Refined construction of antibody-targeted nanoparticles leads to superior antigen binding and enhanced delivery of an entrapped payload to pancreatic cancer cells

Overcoming therapy resistance in pancreatic cancer: New insights and future directions

Pancreatic adenocarcinoma (PDAC) is predicted to become the second leading cause of cancer deaths by 2030 and this is mostly due to therapy failure. Limited treatment options and resistance to standard-of-care (SoC) therapies makes PDAC one of the cancer types with poorest prognosis and survival rates [1,2]. Pancreatic tumors are renowned for their poor response to therapeutic interventions including targeted therapies, chemotherapy and radiotherapy. Herein, we review hallmarks of therapy resistance in PDAC and current strategies aiming to tackle escape mechanisms and to re-sensitize cancer cells to therapy. We will further provide insights on recent advances in the field of drug discovery, nanomedicine, and disease models that are setting the ground for future research.

Development of CD33-Targeted Dual Drug-Loaded Nanoparticles for the Treatment of Pediatric Acute Myeloid Leukemia

Paediatric acute myeloid leukemia (AML) is a heterogeneous hematological malignancy still heavily reliant on traditional chemotherapeutic approaches. Combination treatments have shown to be a superior approach, but their success is often hindered by side effects and different drugs' pharmacokinetics. Here, we investigated ABT-737 and Purvalanol A as a potential drug pairing for pediatric AML and described the development of CD33-targeted polymeric nanoparticles (NPs) to enable their simultaneous targeted codelivery. Separate drug encapsulation within poly(lactic-co-glycolic acid) (PLGA) NPs was optimized prior to coencapsulation of both drugs at a synergistic ratio in PEGylated PLGA NPs. The therapeutic effects of formulations were evaluated in a panel of pediatric AML cells, and dual drug-loaded NPs (dual NPs) demonstrated significantly enhanced apoptotic cell death. Moreover, conjugation to gemtuzumab resulted in improved NP binding and internalization in CD33-positive cells. Finally, CD33-targeted dual-loaded NPs showed enhanced cytotoxicity to CD33-positive AML cells via CD33-mediated targeted drug delivery.

Facile Rebridging Conjugation Approach to Attain Monoclonal Antibody-Targeted Nanoparticles with Enhanced Antigen Binding and Payload Delivery

Adopting conventional conjugation approaches to construct antibody-targeted nanoparticles (NPs) has demonstrated suboptimal control over the binding orientation and the structural stability of monoclonal antibodies (mAbs). Hitherto, the developed antibody-targeted NPs have shown proof of concept but lack product homogeneity, batch-to-batch reproducibility, and stability, precluding their advancement toward the clinic. To circumvent these limitations and advance toward clinical application, herein, a refined approach based on site-specific construction of mAb-immobilized NPs will be appraised. Initially, the conjugation of atezolizumab (anti-PDL1 antibody, Amab) with polymeric NPs was developed using bis-haloacetamide (BisHalide) rebridging chemistry, followed by click chemistry (NP-Fab BisHalide Ab and NP-Fc BisHalide Ab). For comparison purposes, mAb-immobilized NPs developed utilizing conventional conjugation methods, namely, N-hydroxysuccinimide (NHS) coupling and maleimide chemistry (NP-NHS Ab and NP-Mal Ab), were included. Next, flow cytometry and confocal microscopy experiments evaluated the actively targeted NPs (loaded with fluorescent dye) for cellular binding and uptake. Our results demonstrated the superior and selective binding and uptake of NP-Fab BisHalide Ab and NP-Fc BisHalide Ab into EMT6 cells by 19-fold and 13-fold, respectively. To evaluate the PDL1-dependent cell uptake and the selectivity of the treatments, a blocking step of the PDL1 receptor with Amab was performed prior to incubation with NP-Fab BisHalide Ab and NP-Fc BisHalide Ab. To our delight, the binding and uptake of fluorescent NPs were reduced significantly by 3-fold for NP-Fab BisHalide Ab, demonstrating the PDL1-mediated uptake. Moreover, NP-Fab BisHalide Ab and NP-Fc BisHalide Ab were entrapped with the paclitaxel payload, and their cytotoxicity was evaluated. They showed significant enhancements compared to free paclitaxel and NP-NHS Ab. Overall, this work will provide a facile conjugation method that could be implemented to actively target NPs with a plethora of therapeutic mAbs approved for various malignancies.

