Engineering extracellular matrix to improve drug delivery for cancer therapy

Advances in tumor stroma-based targeted delivery

The tumor stroma plays a crucial role in tumor progression, and the interactions between the extracellular matrix, tumor cells, and stromal cells collectively influence tumor progression and the efficacy of therapeutic agents. Currently, utilizing components of the tumor stroma for drug delivery is a noteworthy strategy. A number of targeted drug delivery systems designed based on tumor stromal components are entering clinical trials. Therefore, this paper provides a thorough examination of the function of tumor stroma in the advancement of targeted drug delivery systems. One approach is to use tumor stromal components for targeted drug delivery, which includes certain stromal components possessing inherent targeting capabilities like HA, laminin, along with targeting stromal cells homologously. Another method entails directly focusing on tumor stromal components to reshape the tumor stroma and facilitate drug delivery. These drug delivery systems exhibit great potential in more effective cancer therapy strategies, such as precise targeting, enhanced penetration, improved safety profile, and biocompatibility. Ultimately, the deployment of these drug delivery systems can deepen our comprehension of tumor stroma and the advanced development of corresponding drug delivery systems.

Dual-Prodrug-Based Hyaluronic Acid Nanoplatform Provides Cascade-Boosted Drug Delivery for Oxidative Stress-Enhanced Chemotherapy

Insufficient drug accumulation in tumors severely limits the antitumor efficiency of hyaluronic acid (HA) nanomedicine in solid tumors due to superficial penetration depth, low cell uptake, and nonspecific drug release. Hence, we constructed a dual NO prodrug (alkynyl-JSK) and doxorubicin prodrug (cis-DOX)-conjugated HA nanoparticle (HA-DOX-JSK NPs), which achieved cascade-boosted drug delivery efficiency based on a relay strategy of NO-mediated deep tumor penetration─HA target CD44 tumor cell uptake─tumor microenvironment (TME)-responsive drug release. The nanoparticle demonstrated sustained and locoregionally GSH/GST-triggered NO release and GSH/pH-responsive DOX release in the tumor. The released NO first mediated collagen degradation, causing deep tumor penetration of nanoparticles in the dense extracellular matrix. Immediately, HA was relayed to enhance CD44-targeted tumor cell uptake, and then, the nanoparticles were finally triggered by specific TME to release DOX and NO in the deep tumor. Relying on the relayed delivery strategy, a significant improvement of DOX accumulation in tumors was realized. Moreover, NO depleted GSH-induced intracellular reactive oxygen species, enhancing DOX chemotherapy. Based on this strategy, the tumor inhibition rate in breast cancer was up to 87.8% in vivo. The relay drug-delivery HA system would greatly cascade-boost drug accumulation in deep tumors for efficient solid tumor therapy.

Boosting antitumor efficacy of nanoparticles by modulating tumor mechanical microenvironment

Nanoparticles have shown great potential for tumor targeting delivery via enhanced permeability and retention effect. However, the tumor mechanical microenvironment, characterized by dense extracellular matrix (ECM), high tumor stiffness and solid stress, leads to only 0.7% of administered dose accumulating in solid tumors and even fewer (∼0.0014%) reaching tumor cells, limiting the therapeutic efficacy of nanoparticles. Furthermore, the tumor mechanical microenvironment can regulate tumor cell stemness, promote tumor invasion, metastasis and reduce treatment efficacy. In this review, methods detecting the mechanical are introduced. Strategies for modulating the mechanical microenvironment including elimination of dense ECM by physical, chemical and biological methods, disruption of ECM formation, depletion or inhibition of cancer-associated fibroblasts, are then summarized. Finally, prospects and challenges for further clinical applications of mechano-modulating strategies to enhance the therapeutic efficacy of nanomedicines are discussed. This review may provide guidance for the rational design and application of nanoparticles in clinical settings.

