Targeted delivery of doxorubicin to cancer cells by a cruciform DNA nanostructure composed of AS1411 and FOXM1 aptamers

Improving Chemotherapy Effectiveness: Utilizing CuS Nanoparticles Coated with AS1411 Aptamer and Chitosan for Targeted Delivery of Doxorubicin to Cancerous Cells

Here, a novel targeted nanostructure complex was designed as an alternative to the traditional treatment approaches for breast cancer. A delivery system utilizing CuS nanoparticles (CuS NPs) was developed for the purpose of targeted administration of doxorubicin (Dox), an anticancer agent. To regulate Dox release, chitosan (CS), a biodegradable and hydrophilic polymer with biocompatible properties, was applied to coat the Dox-loaded CuS NPs. Furthermore, AS1411 aptamer, served as a targeting agent for breast cancer cells (MCF-7 and 4T1 cells), was conjugated with CS-Dox-CuS NPs effectively. To assess the effectiveness of APT-CS-CuS NPs, various methods such as flow cytometry analysis, MTT assay, fluorescence imaging, and in vivo antitumor efficacy were employed. The hollow core and porous surface of CuS NPs improved the Dox loading capacity and entrapment efficiency (almost 100%). The rate of drug release at the tumor site (citrate buffer with pH 5.6) exhibited a marked increase in comparison to that observed within the physiological environment (phosphate buffer with pH 7.4). The targeted formulation (APT-CS-Dox-CuS NPs) significantly increased cytotoxicity of the Dox payload in target cells, including 4T1 (p ≤ 0.0001 (****)) and MCF7 (p ≤ 0.01 (**)) cells compared to CHO cells. Moreover, the ability of tumor growth inhibition of the targeted system was significantly (p ≤ 0.05 (*)) more than free Dox in tumor-bearing mice. The findings indicate that the targeted formulation augmented effectiveness and specificity while minimizing harm to non-targeted cells, signifying its potential as a sophisticated cancer drug delivery system.

Breaking Barriers: Nucleic Acid Aptamers in Gastrointestinal (GI) Cancers Therapy

Conventional cancer therapies can have significant adverse effects as they are not targeted to cancer cells and may damage healthy cells. Single-stranded oligonucleotides assembled in a particular architecture, known as aptamers, enable them to attach selectively to target areas. Usually, they are created by Systematic Evolution of Ligand by Exponential enrichment (SELEX), and they go through a rigorous pharmacological revision process to change their therapeutic half-life, affinity, and specificity. They could thus offer a viable substitute for antibodies in the targeted cancer treatment market. Although aptamers can be a better choice in some situations, antibodies are still appropriate for many other uses. The technique of delivering aptamers is simple and reasonable, and the time needed to manufacture them is relatively brief. Aptamers do not require animals or an immune response to be produced, in contrast to antibodies. When used as a medication, aptamers can directly suppress tumor cells. As an alternative, they can be included in systems for targeted drug delivery that administer medications specifically to tumor cells while reducing toxicity to healthy cells. The most recent and cutting-edge methods for treating gastrointestinal (GI) tract cancer with aptamers will be covered in this review, with a focus on targeted therapy as a means of conquering resistance to traditional medicines.

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.

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.

Morphology Dictated Immune Activation with Framework Nucleic Acids

Framework nucleic acids (FNAs) of various morphologies, designed using the precise and programmable Watson-Crick base pairing, serve as carriers for biomolecule delivery in biology and biomedicine. However, the impact of their shape, size, concentration, and the spatial presentation of cytosine-phosphate-guanine oligodeoxynucleotides (CpG ODNs) on immune activation remains incompletely understood. In this study, representative FNAs with varying morphologies are synthesized to explore their immunological responses. Low concentrations (50 nM) of all FNAs elicited no immunostimulation, while high concentrations of elongated DNA nanostrings and tetrahedrons triggered strong activation due to their larger size and increased cellular uptake, indicating that the innate immune responses of FNAs depend on both dose and morphology. Notably, CpG ODNs' immune response can be programmed by FNAs through regulating the spatial distance, with optimal spacing of 7-8 nm eliciting the highest immunostimulation. These findings demonstrate FNAs' potential as a designable tool to study nucleic acid morphology's impact on biological responses and provide a strategy for future CpG-mediated immune activation carrier design.

