Self-Assembled Bifunctional Peptide as Effective Drug Delivery Vector with Powerful Antitumor Activity

Multifunctional gold nanorods in low-temperature photothermal interactions for combined tumor starvation and RNA interference therapy

Collateral damage to healthy tissue, uneven heat distribution, inflammatory diseases, and tumor metastasis induction hinder the translation of high-temperature photothermal therapy (PTT) from bench to practical clinical applications. In this report, a multifunctional gold nanorod (GNR)-based nanosystem was designed by attaching siRNA against B7-H3 (B7-H3si), glucose oxidase (GOx), and hyaluronic acid (HA) for efficient low-temperature PTT. Herein, GOx can not only exhaust glucose to induce starvation therapy but also reduce the heat shock protein (HSP), realizing the ablation of tumors without damage to healthy tissues. Evidence shows that B7-H3, a type I transmembrane glycoprotein molecule, plays essential roles in growth, metastasis, and drug resistance. By initiating the downregulation of B7-H3 by siRNA, siRNA-GOx/GNR@HA NPs may promote the effectiveness of treatment. By targeting cluster of differentiation 44 (CD44) and depleting B7-H3 and HSPs sequentially, siRNA-GOx/GNR@HA NPs showed 12.9-fold higher lung distribution than siRNA-GOx/GNR NPs. Furthermore, 50% of A549-bearing mice in the siRNA-GOx/GNR NPs group survived over 50 days. Overall, this low-temperature phototherapeutic nanosystem provides an appropriate strategy for eliminating cancer with high treatment effectiveness and minimal systemic toxicity. STATEMENT OF SIGNIFICANCE: To realize efficient tumor ablation under mild low-temperature (42-45 ℃) and RNA interference simultaneously, here we developed a multifunctional gold nanorod (GNR)-based nanosystem (siRNA-GOx/GNR@HA NPs). This nanoplatform can significantly inhibit tumor cell proliferation and induce cell apoptosis by downregulation of HSP90α, HSP70, B7-H3, p-AKT, and p-ERK and upregulation of cleaved caspase-9 at mild low-temperature due to its superior tumor homing ability and the combined effect of photothermal effect, glucose deprivation-initiated tumor starvation, and B7-H3 gene silence effect. It is believed that this multifunctional low-temperature photothermal nanosystem with efficient and specific anticancer properties, shows a potential application in clinical tumor treatment.

A nanomedicine enables synergistic chemo/photodynamic therapy for pancreatic cancer treatment

Pancreatic cancer is one of the leading causes of cancer-related deaths worldwide. Gemcitabine (Gem) has been a key chemotherapy agent for pancreatic cancer treatment by suppressing cell proliferation and inducing apoptosis. However, the overexpression of inhibitors of apoptosis (IAP) family of proteins during the carcinogenesis of pancreatic cancer can develop resistance to chemotherapy treatment and result in poor efficacy. To achieve the synergistic combinations of multiple strategies for this dismal disease, we developed a robust nanomedicine system, consisting of a photodynamic therapeutic agent (chlorine e6, Ce6) and a pro-apoptotic peptide-Gem conjugate. To have spatiotemporally controlled drug release, the pro-apoptotic peptide-Gem conjugate was designed to have a vinyldithioether linker that was sensitive to reactive oxygen species (ROS). The nanomedicine was fabricated by the direct self-assembly of the pro-apoptotic peptide-Gem conjugate with Ce6. After being delivered into tumors, the nanomedicine disassembled and rapidly released Gem, Ce6, and the pro-apoptotic peptide upon light illumination (660 nm). Both in vitro and in vivo studies in pancreatic cancer models confirmed the tumor inhibition efficacy with low systemic toxicity to animals.

