Aptamer-Based Targeted Protein Degradation

Precision-engineered PROTACs minimize off-tissue effects in cancer therapy

Proteolysis-targeting chimeras (PROTACs) offer a groundbreaking approach to selectively degrade disease-related proteins by utilizing the ubiquitin-proteasome system. While this strategy shows great potential in preclinical and clinical settings, off-tissue effects remain a major challenge, leading to toxicity in healthy tissues. This review explores recent advancements aimed at improving PROTAC specificity, including tumor-specific ligand-directed PROTACs, pro-PROTACs activated in tumor environments, and E3 ligase overexpression strategies. Innovations such as PEGylation and nanotechnology also play a role in optimizing PROTAC efficacy. These developments hold promise for safer, more effective cancer therapies, though challenges remain for clinical translation.

CRBN-PROTACs in Cancer Therapy: From Mechanistic Insights to Clinical Applications

Cereblon (CRBN), a member of the E3 ubiquitin ligase complex, has gained significant attention as a therapeutic target in cancer. CRBN regulates the degradation of various proteins in cancer progression, including transcription factors and signaling molecules. PROTACs (proteolysis-targeting chimeras) are a novel approach that uses the cell's degradation system to remove disease-causing proteins selectively. CRBN-dependent PROTACs work by tagging harmful proteins for destruction through the ubiquitin-proteasome system. This strategy offers several advantages over traditional protein inhibition methods, including the potential to overcome drug resistance. Recent progress in developing CRBN-based PROTACs has shown promising preclinical results in both hematologic malignancies and solid tumors. Additionally, CRBN-based PROTACs have enhanced our understanding of CRBN's role in cancer, potentially serving as biomarkers for patient stratification and predicting therapeutic responses. In this review, we delineate the mechanisms of action for CRBN-dependent PROTACs (CRBN-PROTACs), summarize recent advances in preclinical and clinical applications, and provide our perspective on future development.

How to target membrane proteins for degradation: Bringing GPCRs into the TPD fold

We are now in the middle of a so-called "fourth wave" of drug innovation: multispecific medicines aimed at diseases and targets previously thought to be "undruggable"; by inducing proximity between two or more proteins, for example, a target and an effector that do not naturally interact, such modalities have potential far beyond the scope of conventional drugs. In particular, targeted protein degradation (TPD) strategies to destroy disease-associated proteins have emerged as an exciting pipeline in drug discovery. Most efforts are focused on intracellular proteins, whereas membrane proteins have been less thoroughly explored despite the fact that they comprise roughly a quarter of the human proteome with G-protein coupled receptors (GPCRs) notably dysregulated in many diseases. Here, we discuss the opportunities and challenges of developing degraders for membrane proteins with a focus on GPCRs. We provide an overview of different TPD platforms in the context of membrane-tethered targets, and we present recent degradation technologies highlighting their potential application to GPCRs.

Flower-Shaped PCR Scaffold-Based Lateral Flow Bioassay for Bacillus cereus Endospores Detection

Bacillus cereus, a foodborne pathogen, produces resilient endospores that are challenging to detect with conventional methods. This study presents a novel Flower-Shaped PCR Scaffold-based Lateral Flow Biosensor (FSPCRS-LFB), which employs an aptamer-integrated PCR scaffold as capture probes, replacing the traditional streptavidin-biotin (SA-Bio) approach. The FSPCRS-LFB demonstrates high sensitivity and cost-efficiency in detecting B. cereus endospores, with a limit of detection (LOD) of 4.57 endospores/mL a visual LOD of 102 endospores/mL, and a LOD of 6.78 CFU/mL for endospore-cell mixtures. In chicken and tea samples, the platform achieved LODs of 74.5 and 52.8 endospores/mL, respectively, with recovery rates of 82.19% to 97.88%. Compared to existing methods, the FSPCRS-LFB offers a 3.7-fold increase in sensitivity while reducing costs by 26% over the SA-Bio strategy and 87.5% over rolling circle amplification (RCA). This biosensor provides a rapid, sensitive and cost-effective solution for point-of-care testing (POCT) of B. cereus endospores, expanding detection capabilities and offering novel approaches for pathogen detection.