Addressing the in vivo delivery of nucleic-acid nanostructure therapeutics

DNA and RNA nanostructures are being investigated as therapeutics, vaccines, and drug delivery systems. These nanostructures can be functionalized with guests ranging from small molecules to proteins with precise spatial and stoichiometric control. This has enabled new strategies to manipulate drug activity and to engineer devices with novel therapeutic functionalities. Although existing studies have offered encouraging in vitro or pre-clinical proof-of-concepts, establishing mechanisms of in vivo delivery is the new frontier for nucleic-acid nanotechnologies. In this review, we first provide a summary of existing literature on the in vivo uses of DNA and RNA nanostructures. Based on their application areas, we discuss current models of nanoparticle delivery, and thereby highlight knowledge gaps on the in vivo interactions of nucleic-acid nanostructures. Finally, we describe techniques and strategies for investigating and engineering these interactions. Together, we propose a framework to establish in vivo design principles and advance the in vivo translation of nucleic-acid nanotechnologies.

Aptamer-Based Probes for Cancer Diagnostics and Treatment

Aptamers are single-stranded DNA or RNA oligomers that have the ability to generate unique and diverse tertiary structures that bind to cognate molecules with high specificity. In recent years, aptamer researches have witnessed a huge surge, owing to its unique properties, such as high specificity and binding affinity, low immunogenicity and toxicity, and simplicity of synthesis with negligible batch-to-batch variation. Aptamers may bind to targets, such as various cancer biomarkers, making them applicable for a wide range of cancer diagnosis and treatment. In cancer diagnostic applications, aptamers are used as molecular probes instead of antibodies. They have the potential to detect various cancer-associated biomarkers. For cancer therapeutic purposes, aptamers can serve as therapeutic or delivery agents. The chemical stabilization and modification strategies for aptamers may expand their serum half-life and shelf life. However, aptamer-based probes for cancer diagnosis and therapy still face several challenges for successful clinical translation. A deeper understanding of nucleic acid chemistry, tissue distribution, and pharmacokinetics is required in the development of aptamer-based probes. This review summarizes their application in cancer diagnostics and treatments based on different localization of target biomarkers, as well as current challenges and future prospects.

A novel dual-targeting delivery system for specific delivery of CRISPR/Cas9 using hyaluronic acid, chitosan and AS1411

A facile method was designed that can specifically deliver CRISPR/Cas9 into target cells nuclei and reduce the off-target effects. A multifunctional delivery vector for FOXM1 knockout was composed by integration of cell targeting polymer (hyaluronic acid) and cell and nuclear targeting group (AS1411 aptamer) on the surface of nanoparticles formed by genome editing plasmid and chitosan (CS) as the core (Apt-HA-CS-CRISPR/Cas9). The data of cytotoxicity experiment and western blot confirmed this issue. The results of flow cytometry analysis and fluorescence imaging demonstrated that Apt-HA-CS-CRISPR/Cas9 was significantly internalized into target cells (MCF-7, SK-MES-1, HeLa) but not into nontarget cells (HEK293). Furthermore, the in vivo studies displayed that the Apt-HA-CS-CRISPR/Cas9 was strongly rendered tumor inhibitory effect and delivered efficiently CRISPR/Cas9 into the tumor with no detectable distribution in other organs compared with naked plasmid. This approach provides an avenue for specific in vivo gene editing therapeutics with the lowest side effect.

