CD123 Antagonistic Peptides Assembled with Nanomicelles Act as Monotherapeutics to Combat Refractory Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. Due to the development of drug resistance to traditional chemotherapies and high relapse rate, AML still has a low survival rate and there is in an urgent need for better treatment strategies. CD123 is widely expressed by AML cells, also associated with the poor prognosis of AML. In this study, we fabricated nanomicelles loaded with a lab-designed CD123 antagonistic peptide, which were referred to as ^mPO-6. The antagonistic and therapeutic effects were investigated with CD123⁺ AML cell lines and a refractory AML mouse (AE and CKIT^D816V) model. Results show that ^mPO-6 can specifically bind to the CD123⁺ AML cells and inhibit the cell viability effectively. Intravenous administration of ^mPO-6 significantly reduces the percentage of AML cells' infiltration and prolongs the median survival of AML mice. Further, the efficiency of ^mPO-6 is demonstrated to interfere with the axis of CD123/IL-3 via regulating the activation of STAT5, PI3K/AKT, and NF-κB signaling pathways related to cell proliferation or apoptosis at the level of mRNA and protein in vivo and in vitro. In conclusion, the novel CD123 antagonistic peptide micelle formulation ^mPO-6 can significantly enhance apoptosis and prolong the survival of AML mice by effectively interfering with the axis of CD123/IL-3 and therefore is a promising therapeutic candidate for the treatment of refractory AML.