Surface Bio-engineered Polymeric Nanoparticles

Surface bio-engineering of polymeric nanoparticles (PNPs) has emerged as a cornerstone in contemporary biomedical research, presenting a transformative avenue that can revolutionize diagnostics, therapies, and drug delivery systems. The approach involves integrating bioactive elements on the surfaces of PNPs, aiming to provide them with functionalities to enable precise, targeted, and favorable interactions with biological components within cellular environments. However, the full potential of surface bio-engineered PNPs in biomedicine is hampered by obstacles, including precise control over surface modifications, stability in biological environments, and lasting targeted interactions with cells or tissues. Concerns like scalability, reproducibility, and long-term safety also impede translation to clinical practice. In this review, these challenges in the context of recent breakthroughs in developing surface-biofunctionalized PNPs for various applications, from biosensing and bioimaging to targeted delivery of therapeutics are discussed. Particular attention is given to bonding mechanisms that underlie the attachment of bioactive moieties to PNP surfaces. The stability and efficacy of surface-bioengineered PNPs are critically reviewed in disease detection, diagnostics, and treatment, both in vitro and in vivo settings. Insights into existing challenges and limitations impeding progress are provided, and a forward-looking discussion on the field's future is presented. The paper concludes with recommendations to accelerate the clinical translation of surface bio-engineered PNPs.

Recent Advances in Biomedical Nanotechnology Related to Natural Products

Natural product processing via nanotechnology has opened the door to innovative and significant applications in medical fields. On one hand, plants-derived bioactive ingredients such as phenols, pentacyclic triterpenes and flavonoids exhibit significant pharmacological activities, on another hand, most of them are hydrophobic in nature, posing challenges to their use. To overcome this issue, nanoencapsulation technology is employed to encapsulate these lipophilic compounds and enhance their bioavailability. In this regard, various nano-sized vehicles, including degradable functional polymer organic compounds, mesoporous silicon or carbon materials, offer superior stability and retention for bioactive ingredients against decomposition and loss during delivery as well as sustained release. On the other hand, some naturally occurring polymers, lipids and even microorganisms, which constitute a significant portion of Earth's biomass, show promising potential for biomedical applications as well. Through nano-processing, these natural products can be developed into nano-delivery systems with desirable characteristics for encapsulation a wide range of bioactive components and therapeutic agents, facilitating in vivo drug transport. Beyond the presentation of the most recent nanoencapsulation and nano-processing advancements with formulations mainly based on natural products, this review emphasizes the importance of their physicochemical properties at the nanoscale and their potential in disease therapy.

Signalling in pancreatic cancer: from pathways to therapy

Pancreatic cancer (PC) is a common malignant tumour in the digestive system. Due to the lack of sensitive diagnostic markers, strong metastasis ability, and resistance to anti-cancer drugs, the prognosis of PC is inferior. In the past decades, increasing evidence has indicated that the development of PC is closely related to various signalling pathways. With the exploration of RAS-driven, epidermal growth factor receptor, Hedgehog, NF-κB, TGF-β, and NOTCH signalling pathways, breakthroughs have been made to explore the mechanism of pancreatic carcinogenesis, as well as the novel therapies. In this review, we discussed the signalling pathways involved in PC and summarised current targeted agents in the treatment of PC. Furthermore, opportunities and challenges in the exploration of potential therapies targeting signalling pathways were also highlighted.

Advances and Prospects in the Treatment of Pancreatic Cancer

Pancreatic cancer is a highly malignant and incurable disease, characterized by its aggressive nature and high fatality rate. The most common type is pancreatic ductal adenocarcinoma (PDAC), which has poor prognosis and high mortality rate. Current treatments for pancreatic cancer mainly encompass surgery, chemotherapy, radiotherapy, targeted therapy, and combination regimens. However, despite efforts to improve prognosis, and the 5-year survival rate for pancreatic cancer remains very low. Therefore, it's urgent to explore novel therapeutic approaches. With the rapid development of therapeutic strategies in recent years, new ideas have been provided for treating pancreatic cancer. This review expositions the advancements in nano drug delivery system, molecular targeted drugs, and photo-thermal treatment combined with nanotechnology for pancreatic cancer. It comprehensively analyzes the prospects of combined drug delivery strategies for treating pancreatic cancer, aiming at a deeper understanding of the existing drugs and therapeutic approaches, promoting the development of new therapeutic drugs, and attempting to enhance the therapeutic effect for patients with this disease.

