A new approach for elimination of apoptotic resistance caused by MDM2/MDMX amplification in chronic lymphocytic leukemia: combination of ALRN-6924 and radiofrequency exposure.

Chronic lymphocytic leukemia (CLL) is characterized by mature B lymphocyte accumulation and frequent MDM2/MDMX overexpression, leading to p53 inactivation and apoptotic resistance. ALRN-6924, a stapled peptide dual inhibitor, targets MDM2/MDMX to restore p53 function. This study evaluated ALRN-6924 efficacy alone and combined with radiofrequency (RF) exposure in CLL cell lines. Molecular docking assessed ALRN-6924-MDM2 binding affinity. Cytotoxic and apoptotic effects were evaluated using XTT assays and flow cytometry in HG-3 (wild-type p53) and MEC-1 (mutant p53) cell lines. Treatments included ALRN-6924 monotherapy and combination with 900 MHz RF exposure (120 mW/cm). MDM2, MDMX, BCL-2, and p53 protein levels were quantified by ELISA. Molecular docking revealed strong ALRN-6924-MDM2 binding (energy: - 9.30 kcal/mol, Ki: 163.9 nM). ALRN-6924 demonstrated potent cytotoxicity in HG-3 cells (IC: 7.54 μM at 24 h, 5.88 μM at 48 h) versus resistance in MEC-1 cells (IC: ~ 36 μM). In HG-3 cells, ALRN-6924 significantly induced apoptosis and necroptosis, reduced MDM2/MDMX expression, and enhanced p53 levels. RF combination therapy showed synergistic effects, further improving efficacy compared to monotherapy. BCL-2 expression was significantly reduced in the combination group. ALRN-6924 demonstrates promising therapeutic potential in wild-type p53 CLL cells, with enhanced efficacy when combined with RF exposure. The compound effectively disrupts the MDM2/MDMX-p53 axis, restoring p53 function and inducing programmed cell death. In mutant p53 cells, combination therapy may provide partial benefits. These findings support ALRN-6924 clinical development as targeted therapy for p53-functional CLL, particularly in combination strategies.