Targeting CD33 With Hesperidin: A Natural Strategy for Acute Myeloid Leukemia Treatment.

CD33 is widely expressed on blasts in most acute myeloid leukemia (AML) patients, serving as a marker of myeloid differentiation. The broad expression of CD33 on AML blasts has made it an attractive drug target so that therapies could be developed to eliminate malignant cells while sparing normal hematopoietic stem cells. Targeting CD33 by natural compounds can be an attractive therapeutic strategy to identify and develop small natural molecule inhibitors. Molecular docking was performed to analyze the interaction between a library of phytocompounds and CD33 using AutoDock Vina software. Hesperidin emerged as the top-performing compound, based on its binding affinity with CD33. A wide array of pharmacological effects, including anticancer properties, such as the ability to protect against malignant transformation and tumor progression are exhibited by hesperidin. In this report, the mechanism of interaction of hesperidin with CD33 was studied by spectroscopic techniques such as UV-visible absorption, fluorescence spectroscopy, and circular dichroism. Fluorescence quenching of CD33 by hesperidin demonstrated the formation of CD33-hesperidin complex by static quenching mechanism. Binding parameters calculated by the Stern-Volmer method showed that hesperidin binds to CD33 with moderate to high affinity with stoichiometry of 1:1. The thermodynamic analysis revealed that the binding was spontaneous and enthalpy driven with hydrogen bonding playing a major role in hesperidin-CD33 binding. CD spectra analysis suggests very little conformational changes in CD33 on hesperidin binding. In vitro observations were further complemented by molecular dynamics simulation analyses which confirmed the formation of a stable CD33-hesperidin complex. These substantial in vitro and in silico studies provide the basis for the therapeutic implication of hesperidin in AML after required in vivo validation.