Ligand-targeted theranostic nanomedicines against cancer

Nanoformulations of chemotherapeutic activators of the cGAS-STING pathway in tumor chemoimmunotherapy

Chemotherapeutic drugs to activate the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway have been exploited for tumor chemoimmunotherapy. The clinical translation of chemotherapeutic cGAS-STING activators is hindered by the lack of safe, efficient, and specific delivery strategies. Nanodrug delivery systems (NDDS) designed for reducing toxic effects and improving transport effectiveness potentiate in vivo delivery of chemotherapeutic cGAS-STING activators. cGAS-STING monotherapy often encounters tumor resistance without providing satisfactory therapeutic benefit; therefore combination therapy is desirable. This review describes NDDS strategies for surmounting delivery obstacles of chemotherapeutic cGAS-STING activators and highlights combinatorial regimens, which utilize therapeutics that work by different mechanisms, for optimal therapy.

Emerging natural polymer-based architectured nanotherapeutics for the treatment of cancer

The field of cancer therapy is advancing rapidly, placing a crucial emphasis on innovative drug delivery systems. The increasing global impact of cancer highlights the need for creative therapeutic strategies. Natural polymer-based nanotherapeutics have emerged as a captivating avenue in this pursuit, drawing substantial attention due to their inherent attributes. These attributes include biodegradability, biocompatibility, negligible toxicity, extended circulation time, and a wide range of therapeutic payloads. The unique size, shape, and morphological characteristics of these systems facilitate profound tissue penetration, complementing active and passive targeting strategies. Moreover, these nanotherapeutics exploit specific cellular and subcellular trafficking pathways, providing precise control over drug release kinetics. This comprehensive review emphasizes the utilization of naturally occurring polymers such as polysaccharides (e.g., chitosan, hyaluronic acid, alginates, dextran, and cyclodextrin) and protein-based polymers (e.g., ferritin, gelatin, albumin) as the foundation for nanoparticle development. The paper meticulously examines their in vitro characteristics alongside in vivo efficacy, particularly focusing on their pivotal role in ameliorating diverse types of solid tumors within cancer therapy. The amalgamation of material science ingenuity and biological insight has led to the formulation of these nanoparticles, showcasing their potential to reshape the landscape of cancer treatment.

Bioconjugation Techniques for Enhancing Stability and Targeting Efficiency of Protein and Peptide Therapeutics

Bioconjugation techniques have emerged as powerful tools for enhancing the stability and targeting efficiency of protein and peptide therapeutics. This review provides a comprehensive analysis of the various bioconjugation strategies employed in the field. The introduction highlights the significance of bioconjugation techniques in addressing stability and targeting challenges associated with protein and peptide-based drugs. Chemical and enzymatic bioconjugation methods are discussed, along with crosslinking strategies for covalent attachment and site-specific conjugation approaches. The role of bioconjugation in improving stability profiles is explored, showcasing case studies that demonstrate successful stability enhancement. Furthermore, bioconjugation techniques for ligand attachment and targeting are presented, accompanied by examples of targeted protein and peptide therapeutics. The review also covers bioconjugation approaches for prolonging circulation and controlled release, focusing on strategies to extend half-life, reduce clearance, and design-controlled release systems. Analytical characterization techniques for bioconjugates, including the evaluation of conjugation efficiency, stability, and assessment of biological activity and targeting efficiency, are thoroughly examined. In vivo considerations and clinical applications of bioconjugated protein and peptide therapeutics, including pharmacokinetic and pharmacodynamic considerations, as well as preclinical and clinical developments, are discussed. Finally, the review concludes with an overview of future perspectives, emphasizing the potential for novel conjugation methods and advanced targeting strategies to further enhance the stability and targeting efficiency of protein and peptide therapeutics.

Sulfur dioxide-releasing polymeric micelles based on modified hyaluronic acid for combined cancer therapy

In this study, an amphiphilic polymer mPEG-HA(SA)-DNs was designed and synthesized to fabricate a multifunctional micellar system to enhance the therapeutic efficacy and reduce the toxic effect of paclitaxel (PTX). The polymer was prepared by introducing mPEG, stearic acid (SA) and 2,4-dinitrobenzenesulfonic acid (DNs) to the backbone of hyaluronic acid (HA). With above modifications, the fabricated micelles could encapsulate PTX in the core with high drug loading. The optimized PTX-loaded micelles had a mean size of 158.3 nm. Upon the effect of mPEG, the mPEG-HA(SA)-DNs micelles reduced the non-specific protein adsorption. In vitro drug release study revealed the excellent glutathione (GSH)-triggered PTX release behavior of the micelles. Moreover, GSH could trigger the detachment of DNs segment from mPEG-HA(SA)-DNs, and result in the release of SO2. In vitro and in vivo antitumor efficacy studies demonstrated that the PTX-loaded mPEG-HA(SA)-DNs micelles exhibited outstanding tumor suppression effect. The micelles would be potential carriers for combination cancer therapy by SO2 and PTX.

New role of bacteriophages in medical oncology

Targeted treatment of cancer is one of the most paramount approaches in cancer treatment. Despite significant advances in cancer diagnosis and treatment methods, there are still significant limitations and disadvantages in the field, including high costs, toxicity, and unwanted damage to healthy cells. The phage display technique is an innovative method for designing carriers containing exogenic peptides with cancer diagnostic and therapeutic properties. Bacteriophages possess unique properties making them effective in cancer treatment. These characteristics include the small size enabling them to penetrate vessels; having no pathogenicity to mammals; easy manipulation of their genetic information and surface proteins to introduce vaccines and drugs to cancer tissues; lower cost of large-scale production; and greater stimulation of the immune system. Bacteriophages will certainly play a more effective role in the future of medical oncology; however, studies are in the early stages of conception and require more extensive research. We aimed in this review to provide some related examples and bring insights into the potential of phages as targeted vectors for use in cancer diagnosis and treatment, especially regarding their capability in gene and drug delivery to cancer target cells, determination of tumor markers, and vaccine design to stimulate anticancer immunity.

Ligand-based active targeting strategies for cancer theranostics

In the past decades, for the intermediate or advanced cancerous stages, preclinical and clinical applications of nanomedicines in cancer theranostics have been extensively studied. Nevertheless, decreased specificity and poor targeting efficiency with low target concentration of theranostic are the major drawbacks of nanomedicine in employing clinical substitution over conventional systemic therapy. Consequently, ligand decorated nanocarrier-mediated targeted drug delivery system can transcend the obstructions through their enhanced retention activity and increased permeability with effective targeting. The highly efficient and specific nanocarrier-mediated ligand-based active therapy is one of the novel and promising approaches for delivery of the therapeutics for different cancers in recent years to restrict various cancer growth in vivo without harming healthy cells. The article encapsulates the features of nanocarrier-mediated ligands in augmentation of active targeting approaches of various cancers and summarizes ligand-based targeted delivery systems in treatment of cancer as plausible theranostics.

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.