The Impact of Nanobody Density on the Targeting Efficiency of PEGylated Liposomes

Nanoparticles (NPs) are commonly modified with tumor-targeting moieties that recognize proteins overexpressed on the extracellular membrane to increase their specific interaction with target cells. Nanobodies (Nbs), the variable domain of heavy chain-only antibodies, are a robust targeting ligand due to their small size, superior stability, and strong binding affinity. For the clinical translation of targeted Nb-NPs, it is essential to understand how the number of Nbs per NP impacts the receptor recognition on cells. To study this, Nbs targeting the hepatocyte growth factor receptor (MET-Nbs) were conjugated to PEGylated liposomes at a density from 20 to 800 per liposome and their targeting efficiency was evaluated in vitro. MET-targeted liposomes (MET-TLs) associated more profoundly with MET-expressing cells than non-targeted liposomes (NTLs). MET-TLs with approximately 150-300 Nbs per liposome exhibited the highest association and specificity towards MET-expressing cells and retained their targeting capacity when pre-incubated with proteins from different sources. Furthermore, a MET-Nb density above 300 Nbs per liposome increased the interaction of MET-TLs with phagocytic cells by 2-fold in ex vivo human blood compared to NTLs. Overall, this study demonstrates that adjusting the MET-Nb density can increase the specificity of NPs towards their intended cellular target and reduce NP interaction with phagocytic cells.

Modification of Fab Fragments by Dibromopyridazinediones Carrying Mono- and Double-Biotin Functionalities

To verify the potencies of dibromopyridazinediones with mono- and double-biotin groups, the functions as cysteine-selective biotinylation reagents were evaluated through conjugation with a goat anti-mouse IgG Fab fragment as a functional protein model. The starting Fab was reduced with tris(2-carboxyethyl)phosphine to cleave the disulfide bond and then treated with the reagents. These reagents simultaneously introduced biotin groups into the reduced Fab and re-bridged the disulfide moiety. Furthermore, we demonstrated that the biotin-labeled Fabs were reactive to an antigen and streptavidin.

Ultrasonic Film Rehydration Synthesis of Mixed Polylactide Micelles for Enzyme-Resistant Drug Delivery Nanovehicles

A facile technique for the preparation of mixed polylactide micelles from amorphous poly-D,L-lactide-block-polyethyleneglycol and crystalline amino-terminated poly-L-lactide is described. In comparison to the classical routine solvent substitution method, the ultrasonication assisted formation of polymer micelles allows shortening of the preparation time from several days to 15-20 min. The structure and morphology of mixed micelles were analyzed with the assistance of electron microscopy, dynamic and static light scattering and differential scanning calorimetery. The resulting polymer micelles have a hydrodynamic radius of about 150 nm and a narrow size distribution. The average molecular weight of micelles was found to be 2.1 × 107 and the aggregation number was calculated to be 6000. The obtained biocompatible particles were shown to possess low cytotoxicity, high colloid stability and high stability towards enzymatic hydrolysis. The possible application of mixed polylactide micelles as drug delivery vehicles was studied for the antitumor hydrophobic drug paclitaxel. The lethal concentration (LC50) of paclitaxel encapsulated in polylactide micelles was found to be 42 ± 4 µg/mL-a value equal to the LC50 of paclitaxel in the commercial drug Paclitaxel-Teva.