Proteolysis-targeting drug delivery system (ProDDS): integrating targeted protein degradation concepts into formulation design

Targeted protein degradation (TPD) has emerged as a revolutionary paradigm in drug discovery and development, offering a promising avenue to tackle challenging therapeutic targets. Unlike traditional drug discovery approaches that focus on inhibiting protein function, TPD aims to eliminate proteins of interest (POIs) using modular chimeric structures. This is achieved through the utilization of proteolysis-targeting chimeras (PROTACs), which redirect POIs to E3 ubiquitin ligases, rendering them for degradation by the cellular ubiquitin-proteasome system (UPS). Additionally, other TPD technologies such as lysosome-targeting chimeras (LYTACs) and autophagy-based protein degraders facilitate the transportation of proteins to  endo-lysosomal or autophagy-lysosomal pathways for degradation, respectively. Despite significant growth in preclinical TPD research, many chimeras fail to progress beyond this stage in the drug development. Various factors contribute to the limited success of TPD agents, including a significant hurdle of inadequate delivery to the target site. Integrating TPD into delivery platforms could surmount the challenges of in vivo applications of TPD strategies by reshaping their pharmacokinetics and pharmacodynamic profiles. These proteolysis-targeting drug delivery systems (ProDDSs) exhibit superior delivery performance, enhanced targetability, and reduced off-tissue side effects. In this review, we will survey the latest progress in TPD-inspired drug delivery systems, highlight the importance of introducing delivery ideas or technologies to the development of protein degraders, outline design principles of protein degrader-inspired delivery systems, discuss the current challenges, and provide an outlook on future opportunities in this field.

Hydrophobic CPP/HDO conjugates: a new frontier in oligonucleotide-warheaded PROTAC delivery

Proteolysis-targeting chimeras (PROTACs) have emerged as a potent strategy for inducing targeted degradation of proteins, offering promising therapeutic potential to treat diseases such as cancer. However, oligonucleotide-based PROTACs face significant delivery challenges because of their anionic nature and chemical instability. To address these issues, we developed a novel hydrophobic cell-penetrating peptide (CPP) and heteroduplex oligonucleotide (HDO)-conjugated PROTAC, CPP/HDO-PROTAC, to enhance intracellular delivery and degradation efficiency. CPP/HDO-PROTAC was designed to enter the cell through the activity of the conjugated hydrophobic CPP and release decoy oligonucleotide-based PROTACs by RNase H-mediated RNA strand breaks. Our findings demonstrated that CPP/HDO-PROTAC binds to the estrogen receptor α (ERα) with higher affinity than previous constructs, significantly degrades ERα in MCF-7 human breast cancer cells and inhibits cell proliferation at 10 μM. This research highlights the potential of CPP/HDO-PROTAC as a viable method for delivering and activating decoy oligonucleotide-based PROTACs within cells, overcoming the limitations of traditional transfection methods and paving the way for their clinical application.

DNA-templated spatially controlled proteolysis targeting chimeras for CyclinD1-CDK4/6 complex protein degradation

Constraining proximity-based drugs, such as proteolysis-targeting chimeras (PROTACs), into its bioactive conformation can significantly impact their selectivity and potency. However, traditional methods for achieving this often involve complex and time-consuming synthetic procedures. Here, we introduced an alternative approach by demonstrating DNA-templated spatially controlled PROTACs (DTACs), which leverage the programmability of nucleic-acid based self-assembly for efficient synthesis, providing precise control over inhibitors' spacing and orientation. The resulting constructs revealed distance- and orientation-dependent selectivity and degradation potency for the CyclinD1-CDK4/6 protein complex in cancer cells. Notably, an optimal construct DTAC-V1 demonstrated the unprecedented synchronous degradation of entire CyclinD1-CDK4/6 complex. This resulted in the effective cell cycle arrest in G1 phase, and further therapeutic studies showed its potent anti-tumor effects compared to inhibitors alone. These findings present a novel framework for PROTACs design, offering critical insights that may inform the development of other proximity-induced therapeutic modalities.