Ceramide as an endothelial cell surface receptor and a lung-specific lipid vascular target for circulating ligands

The vascular endothelium from individual organs is functionally specialized, and it displays a unique set of accessible molecular targets. These serve as endothelial cell receptors to affinity ligands. To date, all identified vascular receptors have been proteins. Here, we show that an endothelial lung-homing peptide (CGSPGWVRC) interacts with C16-ceramide, a bioactive sphingolipid that mediates several biological functions. Upon binding to cell surfaces, CGSPGWVRC triggers ceramide-rich platform formation, activates acid sphingomyelinase and ceramide production, without the associated downstream apoptotic signaling. We also show that the lung selectivity of CGSPGWVRC homing peptide is dependent on ceramide production in vivo. Finally, we demonstrate two potential applications for this lipid vascular targeting system: i) as a bioinorganic hydrogel for pulmonary imaging and ii) as a ligand-directed lung immunization tool against COVID-19. Thus, C16-ceramide is a unique example of a lipid-based receptor system in the lung vascular endothelium targeted in vivo by circulating ligands such as CGSPGWVRC.

Surface Functionalization of Gold Nanoparticles for Targeting the Tumor Microenvironment to Improve Antitumor Efficiency

Gold nanoparticles (AuNPs) have undergone significant research for their use in the treatment of cancer. Numerous researchers have established their potent antitumor properties, which have greatly impacted the treatment of cancer. AuNPs have been used in four primary anticancer treatment modalities, namely radiation, photothermal therapy, photodynamic therapy, and chemotherapy. However, the ability of AuNPs to destroy cancer is lacking and can even harm healthy cells without the right direction to transport them to the tumor microenvironment. Consequently, a suitable targeting technique is needed. Based on the distinct features of the human tumor microenvironment, this review discusses four different targeting strategies that target the four key features of the tumor microenvironment, including abnormal vasculature, overexpression of specific receptors, an acidic microenvironment, and a hypoxic microenvironment, to direct surface-functionalized AuNPs to the tumor microenvironment and increase antitumor efficacies. In addition, some current completed or ongoing clinical trials of AuNPs will also be discussed below to further reinforce the concept of using AuNPs in anticancer therapy.

Cyclic RGD-Functionalized pH/ROS Dual-Responsive Nanoparticle for Targeted Breast Cancer Therapy

Breast cancer is the most common malignant tumor in women and is a big challenge to clinical treatment due to the high morbidity and mortality. The pH/ROS dual-responsive nanoplatforms may be an effective way to significantly improve the therapeutic efficacy of breast cancer. Herein, we report a docetaxel (DTX)-loaded pH/ROS-responsive NP that could achieve active targeting of cancer cells and selective and complete drug release for effective drug delivery. The pH/ROS-responsive NPs were fabricated using nanocarriers that consist of an ROS-responsive moiety (4-hydroxymethylphenylboronic acid pinacol ester, HPAP), cinnamaldehyde (CA, an aldehyde organic compound with anticancer activities) and cyclodextrin (α-CD). The NPs were loaded with DTX, modified with a tumor-penetration peptide (circular RGD, cRGD) and named DTX/RGD NPs. The cRGD could promote DTX/RGD NPs penetration into deep tumor tissue and specifically target cancer cells. After internalization by cancer cells through receptor-mediated endocytosis, the pH-responsive acetal was cleaved to release CA in the lysosomal acidic environment. Meanwhile, the high ROS in tumor cells induced the disassembly of NPs with complete release of DTX. In vitro cellular assays verified that DTX/RGD NPs could be effectively internalized by 4T1 cells, obviously inducing apoptosis, blocking the cell cycle of 4T1 cells and consequently, killing tumor cells. In vivo animal experiments demonstrated that the NPs could target to the tumor sites and significantly inhibit the tumor growth in 4T1 breast cancer mice. Both in vitro and in vivo investigations demonstrated that DTX/RGD NPs could significantly improve the antitumor effect compared to free DTX. Thus, the DTX/RGD NPs provide a promising strategy for enhancing drug delivery and cancer therapy.

Applications of the phage display technology in molecular biology, biotechnology and medicine

The phage display technology is based on the presentation of peptide sequences on the surface of virions of bacteriophages. Its development led to creation of sophisticated systems based on the possibility of the presentation of a huge variability of peptides, attached to one of proteins of bacteriophage capsids. The use of such systems allowed for achieving enormous advantages in the processes of selection of bioactive molecules. In fact, the phage display technology has been employed in numerous fields of biotechnology, as diverse as immunological and biomedical applications (in both diagnostics and therapy), the formation of novel materials, and many others. In this paper, contrary to many other review articles which were focussed on either specific display systems or the use of phage display in selected fields, we present a comprehensive overview of various possibilities of applications of this technology. We discuss an usefulness of the phage display technology in various fields of science, medicine and the broad sense of biotechnology. This overview indicates the spread and importance of applications of microbial systems (exemplified by the phage display technology), pointing to the possibility of developing such sophisticated tools when advanced molecular methods are used in microbiological studies, accompanied with understanding of details of structures and functions of microbial entities (bacteriophages in this case).

Recombinant antibodies by phage display for bioanalytical applications

Antibody phage display, aimed at preparing antibodies to defined antigens, is a useful replacement for hybridoma technology. The phage system replaces all work stages that follow animal immunization with simple procedures for manipulating DNA and bacteria. It enables the time needed to generate stable antibody-producing clones to be shortened considerably, making the process noticeably cheaper. Antibodies prepared by phage display undergo several affinity selection steps and can be used as selective receptors in biosensors. This article briefly describes the techniques used in the making of phage antibodies to various antigens. The possibilities and prospects are discussed of using phage antibodies as selective agents in analytical systems, including biosensors.

Porphyrin Centered Paclitaxel Tetrameric Prodrug Nanoassemblies as Tumor-Selective Theranostics for Synergized Breast Cancer Therapy

Although having undergone decades of development, nanoparticulate drug delivery vehicles for efficient cancer therapy remain a challenge, confined by low drug loading, instability, and poor cancer tissue selectivity. A self-assembled prodrug, the combination of prodrug strategy and the self-assembly merits, represents a special chemical entity which spontaneously organizes into supramolecular composites with defined architecture, therefore also providing a strategy to develop new medications. Paclitaxel (PTX) is still among the most generally prescribed chemotherapeutics in oncology but is restricted by poor solubility. Although photodynamic therapy, with its noninvasive features and barely developed drug resistance, signifies an alternative tool to suppress life-threatening cancer, sole use hardly fulfills its potential. To this end, a reduction-activatable heterotetrameric prodrug with the photosensitizer is synthesized, then formulated into self-assembled nanoparticles (NPs) for tumor imaging and combined chemo- and photodynamic therapy. Coating the NPs with amphiphilic polymer distearylphosphatidylethanolamine-polyethylene glycol-arginine-glycine-aspartate (DSPE-PEG-RGD) offers high stability and enables cancer tissue targeting. The as-prepared NPs enlighten disease cells and reveal more potent cytotoxicity comparing to PTX and the photosensitizer alone. Furthermore, the NPs selectively accumulates into tumors and synergistically inhibits tumor proliferation with reduced side effects in mice.

Polymer/magnetite carriers functionalized by HER2-DARPin: Avoiding lysosomes during internalization and controlled toxicity of doxorubicin by focused ultrasound induced release

Nanomedicine has revolutionized the available treatment options during the last decade, but poor selectivity of targeted drug delivery and release is still poses a challenge. In this study, doxorubicin (DOX) and magnetite nanoparticles were encapsulated by freezing-induced loading, coated with polymeric shell bearing two bi-layers of polyarginine/dextran sulphate and finally modified with HER2-specific DARPin proteins. We demonstrated that the enhanced cellular uptake of these nanocarriers predominantly occurs by SKOV-3 (HER2+) cells, in comparison to CHO (HER2-) cells, together with the controlled DOX release using low intensity focused ultrasound (LIFU). In addition, a good ability of DARPin+ capsules to accumulate in the tumor and the possibility of combination therapy with LIFU were demonstrated. A relatively high sensitivity of the obtained nanocarriers to LIFU and their preferential interactions with mitochondria in cancer cells make these carriers promising candidates for cancer treatment, including novel approaches to overcome drug resistance.