Enhancing the tumor penetration of multiarm polymers by collagenase modification

Tumor penetration is a critical determinant of the therapy efficacy of nanomedicines. However, the dense extracellular matrix (ECM) in tumors significantly hampers the deep penetration of nanomedicines, resulting in large drug-untouchable areas and unsatisfactory therapy efficacy. Herein, we synthesized a third-generation PAMAM-cored multiarm copolymer and modified the polymer with collagenase to enhance its tumor penetration. Each arm of the copolymer was a diblock copolymer of poly(glutamic acid)-b-poly(carboxybetaine), in which the polyglutamic acid block with abundant side groups was used to link the anticancer agent doxorubicin through the pH-sensitive acylhydrazone linkage, and the zwitterionic poly(carboxybetaine) block provided desired water solubility and anti-biofouling capability. The collagenase was conjugated to the ends of the arms via the thiol-maleimide reaction. We demonstrated that the polymer-bound collagenase could effectively catalyze the degradation of the collagen in the tumor ECM, and consequently augmented the tumor penetration and antitumor efficacy of the drug-loaded polymers.

Senescence of Hepatic Stellate Cells by Specific Delivery of Manganese for Limiting Liver Fibrosis

Senescence of activated hepatic stellate cells (HSCs) is crucial for the regression of liver fibrosis. However, impaired immune clearance can result in the accumulation of senescent HSCs, exacerbating liver fibrosis. The activation of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway is essential for both senescence and the innate immune response. Additionally, the specific delivery to activated HSCs is hindered by their inaccessible anatomical location, capillarization of liver sinusoidal endothelial cells (LSECs), and loss of substance exchange. Herein, we propose an antifibrotic strategy that combines prosenescence with enhanced immune clearance through targeted delivery of manganese (a cGAS-STING stimulator) via albumin-mediated transcytosis, specifically aimed at inducing senescence and eliminating activated HSCs in liver fibrosis. Our findings demonstrate that only albumin efficiently transfers manganese to activated HSCs from LSECs via transcytosis compared to liposomes, resulting in significant antifibrotic effects in vivo while exhibiting negligible toxicity.

Recent advances in nano/micro systems for improved circulation stability, enhanced tumor targeting, penetration, and intracellular drug delivery: a review

In recent years, nanoparticles (NPs) have been extensively developed as drug carriers to overcome the limitations of cancer therapeutics. However, there are several biological barriers to nanomedicines, which include the lack of stability in circulation, limited target specificity, low penetration into tumors and insufficient cellular uptake, restricting the active targeting toward tumors of nanomedicines. To address these challenges, a variety of promising strategies were developed recently, as they can be designed to improve NP accumulation and penetration in tumor tissues, circulation stability, tumor targeting, and intracellular uptake. In this Review, we summarized nanomaterials developed in recent three years that could be utilized to improve drug delivery for cancer treatments.

Intermittent Fasting Primes the Tumor Microenvironment and Improves Nanomedicine Delivery in Hepatocellular Carcinoma

Fasting has many health benefits, including reduced chemotherapy toxicity and improved efficacy. It is unclear how fasting affects the tumor microenvironment (TME) and tumor-targeted drug delivery. Here the effects of intermittent (IF) and short-term (STF) fasting are investigated on tumor growth, TME composition, and liposome delivery in allogeneic hepatocellular carcinoma (HCC) mouse models. To this end, mice are inoculated either subcutaneously or intrahepatically with Hep-55.1C cells and subjected to IF for 24 d or to STF for 1 d. IF but not STF significantly slows down tumor growth. IF increases tumor vascularization and decreases collagen density, resulting in improved liposome delivery. In vitro, fasting furthermore promotes the tumor cell uptake of liposomes. These results demonstrate that IF shapes the TME in HCC towards enhanced drug delivery. Finally, when combining IF with liposomal doxorubicin treatment, the antitumor efficacy of nanochemotherapy is found to be increased, while systemic side effects are reduced. Altogether, these findings exemplify that the beneficial effects of fasting on anticancer therapy outcomes go beyond modulating metabolism at the molecular level.