Insights on prospects of nano-siRNA based approaches in treatment of Cancer

siRNA interference, commonly referred to as gene silence, is a biological mechanism that inhibits gene expression in disorders such as cancer. It may enhance the precision, efficacy, and stability of medicines, especially genetic therapies to some extent. However, obstacles such as the delivery of oligonucleotide drugs to inaccessible areas of the body and the prevalence of severe side effects must be overcome. To maximize their potential, it is thus essential to optimize their distribution to target locations and limit their toxicity to healthy cells. The action of siRNA may be harnessed to delete a similar segment of mRNA that encodes a protein that causes sickness. The absence of an efficient delivery mechanism that shields siRNA from nuclease degradation, delivers it to cancer cells and releases it into the cytoplasm of specific cancer cells without causing side effects is currently the greatest obstacle to the practical implementation of siRNA therapy. This article focuses on combinations of siRNA with chemotherapeutic drug delivery systems for the treatment of cancer and gives an overview of several nanocarrier formulations in both research and clinical applications.

Interaction of Proteins with Inverted Repeats and Cruciform Structures in Nucleic Acids

Cruciforms occur when inverted repeat sequences in double-stranded DNA adopt intra-strand hairpins on opposing strands. Biophysical and molecular studies of these structures confirm their characterization as four-way junctions and have demonstrated that several factors influence their stability, including overall chromatin structure and DNA supercoiling. Here, we review our understanding of processes that influence the formation and stability of cruciforms in genomes, covering the range of sequences shown to have biological significance. It is challenging to accurately sequence repetitive DNA sequences, but recent advances in sequencing methods have deepened understanding about the amounts of inverted repeats in genomes from all forms of life. We highlight that, in the majority of genomes, inverted repeats are present in higher numbers than is expected from a random occurrence. It is, therefore, becoming clear that inverted repeats play important roles in regulating many aspects of DNA metabolism, including replication, gene expression, and recombination. Cruciforms are targets for many architectural and regulatory proteins, including topoisomerases, p53, Rif1, and others. Notably, some of these proteins can induce the formation of cruciform structures when they bind to DNA. Inverted repeat sequences also influence the evolution of genomes, and growing evidence highlights their significance in several human diseases, suggesting that the inverted repeat sequences and/or DNA cruciforms could be useful therapeutic targets in some cases.

Aptamer grafted nanoparticle as targeted therapeutic tool for the treatment of breast cancer

Breast carcinomas repeat their number and grow exponentially making it extremely frequent malignancy among women. Approximately, 70-80% of early diagnosed or non-metastatic conditions are treatable while the metastatic cases are considered ineffective to treat with current ample amount of therapy. Target based anti-cancer treatment has been in the limelight for decades and is perceived significant consideration of scientists. Aptamers are the 'coming of age' therapeutic approach, selected using an appropriate tool from the library of sequences. Aptamers are non-immunogenic, stable, and high-affinity ligand which are poised to reach the clinical benchmark. With the heed in nanoparticle application, the delivery of aptamer to the specific site could be enhanced which also protects them from nuclease degradation. Moreover, nanoparticles due to robust structure, high drug entrapment, and modifiable release of cargo could serve as a successful candidate in the treatment of breast carcinoma. This review would showcase the method and modified method of selection of aptamers, aptamers that were able to make its way towards clinical trial and their targetability and selectivity towards breast cancers. The appropriate usage of aptamer-based biosensor in breast cancer diagnosis have also been discussed.

Self-Assembling Nucleic Acid Nanostructures Functionalized with Aptamers

Researchers have worked for many decades to master the rules of biomolecular design that would allow artificial biopolymer complexes to self-assemble and function similarly to the diverse biochemical constructs displayed in natural biological systems. The rules of nucleic acid assembly (dominated by Watson-Crick base-pairing) have been less difficult to understand and manipulate than the more complicated rules of protein folding. Therefore, nucleic acid nanotechnology has advanced more quickly than de novo protein design, and recent years have seen amazing progress in DNA and RNA design. By combining structural motifs with aptamers that act as affinity handles and add powerful molecular recognition capabilities, nucleic acid-based self-assemblies represent a diverse toolbox for use by bioengineers to create molecules with potentially revolutionary biological activities. In this review, we focus on the development of self-assembling nucleic acid nanostructures that are functionalized with nucleic acid aptamers and their great potential in wide ranging application areas.

