Peptide-Based Bioconjugates and Therapeutics for Targeted Anticancer Therapy

Advances in nanomedicine for retinal drug delivery: overcoming barriers and enhancing therapeutic outcomes

Nanomedicine offers a promising avenue for improving retinal drug delivery, effectively addressing challenges associated with ocular diseases like age-related macular degeneration and diabetic retinopathy. Nanoparticles, with their submicron size and customisable surface properties, enable enhanced permeability and retention within retinal tissues, supporting sustained drug release and minimising systemic side effects. Nanostructured scaffolds further provide a supportive environment for retinal cell growth and tissue regeneration, crucial for treating degenerative conditions. Additionally, advanced nanodevices facilitate real-time monitoring and controlled drug release, marking significant progress in retinal therapy. This study reviews recent advancements in nanomedicine for retinal drug delivery, critically analysing design innovations, therapeutic benefits, and limitations of these systems. By advancing nanotechnology integration in ocular therapies, this field holds strong potential for overcoming current barriers, ultimately improving patient outcomes and quality of life.

One Change, Many Benefits: A Glycine-Modified Bacteriochlorin with NIR Absorption and a Type I Photochemical Mechanism for Versatile Photodynamic Therapy

Difluorinated sulfonamide porphyrin (F2PGly) and bacteriochlorin (F2BGly), modified by glycine residues, were synthesized and evaluated for photodynamic therapy (PDT). F₂PGly exhibits superior stability and singlet oxygen generation efficiency but features a low-intensity band in the red range (λmax = 639 nm). In contrast, F2BGly shows a favorable, red-shifted absorption spectrum (λmax = 746 nm) that aligns well with phototherapeutic window, facilitating deeper tissue penetration. Moreover, it demonstrates reasonable photostability, necessary for the efficient generation of both singlet oxygen (type II) and oxygen-centered radicals (type I mechanism) which contributes to enhanced therapeutic efficacy. Importantly, the glycine modifications in F2BGly enhance its uptake in MCF-7 cells, known for their resistance to PDT due to efflux transport proteins like LAT1, showing great potential in the cancer cell-targeted PDT. The glycine groups potentially enable F2BGly to bypass these barriers, resulting in increased intracellular accumulation and more effective Reactive Oxygen Species (ROS) generation under illumination. In vivo studies indicated promising vascular-targeted PDT results, with real-time fluorescence imaging used to monitor photosensitizer distribution prior to irradiation. These findings suggest that F2BGly is a promising photosensitizer candidate with enhanced cancer cell selectivity and photodynamic efficiency, meriting further exploration in targeted PDT applications for multiple types of cancers.

Recent Advances in Peptide Drug Discovery: Novel Strategies and Targeted Protein Degradation

Recent technological advancements, including computer-assisted drug discovery, gene-editing techniques, and high-throughput screening approaches, have greatly expanded the palette of methods for the discovery of peptides available to researchers. These emerging strategies, driven by recent advances in bioinformatics and multi-omics, have significantly improved the efficiency of peptide drug discovery when compared with traditional in vitro and in vivo methods, cutting costs and improving their reliability. An added benefit of peptide-based drugs is the ability to precisely target protein-protein interactions, which are normally a particularly challenging aspect of drug discovery. Another recent breakthrough in this field is targeted protein degradation through proteolysis-targeting chimeras. These revolutionary compounds represent a noteworthy advancement over traditional small-molecule inhibitors due to their unique mechanism of action, which allows for the degradation of specific proteins with unprecedented specificity. The inclusion of a peptide as a protein-of-interest-targeting moiety allows for improved versatility and the possibility of targeting otherwise undruggable proteins. In this review, we discuss various novel wet-lab and computational multi-omic methods for peptide drug discovery, provide an overview of therapeutic agents discovered through these cutting-edge techniques, and discuss the potential for the therapeutic delivery of peptide-based drugs.