Nanoparticle protein corona: from structure and function to therapeutic targeting

Nanoparticle (NP)-based therapeutics have ushered in a new era in translational medicine. However, despite the clinical success of NP technology, it is not well-understood how NPs fundamentally change in biological environments. When introduced into physiological fluids, NPs are coated by proteins, forming a protein corona (PC). The PC has the potential to endow NPs with a new identity and alter their bioactivity, stability, and destination. Additionally, the conformation of proteins is sensitive to their physical and chemical surroundings. Therefore, biological factors and protein-NP-interactions can induce changes in the conformation and orientation of proteins in vivo. Since the function of a protein is closely connected to its folded structure, slight differences in the surrounding environment as well as the surface characteristics of the NP materials may cause proteins to lose or gain a function. As a result, this can alter the downstream functionality of the NPs. This review introduces the main biological factors affecting the conformation of proteins associated with the PC. Then, four types of NPs with extensive utility in biomedical applications are described in greater detail, focusing on the conformation and orientation of adsorbed proteins. This is followed by a discussion on the instances in which the conformation of adsorbed proteins can be leveraged for therapeutic purposes, such as controlling protein conformation in assembled matrices in tissue, as well as controlling the PC conformation for modulating immune responses. The review concludes with a perspective on the remaining challenges and unexplored areas at the interface of PC and NP research.

Photothermal Attenuation of Cancer Cell Stemness, Chemoresistance, and Migration Using CD44-Targeted MoS2 Nanosheets

Cancer stem-like cells (CSCs) play key roles in chemoresistance, tumor metastasis, and clinical relapse. However, current CSC inhibitors lack specificity, efficacy, and applicability to different cancers. Herein, we introduce a nanomaterial-based approach to photothermally induce the differentiation of CSCs, termed "photothermal differentiation", leading to the attenuation of cancer cell stemness, chemoresistance, and metastasis. MoS2 nanosheets and a moderate photothermal treatment were applied to target a CSC surface receptor (i.e., CD44) and modulate its downstream signaling pathway. This treatment forces the more stem-like cancer cells to lose the mesenchymal phenotype and adopt an epithelial, less stem-like state, which shows attenuated self-renewal capacity, more response to anticancer drugs, and less invasiveness. This approach could be applicable to various cancers due to the broad availability of the CD44 biomarker. The concept of using photothermal nanomaterials to regulate specific cellular activities driving the differentiation of CSCs offers a new avenue for treating refractory cancers.

The effects of serum albumin pre-adsorption of nanoparticles on protein corona and membrane interaction: A molecular simulation study

As a platform to deliver imaging and therapeutic agents to targeted sites in vivo, nanoparticles (NPs) have widespread applications in diagnosis and treatment of cancer. However, the poor in vivo delivery efficiency of nanoparticles limits its potential for further application. Once enter the physiological environment, nanoparticles immediately interact with proteins and form protein corona, which changes the physicochemical properties of nanoparticle surface and further affects their transport. In this study, we performed molecular dynamics simulations to study the adsorption mechanism of nanoparticles with various surface modifications and different proteins (e.g., human serum albumin, complement protein C3b), and their interactions with cell membrane. The results show that protein human serum albumin prefers to interact with hydrophobic and positively charged nanoparticles, while the protein C3b prefers the hydrophobic and charged nanoparticles. The pre-adsorption of human serum albumin on the nanoparticle surface obviously decreases the interaction of nanoparticle with C3b. Furthermore, the high amount of protein pre-adsorption could decrease the probability of nanoparticle-membrane interaction. These results indicate that appropriate modification of nanoparticles with protein provides nanoparticles with better capability of targeting, which could be used to guide nanoparticle design and improve transport efficiency.

Enhanced Intracellular Transcytosis of Nanoparticles by Degrading Extracellular Matrix for Deep Tissue Radiotherapy of Pancreatic Adenocarcinoma

Intracellular transcytosis can enhance the penetration of nanomedicines to deep avascular tumor tissues, but strategies that can improve transcytosis are limited. In this study, we discovered that pyknomorphic extracellular matrix (ECM) is a shield that impairs endocytosis of nanoparticles and their movement between adjacent cells and thus limits their active transcytosis in tumors. We further showed that degradation of pivotal constituent of ECM (i.e., collagen) effectively enhances intracellular transcytosis of nanoparticles. Specifically, a collagenase conjugating transcytosis nanoparticle (Col-TNP) can dissociate into collagenase and cationized gold nanoparticles in response to tumor acidity, which enables their ECM tampering ability and active transcytosis in tumors. The breakage of ECM further enhances the active transcytosis of cationized nanoparticles into deep tumor tissues as well as radiosensitization efficacy of pancreatic adenocarcinoma. Our study opens up new paths to enhance the active transcytosis of nanomedicines for the treatment of cancers and other diseases.