Smart Nanotherapeutics and Lung Cancer

Lung cancer is a significant health problem worldwide. Unfortunately, current therapeutic strategies lack a sufficient level of specificity and can harm adjacent healthy cells. Consequently, to address the clinical need, novel approaches to improve treatment efficiency with minimal side effects are required. Nanotechnology can substantially contribute to the generation of differentiated products and improve patient outcomes. Evidence from previous research suggests that nanotechnology-based drug delivery systems could provide a promising platform for the targeted delivery of traditional chemotherapeutic drugs and novel small molecule therapeutic agents to treat lung cancer cells more effectively. This has also been found to improve the therapeutic index and reduce the required drug dose. Nanodrug delivery systems also provide precise control over drug release, resulting in reduced toxic side effects, controlled biodistribution, and accelerated effects or responses. This review highlights the most advanced and novel nanotechnology-based strategies, including targeted nanodrug delivery systems, stimuli-responsive nanoparticles, and bio-nanocarriers, which have recently been employed in preclinical and clinical investigations to overcome the current challenges in lung cancer treatments.

Prospective Cancer Therapies Using Stimuli-Responsive DNA Nanostructures

Nanostructures based on DNA self-assembly present an innovative way to address the increasing need for target-specific delivery of therapeutic molecules. Currently, most of the chemotherapeutics being used in clinical practice have undesired and exceedingly high off-target toxicity. This is a challenge in particular for small molecules, and hence, developing robust and effective methods to lower these side effects and enhance the antitumor activity is of paramount importance. Prospectively, these issues could be tackled with the help of DNA nanotechnology, which provides a route for the fabrication of custom, biocompatible, and multimodal structures, which can, to some extent, resist nuclease degradation and survive in the cellular environment. Similar to widely employed liposomal products, the DNA nanostructures (DNs) are loaded with selected drugs, and then by employing a specific stimulus, the payload can be released at its target region. This review explores several strategies and triggers to achieve targeted delivery of DNs. Notably, different modalities are explained through which DNs can interact with their respective targets as well as how structural changes triggered by external stimuli can be used to achieve the display or release of the cargo. Furthermore, the prospects and challenges of this technology are highlighted.

DNA Nanotechnology-Based Biosensors and Therapeutics

Over the past few decades, DNA nanotechnology engenders a vast variety of programmable nanostructures utilizing Watson-Crick base pairing. Due to their precise engineering, unprecedented programmability, and intrinsic biocompatibility, DNA nanostructures cannot only interact with small molecules, nucleic acids, proteins, viruses, and cancer cells, but also can serve as nanocarriers to deliver different therapeutic agents. Such addressability innate to DNA nanostructures enables their use in various fields of biomedical applications such as biosensors and cancer therapy. This review is begun with a brief introduction of the development of DNA nanotechnology, followed by a summary of recent applications of DNA nanostructures in biosensors and therapeutics. Finally, challenges and opportunities for practical applications of DNA nanotechnology are discussed.

A molecular hybrid comprising AS1411 and PDGF-BB aptamer, cholesterol, and doxorubicin for inhibiting proliferation of SW480 cells

Cancer treatment commonly relies on chemotherapy. This treatment faces many challenges, including treatment specificity and undesired side effects. To address these, a Dox-loaded Chol-aptamer molecular hybrid (Dox-CAH) was developed. This multivalent interaction system combines the key function of each integrated species: doxorubicin, cholesterol, and two aptamers binding to nucleolin and platelet-derived growth factor BB (PDGF-BB). The study has four stages: preparation of CAH via oligonucleotide hybridization, intercalation of doxorubicin into CAH, verification of CAH binding on SW480 by fluorescence microscopy and flow cytometry, and investigation of effect of Dox-CAH on SW480 proliferation. CAH was successfully prepared, as confirmed by electrophoresis. Flow cytometry and fluorescence microscopy demonstrated CAH binding to SW480, due to the presence of the AS1411 aptamer. This molecular hybrid exhibited specific binding because it did not bind to CCD 841 CoN. CAH binding to PDGF-BB compromises its function, as shown by enzyme-linked immunosorbent assay (ELISA) and cell assay. The DNA duplex in this molecular hybrid reduces the cytotoxicity of the Dox-CAH. Binding and the reduction of Dox-CAH toxicity may improve treatment specificity and minimize side effects. Dox-CAH is a model for more effective anticancer therapy, allowing incorporation of chemotherapeutic drugs and recognition elements.