Recent Advances and Challenges in Targeted Drug Delivery Using Biofunctional Coatings

Globally, clinics are overwhelmed by drugs targeting undesired cells and organs, causing adverse systemic effects on the body. This shortfall in targeting specificity, safety, and efficiency has noticeably contributed to the failure of the bench-to-bedside transition. Activation or impairment of immune activity due to a misdirected drug and its carrier fuels complications, extending the range of destruction which can convert the course of disease into a life-threatening route. To address these great challenges, advanced coatings as indispensable components of future medicine have been investigated over the last few decades for precisely targeted drug delivery to achieve favorable prognoses in the treatment of a broad spectrum of diseases. Complemented by advancements in the pharmacological parameters, these systems hold great promise for the field. This chapter aims to discuss recent progress on new coatings for targeted drug delivery and the parameters for manufacturing these platforms for their cargo based on major determinants such as biocompatibility and bioactivity. A brief overview of the various applications of targeted drug delivery with functional coatings is also provided to offer a new perspective on the field.

Targeted therapy of non-small cell lung cancer: mechanisms and clinical trials

Lung cancer is a leading cause of cancer-related deaths globally, and traditional chemotherapy has limited efficacy in treating advanced non-small cell lung cancer (NSCLC). In recent years, the prognosis for patients with NSCLC has significantly improved due to the development of new treatment modalities, including targeted therapies. Targeted therapies utilize monoclonal antibodies (mAbs), antibody-drug conjugates (ADCs), or small molecule tyrosine kinase inhibitors (TKIs) directed against specific mutated genes such as EGFR and ALK. The development of these drugs has deepened our understanding of NSCLC and improved treatment outcomes for patients. This review aims to summarize the mechanisms and current status of targeted therapy for NSCLC, discuss strategies to overcome acquired resistance, and address current challenges in the field.

Advancements in Nanoporous Materials for Biomedical Imaging and Diagnostics

This review explores the latest advancements in nanoporous materials and their applications in biomedical imaging and diagnostics. Nanoporous materials possess unique structural features, including high surface area, tunable pore size, and versatile surface chemistry, making them highly promising platforms for a range of biomedical applications. This review begins by providing an overview of the various types of nanoporous materials, including mesoporous silica nanoparticles, metal-organic frameworks, carbon-based materials, and nanoporous gold. The synthesis method for each material, their current research trends, and prospects are discussed in detail. Furthermore, this review delves into the functionalization and surface modification techniques employed to tailor nanoporous materials for specific biomedical imaging applications. This section covers chemical functionalization, bioconjugation strategies, and surface coating and encapsulation methods. Additionally, this review examines the diverse biomedical imaging techniques enabled by nanoporous materials, such as fluorescence imaging, magnetic resonance imaging (MRI), computed tomography (CT) imaging, ultrasound imaging, and multimodal imaging. The mechanisms underlying these imaging techniques, their diagnostic applications, and their efficacy in clinical settings are thoroughly explored. Through an extensive analysis of recent research findings and emerging trends, this review underscores the transformative potential of nanoporous materials in advancing biomedical imaging and diagnostics. The integration of interdisciplinary approaches, innovative synthesis techniques, and functionalization strategies offers promising avenues for the development of next-generation imaging agents and diagnostic tools with enhanced sensitivity, specificity, and biocompatibility.

Antibody-drug conjugates for non-small cell lung cancer: Advantages and challenges in clinical translation

Lung cancer is the leading cause of cancer death, with non-small cell lung cancer (NSCLC) accounting for approximately 85 % of all lung cancers and having a poor treatment and prognosis. Conventional clinical chemotherapy and immunotherapy are challenged by systemic toxicity and drug resistance, so researchers are increasingly focusing on antibody-drug conjugate (ADC), an innovative concept combining chemotherapy and targeted therapy, in which a drug selectively binds to antigens on the surface of a tumor cell via antibodies, which internalize the ADC, and then transfers the ADC to the lysosome via the endosomes to degrade the drug and kill the tumor cell. Despite the promising nature of ADCs, no ADC product for any indication including NSCLC has been approved for marketing by the FDA to date. In this review, we summarize the main advantages of ADCs and discuss in depth the design of the most desirable ADCs for NSCLC therapy. In addition to preclinical studies, we focus on the current state of clinical research on ADCs as interventions for the treatment of NSCLC by summarizing real-time clinical trial data from ClinicalTrials.gov, and reasonably speculate on the direction of the design of future generations of ADCs.