Tumor-activated carrier-free prodrug nanoparticles for targeted cancer Immunotherapy: Preclinical evidence for safe and effective drug delivery

As immunogenic cell death (ICD) inducers initiating antitumor immune responses, certain chemotherapeutic drugs have shown considerable potential to reverse the immunosuppressive tumor microenvironment (ITM) into immune-responsive tumors. The application of these drugs in nanomedicine provides a more enhanced therapeutic index by improving unfavorable pharmacokinetic (PK) profiles and inefficient tumor targeting. However, the clinical translation of conventional nanoparticles is restricted by fundamental problems, such as risks of immunogenicity and potential toxicity by carrier materials, premature drug leakage in off-target sites during circulation, low drug loading contents, and complex structure and synthetic processes that hinder quality control (QC) and scale-up industrial production. To address these limitations, tumor-activated carrier-free prodrug nanoparticles (PDNPs), constructed only by the self-assembly of prodrugs without any additional carrier materials, have been widely investigated with distinct advantages for safe and more effective drug delivery. In addition, combination immunotherapy based on PDNPs with other diverse modalities has efficiently reversed the ITM to immune-responsive tumors, potentiating the response to immune checkpoint blockade (ICB) therapy. In this review, the trends and advances in PDNPs are outlined, and each self-assembly mechanism is discussed. In addition, various combination immunotherapies based on PDNPs are reviewed. Finally, a physical tumor microenvironment remodeling strategy to maximize the potential of PDNPs, and key considerations for clinical translation are highlighted.

Modification of Lipid-Based Nanoparticles: An Efficient Delivery System for Nucleic Acid-Based Immunotherapy

Lipid-based nanoparticles (LBNPs) are biocompatible and biodegradable vesicles that are considered to be one of the most efficient drug delivery platforms. Due to the prominent advantages, such as long circulation time, slow drug release, reduced toxicity, high transfection efficiency, and endosomal escape capacity, such synthetic nanoparticles have been widely used for carrying genetic therapeutics, particularly nucleic acids that can be applied in the treatment for various diseases, including congenital diseases, cancers, virus infections, and chronic inflammations. Despite great merits and multiple successful applications, many extracellular and intracellular barriers remain and greatly impair delivery efficacy and therapeutic outcomes. As such, the current state of knowledge and pitfalls regarding the gene delivery and construction of LBNPs will be initially summarized. In order to develop a new generation of LBNPs for improved delivery profiles and therapeutic effects, the modification strategies of LBNPs will be reviewed. On the basis of these developed modifications, the performance of LBNPs as therapeutic nanoplatforms have been greatly improved and extensively applied in immunotherapies, including infectious diseases and cancers. However, the therapeutic applications of LBNPs systems are still limited due to the undesirable endosomal escape, potential aggregation, and the inefficient encapsulation of therapeutics. Herein, we will review and discuss recent advances and remaining challenges in the development of LBNPs for nucleic acid-based immunotherapy.

Anticancer nanomedicines harnessing tumor microenvironmental components

INTRODUCTION

Small-molecular drugs are extensively used in cancer therapy, while they have issues of nonspecific distribution and consequent side effects. Nanomedicines that incorporate chemotherapeutic drugs have been developed to enhance the therapeutic efficacy of these drugs and reduce their side effects. One of the promising strategies is to prepare nanomedicines by harnessing the unique tumor microenvironment (TME).

AREAS COVERED

The TME contains numerous cell types that specifically express specific antibodies on the surface including tumor vascular endothelial cells, tumor-associated adipocytes, tumor-associated fibroblasts, tumor-associated immune cells and cancer stem cells. The physicochemical environment is characterized with a low pH, hypoxia, and a high redox potential resulting from tumor-specific metabolism. The intelligent nanomedicines can be categorized into two groups: the first group which is rapidly responsive to extracellular chemical/biological factors in the TME and the second one which actively and/or specifically targets cellular components in the TME.

