Challenging cancer targets for aptamer delivery

Targeted Delivery of Catalase and Photosensitizer Ce6 by a Tumor-Specific Aptamer Is Effective against Bladder Cancer In Vivo

Photodynamic therapy (PDT) is often applied in a clinical setting to treat bladder cancer. However, current photosensitizers report drawbacks such as low efficacy, low selectivity, and numerous side effects, which have limited the clinical values of PDT for bladder cancer. Previously, we developed the first bladder cancer-specific aptamer that can selectively bind to and be internalized by bladder tumor cells versus normal uroepithelium cells. Here, we use an aptamer-based drug delivery system to deliver photosensitizer chlorine e6 (Ce6) into bladder tumor cells. In addition to Ce6, we also incorporate catalase into the drug complex to increase local oxygen levels in the tumor tissue. Compared with free Ce6, an aptamer-guided DNA nanotrain (NT) loaded with Ce6 and catalase (NT-Catalase-Ce6) can specifically recognize bladder cancer cells, produce oxygen locally, induce ROS in tumor cells, and cause mitochondrial apoptosis. In an orthotopic mouse model of bladder cancer, the intravesical instillation of NT-Catalase-Ce6 exhibits faster drug internalization and a longer drug retention time in tumor tissue compared with that in normal urothelium. Moreover, our modified PDT significantly inhibits tumor growth with fewer side effects such as cystitis than free Ce6. This aptamer-based photosensitizer delivery system can therefore improve the selectivity and efficacy and reduce the side effects of PDT treatment in mouse models of bladder cancer, bearing a great translational value for bladder cancer intravesical therapy.

PLGA nanomedical consignation: A novel approach for the management of prostate cancer

The malignancy of the prostate is a complicated ailment which impacts millions of male populations around the globe. Despite the multitude of endeavour accomplished within this domain, modalities that are involved in the ameliorative management of predisposed infirmity are still relent upon non-specific and invasive procedures, thus imposing a detrimental mark on the living standard of the individual. Also, the orchestrated therapeutic interventions are still incompetent in substantiating a robust and unabridged therapeutic end point owing to their inadequate solubility, low bioavailability, limited cell assimilation, and swift deterioration, thereby muffling the clinical application of these existing treatment modalities. Nanotechnology has been employed in an array of modalities for the medical management of malignancies. Among the assortment of available nano-scaffolds, nanocarriers composed of a bio-decomposable and hybrid polymeric material like PLGA hold an opportunity to advance as standard chemotherapeutic modalities. PLGA-based nanocarriers have the prospect to address the drawbacks associated with conventional cancer interventions, owing to their versatility, durability, nontoxic nature, and their ability to facilitate prolonged drug release. This review intends to describe the plethora of evidence-based studies performed to validate the applicability of PLGA nanosystem in the amelioration of prostate malignancies, in conjunction with PLGA focused nano-scaffold in the clinical management of prostate carcinoma. This review seeks to explore numerous evidence-based studies confirming the applicability of PLGA nanosystems in ameliorating prostate malignancies. It also delves into the role of PLGA-focused nano-scaffolds in the clinical management of prostate carcinoma, aiming to provide a comprehensive perspective on these advancements.

Based on Unmodified Aptamer-Gold Nanoparticles Colorimetric Detection of Dexamethasone in Food

Residue and illegal addition of Dexamethasone (DEX) in food has received widespread attention over the past few decades. Long-term intake of DEX will have a strong endocrine-disrupting effect, and there is an urgent need to develop highly sensitive and rapid on-site detection methods. In this work, a colorimetric sensor based on an unmodified aptamer and gold nanoparticles (Au NPs) was designed to detect DEX in milk and glucosamine. Under optimized conditions, the absorbance ratio of Au NPs increased linearly with DEX concentration over the range of 10-350 nmol/mL (r² = 0.997), with a limit of detection (LOD) of 0.5 nmol/mL, and the recoveries ranged from 93.6 to 117%. To explore the interaction mechanism between aptamer and DEX, molecular docking and molecular dynamics simulations were applied to probe intermolecular interactions and structures of the complex. The establishment of aptamer-based sensors effectively avoids the antibody screening response, with a cost-efficient, excellent selective and great potential in DEX determination.

