A Novel pH-Sensitive Multifunctional DNA Nanomedicine: An Enhanced and Harmless GD2 Aptamer-Mediated Strategy for Guiding Neuroblastoma Antitumor Therapy

Abstract

Background: GD2 is a mainstream biomarker for neuroblastoma (NB)-targeted therapy. Current anti-GD2 therapeutics exhibit several side effects since GD2 is also expressed at low levels on normal cells. Thus, current anti-GD2 therapeutics can be compromised by the coexistence of the target receptor on both cancer cells and normal cells. Propose: Aptamers are promising and invaluable molecular tools. Because of the pH difference between tumor and normal cells, in this study, we constructed a pH-sensitive aptamer-mediated drug delivery system (IGD-Targeted). Methods: In vivo Systematic Evolution of Ligands by Exponential Enrichment (SELEX) was used to generate a novel GD2 aptamer. Flow cytometry and molecular docking were applied to assess the binding specificities, affinities abilities of the aptamers. Confocal microscope, CCK8 assay, and BrdU assay were utilized to evaluate whether IGD-Targeted could only bind with GD2 at acidic environment. To evaluate whether IGD-Targeted could inhibit GD2-positive tumor and protect normal cells, in vivo living imaging, histomorphological staining, blood test, and RNA-sequencing were observed in animal model. Results: GD2 aptamer termed as DB67 could bind with GD2-positive cells with high specificity, while has minimal cross-reactivities to other negative cells. It has been validated that the i-motif in IGD-Targeted facilitates the binding specificity and affinity of the GD2 aptamer to GD2-positive NB tumor cells but does not interfere with GD2-positive normal cells at the pH of the cellular microenvironment. In addition, IGD-Targeted is capable of delivering Dox to only GD2-positive NB tumor cells and not to normal cells in vivo and in vitro, resulting in precise inhibition of tumor cells and protection of normal cells. Conclusion:This study suggests that IGD-Targeted as a promising platform for NB therapy which could show greater tumor inhibition and fewer side effects to normal cells, regardless of the existence of the same receptor on the target and nontarget cells.

GD2-targeting therapy: a comparative analysis of approaches and promising directions

“…In addition to mAb, "chemical antibody" aptamers were developed, which are single-stranded DNA or RNA molecules selected by an iterative selection process called systematic ligand evolution by exponential enrichment (SELEX) (227). High affinity aptamers recognize the GD2 antigen, so they can be conjugated to other molecules and toxins for drug delivery or imaging (228,229). The main advantages of aptamers over mAbs include small molecular size and high permeability through blood vessels and GEB, high affinity, non-immunogenicity, safety, and low cost.…”

“…The main advantages of aptamers over mAbs include small molecular size and high permeability through blood vessels and GEB, high affinity, non-immunogenicity, safety, and low cost. At the same time, the structure of the molecules can be easily synthesized and modified for various therapeutic purposes due to geometric conformational flexibility and synthetic dynamics (229,230). To date, two GD2 aptamers with doxirubicin incorporated into the structure were developed, one containing a pH-sensitive motif to reduce side effects and the ability to be activated in an anaerobic environment by TME (DB67) (229), and the otherby MYCN-siRNA (DB99) (230).…”

Molecular Complementarity of Proteomimetic Materials for Target‐Specific Recognition and Recognition‐Mediated Complex Functions

“…Some nucleic acids have been reported to possess pH-dependent secondary structures, such as the i-motif, A-motif, and triplex DNAs, and diverse repertoires of pH-responsive nucleic acid motifs can be combined with targeting aptamers and DNA-intercalating drugs or drug-containing hydrogels to achieve pH-selective and targetspecific drug release. [301][302][303] Efforts to generate pH-responsive antibody-mimic entailed a rational design that links known pH-dependent nucleic acid motifs with existing target-specific aptamers. [304][305][306][307][308][309] For example, a combination of an aptamer with a cytosine-rich i-motif through formation of a hairpin structure preferentially stabilized a tyrosine kinase-7 aptamer in acidic conditions, with a K d value of 52.9 ± 1.5 nm at pH 6.5 and >1000 nm at pH 7.3 (Figure 5b).…”

Ultrasound-Responsive Micelle-Encapsulated Mesenchymal Stem Cell-Derived EVs for the Treatment of Lower Limb Microcirculation Disease

“…29 In Vitro Cytotoxicity Analysis. CCK-8 and live/dead cell staining 30 were utilized to observe the impact of micelles on umbilical vein endothelial cells. Endothelial cells from the umbilical vein of humans (HUVECs) were placed in 96-well plates with a seeding density of 1 × 10 4 cells per well.…”