G4-Tetra DNA Duplex Induce Lung Cancer Cell Apoptosis in A549 Cells

Aptamer AS411 interacts with the KRAS promoter/hnRNP A1 complex and shows increased potency against drug-resistant lung cancer

G-quadruplex (G4) aptamers that can competitively binding protein with oncogene promoter G4 hold promise for cancer treatment. In this study, a neutral cytidinyl lipid, DNCA, was shown to transfect and deliver G4 aptamers (AS1411, TBA) into tumour cells, including multidrug-resistant tumour cells, and their nuclear localizations were clearly detected. Both AS1411/DNCA and TBA/DNCA showed excellent antitumour efficacies in the drug-resistant non-small cell lung cancer cell line A549/TXL at a low concentration (100 nM). Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) was identified as a new target of AS1411 and TBA. The binding affinities were measured, and the Kd values of AS1411/hnRNP A1 and TBA/hnRNP A1 were 17.5 nM and 21.1 nM, respectively. Then the expression of KRAS mRNA in A549/TXL cells was found to be higher than that in A549 cells, and KRAS mRNA was reduced by approximately 40% after administration of AS1411 or TBA in A549/TXL cells. Further, it was confirmed for the first time that AS1411 targeted not only hnRNP A1 but also the KRAS promoter/hnRNP A1 complexes. And although TBA cannot target the KRAS promoter/hnRNP A1 complexes, the biolayer interferometry (BLI) experiment showed that TBA and AS1411 have similar effects on several key proteins in tumour cells, especially hnRNP A1. Molecular docking and molecular dynamics simulation showed that AS1411 and the KRAS promoter bound to the same domain of hnRNP A1 protein, while TBA bound to another domain.

Harnessing G-quadruplex ligands for lung cancer treatment: A comprehensive overview

Lung cancer (LC) remains a leading cause of mortality worldwide, and new therapeutic strategies are urgently needed. One such approach revolves around the utilization of four-stranded nucleic acid secondary structures, known as G-quadruplexes (G4), which are formed by G-rich sequences. Ligands that bind selectively to G4 structures present a promising strategy for regulating crucial cellular processes involved in the progression of LC, rendering them potent agents for lung cancer treatment. In this review, we offer a summary of recent advancements in the development of G4 ligands capable of targeting specific genes associated with the development and progression of lung 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.

Advances in regenerative medicine applications of tetrahedral framework nucleic acid-based nanomaterials: an expert consensus recommendation

With the emergence of DNA nanotechnology in the 1980s, self-assembled DNA nanostructures have attracted considerable attention worldwide due to their inherent biocompatibility, unsurpassed programmability, and versatile functions. Especially promising nanostructures are tetrahedral framework nucleic acids (tFNAs), first proposed by Turberfield with the use of a one-step annealing approach. Benefiting from their various merits, such as simple synthesis, high reproducibility, structural stability, cellular internalization, tissue permeability, and editable functionality, tFNAs have been widely applied in the biomedical field as three-dimensional DNA nanomaterials. Surprisingly, tFNAs exhibit positive effects on cellular biological behaviors and tissue regeneration, which may be used to treat inflammatory and degenerative diseases. According to their intended application and carrying capacity, tFNAs could carry functional nucleic acids or therapeutic molecules through extended sequences, sticky-end hybridization, intercalation, and encapsulation based on the Watson and Crick principle. Additionally, dynamic tFNAs also have potential applications in controlled and targeted therapies. This review summarized the latest progress in pure/modified/dynamic tFNAs and demonstrated their regenerative medicine applications. These applications include promoting the regeneration of the bone, cartilage, nerve, skin, vasculature, or muscle and treating diseases such as bone defects, neurological disorders, joint-related inflammatory diseases, periodontitis, and immune diseases.