EXPERT OPINION

In this paper, we review recent progress of nanomedicines by harnessing the TME and illustrate the principles and advantages of different strategies for designing nanomedicines, which are of great significance for exploring novel nanomedicines or translating current nanomedicines into clinical practice. We will discuss the challenges and prospects of preparing nanomedicines to utilize or alter the TME for achieving effective, safe anticancer treatment.

Nanomedicine Strategies to Circumvent Intratumor Extracellular Matrix Barriers for Cancer Therapy

The dense and heterogeneous physical network of the extracellular matrix (ECM) in tumors represents a formidable barrier that limits intratumor drug delivery and the therapeutic efficacy of many anticancer therapies. Here, the two major nanomedicine strategies to circumvent intratumor ECM barriers: regulating the physiochemical properties of nanomedicines and remodeling the components and structure of the ECM are summarized. Nanomedicines can be rationally regulated by optimizing physiochemical properties or designed with biomimetic features to promote ECM permeation capability. Meanwhile, they can also be designed to remodel the ECM by modulating signaling pathways or destroying the components and architecture of the ECM via chemical, biological, or physical treatments. These efforts produce profound improvements in intratumor drug delivery and anticancer efficacy. Moreover, to aid in their anticancer efficacy, feasible approaches for improving ECM-circumventing nanomedicines are proposed.

Engineered strategies to enhance tumor penetration of drug-loaded nanoparticles

Nanocarriers have been widely employed in preclinical studies and clinical trials for the delivery of anticancer drugs. The most important causes of failure in clinical translation of nanocarriers is their inefficient accumulation and penetration which arises from special characteristics of tumor microenvironment such as insufficient blood supply, dense extracellular matrix, and elevated interstitial fluid pressure. Various strategies such as engineering extracellular matrix, optimizing the physicochemical properties of nanocarriers have been proposed to increase the depth of tumor penetration; however, these strategies have not been very successful so far. Novel strategies such as transformable nanocarriers, transcellular transport of peptide-modified nanocarriers, and bio-inspired carriers have recently been emerged as an advanced generation of drug carriers. In this study, the latest developments of nanocarrier-based drug delivery to solid tumor are presented with their possible limitations. Then, the prospects of advanced drug delivery systems are discussed in detail.

The Evolution and Future of Targeted Cancer Therapy: From Nanoparticles, Oncolytic Viruses, and Oncolytic Bacteria to the Treatment of Solid Tumors

While many classes of chemotherapeutic agents exist to treat solid tumors, few can generate a lasting response without substantial off-target toxicity despite significant scientific advancements and investments. In this review, the paths of development for nanoparticles, oncolytic viruses, and oncolytic bacteria over the last 20 years of research towards clinical translation and acceptance as novel cancer therapeutics are compared. Novel nanoparticle, oncolytic virus, and oncolytic bacteria therapies all start with a common goal of accomplishing therapeutic drug activity or delivery to a specific site while avoiding off-target effects, with overlapping methodology between all three modalities. Indeed, the degree of overlap is substantial enough that breakthroughs in one therapeutic could have considerable implications on the progression of the other two. Each oncotherapeutic modality has accomplished clinical translation, successfully overcoming the potential pitfalls promising therapeutics face. However, once studies enter clinical trials, the data all but disappears, leaving pre-clinical researchers largely in the dark. Overall, the creativity, flexibility, and innovation of these modalities for solid tumor treatments are greatly encouraging, and usher in a new age of pharmaceutical development.

