Recent advances of DNAzyme-based nanotherapeutic platform in cancer gene therapy

Advancing cancer treatments: The role of oligonucleotide-based therapies in driving progress

Although recent advancements in cancer immunology have resulted in the approval of numerous immunotherapies, minimal progress has been observed in addressing hard-to-treat cancers. In this context, therapeutic oligonucleotides, including interfering RNAs, antisense oligonucleotides, aptamers, and DNAzymes, have gained a central role in cancer therapeutic approaches due to their capacity to regulate gene expression and protein function with reduced toxicity compared with conventional chemotherapeutics. Nevertheless, systemic administration of naked oligonucleotides faces many extra- and intracellular challenges that can be overcome by using effective delivery systems. Thus, viral and non-viral carriers can improve oligonucleotide stability and intracellular uptake, enhance tumor accumulation, and increase the probability of endosomal escape while minimizing other adverse effects. Therefore, gaining more insight into fundamental mechanisms of actions of various oligonucleotides and the challenges posed by naked oligonucleotide administration, this article provides a comprehensive review of the recent progress on oligonucleotide delivery systems and an overview of completed and ongoing cancer clinical trials that can shape future oncological treatments.

Nanosized DNA Hydrogel Functionalized with a DNAzyme Tetrahedron for Highly Efficient Gene Silencing

DNAzymes are DNA oligonucleotides that have catalytic activity without the assistance of protein enzymes. In particular, RNA-cleaving DNAzymes were considered as ideal candidates for gene therapy due to their unique characteristics. Nevertheless, efforts to use DNAzyme as a gene therapeutic agent are limited by issues such as their low physiological stability in serum and intracellular delivery efficiency. In this study, we developed a nanosized synthetic DNA hydrogel functionalized with a DNAzyme tetrahedron (TDz Dgel) to overcome these limitations. We observed remarkable improvement in the gene-silencing effect as well as intracellular uptake without the support of gene transfection reagents using TDz Dgel. The improved catalytic activity of the DNAzyme resulted from the combination of the cell-penetrating DNA tetrahedron structure and high stability of DNA hydrogel. We envision that this approach will become a convenient and efficient strategy for gene-silencing therapy using DNAzyme in the future.

DNAzyme-based ultrasensitive immunoassay: Recent advances and emerging trends

Immunoassay, as the most commonly used method for protein detection, is simple to operate and highly specific. Sensitivity improvement is always the thrust of immunoassays, especially for the detection of trace quantities. The emergence of artificial enzyme, i.e., DNAzyme, provides a novel approach to improve the detection sensitivity of immunoassay. Simultaneously, its advantages of simple synthesis and high stability enable low cost, broad applicability and long shelf life for immunoassay. In this review, we summarized the recent advances in DNAzyme-based immunoassay. First, we summarized the existing different DNAzymes based on their catalytic activities. Next, the common signal amplification strategies used for DNAzyme-based immunoassays were reviewed to cater to diverse detection requirements. Following, the wide applications in disease diagnosis, environmental monitoring and food safety were discussed. Finally, the current challenges and perspectives on the future development of DNAzyme-based immunoassays were also provided.

Towards the development of a DNA automaton: modular RNA-cleaving deoxyribozyme logic gates regulated by miRNAs

Advancements in DNA computation have unlocked molecular-scale information processing possibilities, utilizing the intrinsic properties of DNA for complex logical operations with transformative applications in biomedicine. DNA computation shows promise in molecular diagnostics, enabling precise and sensitive detection of genetic mutations and disease biomarkers. Moreover, it holds potential for targeted gene regulation, facilitating personalized therapeutic interventions with enhanced efficacy and reduced side effects. Herein, we have developed six DNAzyme-based logic gates able to process YES, AND, and NOT Boolean logic. The novelty of this work lies in their additional functionalization with a common DNA scaffold for increased cooperativity in input recognition. Moreover, we explored hierarchical input binding to multi-input logic gates, which helped gate optimization. Additionally, we developed a new design of an allosteric hairpin switch used to implement NOT logic. All DNA logic gates achieved the desired true-to-false output signal when detecting a panel of miRNAs, known for their important role in malignancy regulation. This is the first example of DNAzyme-based logic gates having all input-recognizing elements integrated in a single DNA nanostructure, which provides new opportunities for building DNA automatons for diagnosis and therapy of human diseases.