Targeted Liposomes: A Nonviral Gene Delivery System for Cancer Therapy

Cancer is the second most frequent cause of death worldwide, with 28.4 million new cases expected for 2040. Despite de advances in the treatment, it remains a challenge because of the tumor heterogenicity and the increase in multidrug resistance mechanisms. Thus, gene therapy has been a potential therapeutic approach owing to its ability to introduce, silence, or change the content of the human genetic code for inhibiting tumor progression, angiogenesis, and metastasis. For the proper delivery of genes to tumor cells, it requires the use of gene vectors for protecting the therapeutic gene and transporting it into cells. Among these vectors, liposomes have been the nonviral vector most used because of their low immunogenicity and low toxicity. Furthermore, this nanosystem can have its surface modified with ligands (e.g., antibodies, peptides, aptamers, folic acid, carbohydrates, and others) that can be recognized with high specificity and affinity by receptor overexpressed in tumor cells, increasing the selective delivery of genes to tumors. In this context, the present review address and discuss the main targeting ligands used to functionalize liposomes for improving gene delivery with potential application in cancer treatment.

Targeting lung cancer cells with MUC1 aptamer-functionalized PLA-PEG nanocarriers

MUC1 aptamer-functionalized PLA-PEG nanocarriers at various w/w ratios (polymer to doxorubicin weight ratio) were prepared by a double emulsion method. Physiochemical properties, encapsulation efficiency (EE), loading content (LC) and in vitro release kinetics of DOX were assessed. Furthermore, cytotoxicity and antitumor activity of prepared PLA-PEG-Apt/DOX NPs at w/w ratio 10:1 were evaluated by MTT assay and flow cytometry against MUC1-overexpressing A-549 cell line. Targeted nanocarriers (PLA-PEG-Apt/DOX NPs at w/w ratio 10:1) induced higher apoptosis rate (36.3 ± 3.44%) for 24 h in MUC1 positive A-549 cancer cells in compare to non-targeted form (PLA-PEG/DOX NPs at w/w ratio 10:1, 11.37 ± 1.65%) and free DOX (4.35 ± 0.81%). In other word, the percentage of cell death in A-549 lung cancer cells treated with PLA-PEG-Apt/DOX NPs at w/w ratio 10:1 is 3.19 and 8.34 fold higher than in non-targeted form and Free DOX treated cancer cells, respectively. Therefore, PLA-PEG-Apt/DOX NPs might be considered a promising drug delivery system for targeted drug delivery towards MUC1-overexpressing tumors cells.

Efficient Eradication of Bacterial Biofilms with Highly Specific Graphene-Based Nanocomposite Sheets

Bacterial biofilms are usually resistant to antibiotics, thus powerful methods are required for removal. Nanomaterial involving a combination of treatment modalities recently has been recognized as an effective alternative to combat biofilm. However, its targeted and controlled release in bacterial infection is still a major challenge. Here, we present an intelligent phototherapeutic nanoplatform consisting of an aptamer (Apt), indocyanine green (ICG), and carboxyl-functionalized graphene oxide (GO-COOH), namely, ICG@GO-Apt, for targeted treatment of the biofilm formed by Salmonella Typhimurium. Since Apt-conjugated nanosheets (NSs) can specifically accumulate near abscess caused by the pathogens, they enhance greatly the local drug molecule concentration and promote their precise delivery. They can simultaneously generate heat and reactive oxygen species under near-infrared irradiation for photothermal/photodynamic therapy, thereby significantly enhancing biofilm elimination. The phototherapeutic ICG@GO-Apt also displays a good biocompatibility. More importantly, the multifunction phototherapeutic platform shows an efficient biofilm elimination with an efficiency of greater than 99.99% in an abscess formation model. Therefore, ICG@GO-Apt NSs with bacteria-targeting capability provide a reliable tool for clinical bacterial infection that circumvents antibiotic resistance.

A putative role for lncRNAs in epigenetic regulation of memory

The central dogma of molecular genetics is defined as encoded genetic information within DNA, transcribed into messenger RNA, which contain the instructions for protein synthesis, thus imparting cellular functionality and ultimately life. This molecular genetic theory has given birth to the field of neuroepigenetics, and it is now well established that epigenetic regulation of gene transcription is critical to the learning and memory process. In this review, we address a potential role for a relatively new player in the field of epigenetic crosstalk - long non-coding RNAs (lncRNAs). First, we briefly summarize epigenetic mechanisms in memory formation and examine what little is known about the emerging role of lncRNAs during this process. We then focus discussions on how lncRNAs interact with epigenetic mechanisms to control transcriptional programs under various conditions in the brain, and how this may be applied to regulation of gene expression necessary for memory formation. Next, we explore how epigenetic crosstalk in turn serves to regulate expression of various individual lncRNAs themselves. To highlight the importance of further exploring the role of lncRNA in epigenetic regulation of gene expression, we consider the significant relationship between lncRNA dysregulation and declining memory reserve with aging, Alzheimer's disease, and epilepsy, as well as the promise of novel therapeutic interventions. Finally, we conclude with a discussion of the critical questions that remain to be answered regarding a role for lncRNA in memory.