Polymer-DNA assembled nanoflower for targeted delivery of dolastatin-derived microtubule inhibitors

Dolastatin derivatives possess excellent anticancer activity and have been translated into clinical trials for cancer therapy. Drug delivery systems enable dolastatin derivatives to break the limitation of instability during blood circulation and ineffective cell internalization in the application. Nevertheless, their potential has not been thoroughly established because of the limited loading efficacy and complicated chemical modification. Herein, we rationally propose a rolling circle amplification-based polymer-DNA assembled nanoflower for targeted and efficient delivery of dolastatin-derived drugs to achieve efficient anticancer therapy. The polymer-DNA assembled nanoflower with targeted aptamer conjugate is widely applicable for loading dolastatin-derived drugs with high encapsulation efficiency. The developed monomethyl auristatin E (MMAE) loaded PN@M exhibited increased cellular uptake and enhanced inhibitory effect, especially in multidrug-resistant tumor cells. The results of in vivo anticancer effects indicate that nanoflower as a dolastatin derivatives delivery system holds considerable potential for the treatment of malignant cancer.

Advances in peptide-based drug delivery systems

Drug delivery systems (DDSs) are designed to deliver drugs to their specific targets to minimize their toxic effects and improve their susceptibility to clearance during targeted transport. Peptides have high affinity, low immunogenicity, simple amino acid composition, and adjustable molecular size; therefore, most peptides can be coupled to drugs via linkers to form peptide-drug conjugates (PDCs) and act as active pro-drugs. PDCs are widely thought to be promising DDSs, given their ability to improve drug bio-compatibility and physiological stability. Peptide-based DDSs are often used to deliver therapeutic substances such as anti-cancer drugs and nucleic acid-based drugs, which not only slow the degradation rate of drugs in vivo but also ensure the drug concentration at the targeted site and prolong the half-life of drugs in vivo. This article provides an profile of the advancements and future development in functional peptide-based DDSs both domestically and internationally in recent years, in the expectation of achieving targeted drug delivery incorporating functional peptides and taking full advantage of synergistic effects.

Different Targeting Ligands-Mediated Drug Delivery Systems for Tumor Therapy

Traditional tumor treatments have the drawback of harming both tumor cells and normal cells, leading to significant systemic toxic side effects. As a result, there is a pressing need for targeted drug delivery methods that can specifically target cells or tissues. Currently, researchers have made significant progress in developing targeted drug delivery systems for tumor therapy using various targeting ligands. This review aims to summarize recent advancements in targeted drug delivery systems for tumor therapy, focusing on different targeting ligands such as folic acid, carbohydrates, peptides, aptamers, and antibodies. The review also discusses the advantages, challenges, and future prospects of these targeted drug delivery systems.

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.

MS2 Virus-like Particles as a Versatile Peptide Presentation Platform: Insights into the Deterministic Abilities for Accommodating Heterologous Peptide Lengths