Functionalized-DNA nanostructures as potential targeted drug delivery systems for cancer therapy

Seeman's pioneer idea has led to the foundation of DNA nanostructures, resulting in a remarkable advancement in DNA nanotechnology. Over the last few decades, remarkable advances in drug delivery techniques have resulted in the self-assembly of DNA for encapsulating candidate drug molecules. The nuclear targeting capability of DNA nanostructures is lies within their high spatial addressability and tremendous potential for active targeting. However, effective programming and assembling those DNA molecules remains a challenge, making the path to DNA nanostructures for real-world applications difficult. Because of their small size, most nanostructures are self-capable of infiltrating into the tumor cellular environment. Furthermore, to enable controlled and site-specific delivery of encapsulated drug molecules, DNA nanostructures are functionalized with special moieties that allow them to bind specific targets and release cargo only at targeted sites rather than non-specific sites, resulting in the prevention/limitation of cellular toxicity. In light of this, the current review seeks to shed light on the versatility of the DNA molecule as a targeting and encapsulating moiety for active drugs in order to achieve controlled and specific drug release with spatial and temporal precision. Furthermore, this review focused on the challenges associated with the construction of DNA nanostructures as well as the most recent advances in the functionalization of DNA nanostructures using various materials for controlled and targeted delivery of medications for cancer therapy.

G-Quadruplex-Based Drug Delivery Systems for Cancer Therapy

G-quadruplexes (G4s) are a class of nucleic acids (DNA and RNA) with single-stranded G-rich sequences. Owing to the selectivity of some G4s, they are emerging as targeting agents to overtake side effects of several potential anticancer drugs, and delivery systems of small molecules to malignant cells, through their high affinity or complementarity to specific targets. Moreover, different systems are being used to improve their potential, such as gold nano-particles or liposomes. Thus, the present review provides relevant data about the different studies with G4s as drug delivery systems and the challenges that must be overcome in the future research.

Polypod-like structured guanine-rich oligonucleotide aptamer as a selective and cytotoxic nanostructured DNA to cancer cells

Guanine-rich oligonucleotide (GRO) can be developed as an effective anticancer agent owing to its high selectivity, affinity and antiproliferative activity in cancer cells. In this study, to increase the potency of GRO29A, a 29-mer GRO aptamer against nucleolin, an overexpressed protein in cancer cells, GRO29A was incorporated into three or six pods of polypod-like structured DNA (polypodna), tripodna or hexapodna, respectively. The polypod-like structured GROs, tri-G3, consisting of one tripodna and three GRO29A, or hexa-G1, hexa-G3 or hexa-G6, each of which comprises one hexapodna and one, three or six GRO29A, respectively, were designed. Tri-G3, hexa-G1 and hexa-G3 were prepared in high yield, except for hexa-G6. Polypod-like structured GROs had quadruplex structures under physiological salt conditions, and degraded at a slower rate in buffer containing serum. Cellular interaction experiments using fluorescently labelled DNA samples showed that the uptake of hexa-G3 by nucleolin-positive MCF-7 cells was more than 2-fold higher than GRO29A, and the interaction was increasingly dependent on the number of GRO29A in the structures. Hexa-G3 inhibited the proliferation of MCF-7 cells in more than 40%, but not of CHO cells. These results indicate that polypod-like structured GROs are useful DNA aptamers with high selectivity and cytotoxicity against nucleolin-positive cancer cells.

Progress in Biomedical Applications of Tetrahedral Framework Nucleic Acid-Based Functional Systems

The past decades have witnessed the development of DNA nanotechnology and the emergence of various spatial DNA nanostructures, from two-dimensions to three-dimensions. The typical example is the tetrahedral framework nucleic acid (tFNA). In this review, we summarize the progress in fabrication, modification of tFNA-based functional systems and their potentials in biomedical applications. Through a one-step assembly process, tFNA is synthesized via four single stranded DNAs with three short sequences complementary to the other sequence of another single strand. Characterizations including polyacrylamide gel electrophoresis, atomic force microscopy, and dynamic light scattering measurement show tFNA as a pyramid-like nanostructure with the size of around 10 nm. Feathered with intrinsic biocompatibility and satisfactory cellular membrane permeability, the first generation of tFNA shows promising capacities in regulating cell biological behavior, promoting tissue regeneration, and immunomodulation. Along with excellent editability and relative biostability in complicated conditions, tFNA could be modified via hanging functional domains on the vertex or side arm and incorporating small-molecular-weight drugs to form the second generation, for reversing multidrug resistance in tumor cells or microorganisms, target therapy, anticancer and antibacterial treatments. The third generation of tFNA is currently tried via a multistep assembly process for stimuli-response and precise drug release. Although tFNAs show promising potentials in cargo delivery, massive efforts still need to be made to improve biostability, maximal load, and structural controllability.