Programming DNA Nanoassemblies into Polyvalent Lysosomal Degraders for Potent Degradation of Pathogenic Membrane Proteins

Lysosome-targeting chimera (LYTAC) shows great promise for protein-based therapeutics by targeted degradation of disease-associated membrane or extracellular proteins, yet its efficiency is constrained by the limited binding affinity between LYTAC reagents and designated proteins. Here, we established a programmable and multivalent LYTAC system by tandem assembly of DNA into a high-affinity protein degrader, a heterodimer aptamer nanostructure targeting both pathogenic membrane protein and lysosome-targeting receptor (insulin-like growth factor 2 receptor, IGF2R) with adjustable spatial distribution or organization pattern. The DNA-based multivalent LYTACs showed enhanced efficacy in removing immune-checkpoint protein programmable death-ligand 1 (PD-L1) and vascular endothelial growth factor receptor 2 (VEGFR2) in tumor cell membrane that respectively motivated a significant increase in T cell activity and a potent effect on cancer cell growth inhibition. With high programmability and versatility, this multivalent LYTAC system holds considerable promise for realizing protein therapeutics with enhanced activity.

Nanomedicine-induced programmed cell death in cancer therapy: mechanisms and perspectives

The balance of programmed cell death (PCD) mechanisms, including apoptosis, autophagy, necroptosis and others, is pivotal in cancer progression and treatment. Dysregulation of these pathways results in uncontrolled cell growth and resistance to conventional therapies. Nanomedicine offers a promising solution in oncology through targeted drug delivery enabling precise targeting of cancer cells while preserving healthy tissues. This approach reduces the side effects of traditional chemotherapy and enhances treatment efficacy by engaging PCD pathways. We details each PCD pathway, their mechanisms, and innovative nanomedicine strategies to activate these pathways, thereby enhancing therapeutic specificity and minimizing harm to healthy tissues. The precision of nanotechnology in targeting PCD pathways promises significant improvements in cancer treatment outcomes. This synergy between nanotechnology and targeted PCD activation could lead to more effective and less toxic cancer therapies, heralding a new era in cancer treatment.

An Aptamer Glue Enables Hyperefficient Targeted Membrane Protein Degradation

Targeted membrane protein degradation (TMPD) offers significant therapeutic potential by enabling the removal of harmful membrane-anchored proteins and facilitating detailed studies of complex biological pathways. However, existing TMPD methodologies face challenges such as complex molecular architectures, scarce availability, and cumbersome construction requirements. To address these issues, this study presents a highly efficient TMPD system (TMPDS) that integrates an optimized bivalent aptamer glue with a potent protein transport shuttle. Utilizing this approach, we successfully degraded both the highly expressed protein tyrosine kinase 7 in CCRF-CEM cells and the poorly expressed PTK7 in MV-411 cells. This system represents significant advancement in the field of molecular medicine, offering a new avenue for targeted therapeutic interventions and the exploration of cellular mechanisms.

Advances in Aptamer-Based Biosensors for the Detection of Foodborne Mycotoxins

Foodborne mycotoxins (FBMTs) are toxins produced by food itself or during processing and transportation that pose an enormous threat to public health security. However, traditional instrumental and chemical methods for detecting toxins have shortcomings, such as high operational difficulty, time consumption, and high cost, that limit their large-scale applications. In recent years, aptamer-based biosensors have become a new tool for food safety risk assessment and monitoring due to their high affinity, good specificity, and fast response. In this review, we focus on the progress of single-mode and dual-mode aptasensors in basic research and device applications over recent years. Furthermore, we also point out some problems in the current detection strategies, with the aim of stimulating future toxin detection systems for a transition toward ease of operation and rapid detection.