Virus-like particles (VLPs) are nanostructures with the potential to present heterologous peptides at high density, thereby triggering heightened immunogenicity. RNA bacteriophage MS2 VLPs are a compelling delivery platform among them. However, a notable hurdle arises from the immune response toward MS2 coat protein, swiftly eliminating subsequent vaccinations via the same vector. Although larger inserts effectively mask carrier epitopes, current research predominantly focuses on displaying short conserved peptides (<30 aa). A systematic evaluation regarding the deterministic ability of MS2 VLPs as a platform for presenting heterologous peptides remains a gap. In light of this, we employed the "single-chain dimer" paradigm to scrutinize the tolerance of MS2 VLPs for peptide/protein insertions. The results unveiled functional MS2 VLP assembly solely for inserts smaller than 91 aa. Particularly noteworthy is the largest insertion achieved on the MS2 VLPs to date: the RNA helicase A (RHA) dsRNA-binding domains (dsRBD1). Attempts to introduce additional linkers or empty coat subunits fail to augment the expression level or assembly of the MS2 VLPs displaying dsRBD1, affirming 91 aa as the upper threshold for exogenous protein presentation. By illuminating the precise confines of MS2 VLPs in accommodating distinct peptide lengths, our study informs the selection of appropriate peptide and protein dimensions. This revelation not only underscores the scope of MS2 VLPs but also establishes a pivotal reference point, facilitating the strategic manipulation of MS2 VLPs to design next-generation epitope/antibody-based therapeutics.

Rational design of hybrid peptide with high antimicrobial property derived from Melittin and Lasioglossin

Hybridization of Antimicrobial peptides (AMPs) with unique abilities is now considered to improve AMPs' function as promising therapeutic candidates. In the current research, Lasioglossin (LL-III) with a high antimicrobial effect on Acinetobacter (A.) baumanni and Melittin with a high antimicrobial effect against Staphylococcus (S.) aureus were selected for designing a hybrid peptide with modified properties. In the present study, a hybrid peptide with modified properties was designed. Molecular dynamic (MD) and coarse-grained (CG) simulations were done to evaluate the stability and interaction of the hybrid peptide with related membrane models. In this study, a truncated Melittin peptide (11 amino acids) was fused to an LL-III peptide (15 amino acids) to raise the antimicrobial activity. A new hybrid peptide analog (LM1) was selected by replacing the arginine with isoleucine in the fifth position of truncated Melittin to raise the antimicrobial rate of the peptide. The potential for binding of the LM1 to lipid membrane (D factor) was increased from 2.02 related to Melittin to 3.62. Based on VMD results, the N-terminal of LM1 peptide related to LL-III was the alpha helix during 200 ns. However, the C-terminal region related to the Melittin peptide only at 50 ns was in alpha helix form. The RMSD of the LM1 peptide was in the range of 0.2 to 0.8, which, after 160 ns, reached stability. RMSD and RMSF results indicated no unwanted fluctuations during the 200 ns MD simulation. A significant movement of LM1 peptide inside the S. aureus membrane(4.76 nm) and A. baumanni membrane (3.2 nm) was observed by CG simulation. Our findings highlight the high stability of the designed hybrid peptide and its antimicrobial potential to halter A. baumanii and S. aureus bacteria.Communicated by Ramaswamy H. Sarma.

Development of a Peptide-Based Nano-Sized Cathepsin B Inhibitor for Anticancer Therapy

Numerous cathepsin B inhibitors have been developed and are under investigation as potential cancer treatments. They have been evaluated for their ability to inhibit cathepsin B activity and reduce tumor growth. However, they have shown critical limitations, including low anticancer efficacy and high toxicity, due to their low selectivity and delivery problems. In this study, we developed a novel peptide and drug conjugate (PDC)-based cathepsin B inhibitor using cathepsin-B-specific peptide (RR) and bile acid (BA). Interestingly, this RR and BA conjugate (RR–BA) was able to self-assemble in an aqueous solution, and as a result, it formed stable nanoparticles. The nano-sized RR–BA conjugate showed significant cathepsin B inhibitory effects and anticancer effects against mouse colorectal cancer (CT26) cells. Its therapeutic effect and low toxicity were also confirmed in CT26 tumor-bearing mice after intravenous injection. Therefore, based on these results, the RR–BA conjugate could be developed as an effective anticancer drug candidate for inhibiting cathepsin B in anticancer therapy.

