Targeting MDM2-mediated suppression of p53 with idasanutlin: a promising therapeutic approach for acute lymphoblastic leukemia

Abstract

Despite available treatments for acute lymphoblastic leukemia (ALL), the disease's high clinical variability necessitates new therapeutic strategies, particularly for patients with high-risk features. The tumor suppressor protein p53, encoded by the TP53 gene and known as the guardian of the genome, plays a crucial role in preventing tumor development. Over 90% of ALL cases initially harbor wild-type TP53. Reactivation of p53, which is encoded from the wild type TP53 but lost its function for several reasons, is an attractive therapeutic approach in cancer treatment. p53 can be activated in a non-genotoxic manner by targeting its primary repressor, the MDM2 protein. Clinical trials involving MDM2 inhibitors are currently being conducted in a growing body of investigation, reflecting of the interest in incorporating these treatments into cancer treatment strategies. Early-phase clinical trials have demonstrated the promise of idasanutlin (RG7388), one of the developed compounds. It is a second-generation MDM2-p53 binding antagonist with enhanced potency, selectivity, and bioavailability. The aim of this study is to evaluate the efficacy of RG7388 as a therapeutic strategy for ALL and to investigate its potential impact on improving treatment outcomes for high-risk patients. RG7388 potently decreased the viability in five out of six ALL cell lines with diverse TP53 mutation profiles, whereas only one cell line exhibited high resistance. RG7388 induced a pro-apoptotic gene expression signature with upregulation of p53-target genes involved in the intrinsic and extrinsic pathways of apoptosis. Consequently, RG7388 led to a concentration-dependent increase in caspase-3/7 activity and cleaved poly (ADP-ribose) polymerase. In this research, RG7388 was investigated with pre-clinical methods in ALL cells as a novel treatment strategy. This study suggests further functional research and in-vivo evaluation, and it highlights the prospect of treating p53-functional ALL with MDM2 inhibitors.