The G-Quadruplex experimental drug QN-302 effectively impairs liposarcoma cell viability by inhibiting MDM2 expression and restoring p53 levels [CUT&Tag]

Well-differentiated (WD) and dedifferentiated (DD) liposarcomas (LPS) account for ~60% of all liposarcomas, characterized by 12q13–q15 region amplification and aberrant MDM2 expression. Current therapies are limited, particularly for advanced stages, leading to poor outcomes. G-quadruplexes (G4s), secondary structures in G-rich nucleic acid sequences, were identified in the MDM2 P2 promoter. We investigated MDM2 inhibition via small molecule G4 ligands. Laboratory and patient-derived LPS cell lines, and normal pre-adipocytes were analyzed using CUT&Tag, RNA-seq, cell viability, qRT-PCR, Western blot, siRNA, and nascent transcript assays. QN-302, a naphthalene diimide (NDI)-derivative, emerged as the most effective G4 ligand, significantly impairing WD/DDLPS cell growth in a dose-dependent manner by stabilizing MDM2 G4 at the P2 promoter, inhibiting polymerase progression, and reducing full-length MDM2 transcripts, leading to p53 accumulation and apoptotic cell death. In vivo, QN-302 reduced tumor volume and was well-tolerated in xenograft models. This novel therapeutic strategy to inhibit MDM2 and reactivate p53 in WD/DDLPS could extend to all tumors with wild-type TP53 and enhance anticancer efficacy when combined with other drugs.