Blocker-SELEX: a structure-guided strategy for developing inhibitory aptamers disrupting undruggable transcription factor interactions

Despite the well-established significance of transcription factors (TFs) in pathogenesis, their utilization as pharmacological targets has been limited by the inherent challenges in modulating their protein interactions. The lack of defined small-molecule binding pockets and the nuclear localization of TFs do not favor the use of traditional tools. Aptamers possess large molecular weights, expansive blocking surfaces and efficient cellular internalization, making them compelling tools for modulating TF interactions. Here, we report a structure-guided design strategy called Blocker-SELEX to develop inhibitory aptamers (iAptamers) that selectively block TF interactions. Our approach leads to the discovery of iAptamers that cooperatively disrupt SCAF4/SCAF8-RNAP2 interactions, dysregulating RNAP2-dependent gene expression, which impairs cell proliferation. This approach is further applied to develop iAptamers blocking WDR5-MYC interactions. Overall, our study highlights the potential of iAptamers in disrupting pathogenic TF interactions, implicating their potential utility in studying the biological functions of TF interactions and in nucleic acids drug discovery.

Progress of proteolysis-targeting chimeras (PROTACs) delivery system in tumor treatment

Proteolysis targeting chimeras (PROTACs) can use the intrinsic protein degradation system in cells to degrade pathogenic target proteins, and are currently a revolutionary frontier of development strategy for tumor treatment with small molecules. However, the poor water solubility, low cellular permeability, and off-target side effects of most PROTACs have prevented them from passing the preclinical research stage of drug development. This requires the use of appropriate delivery systems to overcome these challenging hurdles and ensure precise delivery of PROTACs towards the tumor site. Therefore, the combination of PROTACs and multifunctional delivery systems will open up new research directions for targeted degradation of tumor proteins. In this review, we systematically reviewed the design principles and the most recent advances of various PROTACs delivery systems. Moreover, the constructive strategies for developing multifunctional PROTACs delivery systems were proposed comprehensively. This review aims to deepen the understanding of PROTACs drugs and promote the further development of PROTACs delivery system.

Aptamer-based assembly systems for SARS-CoV-2 detection and therapeutics

Nucleic acid aptamers are oligonucleotide chains with molecular recognition properties. Compared with antibodies, aptamers show advantages given that they are readily produced via chemical synthesis and elicit minimal immunogenicity in biomedicine applications. Notably, aptamer-encoded nucleic acid assemblies further improve the binding affinity of aptamers with the targets due to their multivalent synergistic interactions. Specially, aptamers can be engineered with special topological arrangements in nucleic acid assemblies, which demonstrate spatial and valence matching towards antigens on viruses, thus showing potential in the detection and therapeutic applications of viruses. This review presents the recent progress on the aptamers explored for SARS-CoV-2 detection and infection treatment, wherein applications of aptamer-based assembly systems are introduced in detail. Screening methods and chemical modification strategies for aptamers are comprehensively summarized, and the types of aptamers employed against different target domains of SARS-CoV-2 are illustrated. The evolution of aptamer-based assembly systems for the detection and neutralization of SARS-CoV-2, as well as the construction principle and characteristics of aptamer-based DNA assemblies are demonstrated. The typically representative works are presented to demonstrate how to assemble aptamers rationally and elaborately for specific applications in SARS-CoV-2 diagnosis and neutralization. Finally, we provide deep insights into the current challenges and future perspectives towards aptamer-based nucleic acid assemblies for virus detection and neutralization in nanomedicine.

Securing LYTAC with Logic-Identification System for Cancer Cell-Selective Membrane Protein Degradation