Nanotechnology-based siRNA delivery strategies for treatment of triple negative breast cancer

Triple negative breast cancer (TNBC) is a subtype of breast cancer characterized by absence of estrogen (ER) receptor, progesterone (PR) receptor, and human epidermal growth factor-2 (HER-2) receptor. TNBC is an aggressive disease that develops early Chemoresistance. The major pitfall associated is its poor prognosis, low overall survival, high relapse, and mortality as compared to other types of breast cancer. Chemotherapy could be helpful but do not contribute to an increase in survival of patient. To overcome such obstacles, in our article we explored advanced therapy using genes and nanocarrier along with its conjugation to achieve high therapeutic profile with reduced side effect. siRNAs are one of the class of RNA associated with gene silencing. They also regulate the expression of certain proteins that are involved in development of tumor cells. But they are highly unstable. So, for efficient delivery of siRNA, very intelligent, efficient delivery systems are required. Several nanotechnologies based non-viral vectors such as liposome, micelles, nanoparticles, dendrimers, exosomes, nanorods and nanobubbles etc. offers enormous unique properties such as nanometric size range, targeting potential with the capability to link with several targeting moieties for the gene delivery. These non-viral vectors are much safer, effective and efficient system for the delivery of genes along with chemotherapeutics. This review provides an overview of TNBC, conventional and advanced treatment approach of TNBC along with understanding of current status of several nanocarriers used for the delivery of siRNA for the treatment of TNBC.

The Anticancer Effects of FDI-6, a FOXM1 Inhibitor, on Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) presents an important clinical challenge, as it does not respond to endocrine therapies or other available targeting agents. FOXM1, an oncogenic transcriptional factor, has reported to be upregulated and associated with poor clinical outcomes in TNBC patients. In this study, we investigated the anti-cancer effects of FDI-6, a FOXM1 inhibitor, as well as its molecular mechanisms, in TNBC cells. Two TNBC cell lines, MDA-MB-231 and HS578T, were used in this study. The anti-cancer activities of FDI-6 were evaluated using various 2D cell culture assays, including Sulforhodamine B (SRB), wound healing, and transwell invasion assays together with 3D spheroid assays, mimicking real tumour structural properties. After treatment with FDI-6, the TNBC cells displayed a significant inhibition in cell proliferation, migration, and invasion. Increased apoptosis was also observed in the treated cells. In addition, we found that FDI-6 lead to the downregulation of FOXM1 and its key oncogenic targets, including CyclinB1, Snail, and Slug. Interestingly, we also found that the FDI-6/Doxorubicin combination significantly enhanced the cytotoxicity and apoptotic properties, suggesting that FDI-6 might improve chemotherapy treatment efficacy and reduce unwanted side effects. Altogether, FDI-6 exhibited promising anti-tumour activities and could be developed as a newly effective treatment for TNBC.

Self-targeted polymersomal co-formulation of doxorubicin, camptothecin and FOXM1 aptamer for efficient treatment of non-small cell lung cancer

