms contribute to MDM2 oncoprotein over-production in soft tissue sarcoma.
- MDM2 oncoprotein over-production is functionally relevant, associated with decreased G(0)/G(1) cell cycle arrest.
- Therapeutic strategies targeting MDM2 over-production, such as transcriptional repression or RNA antisense approaches, may be effective.
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