Lysosome-targeting chimera (LYTAC) links proteins of interest (POIs) with lysosome-targeting receptors (LTRs) to achieve membrane protein degradation, which is becoming a promising therapeutic modality. However, cancer cell-selective membrane protein degradation remains a big challenge considering expressions of POIs in both cancer cells and normal cells, as well as broad tissue distribution of LTRs. Here a logic-identification system is designed, termed Logic-TAC, based on cell membrane-guided DNA calculations to secure LYTAC selectively for cancer cells. Logic-TAC is designed as a duplex DNA structure, with both POI and LTR recognition regions sealed to avoid systematic toxicity during administration. MCF-7 and MCF-10A are chosen as sample cancer cell and normal cell respectively. As input 1 for logic-identification, membrane proteins EpCAM, which is highly expressed by MCF-7 but barely by MCF-10A, reacts with Logic-TAC to expose POI recognition region. As input 2 for logic-identification, Logic-TAC binds to POI, membrane protein MUC1, to expose LTR recognition region. As output, MUC1 is connected to LTR and degraded via lysosome pathway selectively for cancer cell MCF-7 with little side effect on normal cell MCF-10A. The logic-identification system also demonstrated satisfactory in vivo therapeutic results, indicating its promising potential in precise targeted therapy.

Expanding the horizons of targeted protein degradation: A non-small molecule perspective

Targeted protein degradation (TPD) represented by proteolysis targeting chimeras (PROTACs) marks a significant stride in drug discovery. A plethora of innovative technologies inspired by PROTAC have not only revolutionized the landscape of TPD but have the potential to unlock functionalities beyond degradation. Non-small-molecule-based approaches play an irreplaceable role in this field. A wide variety of agents spanning a broad chemical spectrum, including peptides, nucleic acids, antibodies, and even vaccines, which not only prove instrumental in overcoming the constraints of conventional small molecule entities but also provided rapidly renewing paradigms. Herein we summarize the burgeoning non-small molecule technological platforms inspired by PROTACs, including three major trajectories, to provide insights for the design strategies based on novel paradigms.

Aptamers: Promising Reagents in Biomedicine Application

Nucleic acid aptamers, often termed "chemical antibodies," are short, single-stranded DNA or RNA molecules, which are selected by SELEX. In addition to their high specificity and affinity comparable to traditional antibodies, aptamers have numerous unique advantages such as wider identification of targets, none or low batch-to-batch variations, versatile chemical modifications, rapid mass production, and lack of immunogenicity. These characteristics make aptamers a promising recognition probe for scientific research or even clinical application. Aptamer-functionalized nanomaterials are now emerged as a promising drug delivery system for various diseases with decreased side-effects and improved efficacy. In this review, the technological strategies for generating high-affinity and biostable aptamers are introduced. Moreover, the development of aptamers for their application in biomedicine including aptamer-based biosensors, aptamer-drug conjugates and aptamer functionalized nanomaterials is comprehensively summarized.

Connective Tissue Growth Factor: Regulation, Diseases, and Drug Discovery

In drug discovery, selecting targeted molecules is crucial as the target could directly affect drug efficacy and the treatment outcomes. As a member of the CCN family, CTGF (also known as CCN2) is an essential regulator in the progression of various diseases, including fibrosis, cancer, neurological disorders, and eye diseases. Understanding the regulatory mechanisms of CTGF in different diseases may contribute to the discovery of novel drug candidates. Summarizing the CTGF-targeting and -inhibitory drugs is also beneficial for the analysis of the efficacy, applications, and limitations of these drugs in different disease models. Therefore, we reviewed the CTGF structure, the regulatory mechanisms in various diseases, and drug development in order to provide more references for future drug discovery.

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

Background

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

Aim

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

Methods

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

Results

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

Conclusion

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

Aptamer Based SPREETA Sensor for the Detection of Porphyromonas gingivalis G-Protein

We have developed an aptamer that specifically binds to Porphyromonas gingivalis to reduce the cellular damage caused by P. gingivalis infection and applied it as a biosensor. P. gingivalis is one of the major pathogens causing destructive periodontal disease among the periodontal microorganisms constituting complex biofilms. Porphyromonas gingivalis G-protein (PGP) known to play an important role in the transmission of germs was used as a target protein for the screening of aptamer. The aptamer that has binds to the G-protein of P. gingivalis, was screened and developed through the Systemic Evolution of Ligands by Exponential Energy (SELEX) method. Modified-Western blot analysis was performed with the aptamer which consisted of 38 single-stranded DNA to confirm the selectivity. ELONA (enzyme linked oligonucleotide assay) used to confirm that the aptamer was sensitive to PGP even at low concentration of 1 μg/ml. For the rapid detection of P. gingivalis, we constructed a surface plasmon resonance biosensor with SPREETA using the PGP aptamer. It was confirmed that PGP could be detected as low concentration as at 0.1 pM, which is the minimum concentration of aptamer sensor within 5 min. Based on these results, we have constructed a SPREETA biosensor based on aptamer that can bind to P. gingivalis G-protein. It can be used as an infection diagnosis system to rapidly diagnose and analyze oral diseases caused by P. gingivalis.