Bridging the In Vitro to In Vivo gap: Using the Chick Embryo Model to Accelerate Nanoparticle Validation and Qualification for In Vivo studies

We postulate that nanoparticles (NPs) for use in therapeutic applications have largely not realized their clinical potential due to an overall inability to use in vitro results to predict NP performance in vivo. The avian embryo and associated chorioallantoic membrane (CAM) has emerged as an in vivo preclinical model that bridges the gap between in vitro and in vivo, enabling rapid screening of NP behavior under physiologically relevant conditions and providing a rapid, accessible, economical, and more ethical means of qualifying nanoparticles for in vivo use. The CAM is highly vascularized and mimics the diverging/converging vasculature of the liver, spleen, and lungs that serve as nanoparticle traps. Intravital imaging of fluorescently labeled NPs injected into the CAM vasculature enables immediate assessment and quantification of nano-bio interactions at the individual NP scale in any tissue of interest that is perfused with a microvasculature. In this review, we highlight how utilization of the avian embryo and its CAM as a preclinical model can be used to understand NP stability in blood and tissues, extravasation, biocompatibility, and NP distribution over time, thereby serving to identify a subset of NPs with the requisite stability and performance to introduce into rodent models and enabling the development of structure-property relationships and NP optimization without the sacrifice of large populations of mice or other rodents. We then review how the chicken embryo and CAM model systems have been used to accelerate the development of NP delivery and imaging agents by allowing direct visualization of targeted (active) and nontargeted (passive) NP binding, internalization, and cargo delivery to individual cells (of relevance for the treatment of leukemia and metastatic cancer) and cellular ensembles (e.g., cancer xenografts of interest for treatment or imaging of cancer tumors). We conclude by showcasing emerging techniques for the utilization of the CAM in future nano-bio studies.

Polymeric nanoparticles targeting Sialyl-Tn in gastric cancer: A live tracking under flow conditions

Drug delivery using nanoparticles (NPs) represents a potential approach for therapy in cancer, such gastric cancer (GC) due to their targeting ability and controlled release properties. The use of advanced nanosystems that deliver anti-cancer drugs specifically to tumor cells may strongly rely on the expression of cancer-associated targets. Glycans aberrantly expressed by cancer cells are attractive targets for such delivery strategy. Sialylated glycans, such as Sialyl-Tn (STn) are aberrantly expressed in several epithelial tumors, including GC, being a potential target for a delivery nanosystem. The aim of this study was the development of NPs surface-functionalized with a specific antibody targeting the STn glycan and further evaluate this nanosystem effectiveness regarding its specificity and recognition capacity. Our results showed that the NPs surface-functionalized with anti-STn antibody efficiently are recognized by cells displaying the cancer-associated STn antigen under static and live cell monitoring flow conditions. This uncovers the potential use of such NPs for drug delivery in cancer. However, flow exposure was disclosed as an important biomechanical parameter to be taken into consideration. Here we presented an innovative and successful methodology to live track the NPs targeting STn antigen under shear stress, simulating the physiological flow. We demonstrate that unspecific binding of NPs agglomerates did not occur under flow conditions, in contrast with static assays. This robust approach can be applied for in vitro drug studies, giving valuable insights for in vivo studies.

A Perspective on EGFR and Proteasome-based Targeted Therapy for Cancer

BACKGROUND

Cancer is known to be the most leading cause of death worldwide. It is understood that the sources causing cancer mainly include the activity of endogenous oncogenes, nonviral compounds and the fundamental portion of these oncogenes; the tyrosine kinase activity and proteasome activity are the main biomarkers responsible for cell proliferation. These biomarkers can be used as main targets and are believed to be the 'prime switches' for the signal communication activity to regulate cell death and cell cycle. Thus, signal transduction inhibitors (ligandreceptor tyrosine kinase inhibitors) and proteasome inhibitors can be used as a therapeutic modality to block the action of signaling between the cells as well as protein breakdown in order to induce cell apoptosis.

AIMS

This article highlights the key points and provides an overview of the recent patents on EGFR and proteosome-based inhibitors having therapeutic efficacy. This review focuses on the patents related to therapeutic agents, their preparation process and the final outcome.

OBJECTIVE

The main objective of this study is to facilitate the advancement and current perspectives in the treatment of cancer.

CONCLUSION

There are numerous strategies discussed in these patents to improve the pharmacokinetics and pharmacodynamics of EGFR and proteasome inhibitors. Further, the resistance to targeted therapy after long-term treatment can be overcome by using various excipients that can be used as a strategy to carry the drug. However, there is a need and scope for improving targeted therapeutics for cancer treatment with better fundamentals and characteristics. The widespread research on cancer therapy can create the path for future advancements in therapy with more prominent outcomes.

Exploring the role of nanomedicines for the therapeutic approach of central nervous system dysfunction: At a glance

In recent decades, research scientists, molecular biologists, and pharmacologists have placed a strong emphasis on cutting-edge nanostructured materials technologies to increase medicine delivery to the central nervous system (CNS). The application of nanoscience for the treatment of neurodegenerative diseases (NDs) such as Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple sclerosis (MS), Huntington’s disease (HD), brain cancer, and hemorrhage has the potential to transform care. Multiple studies have indicated that nanomaterials can be used to successfully treat CNS disorders in the case of neurodegeneration. Nanomedicine development for the cure of degenerative and inflammatory diseases of the nervous system is critical. Nanoparticles may act as a drug transporter that can precisely target sick brain sub-regions, boosting therapy success. It is important to develop strategies that can penetrate the blood–brain barrier (BBB) and improve the effectiveness of medications. One of the probable tactics is the use of different nanoscale materials. These nano-based pharmaceuticals offer low toxicity, tailored delivery, high stability, and drug loading capacity. They may also increase therapeutic effectiveness. A few examples of the many different kinds and forms of nanomaterials that have been widely employed to treat neurological diseases include quantum dots, dendrimers, metallic nanoparticles, polymeric nanoparticles, carbon nanotubes, liposomes, and micelles. These unique qualities, including sensitivity, selectivity, and ability to traverse the BBB when employed in nano-sized particles, make these nanoparticles useful for imaging studies and treatment of NDs. Multifunctional nanoparticles carrying pharmacological medications serve two purposes: they improve medication distribution while also enabling cell dynamics imaging and pharmacokinetic study. However, because of the potential for wide-ranging clinical implications, safety concerns persist, limiting any potential for translation. The evidence for using nanotechnology to create drug delivery systems that could pass across the BBB and deliver therapeutic chemicals to CNS was examined in this study.

