ɑvβ3-targeted liposomal drug delivery system with attenuated immunogenicity enabled by linear pentapeptide for glioma therapy

Functionalized liposomes: an enticing nanocarrier for management of glioma

Glioma is one of the most severe central nervous systems (CNS)-specific tumors, with rapidly growing malignant glial cells accounting for roughly half of all brain tumors and having a poor survival rate ranging from 12 to 15 months. Despite being the most often used technique for glioma therapy, conventional chemotherapy suffers from low permeability of the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB) to anticancer drugs. When it comes to nanocarriers, liposomes are thought of as one of the most promising nanocarrier systems for glioma treatment. However, owing to BBB tight junctions, non-targeted liposomes, which passively accumulate in most cancer cells primarily via the increased permeability and retention effect (EPR), would not be suitable for glioma treatment. The surface modification of liposomes with various active targeting ligands has shown encouraging outcomes in the recent times by allowing various chemotherapy drugs to pass across the BBB and BBTB and enter glioma cells. This review article introduces by briefly outlining the landscape of glioma, its classification, and some of the pathogenic causes. Further, it discusses major barriers for delivering drugs to glioma such as the BBB, BBTB, and tumor microenvironment. It further discusses modified liposomes such as long-acting circulating liposomes, actively targeted liposomes, stimuli responsive liposomes. Finally, it highlighted the limitations of liposomes in the treatment of glioma and the various actively targeted liposomes undergoing clinical trials for the treatment of glioma.

Doxorubicin-Loaded Liposome with the Function of "Killing Two Birds with One Stone" against Glioma

The blood-brain barrier (BBB) continues to be one of the main clinical obstacles in the treatment of glioma. Current chemotherapies always bring many different side effects, some even permanent. To date, nanomaterial-based vehicles have shown great potential in treating glioma. Herein, we developed a dual targeting liposomal delivery vector loaded with the anticancer drug doxorubicin (DOX) to treat glioma. SS31, a small peptide, has shown dual targeting effects of penetrating the BBB and specifically targeting mitochondria. In this study, a new liposomal delivery system, LS-DOX, was prepared by modifying DOX-loaded liposomes with SS31 for the treatment of in situ glioma. The liposomes demonstrated a high drug encapsulation rate and drug-loading capacity, satisfactory biocompatibility, high glioma accumulation ability, and good stability in vitro. Experimental results showed that the liposomes could effectively cross the BBB and target gliomas, and mitochondria-targeting of SS31 enhances cell uptake. In addition, the liposomes showed a good therapeutic effect on nude mice with glioma in situ with no obvious toxicity and side effects. Therefore, the present research will provide a novel alternative and reference for the effective treatment of glioma.

Recent Advances on Surface-Modified GBM Targeted Nanoparticles: Targeting Strategies and Surface Characterization

Glioblastoma multiforme (GBM) is the most common malignant brain tumor, associated with low long-term survival. Nanoparticles (NPs) developed against GBM are a promising strategy to improve current therapies, by enhancing the brain delivery of active molecules and reducing off-target effects. In particular, NPs hold high potential for the targeted delivery of chemotherapeutics both across the blood-brain barrier (BBB) and specifically to GBM cell receptors, pathways, or the tumor microenvironment (TME). In this review, the most recent strategies to deliver drugs to GBM are explored. The main focus is on how surface functionalizations are essential for BBB crossing and for tumor specific targeting. We give a critical analysis of the various ligand-based approaches that have been used to target specific cancer cell receptors and the TME, or to interfere with the signaling pathways of GBM. Despite the increasing application of NPs in the clinical setting, new methods for ligand and surface characterization are needed to optimize the synthesis, as well as to predict their in vivo behavior. An expert opinion is given on the future of this research and what is still missing to create and characterize a functional NP system for improved GBM targeting.

Combined Biomimetic MOF-RVG15 Nanoformulation Efficient Over BBB for Effective Anti-Glioblastoma in Mice Model

Introduction

The blood-brain barrier (BBB) is a key obstacle to the delivery of drugs into the brain. Therefore, it is essential to develop an advanced drug delivery nanoplatform to solve this problem. We previously screened a small rabies virus glycoprotein 15 (RVG₁₅) peptide with 15 amino acids and observed that most of the RVG₁₅-modified nanoparticles entered the brain within 1 h of administration. The high BBB penetrability gives RVG₁₅ great potential for brain-targeted drug delivery systems. Moreover, a multifunctional integrated nanoplatform with a high drug-loading capacity, tunable functionality, and controlled drug release is crucial for tumor treatment. Zeolitic imidazolate framework (ZIF-8) is a promising nanodrug delivery system.