Emerging prospects of protein/peptide-based nanoassemblies for drug delivery and vaccine development

Proteins have been widely used in the biomedical field because of their well-defined architecture, accurate molecular weight, excellent biocompatibility and biodegradability, and easy-to-functionalization. Inspired by the wisdom of nature, increasing proteins/peptides that possess self-assembling capabilities have been explored and designed to generate nanoassemblies with unique structure and function, including spatially organized conformation, passive and active targeting, stimuli-responsiveness, and high stability. These characteristics make protein/peptide-based nanoassembly an ideal platform for drug delivery and vaccine development. In this review, we focus on recent advances in subsistent protein/peptide-based nanoassemblies, including protein nanocages, virus-like particles, self-assemblable natural proteins, and self-assemblable artificial peptides. The origin and characteristics of various protein/peptide-based assemblies and their applications in drug delivery and vaccine development are summarized. In the end, the prospects and challenges are discussed for the further development of protein/peptide-based nanoassemblies.

A Tumor-Specific Ferric-Coordinated Epigallocatechin-3-gallate cascade nanoreactor for glioblastoma therapy

Introduction

Numerous options for treatment of glioblastoma have been explored; however, single-drug therapies and poor targeting have failed to provide effective drugs. Chemotherapy has significant antitumor effect, but the efficacy of single-drug therapies in the clinic is limited over a long period of time. Thus, novel therapeutic approaches are necessary to address these critical issues.

Objectives

The present study, we investigated a tumor-specific metal-tea polyphenol-based cascade nanoreactor for chemodynamic therapy-enhanced chemotherapy.

Methods

HA-EGCG was synthesized for the first time by introducing epigallocatechin-3-gallate (EGCG) into the skeleton of hyaluronic acid (HA) with reducible disulfide bonds. A rapid and green method was developed to fabricate the metal-tea polyphenol networks (MTP) with an HA-EGCG coating (DOX@MTP/HA-EGCG) based on Fe3+ and EGCG for targeted delivery of doxorubicin hydrochloride (DOX). GL261 cells were used to evaluate the antitumor efficacy of the DOX@MTP/HA-EGCG nanoreactor in vitro and in vivo.

Results

DOX@MTP/HA-EGCG nanoreactors were able to disassemble, resulting in escape of their components from lysosomes and precise release of DOX, Fe3+, and EGCG in the tumor cells. HA-EGCG depleted glutathione to amplify oxidative stress and enhance chemodynamic therapy. The results of in vivo experiments suggested that DOX@MTP/HA-EGCG specifically accumulates at the CD44-overexpressing GL261 tumor sites and that sustained release of DOX and Fe3+ induced a distinct therapeutic outcome.

Conclusions

The findings suggested the developed nanoreactor has promising potential as a future GL261 glioblastoma therapy.

Smart Nanotherapeutics and Lung Cancer

Lung cancer is a significant health problem worldwide. Unfortunately, current therapeutic strategies lack a sufficient level of specificity and can harm adjacent healthy cells. Consequently, to address the clinical need, novel approaches to improve treatment efficiency with minimal side effects are required. Nanotechnology can substantially contribute to the generation of differentiated products and improve patient outcomes. Evidence from previous research suggests that nanotechnology-based drug delivery systems could provide a promising platform for the targeted delivery of traditional chemotherapeutic drugs and novel small molecule therapeutic agents to treat lung cancer cells more effectively. This has also been found to improve the therapeutic index and reduce the required drug dose. Nanodrug delivery systems also provide precise control over drug release, resulting in reduced toxic side effects, controlled biodistribution, and accelerated effects or responses. This review highlights the most advanced and novel nanotechnology-based strategies, including targeted nanodrug delivery systems, stimuli-responsive nanoparticles, and bio-nanocarriers, which have recently been employed in preclinical and clinical investigations to overcome the current challenges in lung cancer treatments.

Mitochondrial Voltage-Dependent Anion Channel 1-Hexokinase-II Complex-Targeted Strategy for Melanoma Inhibition Using Designed Multiblock Peptide Amphiphiles