A sequentially triggered DNA nanocapsule for targeted drug delivery based on pH-responsive i-motif and tumor cell-specific aptamer

Targeted drug delivery with minor off-target effects is urgently needed for precise cancer treatments. Here, a sequentially triggered strategy based on double targeting elements is designed to meet this purpose. By using an acidic pH-responsive i-motif DNA and a tumor cell-specific aptamer as targeting elements, a smart dual-targeted DNA nanocapsule (ZBI5-DOX) was constructed. ZBI5-DOX can be firstly triggered by acidic pH, and then bind to target cells via aptamer recognition and thus targeted release of the carried DOX chemotherapeutics. With this smart DNA nanocapsule, the carried DOX could be precisely delivered to target SMMC-7721 tumor cells in acidic conditions. After drug treatments, selective cytotoxicity of the DNA nanocapsule was successfully achieved. Meanwhile, the DNA nanocapsule had a specific inhibition effect on target cell migration and invasion. Therefore, this sequentially triggered strategy may provide deep insight into the next generation of targeted drug delivery.

Manganese Schiff Base Complexes, Crystallographic Studies, Anticancer Activities, and Molecular Docking

Choice of ligands is significant to successful synthesis of metal complexes (coordination compounds). This study reports the use of Schiff base as the right ligand to control the poor bioavailability and neurodegenerative toxicity challenges of manganese ion. In line with this study, document analysis was used as the methodological approach to evaluate the significance of Schiff base ligands in easing these manganese’s challenges and aligning the resultant coordination compounds (manganese Schiff base complexes) as therapeutic agents in anticancer studies. Report also involves crystallographic studies where single crystal X-ray crystallography was used as a chemical characterization technique. In addition, molecular docking studies, MOE2008, and AutoDock software were used to reveal the mode of interaction between the Schiff base and the manganese(II) and (III) ions, as well as scrutinizing the biological efficacy of the manganese(II) and manganese(III) Schiff bases coordination compounds as anticancer agents against some anticancer cell lines. Conclusion drawn was that manganese(II) and manganese(III) Schiff bases coordination compounds gave more active and potent activities than the corresponding Schiff bases. As a result, challenges of neurodegenerative toxicity and poor bioavailability of manganese ion were overcome, and the chelation therapy was fulfilled. Results from single crystal X-ray crystallography confirmed the successful synthesis of manganese(II) and manganese(III) Schiff bases coordination compounds and revealed the mechanism of reaction, while the molecular docking buttressed the biological activities of the Schiff base ligand and manganese Schiff base coordination compounds by portraying the structure activity relationship (SAR) between either Schiff base or the manganese Schiff base coordination compounds and the virtual cancer cell line (receptor protein), where hits were obtained for lead optimizations.

Synthesis and evaluation of a novel adapter lipid derivative for preparation of cyclic peptide-modified PEGylated liposomes: Application of cyclic RGD peptide

Peptide ligand modified nanoparticles can simply prepared by post-insertion method to mix pre-formed nanoparticles with peptide-lipid conjugates in an aqueous solution at an optimal temperature. Therefore, water dispersibility of peptide-lipid conjugates is a very important factor for implementing the post-insertion method. We proposed that highly water dispersible peptide-lipid conjugates can be easily synthesized by separately designing novel adapter lipids with different water dispersibility and reacting them with ligands in a highly efficient manner. Adapter lipids have three critical roles; as spacers of ligand-conjugated lipids for efficient ligand presentation, as structures that form discrete molecular weight distributions, and as providing water dispersibility. In this study, we developed a novel adapter-lipid derivative that enables a variety of cyclic peptide modifications using the click reaction. The integrin αvβ₃-targeted cyclic RGDfK (cRGD) peptide was selected as the cyclic peptide ligand. We designed a novel alkyne-tagged lipid with a discrete peptide spacer and bound the cRGD peptide using a click reaction to synthesize a cRGD-conjugated lipid with good water dispersibility for the preparation of cRGD-modified PEGylated liposomes using the post-insertion method. We also revealed that cRGD-modified PEGylated liposomes are efficiently associated with integrin αvβ3-expressing murine colon carcinoma (Colon-26) cells in a modification amount- and peptide sequence-dependent manner, showing high cytotoxicity upon loading with doxorubicin. This novel adapter lipid derivative can be used to synthesize various cyclic peptides by click reactions and will provide useful insights for the future development of cyclic peptide-modified PEGylated liposomes.

Next-Generation Molecular Discovery: From Bottom-Up In Vivo and In Vitro Approaches to In Silico Top-Down Approaches for Therapeutics Neogenesis

Protein and drug engineering comprises a major part of the medical and research industries, and yet approaches to discovering and understanding therapeutic molecular interactions in biological systems rely on trial and error. The general approach to molecular discovery involves screening large libraries of compounds, proteins, or antibodies, or in vivo antibody generation, which could be considered “bottom-up” approaches to therapeutic discovery. In these bottom-up approaches, a minimal amount is known about the therapeutics at the start of the process, but through meticulous and exhaustive laboratory work, the molecule is characterised in detail. In contrast, the advent of “big data” and access to extensive online databases and machine learning technologies offers promising new avenues to understanding molecular interactions. Artificial intelligence (AI) now has the potential to predict protein structure at an unprecedented accuracy using only the genetic sequence. This predictive approach to characterising molecular structure—when accompanied by high-quality experimental data for model training—has the capacity to invert the process of molecular discovery and characterisation. The process has potential to be transformed into a top-down approach, where new molecules can be designed directly based on the structure of a target and the desired function, rather than performing screening of large libraries of molecular variants. This paper will provide a brief evaluation of bottom-up approaches to discovering and characterising biological molecules and will discuss recent advances towards developing top-down approaches and the prospects of this.

Integrin α6-Targeted Molecular Imaging of Central Nervous System Leukemia in Mice

Central nervous system leukemia (CNS-L) is caused by leukemic cells infiltrating into the meninges or brain parenchyma and remains the main reason for disease relapse. Currently, it is hard to detect CNS-L accurately by clinically available imaging models due to the relatively low amount of tumor cells, confined blood supply, and the inferior glucose metabolism intensity. Recently, integrin α6-laminin interactions have been identified to mediate CNS-L, which suggests that integrin α6 may be a promising molecular imaging target for the detection of CNS-L. The acute lymphoblastic leukemia (ALL) cell line NALM6 stabled and transfected with luciferase was used to establish the CNS-L mouse model. CNS-L-bearing mice were monitored and confirmed by bioluminescence imaging. Three of our previously developed integrin α6-targeted peptide-based molecular imaging agents, Cy5-S5 for near-infrared fluorescence (NIRF), Gd-S5 for magnetic resonance (MR), and ¹⁸F-S5 for positron emission tomography (PET) imaging, were employed for the molecular imaging of these CNS-L-bearing mice. Bioluminescence imaging showed a local intensive signal in the heads among CNS-L-bearing mice; meanwhile, Cy5-S5/NIRF imaging produced intensive fluorescence intensity in the same head regions. Moreover, Gd-S5/MR imaging generated superior MR signal enhancement at the site of meninges, which were located between the skull bone and brain parenchyma. Comparatively, MR imaging with the clinically available MR enhancer Gd-DTPA did not produce the distinguishable MR signal in the same head regions. Additionally, ¹⁸F-S5/PET imaging also generated focal radio-concentration at the same head regions, which generated nearly 5-times tumor-to-background ratio compared to the clinically available PET radiotracer ¹⁸F-FDG. Finally, pathological examination identified layer-displayed leukemic cells in the superficial part of the brain parenchyma tissue, and immunohistochemical staining confirmed the overexpression of the integrin α6 within the lesion. These findings suggest the potential application of these integrin α6-targeted molecular imaging agents for the accurate detection of CNS-L.