What influences the activity of Degrader-Antibody conjugates (DACs)

The targeted protein degradation (TPD) technology employing proteolysis-targeting chimeras (PROTACs) has been widely applied in drug chemistry and chemical biology for the treatment of cancer and other diseases. PROTACs have demonstrated significant advantages in targeting undruggable targets and overcoming drug resistance. However, despite the efficient degradation of targeted proteins achieved by PROTACs, they still face challenges related to selectivity between normal and cancer cells, as well as issues with poor membrane permeability due to their substantial molecular weight. Additionally, the noteworthy toxicity resulting from off-target effects also needs to be addressed. To solve these issues, Degrader-Antibody Conjugates (DACs) have been developed, leveraging the targeting and internalization capabilities of antibodies. In this review, we elucidates the characteristics and distinctions between DACs, and traditional Antibody-drug conjugates (ADCs). Meanwhile, we emphasizes the significance of DACs in facilitating the delivery of PROTACs and delves into the impact of various components on DAC activity. These components include antibody targets, drug-antibody ratio (DAR), linker types, PROTACs targets, PROTACs connections, and E3 ligase ligands. The review also explores the suitability of different targets (antibody targets or PROTACs targets) for DACs, providing insights to guide the design of PROTACs better suited for antibody conjugation.

Nano-PROTACs: state of the art and perspectives

PROteolysis TArgeting Chimeras (PROTACs), as a recently identified technique in the field of new drug development, provide new concepts for disease treatment and are expected to revolutionize drug discovery. With high specificity and flexibility, PROTACs serve as an innovative research tool to target and degrade disease-relevant proteins that are not currently pharmaceutically vulnerable to eliminating their functions by hijacking the ubiquitin-proteasome system. To date, PROTACs still face the challenges of low solubility, poor permeability, off-target effects, and metabolic instability. The combination of nanotechnology and PROTACs has been explored to enhance the in vivo performance of PROTACs regarding overcoming these challenging hurdles. In this review, we summarize the latest advancements in the building-block design of PROTAC prodrug nanoparticles and provide an overview of existing/potential delivery systems and loading approaches for PROTAC drugs. Furthermore, we discuss the current status and prospects of the split-and-mix approach for PROTAC drug optimization. Additionally, the advantages and translational potentials of carrier-free nano-PROTACs and their combinational therapeutic effects are highlighted. This review aims to foster a deeper understanding of this rapidly evolving field and facilitate the progress of nano-PROTACs that will continue to push the boundaries of achieving selectivity and controlled release of PROTAC drugs.

Application of PROTACs in Target Identification and Target Validation

PROTAC, as a novel therapeutic drug model, has received widespread attention from the academic and pharmaceutical industries. At the same time, PROTAC technology has led many researchers to focus on developing chemical biology tool properties due to its unique operating mechanism and protein dynamic regulatory properties. In recent years, the rapid development of PROTAC technology has gradually made it an essential tool for target identification and target validation. To further promote the application of PROTAC tools in drug discovery and basic medical sciences research, this review distinguished between target identification and target validation concepts. It summarized the research progress of PROTAC technology in these aspects.