Targeted therapies of melanoma are of urgent need considering the resistance of this aggressive type of cancer to chemotherapeutics. The voltage-dependent anion channel 1 (VDAC1)-hexokinase-II (HK-II) complex is an emerging target for novel anticancer therapies based on induced mitochondria-mediated apoptosis. The low cell membrane permeability of the anticancer 12-mer peptide N-Ter (RDVFTKGYGFGL) derived from the N-terminal fragment of the VDAC1 protein impedes the intracellular targeting. Here, novel multiblock VDAC1-derived cationic amphiphilic peptides (referred to as Pal-N-Ter-TAT, pFL-N-Ter-TAT, and Pal-pFL-N-Ter-TAT) are designed with a self-assembly propensity and cell-penetrating properties. The created multiblock amphiphilic peptides of partial α-helical conformations form nanoparticles of ellipsoid-like shapes and are characterized by enhanced cellular uptake. The amphiphilic peptides can target mitochondria and dissociate the VDAC1-HK-II complex at the outer mitochondrial membrane, which result in mitochondria-mediated apoptosis. The latter is associated with decrease of the mitochondrial membrane potential, cytochrome c release, and changes of the expression levels of the apoptotic proteins in A375 melanoma cells. Importantly, the mitochondrial VDAC1-derived amphiphilic peptides have a comparable IC₅₀ value for melanoma cells to a small-molecule drug, sorafenib, which has been previously used in clinical trials for melanoma. These results demonstrate the potential of the designed peptide constructs for efficient melanoma inhibition.

A review on recent advances in amino acid and peptide-based fluorescence and its potential applications

Fluorescence is widely used to detect functional groups and ions, and peptides are used in various fields due to their excellent biological activity.

Advances in intelligent DNA nanomachines for targeted cancer therapy

As an emerging field, DNA nanotechnology has been applied to the fabrication of drug delivery systems. Unprecedented spatial addressability and intrinsic sequence encoding enable DNA strands to self-assemble into well-defined 2D and 3D DNA nanostructures with specifically controlled sizes, shapes and surface charges. Multifunctional DNA nanostructures have been created and applied as promising platforms for drug delivery, imaging, and theranostics. Advantages of chemotherapy, gene therapy, and immunotherapy, among others, have been integrated into such functional nanodevices, showing potential in tumor-targeted therapy and diagnosis. In this review, we summarize general methods for the construction of DNA nanodevices and focus on targeting strategies favored by the compatibility of DNA nanotechnology. Additionally, we highlight the outlook and challenges facing the use of DNA nanotechnology in cancer therapy.

Modular design and self-assembly of multidomain peptides towards cytocompatible supramolecular cell penetrating nanofibers

The discovery of cell penetrating peptides (CPPs) with unique membrane activity has inspired the design and synthesis of a variety of cell penetrating macromolecules, which offer tremendous opportunity and promise for intracellular delivery of a variety of imaging probes and therapeutics. While cell penetrating macromolecules can be designed and synthesized to have equivalent or even superior cell penetrating activity compared with natural CPPs, most of them suffer from moderate to severe cytotoxicity. Inspired by recent advances in peptide self-assembly and cell penetrating macromolecules, in this work, we demonstrated a new class of peptide assemblies with intrinsic cell penetrating activity and excellent cytocompatibility. Supramolecular assemblies were formed through the self-assembly of de novo designed multidomain peptides (MDPs) with a general sequence of K x (QW)6E y in which the numbers of lysine and glutamic acid can be varied to control supramolecular assembly, morphology and cell penetrating activity. Both supramolecular spherical particles and nanofibers exhibit much higher cell penetrating activity than monomeric MDPs while supramolecular nanofibers were found to further enhance the cell penetrating activity of MDPs. In vitro cell uptake results suggested that the supramolecular cell penetrating nanofibers undergo macropinocytosis-mediated internalization and they are capable of escaping from the lysosome to reach the cytoplasm, which highlights their great potential as highly effective intracellular therapeutic delivery vehicles and imaging probes.

Recent Advances in Peptide-Based Approaches for Cancer Treatment

BACKGROUND

Peptide-based pharmaceuticals have recently experienced a renaissance due to their ability to fill the gap between the two main classes of available drugs, small molecules and biologics. Peptides combine the high potency and selectivity typical of large proteins with some of the characteristic advantages of small molecules such as synthetic accessibility, stability and the potential of oral bioavailability.

METHODS

In the present manuscript we review the recent literature on selected peptide-based approaches for cancer treatment, emphasizing recent advances, advantages and challenges of each strategy.