Hollow mesoporous silica nanoparticles: Effective silica etching using tri-di- and mono-valent cations

Among different hollow nanostructures, the preparation of hollow mesoporous silica nanoparticles (HMSNs) is still a hotspot research field due to their unique properties e.g., large pore sizes and volumes, high drug loading capacity, ease of surface modification, large surface area, and biodegradability. Herein, novel uniform HMSNs are prepared for the first time by a combination of heterogeneous oil-water biphase stratification and simple mono-, di-, and tri-valent etching reactions. The biphase stratification reaction allows self-assembly of reactants at the oil-water interface, while the subsequent step is designed for the efficient selective silica etching under mild conditions. We have studied the effect of cation's valence (NH₄⁺, Ca²⁺, and Al³⁺) on the silica etching reaction coupled with the biphase stratification reaction both in the absence and presence of the auxiliary pore expanded agent 1, 3, 5 trimethylbenzene (TMB). In the absence of TMB, the Brunauer-Emmett-Teller (BET) analysis confirms that Al³⁺ creates materials with the largest pore size (18.0 nm), whereas the use of NH₄⁺ results in the largest pore volume (2.30 cm³/g). The pores generated using Ca²⁺ and Al³⁺ as silica etching agents have a volume 2.01 cm³/g and 2.05 cm³/g, respectively. Similar experiments in the presence of TMB leads to the formation of HMSN with larger pore sizes (24 nm and 21.5 nm) and volumes (2.70 cm³/g and 2.12 cm³/g) when using Al³⁺ and Ca²⁺, respectively, as etching agents. Drug loading capacity using Langmuir adsorption model indicate our hollow MSN material exhibit the high adsorbing DOX up to 558.23 mg per gram of nanoparticles in pH of 7.2. Furthermore, synthetized NPs exhibited high loading capacity for large protein and biomolecules such as BSA. Our findings confirmed that the charge density of cation has a critical role on selective silica etching in the preparation of HMSNs.

Identification and optimization of tunable endosomal escape parameters for enhanced efficacy in peptide-targeted prodrug-loaded nanoparticles

Endosomal escape of nanoparticles (NPs) is a weighty consideration for engineering successful nanomedicines. Although it is well-established that incorporation of histidine (His) in particle design improves endosomal escape for NPs, our understanding of its effects for ligand-targeted nanoparticles (TNPs) remains incomplete. Here, we systematically evaluated the cooperativity between targeting ligands and endosomolytic elements using liposomal TNPs with precise stoichiometric control over functional moieties (>90% loading efficiency). We synthesized endosomolytic lipid conjugates consisting of 1 to 10 consecutive His residues presented at the end of linkers between 2 to 45 repeating units of ethylene glycol (His_n-EG_m). His_n-EG_m had minimal effect on NP size (∼115 nm) and had no significant effect on the receptor specificity of TNPs (>90% inhibition by competing peptide). We evaluated various formulations with 8 different targeting ligands relevant to two disease models. Incorporation of His₁-EG₈ resulted in up to ∼170- and ∼12.9-fold enhancement in intracellular accumulation relative to non-endosomolytic NP and TNP, respectively. These observations were time-dependent, targeted receptor-dependent, and showed different trends for NPs and TNPs. Further evaluation demonstrated short linkers (EG_2-4) significantly enhanced nanoparticle internalization compared to EG₈ or longer by up to ∼2.5-fold. Finally, rationally optimized formulation, His₁-EG₂-TNP, improved in vitro toxicity of a DM1 prodrug to SK-BR-3 cells by ∼4.2-fold, with IC₅₀ ∼8.5 nM compared to ∼36 nM for no-His TNP, and >100 nM for non-targeted/no-His NP. This study uncovers an intricate relationship between endosomal escape and ligand-targeted drug delivery, as well as tunable parameters. Furthermore, our findings highlight the value of rational design and systematic analysis for optimization of multifunctional NPs.

Nanomedicine-enabled chemotherapy-based synergetic cancer treatments

Chemotherapy remains one of the most prevailing regimens hitherto in the fight against cancer, but its development has been being suffering from various fatal side effects associated with the non-specific toxicity of common chemical drugs. Advances in biomedical application of nanomedicine have been providing alternative but promising approaches for cancer therapy, by leveraging its excellent intrinsic physicochemical properties to address these critical concerns. In particular, nanomedicine-enabled chemotherapy has been established as a safer and promising therapeutic modality, especially the recently proposed nanocatalytic medicine featuring the capabilities to generate toxic substances by initiating diverse catalytic reactions within the tumor without directly relying on highly toxic but non-selective chemotherapeutic agents. Of special note, under exogenous/endogenous stimulations, nanomedicine can serve as a versatile platform that allows additional therapeutic modalities (photothermal therapy (PTT), photodynamic therapy (PDT), chemodynamic therapy (CDT), etc.) to be seamlessly integrated with chemotherapy for efficacious synergistic treatments of tumors. Here, we comprehensively review and summarize the representative studies of multimodal synergistic cancer treatments derived from nanomedicine and nanocatalytic medicine-enabled chemotherapy in recent years, and their underlying mechanisms are also presented in detail. A number of existing challenges and further perspectives for nanomedicine-synergized chemotherapy for malignant solid tumor treatments are also highlighted for understanding this booming research area as comprehensively as possible.

Silica-Based Stimuli-Responsive Systems for Antitumor Drug Delivery and Controlled Release

The administration of cytotoxic drugs in classical chemotherapy is frequently limited by water solubility, low plasmatic stability, and a myriad of secondary effects associated with their diffusion to healthy tissue. In this sense, novel pharmaceutical forms able to deliver selectively these drugs to the malign cells, and imposing a space-time precise control of their discharge, are needed. In the last two decades, silica nanoparticles have been proposed as safe vehicles for antitumor molecules due to their stability in physiological medium, high surface area and easy functionalization, and good biocompatibility. In this review, we focus on silica-based nanomedicines provided with specific mechanisms for intracellular drug release. According to silica nature (amorphous, mesostructured, and hybrids) nanocarriers responding to a variety of stimuli endogenously (e.g., pH, redox potential, and enzyme activity) or exogenously (e.g., magnetic field, light, temperature, and ultrasound) are proposed. Furthermore, the incorporation of targeting molecules (e.g., monoclonal antibodies) that interact with specific cell membrane receptors allows a selective delivery to cancer cells to be carried out. Eventually, we present some remarks on the most important formulations in the pipeline for clinical approval, and we discuss the most difficult tasks to tackle in the near future, in order to extend the use of these nanomedicines to real patients.

Smart Nanocarriers as an Emerging Platform for Cancer Therapy: A Review

Cancer is a group of disorders characterized by uncontrolled cell growth that affects around 11 million people each year globally. Nanocarrier-based systems are extensively used in cancer imaging, diagnostics as well as therapeutics; owing to their promising features and potential to augment therapeutic efficacy. The focal point of research remains to develop new-fangled smart nanocarriers that can selectively respond to cancer-specific conditions and deliver medications to target cells efficiently. Nanocarriers deliver loaded therapeutic cargos to the tumour site either in a passive or active mode, with the least drug elimination from the drug delivery systems. This review chiefly focuses on current advances allied to smart nanocarriers such as dendrimers, liposomes, mesoporous silica nanoparticles, quantum dots, micelles, superparamagnetic iron-oxide nanoparticles, gold nanoparticles and carbon nanotubes, to list a few. Exhaustive discussion on crucial topics like drug targeting, surface decorated smart-nanocarriers and stimuli-responsive cancer nanotherapeutics responding to temperature, enzyme, pH and redox stimuli have been covered.