In spite of huge developments in cancer treatment, versatile combinational formulations of different chemotherapeutic agents to enhance anticancer activity while reducing systemic toxicity still remains a challenge. In this regard, in the current study, an amphiphilic hyaluronic acid-b-polycaprolactone diblock copolymer was synthesized using "click chemistry". The synthesized copolymer was self-assembled to form polymersomal structures for co-encapsulation of hydrophilic doxorubicin (DOX) and hydrophobic camptothecin (CPT) in their interior aqueous compartment and their bilayer, respectively with 1:10 and 1:1 ratios. The prepared polymersomal combinational formulation surrounded by hyaluronic acid brush as hydrophilic segment, could provide active targeting of the system against CD44 marker expressed on the surface of cancerous cells. The hyaluronic acid shell could also provide flexible chemistry for the conjugation of therapeutic FOXM1-specific DNA aptamer (Forkhead Box M1; against transcription factor FOXM1) on the surface of polymersomes in order to further suppress cancerous cell proliferation. The obtained results demonstrated that the prepared co-formulation provided sustained, controlled release of the entrapped drugs during 200 h. In vitro cytotoxicity experiments on non-small cell lung cancer, A549 and SK-MES-1 cell lines, demonstrated that the co-formulation of DOX and CPT provided synergistic effect and significantly higher cytotoxicity in comparison with free drugs. The cytotoxicity experiment also indicated that the aptamer conjugation on the co-formulations surface could significantly increase the cytotoxicity and induce apoptosis in combination therapy on both A549 and SK-MES-1 cell lines while aptamer-conjugated blank NPs did not show any cytotoxicity which emphasizes on the sensitization capability of the FOXM1 DNA aptamer against non-small cell lung cancer. Furthermore, it was shown that the co-formulation with or without aptamer renders the formulation specific tumor accumulation in vivo 24 h post-administration, assisting the combination synergy observed in vitro to be translated to in vivo antitumor efficacy. This combinatorial delivery platform strongly offers a novel approach for the synergistic controlled transportation of several chemotherapeutics for the treatment of non-small cell lung cancer.

Targeted delivery system using silica nanoparticles coated with chitosan and AS1411 for combination therapy of doxorubicin and antimiR-21

Herein, a novel targeted delivery system was developed for intracellular co-delivery of doxorubicin (DOX) as a chemotherapeutic drug, antimiR-21 as an oncogenic antagomiR. In this system, DOX was loaded into mesoporous silica nanoparticles (MSNs) and chitosan was applied to cover the surface of MSNs. AS1411 aptamer as targeting nucleolin and antimiR-21 were electrostatically attached onto the surface of the chitosan-coated MSNs and formed the final nanocomplex (AACS nanocomplex). The study of drug release was based on DOX release under pH 7.4 and 5.5. Cellular toxicity and cellular uptake assessments of AACS nanocomplex were carried out in nucleolin positive (C26, MCF-7, and 4T1) and nucleolin negative (CHO) cell lines using MTT assay and flow cytometry analysis, respectively. Also, Anti-tumor efficacy of AACS nanocomplex was evaluated in C26 tumor-bearing mice. Overall, the results show that the combination therapy of DOX and antimiR-21, using AACS nanocomplex, could combat the cancer cell growth rate.

Aptamer-Driven Toxin Gene Delivery in U87 Model Glioblastoma Cells

A novel suicide gene therapy approach was tested in U87 MG glioblastoma multiforme cells. A 26nt G-rich double-stranded DNA aptamer (AS1411) was integrated into a vector at the 5' of a mammalian codon-optimized saporin gene, under CMV promoter. With this plasmid termed "APTSAP", the gene encoding ribosome-inactivating protein saporin is driven intracellularly by the glioma-specific aptamer that binds to cell surface-exposed nucleolin and efficiently kills target cells, more effectively as a polyethyleneimine (PEI)-polyplex. Cells that do not expose nucleolin at the cell surface such as 3T3 cells, used as a control, remain unaffected. Suicide gene-induced cell killing was not observed when the inactive saporin mutant SAPKQ DNA was used in the (PEI)-polyplex, indicating that saporin catalytic activity mediates the cytotoxic effect. Rather than apoptosis, cell death has features resembling autophagic or methuosis-like mechanisms. These main findings support the proof-of-concept of using PEI-polyplexed APTSAP for local delivery in rat glioblastoma models.