RESULTS

One of the applications in which peptide-based approaches have grown rapidly is cancer therapy, with a focus on new and established targets. We describe, with selected examples, some of the novel peptide-based methods for cancer treatment that have been developed in the last few years, ranging from naturally-occurring and modified peptides to peptidedrug conjugates, peptide nanomaterials and peptide-based vaccines.

CONCLUSION

This review brings out the emerging role of peptide-based strategies in oncology research, critically analyzing the advantages and limitations of these approaches and the potential for their development as effective anti-cancer therapies.

Trends in Nanotechnology for in vivo Cancer Diagnosis: Products and Patents

BACKGROUND

Cancer is a set of diseases formed by abnormal growth of cells leading to the formation of the tumor. The diagnosis can be made through symptoms' evaluation or imaging tests, however, the techniques are limited and the tumor detection may be late. Thus, pharmaceutical nanotechnology has emerged to optimize the cancer diagnosis through nanostructured contrast agent's development.

OBJECTIVE

This review aims to identify commercialized nanomedicines and patents for cancer diagnosis.

METHODS

The databases used for scientific articles research were Pubmed, Science Direct, Scielo and Lilacs. Research on companies' websites and articles for the recognition of commercial nanomedicines was performed. The Derwent tool was applied for patent research.

RESULTS

This article aimed to research on nanosystems based on nanoparticles, dendrimers, liposomes, composites and quantum dots, associated to imaging techniques. Commercialized products based on metal and composite nanoparticles, associated with magnetic resonance and computed tomography, have been observed. The research conducted through Derwent tool displayed a small number of patents using nanotechnology for cancer diagnosis. Among these patents, the most significant number was related to the use of systems based on metal nanoparticles, composites and quantum dots.

CONCLUSION

Although few systems are found in the market and patented, nanotechnology appears as a promising field for the development of new nanosystems in order to optimize and accelerate the cancer diagnosis.

Development of a hybrid nanocarrier-recognizing tumor vasculature and penetrating the BBB for glioblastoma multi-targeting therapy

The success of glioma chemotherapy is hampered by poor drug penetration ability across the blood-brain barrier (BBB) and low intratumoral drug concentration. Novel tumor-targeted delivery systems are useful in specifically accumulating in the tumor foci and penetrating into the glioma core after entering into the brain. Here we show that a multi-targeting hybrid nanocarrier (Pep-MLHA HNPs) system based on hyaluronic acid (HA)-modified polymer and a functional peptide possesses multi-target capability and stronger penetration ability into the core of three-dimensional tumor spheroids, could migrate efficiently across the BBB in vitro. The intensity of the Pep-MLHA HNPs after transporting across the BBB was 5.2-fold and 5.6-fold higher than that of ML NPs in C6 and U87 cells, respectively. More interestingly, this multi-targeting hybrid system displayed high colloidal stability in PBS solution, and weak negative zeta potential (-1.99 ± 0.655 mV) minimizing nonspecific interactions with plasma proteins and promoting long-term circulation in vivo. Additionally, the multi-targeting hybrid system induced enhanced tumor localization in U87 in situ-bearing nude mice and xenograft-bearing nude mice after systemic administration. Furthermore, docetaxel (DTX)-loaded Pep-MLHA HNPs showed negligible systemic toxicity and enhanced therapeutic efficacy, with significantly improved survival rates in intracranial C6 glioma-bearing rats. The 50% survival rate of DTX/Pep-MLHA HNPs-treated rats (40 days) was significantly longer than that of rats treated with NS (22 days), Taxotere® (25 days), DTX/ML NPs (25 days), DTX/Pep NPs (32 days) and DTX/MLHA NPs (29 days). All the results suggested that the multi-targeting hybrid nanocarrier system is promising for glioma treatment.