Antibody-Incorporated Nanomedicines for Cancer Therapy

Antibody-based cancer therapy, one of the most significant therapeutic strategies, has achieved considerable success and progress over the past decades. Nevertheless, obstacles including limited tumor penetration, short circulation half-lives, undesired immunogenicity, and off-target side effects remain to be overcome for the antibody-based cancer treatment. Owing to the rapid development of nanotechnology, antibody-containing nanomedicines that have been extensively explored to overcome these obstacles have already demonstrated enhanced anticancer efficacy and clinical translation potential. This review intends to offer an overview of the advancements of antibody-incorporated nanoparticulate systems in cancer treatment, together with the nontrivial challenges faced by these next-generation nanomedicines. Diverse strategies of antibody immobilization, formats of antibodies, types of cancer-associated antigens, and anticancer mechanisms of antibody-containing nanomedicines are provided and discussed in this review, with an emphasis on the latest applications. The current limitations and future research directions on antibody-containing nanomedicines are also discussed from different perspectives to provide new insights into the construction of anticancer nanomedicines.

The use of bromopyridazinedione derivatives in chemical biology

Tools that facilitate the chemical modification of peptides and proteins are gaining an increasing amount of interest across many avenues of chemical biology as they enable a plethora of therapeutic, imaging and diagnostic applications. Cysteine residues and disulfide bonds have been highlighted as appealing targets for modification due to the highly homogenous nature of the products that can be formed through their site-selective modification. Amongst the reagents available for the site-selective modification of cysteine(s)/disulfide(s), pyridazinediones (PDs) have played a particularly important and enabling role. In this review, we outline the unique chemical features that make PDs especially well-suited to cysteine/disulfide modification on a wide variety of proteins and peptides, as well as provide context as to the problems solved (and applications enabled) by this technology.

Nanomedicine in Pancreatic Cancer: Current Status and Future Opportunities for Overcoming Therapy Resistance

Simple Summary

Despite access to a vast arsenal of anticancer agents, many fail to realise their full therapeutic potential in clinical practice. One key determinant of this is the evolution of multifaceted resistance mechanisms within the tumour that may either pre-exist or develop during the course of therapy. This is particularly evident in pancreatic cancer, where limited responses to treatment underlie dismal survival rates, highlighting the urgent need for new therapeutic approaches. Here, we discuss the major features of pancreatic tumours that contribute to therapy resistance, and how they may be alleviated through exploitation of the mounting and exciting promise of nanomedicines; a unique collection of nanoscale platforms with tunable and multifunctional capabilities that have already elicited a widespread impact on cancer management.

Abstract

The development of drug resistance remains one of the greatest clinical oncology challenges that can radically dampen the prospect of achieving complete and durable tumour control. Efforts to mitigate drug resistance are therefore of utmost importance, and nanotechnology is rapidly emerging for its potential to overcome such issues. Studies have showcased the ability of nanomedicines to bypass drug efflux pumps, counteract immune suppression, serve as radioenhancers, correct metabolic disturbances and elicit numerous other effects that collectively alleviate various mechanisms of tumour resistance. Much of this progress can be attributed to the remarkable benefits that nanoparticles offer as drug delivery vehicles, such as improvements in pharmacokinetics, protection against degradation and spatiotemporally controlled release kinetics. These attributes provide scope for precision targeting of drugs to tumours that can enhance sensitivity to treatment and have formed the basis for the successful clinical translation of multiple nanoformulations to date. In this review, we focus on the longstanding reputation of pancreatic cancer as one of the most difficult-to-treat malignancies where resistance plays a dominant role in therapy failure. We outline the mechanisms that contribute to the treatment-refractory nature of these tumours, and how they may be effectively addressed by harnessing the unique capabilities of nanomedicines. Moreover, we include a brief perspective on the likely future direction of nanotechnology in pancreatic cancer, discussing how efforts to develop multidrug formulations will guide the field further towards a therapeutic solution for these highly intractable tumours.

Development of next generation nanomedicine-based approaches for the treatment of cancer: we've barely scratched the surface

Interest in nanomedicines has grown rapidly over the past two decades, owing to the promising therapeutic applications they may provide, particularly for the treatment of cancer. Personalised medicine and 'smart' actively targeted nanoparticles represent an opportunity to deliver therapies directly to cancer cells and provide sustained drug release, in turn providing overall lower off-target toxicity and increased therapeutic efficacy. However, the successful translation of nanomedicines from encouraging pre-clinical findings to the clinic has, to date, proven arduous. In this review, we will discuss the use of nanomedicines for the treatment of cancer, with a specific focus on the use of polymeric and lipid nanoparticle delivery systems. In particular, we examine approaches exploring the surface functionalisation of nanomedicines to elicit active targeting and therapeutic effects as well as challenges and future directions for nanoparticles in cancer treatment.