Acceptor engineering of small-molecule fluorophores for NIR-II fluorescence and photoacoustic imaging

Fluorescence imaging in the second near-infrared window (NIR-II) has been an emerging technique in diverse in vivo applications with high sensitivity/resolution and deep tissue penetration. To date, the design principle of the reported NIR-II organic fluorophores has heavily relied on benzo[1,2-c:4,5-c']bis([1,2,5]thiadiazole) (BBTD) as a strong electron acceptor. Here, we report the rational design and synthesis of a NIR-II fluorescent molecule with the rarely used [1,2,5]thiadiazolo[3,4-f]benzotriazole (TBZ) core to replace BBTD as the electron acceptor. Thanks to the weaker electron deficiency of the TBZ core than BBTD, the newly yielded NIR-II molecule (BTB) based nanoparticles have a higher mass extinction coefficient and quantum yield in water. In contrast, the nanoparticle suspension of its counterpart with BBTD as the core is nearly nonemissive. The NIR-II BTB nanoparticles allow video-rate fluorescence imaging for vasculature imaging in ears, hindlimbs, and the brain of the mouse. Additionally, its large absorptivity in the NIR-I region also promotes bioimaging using photoacoustic microscopy (PAM) and tomography (PAT). Upon surface conjugation with the Arg-Gly-Asp (RGD) peptide, the functionalized nanoparticles ensured targeted detection of integrin-overexpressed tumors through both imaging modalities in two- and three-dimensional views. Thus, our approach to engineering acceptors of organic fluorophores offers a promising molecular design strategy to afford new NIR-II fluorophores for versatile biomedical imaging applications.

Aptamer-mediated doxorubicin delivery reduces HCC burden in 3D organoids model

Epithelial cell adhesion molecule (EpCAM) is a surface marker which is frequently overexpressed in hepatocellular carcinoma (HCC) but minimally expressed on mature hepatocytes. We developed a specific aptamer against EpCAM (EpCAM-apt) and tested its potential as a drug delivery agent for HCC. The targeting ability of EpCAM-apt was confirmed in vitro and in vivo after which the complex was conjugated with doxorubicin (Dox) to form EpCAM-apt-Dox. The targeting efficacy of the drug-loaded complex against liver cancer stem-like cells (LCSCs) and therapeutic effects in HCC were evaluated. EpCAM-expressing (EpCAM⁺) HCC cells showed characteristics of stem like cells including greater proliferative capacity and tumour sphere formation. EpCAM-apt-Dox selectively delivered Dox to EpCAM⁺ HCC cells with high drug retention and accumulation versus control. EpCAM-apt-Dox reduced the self-renewal capacity and stem-like cell frequency in vitro. Elimination of cancer stem-like cells (CSCs) with EpCAM-apt-Dox significantly inhibited the growth of HCC cells and patient-derived HCC organoids but exerted minimal cytotoxicity to normal liver organoids. Moreover, EpCAM-apt-Dox suppressed the growth of xenograft tumours derived from HCC organoids in vivo and prolonged mouse survival without inducing adverse effects to major organs. Thus, aptamer-based drug delivery to the stem-like cell population is a promising strategy for HCC treatment.

Antibacterial Activity of T22, a Specific Peptidic Ligand of the Tumoral Marker CXCR4

CXCR4 is a cytokine receptor used by HIV during cell attachment and infection. Overexpressed in the cancer stem cells of more than 20 human neoplasias, CXCR4 is a convenient antitumoral drug target. T22 is a polyphemusin-derived peptide and an effective CXCR4 ligand. Its highly selective CXCR4 binding can be exploited as an agent for the cell-targeted delivery and internalization of associated antitumor drugs. Sharing chemical and structural traits with antimicrobial peptides (AMPs), the capability of T22 as an antibacterial agent remains unexplored. Here, we have detected T22-associated antimicrobial activity and biofilm formation inhibition over Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, in a spectrum broader than the reference AMP GWH1. In contrast to GWH1, T22 shows neither cytotoxicity over mammalian cells nor hemolytic activity and is active when displayed on protein-only nanoparticles through genetic fusion. Under the pushing need for novel antimicrobial agents, the discovery of T22 as an AMP is particularly appealing, not only as its mere addition to the expanding catalogue of antibacterial drugs. The recognized clinical uses of T22 might allow its combined and multivalent application in complex clinical conditions, such as colorectal cancer, that might benefit from the synchronous destruction of cancer stem cells and local bacterial biofilms.

Preclinical Molecular PET-CT Imaging Targeting CDCP1 in Colorectal Cancer

Colorectal cancer (CRC) is the third most common malignancy in the world, with 22% of patients presenting with metastatic disease and a further 50% destined to develop metastasis. Molecular imaging uses antigen-specific ligands conjugated to radionuclides to detect and characterise primary cancer and metastases. Expression of the cell surface protein CDCP1 is increased in CRC, and here we sought to assess whether it is a suitable molecular imaging target for the detection of this cancer. CDCP1 expression was assessed in CRC cell lines and a patient-derived xenograft to identify models suitable for evaluation of radio-labelled 10D7, a CDCP1-targeted, high-affinity monoclonal antibody, for preclinical molecular imaging. Positron emission tomography-computed tomography was used to compare zirconium-89 (⁸⁹Zr)-10D7 avidity to a nonspecific, isotype control ⁸⁹Zr-labelled IgGκ1 antibody. The specificity of CDCP1-avidity was further confirmed using CDCP1 silencing and blocking models. Our data indicate high avidity and specificity for of ⁸⁹Zr-10D7 in CDCP1 expressing tumors at. Significantly higher levels than normal organs and blood, with greatest tumor avidity observed at late imaging time points. Furthermore, relatively high avidity is detected in high CDCP1 expressing tumors, with reduced avidity where CDCP1 expression was knocked down or blocked. The study supports CDCP1 as a molecular imaging target for CRC in preclinical PET-CT models using the radioligand ⁸⁹Zr-10D7.

Transdermal Delivery of Macromolecules Using Nano Lipid Carriers

Skin being the largest external organ, offers an appealing procedure for transdermal drug delivery, so the drug needs to reach above the outermost layer of the skin, i.e., stratum corneum. Small molecular drug entities obeying the Lipinski rule, i.e., drugs having a molecular weight less than 500 Da, high lipophilicity, and optimum polarity, are favored enough to be used on the skin as therapeutics. Skin's barrier properties prevent the transport of macromolecules at pre-determined therapeutic rates. Notable advancements in macromolecules' transdermal delivery have occurred in recent years. Scientists have opted for liposomes, the use of electroporation, low-frequency ultrasound techniques, etc. Some of these have shown better delivery of macromolecules at clinically beneficial rates. These physical technologies involve complex mechanisms, which may irreversibly incur skin damage. Majorly, two types of lipid-based formulations, including Solid Lipid Nanoparticles (SLNs) and Nanostructured Lipid Carriers (NLCs), are widely investigated as transdermal delivery systems. In this review, the concepts, mechanisms, and applications of nanostructured lipid carriers used to transport macromolecules via transdermal routes are thoroughly reviewed and presented along with their clinical perspective.