Self-assembling peptide-based nanodrug delivery systems

Self-assembling peptide-based nanodrug delivery systems (NDDs), consisting of naturally occurring amino acids, not only share the advantages of traditional nanomedicine but also possess the unique properties of excellent biocompatibility, biodegradability, flexible responsiveness, specific biological function, and synthetic feasibility. Physical methods, enzymatic reaction, chemical reaction, and biosurface induction can yield versatile peptide-based NDDs; flexible responsiveness is their main advantage. Different functional peptides and abundant covalent modifications endow such systems with precise controllability and multifunctionality. Inspired by the above merits, researchers have taken advantage of the self-assembling peptide-based NDDs and achieved the accurate delivery of drugs to the lesion site. The present review outlines the methods for designing self-assembling peptide-based NDDs for small-molecule drugs, with an emphasis on the different drug delivery strategies and their applications in using peptides and peptide conjugates.

Chitosan for gene delivery: Methods for improvement and applications

Gene therapy is a promising strategy for treating challenging diseases. The successful delivery of genes is a critical step for gene therapy. However, concerns about immunogenicity and toxicity are the main obstacles against the widespread use of effective viral systems. Therefore, nonviral vectors are regarded as good alternatives to viral vectors. Chitosan is a natural cationic polysaccharide that could be used to create nonviral gene delivery vectors. Various methods have been developed to improve the properties of chitosan related to gene delivery. This review introduces the features of chitosan in gene delivery, summarizes current progress toward methods promoting the properties of chitosan related to gene delivery, and presents different applications of chitosan in gene delivery vectors. Finally, future prospects of gene vectors based on chitosan are discussed.

Targeted chemotherapy for subcutaneous and orthotopic non-small cell lung tumors with cyclic RGD-functionalized and disulfide-crosslinked polymersomal doxorubicin

Lung cancer, with its high mortality and increasing morbidity, has become one of the most lethal malignancies worldwide. Here, we developed cyclic RGD peptide-directed and disulfide-crosslinked polymersomal doxorubicin (cRGD-PS-Dox) as a targeted chemotherapy for human non-small cell lung cancer (NSCLC). Notably, cRGD-PS-Dox exhibited a high Dox loading (15.2 wt.%), small hydrodynamic diameter (96 nm), superb stability, prominent targetability to α_vβ₃ integrin overexpressing A549 human lung cancer cells, and rapid release of the drug into nuclei, leading to a significantly improved antitumor activity compared with the control groups, i.e., PS-Dox and Lipo-Dox (a liposome injection employed in clinical settings). The pharmacokinetic and biodistribution results for cRGD-PS-Dox revealed similar elimination half-lives but two-fold enhanced tumor accumulation compared with PS-Dox and Lipo-Dox. Intriguingly, cRGD-PS-Dox effectively suppressed the growth of A549 lung tumors in both subcutaneous and orthotopic models with minimal adverse effects at a Dox dose of 12 mg/kg, leading to significant survival benefits compared with PS-Dox and Lipo-Dox. This α_vβ₃ integrin-targeting multifunctional polymersomal doxorubicin is highly promising for targeted chemotherapy of human NSCLC.

When wrapped in an engineered vesicle and augmented with cancer-targeting peptides, chemotherapy drug doxorubicin shows increased efficacy in a preclinical study. Zhiyuan Zhong, from China’s Soochow University, and his team developed the therapeutic (cRGD-PS-Dox) that targets cancer cells that overexpress a specific protein (α_vβ₃ integrin), such as those of non-small cell lung cancer. In vitro assays showed that cRGD-PS-Dox specifically targeted and inhibited cancer cells, and inhibited the growth and metastasis of human tumor grafts in mice. In vivo imaging confirmed a desirable drug stability profile and accumulation within tumors. These results showed clear advantages over non-targeted doxorubicin treatment controls. Mice treated with cRGD-PS-Dox also survived significantly longer than control-treated mice. The preferential attributes of the therapy make it a promising agent for further study into tumors that overexpress α_vβ₃ integrin.