Employing defined bioconjugates to generate chemically functionalised gold nanoparticles for in vitro diagnostic applications

Novel methods for introducing chemical and biological functionality to the surface of gold nanoparticles serve to increase the utility of this class of nanomaterials across a range of applications. To date, methods for functionalising gold surfaces have relied upon uncontrollable non-specific adsorption, bespoke chemical linkers, or non-generalisable protein-protein interactions. Herein we report a versatile method for introducing functionality to gold nanoparticles by exploiting the strong interaction between chemically functionalised bovine serum albumin (f-BSA) and citrate-capped gold nanoparticles (AuNPs). We establish the generalisability of the method by introducing a variety of functionalities to gold nanoparticles using cheap, commercially available chemical linkers. The utility of this approach is further demonstrated through the conjugation of the monoclonal antibody Ontruzant to f-BSA-AuNPs using inverse electron-demand Diels-Alder (iEDDA) click chemistry, a hitherto unexplored chemistry for AuNP-IgG conjugation. Finally, we show that the AuNP-Ontruzant particles generated via f-BSA-AuNPs have a greater affinity for their target in a lateral flow format when compared to conventional physisorption, highlighting the potential of this technology for producing sensitive diagnostic tests.

Antibody therapy in pancreatic cancer: mAb-ye we're onto something?

Pancreatic cancer remains an extremely deadly disease, with little improvement seen in treatment or outcomes over the last 40 years. Targeted monoclonal antibody therapy is one area that has been explored in attempts to tackle this disease. This review examines antibodies that have undergone clinical evaluation in pancreatic cancer. These antibodies target a wide variety of molecules, including tumour cell surface, stromal, immune and embryonic pathway targets. We discuss the therapeutic utility of these therapies both as monotherapeutics and in combination with other treatments such as chemotherapy. While antibody therapy for pancreatic cancer has yet to yield significant success, lessons learned from research thus far highlights future directions that may help overcome observed hurdles to yield clinically efficacious results.

Gene silencing delivery systems for the treatment of pancreatic cancer: Where and what to target next?

Despite intensive research efforts and development of numerous new anticancer drugs and treatment strategies over the past decades, there has been only very limited improvement in overall patient survival and in effective treatment options for pancreatic cancer. Current chemotherapy improves survival in terms of months and death rates in pancreatic cancer patients are almost equivalent to incidence rates. It is imperative to develop new therapeutic approaches. Among them, gene silencing shows promise of effectiveness in both tumor cells and stromal cells by inhibiting tumor-promoting genes. This review summarizes potential targets for gene silencing in both pancreatic cancer cells and abundant stromal cells focusing on non-viral delivery systems for small RNAs and discusses the potential immunological implications. The review concludes with the importance of multifactorial therapy of pancreatic cancer.

Engineering Modular Half-Antibody Conjugated Nanoparticles for Targeting CD44v6-Expressing Cancer Cells

Gastric cancer (GC) remains a major cause of death worldwide mainly because of the late detection in advanced stage. Recently, we proposed CD44v6 as a relevant marker for early detection of GC, opening new avenues for GC-targeted theranostics. Here, we designed a modular nanoscale system that selectively targets CD44v6-expressing GC cells by the site-oriented conjugation of a new-engineered CD44v6 half-antibody fragment to maleimide-modified polystyrene nanoparticles (PNPs) via an efficient bioorthogonal thiol-Michael addition click chemistry. PNPs with optimal particle size (200 nm) for crossing a developed biomimetic CD44v6-associated GC stromal model were further modified with a heterobifunctional maleimide crosslinker and click conjugated to the novel CD44v6 half-antibody fragment, obtained by chemical reduction of full antibody, without affecting its bioactivity. Collectively, our results confirmed the specific targeting ability of CD44v6-PNPs to CD44v6-expressing cells (1.65-fold higher than controls), highlighting the potential of CD44v6 half-antibody conjugated nanoparticles as promising and clinically relevant tools for the early diagnosis and therapy of GC. Additionally, the rational design of our nanoscale system may be explored for the development of several other nanotechnology-based disease-targeted approaches.