Improving Breast Cancer Treatment Specificity Using Aptamers Obtained by 3D Cell-SELEX

Three-dimensional spheroids of non-malignant MCF10A and malignant SKBR3 breast cells were used for subsequent 3D Cell-SELEX to generate aptamers for specific binding and treatment of breast cancer cells. Using 3D Cell-SELEX combined with Next-Generation Sequencing and bioinformatics, ten abundant aptamer families with specific structures were identified that selectively bind to SKBR3, and not to MCF10A cells. Multivalent aptamer polymers were synthesized by co-polymerization and analyzed for binding performance as well as therapeutic efficacy. Binding performance was determined by confocal fluorescence imaging and revealed specific binding and efficient internalization of aptamer polymers into SKBR3 spheroids. For therapeutic purposes, DNA sequences that intercalate the cytotoxic drug doxorubicin were co-polymerized into the aptamer polymers. Viability tests show that the drug-loaded polymers are specific and effective in killing SKBR3 breast cancer cells. Thus, the 3D-selected aptamers enhanced the specificity of doxorubicin against malignant over non-malignant breast cells. The innovative modular DNA aptamer platform based on 3D Cell SELEX and polymer multivalency holds great promise for diagnostics and treatment of breast cancer.

Reducing Doxorubicin resistance in breast cancer by liposomal FOXM1 aptamer: In vitro and in vivo

AIMS

Drug resistance is one of the main obstacles in cancer chemotherapy. The forkhead box M1 (FOXM1) is a transcription factor and its overexpression in breast cancer is related to resistance to chemotherapy. In this study, we prepare liposomal FOXM1 aptamer (Lip-FOXM1apt) and evaluate its effects on Doxorubicin (Dox) resistance in vitro and in vivo.

MAIN METHODS

MTT assay, cell association, cellular uptake, Annexin V-FITC/PI dual staining assay were investigated in MDA-MB-231, MCF-7, 4T1. In vivo studies were performed in 4T1 tumor-bearing BALB/c mice.

KEY FINDINGS

We found that the combination therapy of Dox and Lip-FOXM1apt significantly increases both Dox cytotoxicity on cancer cells as well as Dox-induced apoptosis. Administering Lip-FOXM1apt remarkably improved the anti-tumor efficacy of Dox in mice model that was strikingly more effective than Dox monotherapy.

SIGNIFICANCE

Taken together, this study provides a new strategy to overcome Dox resistance and merits further investigation.

Periodically Ordered, Nuclease-Resistant DNA Nanowires Decorated with Cell-Specific Aptamers as Selective Theranostic Agents

DNA nanostructures have shown potential in cancer therapy. However, their clinical application is hampered by the difficulty to deliver them into cancer cells and susceptibility to nuclease degradation. To overcome these limitations, we report herein a periodically ordered nick-hidden DNA nanowire (NW) with high serum stability and active targeting functionality. The inner core is made of multiple connected DNA double helices, and the outer shell is composed of regularly arranged standing-up hairpin aptamers. All termini of the components are hidden from nuclease attack, whereas the target-binding sites are exposed to allow delivery to the cancer target. The DNA NW remained intact during incubation for 24 h in serum solution. Animal imaging and cell apoptosis showed that NWs loaded with an anticancer drug displayed long blood-circulation time and high specificity in inducing cancer-cell apoptosis, thus validating this approach for the targeted imaging and therapy of cancers.

Therapeutic applications of AS1411 aptamer, an update review

Nucleolin or C23, is one of the most abundant non-ribosomal phosphoproteins of nucleolus. However, in several cancers, nucleolin is highly expressed both intracellularly and on the cell surface. So, it is considered as a potential target for the diagnosis and cancer therapy. Targeting nucleolin by compounds such as AS1411 aptamer can reduce tumor cell growth. In this regard, interest has increased in nucleolin as a molecular target for overcoming cancer therapy challenges. This review paper addressed recent progresses in nucleolin targeting by the G-rich AS1411 aptamer in the field of cancer therapy mainly over the past three years.

Targeted MMP-2 responsive chimeric polymersomes for therapy against colorectal cancer