Inhibitory Effect of Lentivirus-Mediated Gag-Caspase-8 on the Growth of HER-2-Overexpressing Primary Human Breast Cancer Cells

Background: Apoptosis plays an essential role in the development and treatment of tumors, and caspase-8 (CASP8) plays an important role in the enzyme cascade reaction that leads to apoptosis. Human epidermal growth factor receptor 2 (HER-2)-overexpressing breast cancer is highly aggressive and has a high recurrence rate and poor prognosis. This study investigated whether lentivirus-mediated Gag-CASP8 can effectively deliver activated CASP8 into primary human breast cancer cells overexpressing HER-2 to induce apoptosis and explore the underlying mechanism. Materials and Methods: HER-2-overexpressing primary human breast cancer cells were infected with lentivirus-like particles carrying Gag-CASP8. Results: After a 48-h infection of primary human breast cancer cells with HER-2 by lentivirus-mediated Gag-CASP8, significant differences were observed in the survival rate, migration ability, S-phase number of cells, apoptosis rate, and intracellular activated CASP8 and caspase-3 levels in tumor cells compared with those in the control group (p < 0.05). Conclusions: Lentivirus-mediated Gag-CASP8 can deliver activated CASP8 into HER-2-overexpressing primary human breast cancer cells and induce apoptosis by activating caspase-3, a downstream apoptotic executive molecule. By blocking the S-phase to inhibit cell proliferation and migration, lentivirus-mediated Gag-CASP8 provides a reference for tumor gene therapy.

Palladium nanoplates scotch breast cancer lung metastasis by constraining epithelial-mesenchymal transition

Metastasis accounts for the majority of cancer deaths in many tumor types including breast cancer. Epithelial-mesenchymal transition (EMT) is the driving force for the occurrence and progression of metastasis, however, no targeted strategies to block the EMT program are currently available to combat metastasis. Diverse engineered nanomaterials (ENMs) have been reported to exert promising anti-cancer effects, however, no ENMs have been designed to target EMT. Palladium (Pd) nanomaterials, a type of ENM, have received substantial attention in nanomedicine due to their favorable photothermal performance for cancer therapeutics. Herein, Pd nanoplates (PdPL) were found to be preferentially biodistributed to both primary tumors and metastatic tumors. Importantly, PdPL showed a significant inhibition of lung metastasis with and without near-infrared (NIR) irradiation. Mechanistic investigations revealed that EMT was significantly compromised in breast cancer cells upon the PdPL treatment, which was partially due to the inhibition of the transforming growth factor-beta (TGF-β) signaling. Strikingly, the PdPL was found to directly interact with TGF-β proteins to diminish TGF-β functions in activating its downstream signaling, as evidenced by the reduced phosphorylation of Smad2. Notably, TGF-β-independent pathways were also involved in undermining EMT and other important biological processes that are necessary for metastasis. Additionally, NIR irradiation elicited synergistic effects on PdPL-induced inhibition of primary tumors and metastasis. In summary, these results revealed that the PdPL remarkably curbed metastasis by inhibiting EMT signaling, thereby indicating the promising potential of PdPL as a therapeutic agent for treating breast cancer metastasis.

Therapeutic peptides for chemotherapy: Trends and challenges for advanced delivery systems

The past decades witnessed an increasing interest in peptides as clinical therapeutics. Rightfully considered as a potential alternative for small molecule therapy, these remarkable pharmaceuticals can be structurally fine-tuned to impact properties such as high target affinity, selectivity, low immunogenicity along with satisfactory tissue penetration. Although physicochemical and pharmacokinetic challenges have mitigated, to some extent, the clinical applications of therapeutic peptides, their potential impact on modern healthcare remains encouraging. According to recent reports, there are more than 400 peptides under clinical trials and 60 were already approved for clinical use. As the demand for efficient and safer therapy became high, especially for cancers, peptides have shown some exciting developments not only due to their potent antiproliferative action but also when used as adjuvant therapies, either to decrease side effects with tumor-targeted therapy or to enhance the activity of anticancer drugs via transbarrier delivery. The first part of the present review gives an insight into challenges related to peptide product development. Both molecular and formulation approaches intended to optimize peptide's pharmaceutical properties are covered, and some of their current issues are highlighted. The second part offers a comprehensive overview of the emerging applications of therapeutic peptides in chemotherapy from bioconjugates to nanovectorized therapeutics.

In Vitro Cellular Uptake Studies of Self-Assembled Fluorinated Nanoparticles Labelled with Antibodies

Nanoparticles (NPs) functionalized with antibodies (Abs) on their surface are used in a wide range of bioapplications. Whereas the attachment of antibodies to single NPs to trigger the internalization in cells via receptor-mediated endocytosis has been widely studied, the conjugation of antibodies to larger NP assemblies has been much less explored. Taking into account that NP assemblies may be advantageous for some specific applications, the possibility of incorporating targeting ligands is quite important. Herein, we performed the effective conjugation of antibodies onto a fluorescent NP assembly, which consisted of fluorinated Quantum Dots (QD) self-assembled through fluorine-fluorine hydrophobic interactions. Cellular uptake studies by confocal microscopy and flow cytometry revealed that the NP assembly underwent the same uptake procedure as individual NPs; that is, the antibodies retained their targeting ability once attached to the nanoassembly, and the NP assembly preserved its intrinsic properties (i.e., fluorescence in the case of QD nanoassembly).

Correlating Super-Resolution Microscopy and Transmission Electron Microscopy Reveals Multiparametric Heterogeneity in Nanoparticles

The functionalization of nanoparticles with functional moieties is a key strategy to achieve cell targeting in nanomedicine. The interplay between size and ligand number is crucial for the formulation performance and needs to be properly characterized to understand nanoparticle structure-activity relations. However, there is a lack of methods able to measure both size and ligand number at the same time and at the single particle level. Here, we address this issue by introducing a correlative light and electron microscopy (CLEM) method combining super-resolution microscopy (SRM) and transmission electron microscopy (TEM) imaging. We apply our super-resCLEM method to characterize the relationship between size and ligand number and density in PLGA-PEG nanoparticles. We highlight how heterogeneity found in size can impact ligand distribution and how a significant part of the nanoparticle population goes completely undetected in the single-technique analysis. Super-resCLEM holds great promise for the multiparametric analysis of other parameters and nanomaterials.