Rapid pH-responsive self-disintegrating nanoassemblies balance tumor accumulation and penetration for enhanced anti-breast cancer therapy

The dilemma of tumor accumulation and deep penetration has always been a barrier in antitumor therapy. Stimuli-responsive size changeable drug delivery systems provide possible solutions. Nevertheless, the low size-shrinkage efficiency limited the antitumor effects. In this study, an instant pH-responsive size shrinkable nanoassemblies named self-aggregated DOX@HA-CD (SA-DOX@HA-CD) was formulated using small-sized hyaluronic acid modified carbon dots (HA-CD) as monomers, which could self-aggregate into raspberry-like structure via hydrophobicity force in neutral pH and rapidly disassemble into shotgun-like DOX-loaded CD monomer in simulated tumor microenvironment (pH 6.5), owing to the transformation in electrical charge and hydrophobicity/hydrophilicity of this system. The transmission electron microscopy showed that the clustered SA-DOX@HA-CD had a diameter of ~150 nm, and thoroughly disassembled into ~30 nm nanoparticles in response to acidic environment. The disassemble efficiency was approximately 100%. Attributed to this property, SA-DOX@HA-CD led to enhanced cellular internalization and accumulation in 4T1 cells in simulated tumor microenvironment, as well as deep tumor penetration in 3D tumor spheroid model. Besides, the imine bond between DOX and HA-CD endowed DOX with pH-responsive release profile in the acidic lysosome environment. Furthermore, in the orthotopic 4T1 tumor-bearing mouse model, SA-DOX@HA-CD demonstrated higher tumor accumulation than non-aggregated DOX-HA-CD. Meanwhile, in response to the acid tumor microenvironment, the dissociated DOX-HA achieved deep tumor penetration, which consequently resulted in 2.5-fold higher antitumor efficiency. The formulation of self-aggregated SA-DOX@HA-CD provides a simple and effective alternative to prepare pH-responsive size-shrinkable nanodrug delivery systems. STATEMENT OF SIGNIFICANCE: The heterogeneity of tumor vasculature and the high tumor interstitial pressure lead to the barriers in tumor accumulation and deep penetration, which calls for opposite properties (e.g. size) of drug delivery systems. To address this dilemma, various size changeable nanoparticles have been developed utilizing special features of tumor microenvironment, such as pH, enzyme and reactive oxygen species. Nevertheless, the current strategies face the problems of incomplete hydrolysis of chemical bonds or insufficient enzyme degradation, which result in only partial size shrinkage, hindering the tumor deep penetration effects. Here we developed a self-assembled nanocluster, which could respond to acidic pH rapidly and thoroughly disassemble into small nanodots due to the alteration of hydrophobicity/hydrophilicity/charge, leading to approximately 100% dissociation. This strategy provides a new concept for design of size changeable drug delivery systems.

Tumor-Associated Fibroblast-Targeting Nanoparticles for Enhancing Solid Tumor Therapy: Progress and Challenges

Even though nanoparticle drug delivery systems (nanoDDSs) have improved antitumor efficacy by delivering more drugs to tumor sites compared to free and unencapsulated therapeutics, achieving satisfactory distribution and penetration of nanoDDSs inside solid tumors, especially in stromal fibrous tumors, remains challenging. As one of the most common stromal cells in solid tumors, tumor-associated fibroblasts (TAFs) not only promote tumor growth and metastasis but also reduce the drug delivery efficiency of nanoparticles through the tumor's inherent physical and physiological barriers. Thus, TAFs have been emerging as attractive targets, and TAF-targeting nanotherapeutics have been extensively explored to enhance the tumor delivery efficiency and efficacy of various anticancer agents. The purpose of this Review is to opportunely summarize the underlying mechanisms of TAFs on obstructing nanoparticle-mediated drug delivery into tumors and discuss the current advances of a plethora of nanotherapeutic approaches for effectively targeting TAFs.

Interplay within tumor microenvironment orchestrates neoplastic RNA metabolism and transcriptome diversity