Advances in Radionuclides and Radiolabelled Peptides for Cancer Therapeutics

Radiopharmaceutical therapy, which can detect and treat tumours simultaneously, was introduced more than 80 years ago, and it has changed medical strategies with respect to cancer. Many radioactive radionuclides have been developed, and functional, molecularly modified radiolabelled peptides have been used to produce biomolecules and therapeutics that are vastly utilised in the field of radio medicine. Since the 1990s, they have smoothly transitioned into clinical application, and as of today, a wide variety of radiolabelled radionuclide derivatives have been examined and evaluated in various studies. Advanced technologies, such as conjugation of functional peptides or incorporation of radionuclides into chelating ligands, have been developed for advanced radiopharmaceutical cancer therapy. New radiolabelled conjugates for targeted radiotherapy have been designed to deliver radiation directly to cancer cells with improved specificity and minimal damage to the surrounding normal tissue. The development of new theragnostic radionuclides, which can be used for both imaging and therapy purposes, allows for more precise targeting and monitoring of the treatment response. The increased use of peptide receptor radionuclide therapy (PRRT) is also important in the targeting of specific receptors which are overexpressed in cancer cells. In this review, we provide insights into the development of radionuclides and functional radiolabelled peptides, give a brief background, and describe their transition into clinical application.

Design and Evaluation of a Carrier-Free Prodrug-Based Palmitic-DEVD-Doxorubicin Conjugate for Targeted Cancer Therapy

In the development of new drugs, typical polymer- or macromolecule-based nanocarriers suffer from manufacturing process complexity, unwanted systematic toxicity, and low loading capacity. However, carrier-free nanomedicines have made outstanding progress in drug delivery and pharmacokinetics, demonstrating most of the advantages associated with nanoparticles when applied in targeted anticancer therapy. Here, to overcome the problems of nanocarriers and conventional cytotoxic drugs, we developed a novel, carrier-free, self-assembled prodrug consisting of a hydrophobic palmitic (16-carbon chain n-hexadecane chain) moiety and hydrophilic group (or moiety) which is included in a caspase-3-specific cleavable peptide (Asp-Glu-Val-Asp, DEVD) and a cytotoxic drug (doxorubicin, DOX). The amphiphilic conjugate, the palmitic-DEVD-DOX, has the ability to self-assemble into nanoparticles in saline without the need for any carriers or nanoformulations. Additionally, the inclusion of doxorubicin is in its prodrug form and the apoptosis-specific DEVD peptide lead to the reduced side effects of doxorubicin in normal tissue. Furthermore, the carrier-free palmitic-DEVD-DOX nanoparticles could passively accumulate in the tumor tissues of tumor-bearing mice due to an enhanced permeation and retention (EPR) effect. As a result, the palmitic-DEVD-DOX conjugate showed an enhanced therapeutic effect compared with the unmodified DEVD-DOX conjugate. Therefore, this carrier-free palmitic-DEVD-DOX prodrug has great therapeutic potential to treat solid tumors, overcoming the problems of conventional chemotherapy and nanoparticles.

Peptide-Drug Conjugates: A New Hope for Cancer Management

Cancer remains the leading cause of death worldwide despite advances in treatment options for patients. As such, safe and effective therapeutics are required. Short peptides provide advantages to be used in cancer management due to their unique properties, amazing versatility, and progress in biotechnology to overcome peptide limitations. Several appealing peptide-based therapeutic strategies have been developed. Here, we provide an overview of peptide conjugates, the better equivalents of antibody-drug conjugates, as the next generation of drugs for required precise targeting, enhanced cellular permeability, improved drug selectivity, and reduced toxicity for the efficient treatment of cancers. We discuss the basic components of drug conjugates and their release action, including the release of cytotoxins from the linker. We also present peptide-drug conjugates under different stages of clinical development as well as regulatory and other challenges.