Cell-Penetrating Peptides: Applications in Tumor Diagnosis and Therapeutics

Since their identification over twenty-five years ago, the plethora of cell-penetrating peptides (CPP) and their applications has skyrocketed. These 5 to 30 amino acid in length peptides have the unique property of breaching the cell membrane barrier while carrying cargoes larger than themselves into cells in an intact, functional form. CPPs can be conjugated to fluorophores, activatable probes, radioisotopes or contrast agents for imaging tissues, such as tumors. There is no singular mechanism for translocation of CPPs into a cell, and therefore, many CPPs are taken up by a multitude of cell types, creating the challenge of tumor-specific translocation and hindering clinical effectiveness. Varying strategies have been developed to combat this issue and enhance their diagnostic potential by derivatizing CPPs for better targeting by constructing specific cell-activated forms. These methods are currently being used to image integrin-expressing tumors, breast cancer cells, human histiocytic lymphoma and protease-secreting fibrosarcoma cells, to name a few. Additionally, identifying safe, effective therapeutics for malignant tumors has long been an active area of research. CPPs can circumvent many of the complications found in treating cancer with conventional therapeutics by targeted delivery of drugs into tumors, thereby decreasing off-target side effects, a feat not achievable by currently employed conventional chemotherapeutics. Myriad types of chemotherapeutics such as tyrosine kinase inhibitors, antitumor antibodies and nanoparticles can be functionally attached to these peptides, leading to the possibility of delivering established and novel cancer therapeutics directly to tumor tissue. While much research is needed to overcome potential issues with these peptides, they offer a significant advancement over current mechanisms to treat cancer. In this review, we present a brief overview of the research, leading to identification of CPPs with a comprehensive state-of-the-art review on the role of these novel peptides in both cancer diagnostics as well as therapeutics.

Recent progress of nanotechnology-based theranostic systems in cancer treatments

Theranostics that integrates therapy and diagnosis in one system to achieve accurate cancer diagnosis and treatment has attracted tremendous interest, and has been recognized as a potential breakthrough in overcoming the challenges of conventional oncotherapy. Nanoparticles are ideal candidates as carriers for theranostic agents, which is attributed to their extraordinary physicochemical properties, including nanoscale sizes, functional properties, prolonged blood circulation, active or passive tumor targeting, specific cellular uptake, and in some cases, excellent optical properties that ideally meet the needs of phototherapy and imaging at the same time. Overall, with the development of nanotechnology, theranostics has become a reality, and is now in the transition stage of "bench to bedside." In this review, we summarize recent progress on nanotechnology-based theranostics, i.e., nanotheranostics, that has greatly assisted traditional therapies, and has provided therapeutic strategies emerging in recent decades, as well as "cocktail" theranostics mixing various treatment modalities.

Magnetic-core-based silibinin nanopolymeric carriers for the treatment of renal cell cancer

AIMS

Silibinin offers potential anticancer effect with less aqueous solubility and high permeability. The present study aimed to develop biocompatible magnetic-core-based nanopolymeric carriers of poly (D, l-lactide-co-glycolic) acid (PLGA) encapsulated silibinin for the sustained release action on renal cancerous cell.

MAIN METHODS

The synthesized iron oxide nanoparticles were prepared by precipitation method via encapsulation of silibinin in PLGA network using double emulsion method. The nanoparticle formulations were characterized for morphological, physicochemical properties (HRTEM, FTIR, Raman Spectroscopy and VSM), in vitro drug release and cytotoxicity study on kidney cancer cells (A-498). The safety of magnetic-core-based silibinin nanopolymeric carriers was conducted by i.v. administration at a dose of 50 mg/kg in mice.

KEY FINDINGS

The mean particle size, zeta potential and % encapsulation efficiency of magnetic-core-based silibinin nanopolymeric carriers were found to be 285.9 ± 0.28 nm, -14.71 ± 0.15 mV and 84.76 ± 1.29%, respectively. The saturation magnetization of magnetic core and optimized nanoparticles were reported as 36.35 emu/g and 12.78 emu/g, respectively. HRTEM analyses revealed the spherical shapes of the particles with uniform size distribution. The in vitro release profile of silibinin from the nanoparticles exhibited a sustained delivery for 15 days and displayed better cytotoxicity against human kidney cancer cells (A-498) than silibinin. In vivo study showed the safety of magnetic-core-based silibinin nanopolymeric carriers in mice.

SIGNIFICANCE

The magnetic-core-based silibinin nanopolymeric carriers will act as a potential carrier for targeted transportation of actives in cancer therapy.

Applications of Nanoparticle-Antibody Conjugates in Immunoassays and Tumor Imaging

Modern diagnostic technologies rely on both in vitro and in vivo modalities to provide a complete understanding of the clinical state of a patient. Nanoparticle-antibody conjugates have emerged as promising systems to confer increased sensitivity and accuracy for in vitro diagnostics (e.g., immunoassays). Meanwhile, in vivo applications have benefited from the targeting ability of nanoparticle-antibody conjugates, as well as payload flexibility and tailored biodistribution. This review provides an encompassing overview of nanoparticle-antibody conjugates, from chemistry to applications in medical immunoassays and tumor imaging, highlighting the underlying principles and unique features of relevant preclinical applications employing commonly used imaging modalities (e.g., optical/photoacoustics, positron-emission tomography, magnetic resonance imaging, X-ray computed tomography).

Single chain variable fragment fused to maltose binding protein: a modular nanocarrier platform for the targeted delivery of antitumorals

The use of the specific binding properties of monoclonal antibody fragments such as single-chain variable fragments (ScFv) for the selective delivery of antitumor therapeutics for cancer cells is attractive due to their smaller size, low immunogenicity, and low-cost production. Although covalent strategies for the preparation of such ScFv-based therapeutic conjugates are prevalent, this approach is not straightforward, as it requires prior chemical activation and/or modification of both the ScFv and the therapeutics for the application of robust chemistries. A non-covalent alternative based on ScFv fused to maltose-binding protein (MBP) acting as a binding adapter is proposed for active targeted delivery. MBP-ScFv proves to be a valuable modular platform to synergistically bind maltose-derivatized therapeutic cargos through the MBP, while preserving the targeting competences provided by the ScFv. The methodology has been tested by using a mutated maltose-binding protein (MBP I334W) with an enhanced affinity toward maltose and an ScFv coding sequence toward the human epidermal growth factor receptor 2 (HER2). Non-covalent binding complexes of the resulting MBP-ScFv fusion protein with diverse maltosylated therapeutic cargos (a near-infrared dye, a maltosylated supramolecular β-cyclodextrin container for doxorubicin, and non-viral polyplex gene vector) were easily prepared and characterized. In vitro and in vivo assays using cell lines that express or not the HER2 epitope, and mice xenografts of HER2 expressing cells demonstrated the capability and versatility of MBP-ScFv for diagnosis, imaging, and drug and plasmid active targeted tumor delivery. Remarkably, the modularity of the MBP-ScFv platform allows the flexible interchange of both the cargos and the coding sequence for the ScFv, allowing ad hoc solutions in targeting delivery without any further optimization since the MBP acts as a pivotal element.

Bacteriophages as Therapeutic and Diagnostic Vehicles in Cancer

Evolution of nanomedicine is the re-design of synthetic and biological carriers to implement novel theranostic platforms. In recent years, bacteriophage research favors this process, which has opened up new roads in drug and gene delivery studies. By displaying antibodies, peptides, or proteins on the surface of different bacteriophages through the phage display technique, it is now possible to unravel specific molecular determinants of both cancer cells and tumor-associated microenvironmental molecules. Downstream applications are manifold, with peptides being employed most of the times to functionalize drug carriers and improve their therapeutic index. Bacteriophages themselves were proven, in this scenario, to be good carriers for imaging molecules and therapeutics as well. Moreover, manipulation of their genetic material to stably vehiculate suicide genes within cancer cells substantially changed perspectives in gene therapy. In this review, we provide examples of how amenable phages can be used as anticancer agents, especially because their systemic administration is possible. We also provide some insights into how their immunogenic profile can be modulated and exploited in immuno-oncology for vaccine production.