The heterogeneous population of cancer cells within a tumor mass interacts intricately with the multifaceted aspects of the surrounding microenvironment. The reciprocal crosstalk between cancer cells and the tumor microenvironment (TME) shapes the cancer pathophysiome in a way that renders it uniquely suited for immune tolerance, angiogenesis, metastasis, and therapy resistance. This dynamic interaction involves a dramatic reconstruction of the transcriptomic landscape of tumors by altering the synthesis, modifications, stability, and processing of gene readouts. In this review, we categorically evaluate the influence of TME components, encompassing a myriad of resident and infiltrating cells, signaling molecules, extracellular vesicles, extracellular matrix, and blood vessels, in orchestrating the cancer-specific metabolism and diversity of both mRNA and noncoding RNA, including micro RNA, long noncoding RNA, circular RNA among others. We also highlight the transcriptomic adaptations in response to the physicochemical idiosyncrasies of TME, which include tumor hypoxia, extracellular acidosis, and osmotic stress. Finally, we provide a nuanced analysis of existing and prospective therapeutics targeting TME to ameliorate cancer-associated RNA metabolism, consequently thwarting the cancer progression. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Turnover and Surveillance > Regulation of RNA Stability RNA in Disease and Development > RNA in Disease.

Cell-based 3D bionic screening by mimicking the drug-receptor interaction environment in vivo

Most small-molecule drugs influence cell behavior through their interaction with one or more cellular proteins. The efficacy is unanticipated in the later stages of drug development if small-molecule drugs are discovered in the absence of a biological context. Bionic screening is an in vivo drug-receptor interaction platform that can identify small molecules with recognized activity, improving the likelihood of drug efficacy in the clinic. Here, we report the design of an innovative cell-based bionic screening system using 3D microcarrier cultures to simulate in vivo conditions and facilitate small-molecule drug discovery. Through its combination with HPLC/MS, the method can comprehensively identify small-molecule lead compounds in arbitrarily complex systems in an unbiased manner. In particular, cell-covered microcarriers provide a high-density of cells for affinity performance assessments in the absence of appreciable cell damage and maintain immunogenicity, the 3D structure of which is similar to tissue morphology in vivo, thereby mimicking in vivo drug-receptor interactions. The method is scalable, easy to handle, and requires minimal optimization across a range of different cell lines to realize high-throughput drug screening for the corresponding diseases. This provides a valuable tool for lead compound discovery in more physiologically relevant systems and may address the lack of clinically available drugs.

Tailoring patchy nanoparticle design to modulate serum albumin adsorption and membrane interaction

When nanoparticles (NPs) enter into the biological system, a wide range of proteins will coat on their surfaces forming protein corona, which changes the initial synthetic characteristics of NPs to the biological identity, resulting in the loss of their targets or specially designed properties. Although pre-coating with proteins would reduce the protein corona formation, they may diminish the targeting moieties in the transport process. Patchy NPs can offer unique advantages of asymmetry, heterogeneity, and multi-functions. This has inspired us to use the asymmetry to realize the versatility of NPs, to accommodate stealth and targeting functions. In this study, we performed molecular dynamics simulations to investigate the adsorption mechanism between patchy NPs and human serum albumin, and the interaction mechanism between NP-HSA and the membrane. The results show that there is a high probability for HSA to interact with the hydrophobic, or charged brushes of patchy NPs. The adsorption sites, as calculated through the contact probability between NPs and the residues, depend on the NP surface properties. Furthermore, the HSA adsorption on NPs could improve the NP-membrane interaction. The simulation results provide deep understanding of the NP interaction mechanism, which would help the NP design for their biomedical applications.

Oncolytic Virotherapy in Solid Tumors: The Challenges and Achievements

Oncolytic virotherapy (OVT) is a promising approach in cancer immunotherapy. Oncolytic viruses (OVs) could be applied in cancer immunotherapy without in-depth knowledge of tumor antigens. The capability of genetic modification makes OVs exciting therapeutic tools with a high potential for manipulation. Improving efficacy, employing immunostimulatory elements, changing the immunosuppressive tumor microenvironment (TME) to inflammatory TME, optimizing their delivery system, and increasing the safety are the main areas of OVs manipulations. Recently, the reciprocal interaction of OVs and TME has become a hot topic for investigators to enhance the efficacy of OVT with less off-target adverse events. Current investigations suggest that the main application of OVT is to provoke the antitumor immune response in the TME, which synergize the effects of other immunotherapies such as immune-checkpoint blockers and adoptive cell therapy. In this review, we focused on the effects of OVs on the TME and antitumor immune responses. Furthermore, OVT challenges, including its moderate efficiency, safety concerns, and delivery strategies, along with recent achievements to overcome challenges, are thoroughly discussed.