Methods

Inspired by the biomimetic concept, we designed RVG₁₅-coated biomimetic ZIF-8 nanoparticles (RVG₁₅-PEG@DTX@ZIF-8) for docetaxel (DTX) delivery to achieve efficient glioblastoma elimination in mice. This bionic nanotherapeutic system was prepared by one-pot encapsulation, followed by coating with RVG₁₅-PEG conjugates. The size, morphology, stability, drug-loading capacity, and release of RVG₁₅-PEG@DTX@ZIF-8 were thoroughly investigated. Additionally, we performed in vitro evaluation, cell uptake capacity, BBB penetration, and anti-migratory ability. We also conducted an in vivo evaluation of the biodistribution and anti-glioma efficacy of this bionic nanotherapeutic system in a mouse mode.

Results

In vitro studies showed that, this bionic nanotherapeutic system exhibited excellent targeting efficiency and safety in HBMECs and C6 cells and high efficiency in crossing the BBB. Furthermore, the nanoparticles cause rapid DTX accumulation in the brain, allowing deeper penetration into glioma tumors. In vivo antitumor assay results indicated that RVG₁₅-PEG@DTX@ZIF-8 significantly inhibited glioma growth and metastasis, thereby improving the survival of tumor-bearing mice.

Conclusion

Our study demonstrates that our bionic nanotherapeutic system using RVG₁₅ peptides is a promising and powerful tool for crossing the BBB and treating glioblastoma.

Curcumin and berberine co-loaded liposomes for anti-hepatocellular carcinoma therapy by blocking the cross-talk between hepatic stellate cells and tumor cells

Cancer-associated fibroblasts (CAFs) are a major component of the tumor microenvironment (TME). In hepatocellular carcinoma (HCC), quiescent hepatic stellate cells (HSCs) could be activated to become CAFs, which play a critical role in tumor progression and drug resistance. Therefore, recent efforts have been focused on combining anti-HSC and pro-apoptotic activities to improve anti-tumor efficacy of drugs. In this study, glycyrrhetinic acid and hyaluronic acid–modified liposomes (GA-HA-Lip) were prepared for co-delivery of curcumin (CUR) and berberine (BBR) for the treatment of HCC. Furthermore, we established the LX-2+BEL-7402 co-cultured cell model and implanted the m-HSCs+H22 cells into a mouse to evaluate the anti-tumor effect of CUR&BBR/GA-HA-Lip both in vitro and in vivo. The results showed that CUR&BBR/GA-HA-Lip could accumulate in tumor tissues and be taken up by HSCs and BEL-7402 cells simultaneously. Compared with free CUR, the combination therapy based on GA-HA-Lip exhibits stronger pro-apoptotic and anti-proliferation effect both in vitro and in vivo. The anti-tumor mechanistic study revealed that CUR&BBR/GA-HA-Lip could inhibit the activation of HSCs and restrain drug resistance of tumor cells. In summary, CUR&BBR/GA-HA-Lip could be a promising nano-sized formulation for anti-tumor therapy.

Triple branched RGD modification on liposomes: A prospective strategy to enhance the glioma targeting efficiency