Chemically Modified Platforms for Better RNA Therapeutics

RNA-based therapies have catalyzed a revolutionary transformation in the biomedical landscape, offering unprecedented potential in disease prevention and treatment. However, despite their remarkable achievements, these therapies encounter substantial challenges including low stability, susceptibility to degradation by nucleases, and a prominent negative charge, thereby hindering further development. Chemically modified platforms have emerged as a strategic innovation, focusing on precise alterations either on the RNA moieties or their associated delivery vectors. This comprehensive review delves into these platforms, underscoring their significance in augmenting the performance and translational prospects of RNA-based therapeutics. It encompasses an in-depth analysis of various chemically modified delivery platforms that have been instrumental in propelling RNA therapeutics toward clinical utility. Moreover, the review scrutinizes the rationale behind diverse chemical modification techniques aiming at optimizing the therapeutic efficacy of RNA molecules, thereby facilitating robust disease management. Recent empirical studies corroborating the efficacy enhancement of RNA therapeutics through chemical modifications are highlighted. Conclusively, we offer profound insights into the transformative impact of chemical modifications on RNA drugs and delineates prospective trajectories for their future development and clinical integration.

Nanotechnology Reprogramming Metabolism for Enhanced Tumor Immunotherapy

Mutation burden, hypoxia, and immunoediting contribute to altered metabolic profiles in tumor cells, resulting in a tumor microenvironment (TME) characterized by accumulation of toxic metabolites and depletion of various nutrients, which significantly hinder the antitumor immunity via multiple mechanisms, hindering the efficacy of tumor immunotherapies. In-depth investigation of the mechanisms underlying these phenomena are vital for developing effective antitumor drugs and therapies, while the therapeutic effects of metabolism-targeting drugs are restricted by off-target toxicity toward effector immune cells and high dosage-mediated side effects. Nanotechnologies, which exhibit versatility and plasticity in targeted delivery and metabolism modulation, have been widely applied to boost tumor immunometabolic therapies via multiple strategies, including targeting of metabolic pathways. In this review, recent advances in understanding the roles of tumor cell metabolism in both immunoevasion and immunosuppression are reviewed, and nanotechnology-based metabolic reprogramming strategies for enhanced tumor immunotherapies are discussed.

Investigation of the Relationship between Aptamers' Targeting Functions and Human Plasma Proteins

Aptamers are single-stranded DNA or RNA molecules capable of recognizing targets via specific three-dimensional structures. Taking advantage of this unique targeting function, aptamers have been extensively applied to bioanalysis and disease theranostics. However, the targeting functionality of aptamers in the physiological milieu is greatly impeded compared with their in vitro applications. To investigate the physiological factors that adversely affect the in vivo targeting ability of aptamers, we herein systematically studied the interactions between human plasma proteins and aptamers and the specific effects of plasma proteins on aptamer targeting. Microscale thermophoresis and flow cytometry analysis showed that plasma interacted with aptamers, restricting their affinity toward targeted tumor cells. Further pull-down assay and proteomic identification verified that the interactions between aptamers and plasma proteins were mainly involved in complement activation and immune response as well as showed structure-selective and sequence-specific features. Particularly, the fibronectin 1 (FN1) protein showed dramatically specific interactions with nucleolin (NCL) targeting aptamer AS1411. The competitive binding between FN1 and NCL almost deprived the AS1411 aptamer's targeting ability in vivo. In order to maintain the targeting function in the physiological milieu, a series of optimizations were performed via the chemical modifications of AS1411 aptamer, and 3'-terminal pegylation was demonstrated to be resistant to the interaction with FN1, leading to improved tumor-targeting effects. This work emphasizes the physiological environment influences on aptamers targeting functionality and suggests that rational design and modification of aptamers to minimize the nonspecific interaction with plasma proteins might be effective to maintain aptamer functionality in future clinical uses.