In the current study, polyethylene glycol (PEG) was linked to polylactide (PLA) through the synthetic peptide PVGLIG which can be selectively cleaved by the tumor-associated matrix metalloproteinase 2 (MMP-2) enzyme. The synthesized chimeric triblock polymer of PEG-b-PVGLIG-PLA was implemented to form nanoscale self-assemble chimeric polymersomes. The hydrophobic SN38 was loaded into polymersomes with 70.3% ± 3.0% encapsulation efficiency demonstrating monodispersed spherical morphologies with 172 ± 30 nm dimension. The prepared chimeric polymersomal formulation provided controlled release of SN38 at physiological condition while illustrating seven-folds higher release rate when exposed to MMP-2 enzyme. At the next stage, AS1411 aptamer was conjugated onto the surface of MMP-2 responsive polymersomal formulation in order to provide guided drug delivery against nucleolin positive cells. In vitro cellular toxicity assay against C26 cell line (nucleolin positive) demonstrated significantly higher toxicity of targeted formulation in comparison with non-targeted one in low SN38 concentrations (0.15-1.25 μg/mL). In vivo study in mice bearing subcutaneous C26 tumor showed higher therapeutic index for MMP-2 responsive chimeric polymersomal formulation of SN38 in comparison with non-responsive one. On the other hand, AS1411 aptamer-targeted MMP-2 responsive chimeric polymersomal formulation exhibited highest therapeutic index compared to other groups. It could be concluded that the targeted chimeric polymersomes bearing both cleavable peptide sequence between their blocks and targeting ligand on their surface, provide favorable characteristics as an ideal delivery system against cancer.

Targeted Therapy of Colon Cancer by Aptamer-Guided Holliday Junctions Loaded with Doxorubicin

Purpose

Chemotherapy is the primary treatment for advanced colon cancer, but its efficacy is often limited by severe toxicities. Targeted therapy in the form of selectively drug delivery system (SDDS) is an important strategy to reduce adverse effects. Here, we aim to design a novel SDDS with potential for practical application using biocompatible components and scalable production process, for targeted delivery of doxorubicin (Dox) to colon cancer cells.

Methods

The SDDS was made of a self-assembled DNA nano-cross (Holliday junction, or HJ) functionalized by four AS1411 aptamers (Apt-HJ) and loaded with Dox.

Results

Apt-HJ had an average size of 12.45 nm and a zeta potential of −11.6 mV. Compared with the monovalent AS1411 aptamer, the quadrivalent Apt-HJ showed stronger binding to target cancer cells (CT26). A complex of Apt-HJ and doxorubicin (Apt-HJ-Dox) was formed by intercalating Dox into the DNA structure of Apt-HJ, with each complex carrying approximately 17 Dox molecules. Confocal microscopy revealed that Apt-HJ-Dox selectively delivered Dox into CT26 colon cancer cells but not the control cells. Moreover, Apt-HJ-Dox achieved targeted killing of CT26 cancer cells in vitro and reduced the damage to control cells. Importantly, compared with free Dox, Apt-HJ-Dox significantly enhanced the antitumor efficacy in vivo without boosting the adverse effects.

Conclusion

These results suggest that Apt-HJ-Dox has application potential in targeted treatment of colon cancer.

High payload and targeted release of anthracyclines by aptamer-tethered DNA nanotrains - Thermodynamic and release kinetic study

As one of the most promising drug delivery carriers, self-assembled DNA nanostructures are characterized of well-defined sizes, excellent biocompatibility, high drug loading and ability to control drug release. Studying the interactions between anticancer drugs and DNA nanostructures can help to associate microstructure-drug loading-release rate-therapeutic effect. Herein AS1411 aptamer-tethered DNA nanotrains (AS1411NTrs) were constructed and used as anthracyclines carrier with high payload for targeted delivery. The bindings of doxorubicin (DOX), epirubicin (EPI), and daunorubicin (DAU) to AS1411NTrs were investigated by isothermal titration calorimetry and fluorescence spectroscopy, and thermodynamic parameters were obtained. The high drug payload capacity of AS1411NTrs was verified by the large number of binding sites (~20). The binding mode was determined by differential scanning calorimetry and potassium iodide (KI) quenching experiments. The release experiment data showed that DNase I facilitated drug release and the release followed the first-order kinetic model. MTT cell viability assay demonstrated that the drug-loaded AS1411NTrs had significantly higher cytotoxicity against target HeLa cells than normal human liver L02 cells. These findings revealed that AS1411NTrs had high payload and targeted release capacity for DOX, EPI, and DAU. This result can provide a theoretical basis for constructing reasonable DNA nanostructures based on drug carriers.