Aptamers: Cutting edge of cancer therapies

The development of an aptamer-based therapeutic has rapidly progressed following the first two reports in the 1990s, underscoring the advantages of aptamer drugs associated with their unique binding properties. In 2004, the US Food and Drug Administration (FDA) approved the first therapeutic aptamer for the treatment of neovascular age-related macular degeneration, Macugen developed by NeXstar. Since then, eleven aptamers have successfully entered clinical trials for various therapeutic indications. Despite some of the pre-clinical and clinical successes of aptamers as therapeutics, no aptamer has been approved by the FDA for the treatment of cancer. This review highlights the most recent and cutting-edge approaches in the development of aptamers for the treatment of cancer types most refractory to conventional therapies. Herein, we will review (1) the development of aptamers to enhance anti-cancer immunity and as delivery tools for inducing the expression of immunogenic neoantigens; (2) the development of the most promising therapeutic aptamers designed to target the hard-to-treat cancers such as brain tumors; and (3) the development of "carrier" aptamers able to target and penetrate tumors and metastasis, delivering RNA therapeutics to the cytosol and nucleus.

Modelling of SHMT1 riboregulation predicts dynamic changes of serine and glycine levels across cellular compartments

Human serine hydroxymethyltransferase (SHMT) regulates the serine-glycine one carbon metabolism and plays a role in cancer metabolic reprogramming. Two SHMT isozymes are acting in the cell: SHMT1 encoding the cytoplasmic isozyme, and SHMT2 encoding the mitochondrial one. Here we present a molecular model built on experimental data reporting the interaction between SHMT1 protein and SHMT2 mRNA, recently discovered in lung cancer cells. Using a stochastic dynamic model, we show that RNA moieties dynamically regulate serine and glycine concentration, shaping the system behaviour. For the first time we observe an active functional role of the RNA in the regulation of the serine-glycine metabolism and availability, which unravels a complex layer of regulation that cancer cells exploit to fine tune amino acids availability according to their metabolic needs. The quantitative model, complemented by an experimental validation in the lung adenocarcinoma cell line H1299, exploits RNA molecules as metabolic switches of the SHMT1 activity. Our results pave the way for the development of RNA-based molecules able to unbalance serine metabolism in cancer cells.

Glutamate-urea-based PSMA-targeted PLGA nanoparticles for prostate cancer delivery of docetaxel

Targeted drug delivery is a tool to make treatment more specific, selective, and effective and to prevent unwanted complications. Prostate specific membrane antigen (PSMA) is a useful biomarker in order to monitor and control prostate cancer. Glutamate-Urea-R (Glu-Urea-R) is a PSMA enzyme inhibitor capable of binding to this surface marker of prostate cancer cell in an efficient and special manner. The aim of this project was to develop a docetaxel-loaded nanoparticle of poly (lactic-co-glycolic acid) polyethylene glycol which is cojugated to a urea-based anti-PSMA ligand named glutamate-urea-lysine (glu-urea-lys) for targeted delivery of docetaxel in prostate cancer. The obtained nanoparticles, prepared by nanoprecipitation method, were spheres with a particle size of around 150 nm and zeta potential of -7.08 mV. Uptake studies on the PC3 (as PSMA negative) and LNCaP (as PSMA positive) cells demonstrated that drug uptake was efficient by the PSMA positive cells. IC50 of targeted NPs on LNCaP cell line compared to non-targeted ones was reduced by more than 70% in three different incubation times of 24, 48, and 72 h. In conclusion, the nanoparticles are expected to specifically transport docetaxel to PSMA-positive prostate cancer cells and consequently, enhance the antitumor efficacy of docetaxel on these cells.

PPAI: a web server for predicting protein-aptamer interactions

BACKGROUND

The interactions between proteins and aptamers are prevalent in organisms and play an important role in various life activities. Thanks to the rapid accumulation of protein-aptamer interaction data, it is necessary and feasible to construct an accurate and effective computational model to predict aptamers binding to certain interested proteins and protein-aptamer interactions, which is beneficial for understanding mechanisms of protein-aptamer interactions and improving aptamer-based therapies.

