Utilization of novel lectin-conjugated Au nanoparticles as Thomsen-Friedenreich onco-antigen target for in vitro cytotoxicity and apoptosis induction in leukemic cell line

Abstract

Leukemia is a tumor of blood-forming tissues including bone marrow and lymphatic nodes, which comprise biologically distinct subgroups. In the present study, Au NPs-PEG-Lectin was prepared as a drug targeting system for potential Thomsen-Friedenreich antigen (TF-Ag) presented on the surface of leukemic cells to induce cytotoxicity. Gold nanoparticles were prepared using citrate reduction method and conjugated with lectin via SH-PEG-COOH. The conjugate was characterized using UV/Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Zeta potential, and Scanning electron microscopy (SEM) with subsequent applications for cytotoxicity, cell cycle analysis, and apoptosis. Immunophenotypically blood samples from patients with acute lymphoblastic leukemia (ALL) were positively expressed CD45, CD95 dim expression, and low CD176 (TF-Ag) expression. Samples of acute myeloid leukemia (AML) confirmed the expression of all markers. Au NPs-PEG-Lectin conjugate showed an average size of 35.82 nm with zeta potential of −27.33 with accelerated lectin release from the conjugate at acidic pH. Au NPs-PEG-Lectin demonstrated the highest and most significant cytotoxic activity against HL-60 and K562 with IC50 of 132.5 and 314.8 μg mL−1, respectively. Flow cytometric analysis revealed induction of HL-60 cell apoptosis upon conjugate treatment in a dose-dependent pattern up to 51.03 % with no sign of necrosis with cell cycle arrest at G0/G1 phase. HL-60 cells treated with Au NPs-PEG-Lectin exhibited inter-nucleosomal DNA fragmentation. Morphologically, Phospho-Histone/BrdU dual staining indicated that Au NPs-PEG-Lectin initiated HL-60 arrest at G0/G1 phase. Taken together, molecular docking verified the possible interaction between lectin amino acids and different hydroxy groups within TF-Ag forming hydrogen bonds.