PRIMA-1(MET) induces death in soft-tissue sarcomas cell independent of p53.

Background: The aim of this study was to explore the efficacy and define mechanisms of action of PRIMA-1(MET) as a TP53 targeted therapy in soft-tissue sarcoma (STS) cells.

Methods: We investigated effects of PRIMA-1(MET) on apoptosis, cell cycle, and induction of oxidative stress and autophagy in a panel of 6 STS cell lines with different TP53 status.

Results: Cell viability reduction by PRIMA-1(MET) was significantly observed in 5 out of 6 STS cell lines. We found that PRIMA-1(MET) was capable to induce cell death not only in STS cells harboring mutated TP53 but also in TP53-null STS cells demonstrating that PRIMA-1(MET) can induce cell death independently of TP53 in STS cells. We identified an important role of reactive oxygen species (ROS), involved in PRIMA-1(MET) toxicity in STS cells leading to a caspase-independent cell death. ROS toxicity was associated with autophagy induction or JNK pathway activation which represented potential mechanisms of cell death induced by PRIMA-1(MET) in STS.

Conclusions: PRIMA-1(MET) anti-tumor activity in STS partly results from off-target effects involving ROS toxicity and do not deserve further development as a TP53-targeted therapy in this setting.