Nanocatalysts for modulating antitumor immunity: fabrication, mechanisms and applications

Immunotherapy harnesses the inherent immune system in the body to generate systemic antitumor immunity, offering a promising modality for defending against cancer. However, tumor immunosuppression and evasion seriously restrict the immune response rates in clinical settings. Catalytic nanomedicines can transform tumoral substances/metabolites into therapeutic products in situ, offering unique advantages in antitumor immunotherapy. Through catalytic reactions, both tumor eradication and immune regulation can be simultaneously achieved, favoring the development of systemic antitumor immunity. In recent years, with advancements in catalytic chemistry and nanotechnology, catalytic nanomedicines based on nanozymes, photocatalysts, sonocatalysts, Fenton catalysts, electrocatalysts, piezocatalysts, thermocatalysts and radiocatalysts have been rapidly developed with vast applications in cancer immunotherapy. This review provides an introduction to the fabrication of catalytic nanomedicines with an emphasis on their structures and engineering strategies. Furthermore, the catalytic substrates and state-of-the-art applications of nanocatalysts in cancer immunotherapy have also been outlined and discussed. The relationships between nanostructures and immune regulating performance of catalytic nanomedicines are highlighted to provide a deep understanding of their working mechanisms in the tumor microenvironment. Finally, the challenges and development trends are revealed, aiming to provide new insights for the future development of nanocatalysts in catalytic immunotherapy.

Mechanochemical Activation of DNAzyme by Ultrasound

Controlling the activity of DNAzymes by external triggers is an important task. Here a temporal control over DNAzyme activity through a mechanochemical pathway with the help of ultrasound (US) is demonstrated. The deactivation of the DNAzyme is achieved by hybridization to a complementary strand generated through rolling circle amplification (RCA), an enzymatic polymerization process. Due to the high molar mass of the resulting polynucleic acids, shear force can be applied on the RCA strand through inertial cavitation induced by US. This exerts mechanical force and leads to the cleavage of the base pairing between RCA strand and DNAzyme, resulting in the recovery of DNAzyme activity. This is the first time that this release mechanism is applied for the activation of catalytic nucleic acids, and it has multiple advantages over other stimuli. US has higher penetration depth into tissues compared to light, and it offers a more specific stimulus than heat, which has also limited use in biological systems due to cell damage caused by hyperthermia. This approach is envisioned to improve the control over DNAzyme activity for the development of reliable and specific sensing applications.

Targeted therapy in juvenile myelomonocytic leukemia: Where are we now?

Juvenile myelomonocytic leukemia (JMML) is a rare and aggressive clonal neoplasm of early childhood, classified as an overlap myeloproliferative/myelodysplastic neoplasm by the World Health Organization. In 90% of the patients with JMML, typical initiating mutations in the canonical Ras pathway genes NF1, PTPN11, NRAS, KRAS, and CBL can be identified. Hematopoietic stem cell transplantation (HSCT) currently is the established standard of care in most patients, although long-term survival is still only 50-60%. Given the limited therapeutic options and the important morbidity and mortality associated with HSCT, new therapeutic approaches are urgently needed. Hyperactivation of the Ras pathway as disease mechanism in JMML lends itself to the use of targeted therapy. Targeted therapy could play an important role in the future treatment of patients with JMML. This review presents a comprehensive overview of targeted therapies already developed and evaluated in vitro and in vivo in patients with JMML.

Recent Advances in DNA Nanotechnology for Plasmonic Biosensor Construction

Since 2010, DNA nanotechnology has advanced rapidly, helping overcome limitations in the use of DNA solely as genetic material. DNA nanotechnology has thus helped develop a new method for the construction of biosensors. Among bioprobe materials for biosensors, nucleic acids have shown several advantages. First, it has a complementary sequence for hybridizing the target gene. Second, DNA has various functionalities, such as DNAzymes, DNA junctions or aptamers, because of its unique folded structures with specific sequences. Third, functional groups, such as thiols, amines, or other fluorophores, can easily be introduced into DNA at the 5′ or 3′ end. Finally, DNA can easily be tailored by making junctions or origami structures; these unique structures extend the DNA arm and create a multi-functional bioprobe. Meanwhile, nanomaterials have also been used to advance plasmonic biosensor technologies. Nanomaterials provide various biosensing platforms with high sensitivity and selectivity. Several plasmonic biosensor types have been fabricated, such as surface plasmons, and Raman-based or metal-enhanced biosensors. Introducing DNA nanotechnology to plasmonic biosensors has brought in sight new horizons in the fields of biosensors and nanobiotechnology. This review discusses the recent progress of DNA nanotechnology-based plasmonic biosensors.

Fast and sensitive graphene oxide-DNAzyme-based biosensor for Vibrio alginolyticus detection

DNAzymes have been widely and effectively used for the detection of pathogenic bacteria, which pose a serious public health threat. However, the rapid and cost-effective detection of such bacteria remains a major challenge. In this study, we successfully selected Vibrio alginolyticus-specific DNAzymes. The activity of the candidates was assessed via fluorescence intensity and gel electrophoresis. The DNAzyme DT1 had a detection limit of 31 CFU/ml for V. alginolyticus and exhibited high specificity. Graphene oxide (GO) was used to develop a DNAzyme-based fluorescent sensor for the detection of V. alginolyticus, which significantly improved detection performance and shortened the reaction time as little as 10 s. The proposed method was then validated using crab, shrimp, fish, clam, and oyster samples. This study thus provides a new method for the rapid and sensitive detection of V. alginolyticus.

