# The MDM2-p53 Axis in Osteosarcoma: Current Understanding of Regulatory Mechanisms and Targeted Therapeutic Strategies

## TL;DR

This paper reviews the role of the MDM2-p53 pathway in osteosarcoma and explores new targeted therapies, including inhibitors and gene therapy.

## Contribution

The paper provides a systematic review of molecular mechanisms and emerging therapeutic strategies targeting the MDM2-p53 axis in osteosarcoma.

## Key findings

- Dysregulation of the MDM2-p53 pathway contributes to osteosarcoma progression and chemotherapy resistance.
- New MDM2 inhibitors like APG-115 have advanced to Phase II trials, offering potential for precision medicine.
- Future drug development may benefit from single-cell sequencing and AI-aided design to address tumor heterogeneity.

## Abstract

Osteosarcoma, the most prevalent primary malignant bone tumor in children and adolescents, is characterized by high rates of metastasis, recurrence, and chemotherapy resistance, leading to suboptimal patient survival. The MDM2-p53 pathway plays a pivotal role in its tumorigenesis and progression, where dysregulation leads to loss of p53 function. This review systematically elucidates the molecular mechanisms of this pathway and summarizes diverse targeted therapeutic strategies, including small-molecule MDM2 inhibitors, mutant p53 reactivators, and innovative modalities such as gene therapy and Proteolysis Targeting Chimeras (PROTACs). Despite demonstrating potent preclinical activity with low IC50 values, the clinical translation of these agents has faced significant challenges. Early-generation MDM2 inhibitors (e.g., RG7112, Idasanutlin) showed limited monotherapy efficacy and dose-limiting toxicities like thrombocytopenia, halting their development at early-phase clinical trials. In contrast, novel MDM2 inhibitors like APG-115 have advanced to Phase II trials, marking a significant breakthrough. Although not yet tested in dedicated osteosarcoma cohorts, their safety and efficacy in MDM2-amplified solid tumors provide a critical foundation for the development of precision medicine and combination regimens for osteosarcoma. Future efforts to accelerate drug development may leverage single-cell sequencing and AI-aided drug design to decipher osteosarcoma heterogeneity and optimize drug profiles for reduced toxicity.