NIR/pH-triggered aptamer-functionalized DNA origami nanovehicle for imaging-guided chemo-phototherapy

Advancements in Aptamer-Driven DNA Nanostructures for Precision Drug Delivery

DNA nanostructures exhibit versatile geometries and possess sophisticated capabilities not found in other nanomaterials. They serve as customizable nanoplatforms for orchestrating the spatial arrangement of molecular components, such as biomolecules, antibodies, or synthetic nanomaterials. This is achieved by incorporating oligonucleotides into the design of the nanostructure. In the realm of drug delivery to cancer cells, there is a growing interest in active targeting assays to enhance efficacy and selectivity. The active targeting approach involves a "key-lock" mechanism where the carrier, through its ligand, recognizes specific receptors on tumor cells, facilitating the release of drugs. Various DNA nanostructures, including DNA origami, Tetrahedral, nanoflower, cruciform, nanostar, nanocentipede, and nanococklebur, can traverse the lipid layer of the cell membrane, allowing cargo delivery to the nucleus. Aptamers, easily formed in vitro, are recognized for their targeted delivery capabilities due to their high selectivity for specific targets and low immunogenicity. This review provides a comprehensive overview of recent advancements in the formation and modification of aptamer-modified DNA nanostructures within drug delivery systems.

Recent advances in functional nucleic acid decorated nanomaterials for cancer imaging and therapy

Nanomaterials possess unusual physicochemical properties including unique optical, magnetic, electronic properties, and large surface-to-volume ratio. However, nanomaterials face some challenges when they were applied in the field of biomedicine. For example, some nanomaterials suffer from the limitations such as poor selectivity and biocompatibility, low stability, and solubility. To address the above-mentioned obstacles, functional nucleic acid has been widely served as a powerful and versatile ligand for modifying nanomaterials because of their unique characteristics, such as ease of modification, excellent biocompatibility, high stability, predictable intermolecular interaction and recognition ability. The functionally integrating functional nucleic acid with nanomaterials has produced various kinds of nanocomposites and recent advances in applications of functional nucleic acid decorated nanomaterials for cancer imaging and therapy were summarized in this review. Further, we offer an insight into the future challenges and perspectives of functional nucleic acid decorated nanomaterials.

A TSHR-Targeting Aptamer in Monocytes Correlating with Clinical Activity in TAO

Background

Manifestations of thyroid-associated ophthalmopathy (TAO) vary greatly. Few tools and indicators are available to assess TAO, restricting personalized diagnosis and treatment.

Aim

To identify an aptamer targeting thyroid-stimulating hormone receptor (TSHR) and utilize this aptamer to evaluate clinical activity in patients with TAO.

Methods

An aptamer targeting TSHR was developed by exponential enrichment and systematic evaluation of TSHR ligands. After truncation and optimization, the affinity, equilibrium dissociation constant, and serum stability of this aptamer were evaluated. The affinity of the TSHR-targeting aptamer to isolated fibrocytes was assessed, as was aptamer internalization by fibrocytes. The mechanism of binding was determined by molecular docking. The correlation between disease manifestations and the percentage of TSHR-positive cells was assessed by correlation analysis.

Results

The aptamer TSHR-21-42 was developed to bind to TSHR, with the equilibrium dissociation constant being 71.46 Kd. Isolated fibrocytes were shown to bind TSHR-21-42 through TSHR, with its affinity maintained at various temperatures and ion concentrations. TSHR-21-42 could compete with anti-TSHR antibody, both for binding site to TSHR and uptake by cells after binding. In addition, TSHR-21-42 could bind to leukocytes in peripheral blood, with this binding differing in patients with TAO and healthy control subjects. The percentage of TSHR-positive monocytes, as determined by binding of TSHR-21-42, correlated positively with clinical activity score in patients with TAO, indicating that TSHR-21-42 binding could assess the severity of TAO.

Conclusion

This aptamer targeting TSHR may be used to objectively assess disease activity in patients with TAO, by evaluating the percentages of TSHR positive cells in peripheral blood.

SiRNF8 Delivered by DNA Framework Nucleic Acid Effectively Sensitizes Chemotherapy in Colon Cancer

Background

The evident side effects and decreased drug sensitivity significantly restrict the use of chemotherapy. However, nanoparticles based on biomaterials are anticipated to address this challenge.

Methods

Through bioinformatics analysis and colon cancer samples, we initially investigated the expression level of RNF8 in colon cancer. Next, we constructed nanocarrier for delivering siRNF8 based on DNA tetrahedron (si-Tet), and Doxorubicin (DOX) was further intercalated into the DNA structure (si-DOX-Tet) for combination therapy. Further, the effects and mechanism of RNF8 inhibition on the sensitivity of colon cancer cells to DOX chemotherapy have also been studied.

Results

RNF8 expression was increased in colon cancer. Agarose gel electrophoresis, transmission electron microscopy, and size distribution and potential analysis confirmed the successful preparation of the two nanoparticles, with particle sizes of 10.29 and 37.29 nm, respectively. Fluorescence imaging reveals that the carriers can be internalized into colon cancer cells and escape from lysosomes after 12 hours of treatment, effectively delivering siRNF8 and DOX. Importantly, Western blot analysis verified treatment with 50nM si-Tet silenced RNF8 expression by approximately 50% in colon cancer cells, and combined treatment significantly inhibited cell proliferation. Furthermore, the CCK-8 assay demonstrated that si-Tet treatment enhanced the sensitivity of colon cancer cells to the three chemotherapeutic drugs. Significant more DNA damage was detected after treatment with both si-Tet or si-DOX-Tet. Further flow cytometry analysis revealed that si-DOX-Tet treatment led to significantly more apoptosis, approximately 1.6-fold higher than treatment with DOX alone. Mechanistically, inhibiting RNF8 led to decreased ABCG2 expression and DOX efflux, but increased DNA damage, thereby enhancing the chemotherapeutic effect of DOX.

Conclusion

We have successfully constructed si-DOX-Tet. By inhibiting the expression of RNF8, it enhances the chemotherapy sensitivity of DOX. Therefore, this tetrahedral FNA nanocarrier offers a new approach for the combined treatment of colon cancer.

Aptamer-based targeted delivery systems for cancer treatment using DNA origami and DNA nanostructures

Due to the limitations of conventional cancer treatment methods, nanomedicine has appeared as a promising alternative, allowing improved drug targeting and decreased drug toxicity. In the development of cancer nanomedicines, among various nanoparticles (NPs), DNA nanostructures are more attractive because of their precisely controllable size, shape, excellent biocompatibility, programmability, biodegradability, and facile functionalization. Aptamers are introduced as single-stranded RNA or DNA molecules with recognize their corresponding targets. So, incorporating aptamers into DNA nanostructures led to influential vehicles for bioimaging and biosensing as well as targeted cancer therapy. In this review, the recent developments in the application of aptamer-based DNA origami and DNA nanostructures in advanced cancer treatment have been highlighted. Some of the main methods of cancer treatment are classified as chemo-, gene-, photodynamic- and combined therapy. Finally, the opportunities and problems for targeted DNA aptamer-based nanocarriers for medicinal applications have also been discussed.