Targeted protein degradation in drug development: Recent advances and future challenges

Targeted protein degradation (TPD) has emerged as a promising therapeutic approach with potential advantages over traditional occupancy-based inhibitors in terms of dosing, side effects and targeting "undruggable" proteins. Targeted degraders can theoretically bind any nook or cranny of targeted proteins to drive degradation. This offers convenience versus the small-molecule inhibitors that must function in a well-defined pocket. The degradation process depends mainly on two cell self-destruction mechanisms, namely the ubiquitin-proteasome system and the lysosomal degradation pathway. Various TPD strategies (e.g., proteolytic-targeting chimeras, molecular glues, lysosome-targeting chimeras, and autophagy-targeting chimeras) have been developed. These approaches hold great potential for targeting dysregulated proteins, potentially offering therapeutic benefits. In this article, we systematically review the mechanisms of various TPD strategies, potential applications to drug discovery, and recent advances. We also discuss the benefits and challenges associated with these TPD strategies, aiming to provide insight into the targeting of dysregulated proteins and facilitate their clinical applications.

Multistage Self-Assembled Nanomaterials for Cancer Immunotherapy

Advances in nanotechnology have brought innovations to cancer therapy. Nanoparticle-based anticancer drugs have achieved great success from bench to bedside. However, insufficient therapy efficacy due to various physiological barriers in the body remains a key challenge. To overcome these biological barriers and improve the therapeutic efficacy of cancers, multistage self-assembled nanomaterials with advantages of stimuli-responsiveness, programmable delivery, and immune modulations provide great opportunities. In this review, we describe the typical biological barriers for nanomedicines, discuss the recent achievements of multistage self-assembled nanomaterials for stimuli-responsive drug delivery, highlighting the programmable delivery nanomaterials, in situ transformable self-assembled nanomaterials, and immune-reprogramming nanomaterials. Ultimately, we perspective the future opportunities and challenges of multistage self-assembled nanomaterials for cancer immunotherapy.

Structural Optimization of Decoy Oligonucleotide-Based PROTAC That Degrades the Estrogen Receptor

Proteolysis-targeting chimeras (PROTACs) have attracted attention as a chemical method of protein knockdown via the ubiquitin-proteasome system. Some oligonucleotide-based PROTACs have recently been developed for disease-related proteins that do not have optimal small-molecule ligands such as transcription factors. We have previously developed the PROTAC LCL-ER(dec), which uses a decoy oligonucleotide as a target ligand for estrogen receptor α (ERα) as a model transcription factor. However, LCL-ER(dec) has a low intracellular stability because it comprises natural double-stranded DNA sequences. In the present study, we developed PROTACs containing chemically modified decoys to address this issue. Specifically, we introduced phosphorothioate modifications and hairpin structures into LCL-ER(dec). Among the newly designed PROTACs, LCL-ER(dec)-H46, with a T4 loop structure at the end of the decoy, showed long-term ERα degradation activity while acquiring enzyme tolerance. These findings suggest that the introduction of hairpin structures is a useful modification of oligonucleotides in decoy oligonucleotide-based PROTACs.

A cocktail therapeutic strategy based on clofarabine-containing aptamer-PROTAC for enhanced cancer therapy

By introducing a therapeutic nucleoside analogue tail to the parent Aptamer-PROTACs, a PROTAC-cocktail system (ApTCs-3X) was designed and evaluated. ApTCs-3X exhibited improved nuclease resistance and efficiently degraded target protein with subcellular localization preference. This cocktail therapy results in enhanced therapeutic outcomes, making it suitable for advancing PROTAC in combination therapy.

Just Keep Rolling?-An Encompassing Review towards Accelerated Vaccine Product Life Cycles

In light of the recent pandemic, several COVID-19 vaccines were developed, tested and approved in a very short time, a process that otherwise takes many years. Above all, these efforts have also unmistakably revealed the capacity limits and potential for improvement in vaccine production. This review aims to emphasize recent approaches for the targeted rapid adaptation and production of vaccines from an interdisciplinary, multifaceted perspective. Using research from the literature, stakeholder analysis and a value proposition canvas, we reviewed technological innovations on the pharmacological level, formulation, validation and resilient vaccine production to supply bottlenecks and logistic networks. We identified four main drivers to accelerate the vaccine product life cycle: computerized candidate screening, modular production, digitized quality management and a resilient business model with corresponding transparent supply chains. In summary, the results presented here can serve as a guide and implementation tool for flexible, scalable vaccine production to swiftly respond to pandemic situations in the future.