Aptamer cell sensor based on porous graphene oxide decorated ion-selective-electrode: Double sensing platform for cell and ion

Enlightened by the emerging cell-ion detection based on ion-selective-electrode (ISE), an aptamer capturing and ISE transducing (AC&IT) strategy is proposed on the porous graphene oxide (PGO) decorated ISE (PGO-ISE), its performances in both cell and ion detections are examined by use of AS1411 targeted A549 cell detection and iodide-ISE as proof-of-concept. Firstly, GO flakes, exfoliated from graphite by modified Hummers method, are cross-linked by thiourea mediated hydrothermal process, to 3-dimension networked PGO which is identified by scanning-electron-microscope, UV-visible absorbance and X-ray photoelectron spectroscopy; its enhancing effect for cell capturing is evaluated by microscopy. Then, PGO-ISE is constructed by drop-coating PGO film on the surface of ISE and followed by covalently anchoring AS1411. Electrochemistry measurements for different state ISE (blank, PGO coated, AS1411 anchored and A549 captured) are performed by our home-made ISE-measuring system. It is demonstrated that the best cell-sensitivity in buffer is - 25.21 mV/log₁₀C_A549 (R² = 0.91), resolution in blood is 10 cells/ml. Interestingly, due to PGO's scaffold protection to the ionophore, I^--sensitivity is preserved as - 42.98 mV/pI (R² = 0.95, pI = -log₁₀(C_I)). Theoretical explanations are provided for the double-sensing phenomenon according to basic ISE principle. It is believed the PGO-ISE based aptamer cell sensor will be a promising experimental means for biomedical researches.

Isotopic graphene-isolated-Au-nanocrystals with cellular Raman-silent signals for cancer cell pattern recognition

For cancer diagnosis, technologies must be capable of molecular recognition, and they must possess a built-in pattern recognition component for efficient imaging and discrimination of targeted cancer cells. Surface enhanced Raman scattering (SERS) tags based on plasmonically active nanoparticles hold promise for accurate and efficient cancer cell recognition, owing to ultra-narrow peak and sensitive optical properties. However, a complex fingerprint spectrum increases data analysis difficulty, making it necessary to develop multicolor SERS tags with a simple fingerprint spectrum. To address this, we herein fabricated SERS-encoded nanoparticles (NPs) with stable and simple fingerprint spectrum through synthesis of isotopic cellular Raman-silent graphene-isolated-Au-nanocrystals (GIANs) and conjugation with phospholipid-polyethylene glycol-linked aptamers to target proteins overexpressed on the cancer cell surface. GIANs, which possess the properties of graphitic nanomaterials, such as super-stable optical properties and high Raman cross-section, showed enhanced SERS signals. The 2D-band Raman shift of GIAN, which located in the cellular Raman-silent region, was easily regulated through fabrication of isotopic GIANs without changing their molecular structure. Such GIAN tags demonstrated multiplexed Raman imaging capability, both in vivo and in vitro, with low background interference. Moreover, cell membrane protein (nucleolin, mucin and epithelial cell adhesion molecule)-specific, aptamer-conjugated isotopic GIANs were fabricated and feasibly applied to built-in coding for rapid imaging and pattern recognition of targeted cancer cells. Such isotopic GIAN-aptamer-encoders show high potential for efficient cancer cell identification and diagnosis.

DNA Tetrahedron Delivery Enhances Doxorubicin-Induced Apoptosis of HT-29 Colon Cancer Cells

As a nano-sized drug carrier with the advantage of modifiability and proper biocompatibility, DNA tetrahedron (DNA tetra) delivery is hopeful to enhance the inhibitory efficiency of nontargeted anticancer drugs. In this investigation, doxorubicin (Dox) was assembled to a folic acid-modified DNA tetra via click chemistry to prepare a targeted antitumor agent. Cellular uptake efficiency was measured via fluorescent imaging. Cytotoxicity, inhibition efficiency, and corresponding mechanism on colon cancer cell line HT-29 were evaluated by MTT assay, cell proliferation curve, western blot, and flow cytometry. No cytotoxicity was induced by DNA tetra, but the cellular uptake ratio increased obviously resulting from the DNA tetra-facilitated penetration through cellular membrane. Accordingly, folic acid-DNA tetra-Dox markedly increased the antitumor efficiency with increased apoptosis levels. In details, 100 μM was the effective concentration and a 6-h incubation period was needed for apoptosis induction. In conclusion, nano-sized DNA tetrahedron was a safe and effective delivery system for Dox and correspondingly enhanced the anticancer efficiency.