Actively Targeted Magnetothermally Responsive Nanocarriers/Doxorubicin for Thermochemotherapy of Hepatoma

Nanodrug-delivery systems modified with targeting molecules allow antitumor drugs to localize to tumor sites efficiently. CD147 protein is expressed highly on hepatoma cells. Firstly, we synthesized magnetothermally responsive nanocarriers/doxorubicin (MTRN/DOX) which was composed of manganese zinc (Mn-Zn) ferrite magnetic nanoparticles, amphiphilic and thermosensitivity copolymer drug carriers together with DOX. Then CD147-MTRN/DOX was formed with MTRN/DOX and monoclonal antibody that specifically binds to CD147 protein. It could target hepatoma cells actively and improve the DOX concentration in the tumor sites. Subsequently, an external alternating magnetic field elevated the temperature of the thermomagnetic particles, resulting in structural changes in the thermosensitive copolymer drug carriers, thereby releasing DOX. Hence, CD147-MTRN/DOX could enhance the responsiveness of hepatoma cells to the pre-existing chemotherapy drugs owing to active targeting combined synergistically with thermotherapy and chemotherapy, which has more significant anticancer effects than MTRN/DOX.

Recent Advances in Targeted Tumor Chemotherapy Based on Smart Nanomedicines

Efficacy and safety of chemotherapeutic drugs constitute two major criteria in tumor chemotherapy. Nanomedicines with tumor-targeted properties hold great promise for improving the efficacy and safety. To design targeted nanomedicines, the pathological characteristics of tumors are extensively and deeply excavated. Here, the rationale, principles, and advantages of exploiting these pathological characteristics to develop targeted nanoplatforms for tumor chemotherapy are discussed. Homotypic targeting with the ability of self-recognition to source tumors is reviewed individually. In the meanwhile, the limitations and perspective of these targeted nanomedicines are also discussed.

Self-Assembled Bifunctional Peptide as Effective Drug Delivery Vector with Powerful Antitumor Activity

E-cadherin/catenin complex is crucial for cancer cell migration and invasion. The histidine-alanine-valine (HAV) sequence has been shown to inhibit a variety of cadherin-based functions. In this study, by fusing HAV and the classical tumor-targeting Arg-Gly-Asp (RGD) motif and Asn-Gly-Arg (NGR) motif to the apoptosis-inducing peptide sequence-AVPIAQK, a bifunctional peptide has been constructed with enhanced tumor targeting and apoptosis effects. This peptide is further processed as a nanoscale vector to encapsulate the hydrophobic drug docetaxel (DOC). Bioimaging analysis shows that peptide nanoparticles can penetrate into xenograft tumor cells with a significantly long retention in tumors and high tumor targeting specificity. In vivo, DOC/peptide NPs are substantially more effective at inhibiting tumor growth and prolonging survival compared with DOC control. Together, the findings of this study suggest that DOC/peptide NPs may have promising applications in pulmonary carcinoma therapy.

Conjugates of Cell Adhesion Peptides for Therapeutics and Diagnostics Against Cancer and Autoimmune Diseases

Overexpressed cell-surface receptors are hallmarks of many disease states and are often used as markers for targeting diseased cells over healthy counterparts. Cell adhesion peptides, which are often derived from interacting regions of these receptor-ligand proteins, mimic surfaces of intact proteins and, thus, have been studied as targeting agents for various payloads to certain cell targets for cancers and autoimmune diseases. Because many cytotoxic agents in the free form are often harmful to healthy cells, the use of cell adhesion peptides in targeting their delivery to diseased cells has been studied to potentially reduce required effective doses and associated harmful side-effects. In this review, multiple cell adhesion peptides from extracellular matrix and ICAM proteins were used to selectively direct drug payloads, signal-inhibitor peptides, and diagnostic molecules, to diseased cells over normal counterparts. RGD constructs have been used to improve the selectivity and efficacy of diagnostic and drug-peptide conjugates against cancer cells. From this precedent, novel conjugates of antigenic and cell adhesion peptides, called Bifunctional Peptide Inhibitors (BPIs), have been designed to selectively regulate immune cells and suppress harmful inflammatory responses in autoimmune diseases. Similar peptide conjugations with imaging agents have delivered promising diagnostic methods in animal models of rheumatoid arthritis. BPIs have also been shown to generate immune tolerance and suppress autoimmune diseases in animal models of type-1 diabetes, rheumatoid arthritis, and multiple sclerosis. Collectively, these studies show the potential of cell adhesion peptides in improving the delivery of drugs and diagnostic agents to diseased cells in clinical settings.