DNAzyme-Based nanoflowers for reversing P-glycoprotein-mediated multidrug resistance in breast cancer

Multidrug resistance (MDR) of tumors has been recognized as an important cause of chemotherapy failure, which is responsible for about 90% of cancer deaths. Therefore, it is desirable to develop a highly effective strategy to reverse tumor MDR for rebuilding the sensitivity of tumor cells towards chemodrugs. Here, self-assembled DNAzyme nanoflowers (NFs) constructed by rolling circle amplification (RCA) strategy were applied in doxorubicin (Dox) delivery for efficiently ablating Dox-resistant breast cancer. The encoded multiple DNAzymes could catalytically cleave P-glycoprotein (P-gp) mRNA which assists the efflux of chemodrugs, for reversing the MDR. The in vitro and in vivo results showed that the P-gp DNAzymes NFs not only had a high drug-loading capacity (69.21%) and acid-triggered biodegrade ability, but also effectively suppressed the expression of P-gp for reversing MDR of the tumor. Therefore, the DNAzyme-based drug delivery nanoplatform would be a promisingstrategyfor reversing MDR in cancer therapy.

DNAzyme-Functionalized Nanomaterials: Recent Preparation, Current Applications, and Future Challenges

DNAzyme-nanomaterial bioconjugates are a popular hybrid and have received major attention for diverse biomedical applications, such as bioimaging, biosensor development, cancer therapy, and drug delivery. Therefore, significant efforts are made to develop different strategies for the preparation of inorganic and organic nanoparticles (NPs) with specific morphologies and properties. DNAzymes functionalized with metal-organic frameworks (MOFs), gold nanoparticles (AuNPs), graphene oxide (GO), and molybdenum disulfide (MoS₂ ) are introduced and summarized in detail in this review. Moreover, the focus is on representative examples of applications of DNAzyme-nanomaterials over recent years, especially in bioimaging, biosensing, phototherapy, and stimulation response delivery in living systems, with their several advantages and drawbacks. Finally, the perspective regarding the future directions of research addressing these challenges is also discussed and highlighted.

DNAzymes, Novel Therapeutic Agents in Cancer Therapy: A Review of Concepts to Applications

The past few decades have witnessed a rapid evolution in cancer drug research which is aimed at developing active biological interventions to regulate cancer-specific molecular targets. Nucleic acid-based therapeutics, including ribozymes, antisense oligonucleotides, small interference RNA (siRNA), aptamer, and DNAzymes, have emerged as promising candidates regulating cancer-specific genes at either the transcriptional or posttranscriptional level. Gene-specific catalytic DNA molecules, or DNAzymes, have shown promise as a therapeutic intervention against cancer in various in vitro and in vivo models, expediting towards clinical applications. DNAzymes are single-stranded catalytic DNA that has not been observed in nature, and they are synthesized through in vitro selection processes from a large pool of random DNA libraries. The intrinsic properties of DNAzymes like small molecular weight, higher stability, excellent programmability, diversity, and low cost have brought them to the forefront of the nucleic acid-based therapeutic arsenal available for cancers. In recent years, considerable efforts have been undertaken to assess a variety of DNAzymes against different cancers. However, their therapeutic application is constrained by the low delivery efficiency, cellular uptake, and target detection within the tumour microenvironment. Thus, there is a pursuit to identify efficient delivery methods in vivo before the full potential of DNAzymes in cancer therapy is realized. In this light, a review of the recent advances in the use of DNAzymes against cancers in preclinical and clinical settings is valuable to understand its potential as effective cancer therapy. We have thus sought to firstly provide a brief overview of construction and recent improvements in the design of DNAzymes. Secondly, this review stipulates the efficacy, safety, and tolerability of DNAzymes developed against major hallmarks of cancers tested in preclinical and clinical settings. Lastly, the recent advances in DNAzyme delivery systems along with the challenges and prospects for the clinical application of DNAzymes as cancer therapy are also discussed.

The pros and cons of drinking tea

Tea is the most frequently consumed beverage worldwide besides water. Generally, there are five most popular types of tea: green, white, black, Pu’er, and oolong. Tea possesses significant antioxidant, anti-inflammatory, antimicrobial, anticarcinogenic, antihypertensive, neuroprotective, and cholesterol-lowering properties. Several research investigations, epidemiological studies, and meta-analyses suggest that tea and its bioactive polyphenolic constituents have numerous beneficial effects on health, including the prevention of many diseases, such as cancer, diabetes, arthritis, cardiovascular disease, stroke, and obesity. Recently, there are many reports about the resistance of tea to COVID-19 virus on the Internet, which has attracted a lot of attention to tea drinking and the discussion about the pros and cons of tea drinking. Based on our research results and relevant reports form literatures, this review is intended to highlight the beneficial effects and possible side-effects associated with tea consumption, answer 10 questions and point out a few matters for attention.