RESULTS

In this study, a novel web server named PPAI is developed to predict aptamers and protein-aptamer interactions with key sequence features of proteins/aptamers and a machine learning framework integrated adaboost and random forest. A new method for extracting several key sequence features of both proteins and aptamers is presented, where the features for proteins are extracted from amino acid composition, pseudo-amino acid composition, grouped amino acid composition, C/T/D composition and sequence-order-coupling number, while the features for aptamers are extracted from nucleotide composition, pseudo-nucleotide composition (PseKNC) and normalized Moreau-Broto autocorrelation coefficient. On the basis of these feature sets and balanced the samples with SMOTE algorithm, we validate the performance of PPAI by the independent test set. The results demonstrate that the Area Under Curve (AUC) is 0.907 for prediction of aptamer, while the AUC reaches 0.871 for prediction of protein-aptamer interactions.

CONCLUSION

These results indicate that PPAI can query aptamers and proteins, predict aptamers and predict protein-aptamer interactions in batch mode precisely and efficiently, which would be a novel bioinformatics tool for the research of protein-aptamer interactions. PPAI web-server is freely available at http://39.96.85.9/PPAI.

Aptamers, the Nucleic Acid Antibodies, in Cancer Therapy

The arrival of the monoclonal antibody (mAb) technology in the 1970s brought with it the hope of conquering cancers to the medical community. However, mAbs, on the whole, did not achieve the expected wonder in cancer therapy although they do have demonstrated successfulness in the treatment of a few types of cancers. In 1990, another technology of making biomolecules capable of specific binding appeared. This technique, systematic evolution of ligands by exponential enrichment (SELEX), can make aptamers, single-stranded DNAs or RNAs that bind targets with high specificity and affinity. Aptamers have some advantages over mAbs in therapeutic uses particularly because they have little or no immunogenicity, which means the feasibility of repeated use and fewer side effects. In this review, the general properties of the aptamer, the advantages and limitations of aptamers, the principle and procedure of aptamer production with SELEX, particularly the undergoing studies in aptamers for cancer therapy, and selected anticancer aptamers that have entered clinical trials or are under active investigations are summarized.

Live and Let Dye: Visualizing the Cellular Compartments of the Malaria Parasite Plasmodium falciparum

Malaria remains one of the deadliest diseases worldwide and it is caused by the protozoan parasite Plasmodium spp. Parasite visualization is an important tool for the correct detection of malarial cases but also to understand its biology. Advances in visualization techniques promote new insights into the complex life cycle and biology of Plasmodium parasites. Live cell imaging by fluorescence microscopy or flow cytometry are the foundation of the visualization technique for malaria research. In this review, we present an overview of possibilities in live cell imaging of the malaria parasite. We discuss some of the state-of-the-art techniques to visualize organelles and processes of the parasite and discuss limitation and advantages of each technique. © 2019 International Society for Advancement of Cytometry.

Surface functionalized dendrimers as controlled-release delivery nanosystems for tumor targeting

Dendrimers are nano-sized and three-dimensional macromolecules with well-defined globular architecture and are widely used in various aspects such as drug and gene delivery owing to multivalent and host-guest entrapment properties. However, dendrimers like other nanomaterials have some disadvantages for example rapid clearance by reticuloendothelial system, toxicity due to interaction of amine terminated group with cell membrane, low transfection efficiency and lack of controlled release behavior, which reduce their therapeutic efficiency. To solve these problems, surface functionalization of dendrimers can be carried out. Surface functionalization not only mitigates this obstacle but also renders excessive specificity to dendrimer to improve efficiency of cancer therapy. Specific properties in cancer cell compared to normal cells such as overexpression of various receptors and difference in biological condition like pH, temperature and redox of tumor environment can be an appropriate strategy to increase site-specific targeting efficiency. Therefore, in this article we focus on numerous functionalization strategies, which are used in the modification of dendrimers through attachment of lipid, amino acid, protein/peptide, aptamer, vitamin, antibody. Moreover, increased biocompatibility, site-specific delivery based on various ligands, enhanced transfection efficiency, sustained and controlled release behavior based on stimuli responsiveness are benefits of functionalized dendrimer which we discuss in this review. Overall, these functionalized dendrimers can open a new horizon in the field of targeted drug and gene delivery.

Recent advances in cell-mediated nanomaterial delivery systems for photothermal therapy

Cell-mediated “Trojan Horse” delivery vehicles overcome the drug delivery barriers to transport nano-agents enhancing the efficiency of photothermal therapy.