Glioma, as one of the most common primary intracranial tumors, is in an urgent need for specific targeting agents. Multi-branched RGD ligand is a promising alternative for liposome functionalization which combines the benefits of high affinity with α_vβ₃ receptors and proper branching structure in response to the receptor clustering. Herein, we designed and synthesized single branched, double branched and triple branched RGD ligand (1RGD-Chol, 2RGD-Chol and 3RGD-Chol) respectively, which were then modified on the liposomes to prepare six different kinds of liposomes (including 1RGD-Lip, 2RGD-Lip, 3RGD-Lip, 2 × 1RGD-Lip, 3 × 1RGD-Lip and unmodified Lip). Subsequently, a series of assays were conducted. The results exhibited that the liposome decorated with 3RGD-Chol ligand possessed superior cellular internalization ability in C6 cells and bEnd.3 cells, suggesting the strongest ability of 3RGD-Lip to target the blood-brain barrier (BBB) and glioma cells. Besides, both the cytotoxicity and pro-apoptotic assays revealed that PTX-3RGD-Lip had the strongest ability to inhibit the survival of C6 cells. Moreover, the enrichment of liposomes at tumor site was 3RGD-Lip > 3 × 1RGD-Lip ≈ 2RGD-Lip ≈ 2 × 1RGD-Lip > 1RGD-Lip > Lip according to the in vivo imaging of C6-bearing mice, which was consistent with the result of in vitro targeting experiments. To sum up, the targeting efficiency of liposomes can be strongly promoted by improving the amount of targeting molecules, whereas the branching structure and spatial distance of RGD residues also accounted for the affinity between liposomes and α_vβ₃ receptors. Collectively, PTX-3RGD-Lip would be a prospective strategy in glioma treatment.

All-stage targeted therapy for glioblastoma based on lipid membrane coated cabazitaxel nanocrystals

Glioblastoma (GBM) is the most aggressive brain tumor with poor prognosis and frequent recurrence. The blood-brain barrier (BBB), blood-brain tumor barrier (BBTB) hinder the entry of therapeutics into the glioma region. Vasculogenic mimicry (VM) formed by invasive glioma cells is also related to recurrence of GBM. VAP is a D-peptide ligand of GRP78 protein overexpressed on BBTB, VM, and glioma cells but not on normal tissues. Besides, p-hydroxybenzoic acid (pHA) can effectively traverse the BBB. Herein we developed an all-stage glioma-targeted cabazitaxel (CBZ) nanocrystal loaded liposome modified with a "Y" shaped targeting ligand composed of pHA and VAP (pV-Lip/cNC). The pure drug nanocrystal core provided high drug loading, while lipid membrane promoted the stability and circulation time. pV-Lip/cNC exhibited excellent glioma homing, barriers crossing, and tumor spheroid penetrating capability in vitro. Treatment of pV-Lip/cNC displayed enhanced CBZ accumulation in glioma and anti-glioma effect with a median survival time (53 days) significantly longer than that of cNC loaded liposomes modified with either single ligand (42 days for VAP and 45 days for pHA) in the murine orthotopic GBM model. These results indicated pV-Lip/cNC could traverse the BBB and BBTB, destruct VM, and finally kill glioma cells to realize all-stage glioma therapy.

Recent Progress of RGD Modified Liposomes as Multistage Rocket Against Cancer

Cancer is a life-threatening disease, contributing approximately 9.4 million deaths worldwide. To address this challenge, scientific researchers have investigated molecules that could act as speed-breakers for cancer. As an abiotic drug delivery system, liposomes can hold both hydrophilic and lipophilic drugs, which promote a controlled release, accumulate in the tumor microenvironment, and achieve elongated half-life with an enhanced safety profile. To further improve the safety and impair the off-target effect, the surface of liposomes could be modified in a way that is easily identified by cancer cells, promotes uptake, and facilitates angiogenesis. Integrins are overexpressed on cancer cells, which upon activation promote downstream cell signaling and eventually activate specific pathways, promoting cell growth, proliferation, and migration. RGD peptides are easily recognized by integrin over expressed cells. Just like a multistage rocket, ligand anchored liposomes can be selectively recognized by target cells, accumulate at the specific site, and finally, release the drug in a specific and desired way. This review highlights the role of integrin in cancer development, so gain more insights into the phenomenon of tumor initiation and survival. Since RGD is recognized by the integrin family, the fate of RGD has been demonstrated after its binding with the acceptor’s family. The role of RGD based liposomes in targeting various cancer cells is also highlighted in the paper.

Novel brain-targeted nanomicelles for anti-glioma therapy mediated by the ApoE-enriched protein corona in vivo

Background

The interactions between nanoparticles (NPs) and plasma proteins form a protein corona around NPs after entering the biological environment, which provides new biological properties to NPs and mediates their interactions with cells and biological barriers. Given the inevitable interactions, we regard nanoparticle‒protein interactions as a tool for designing protein corona-mediated drug delivery systems. Herein, we demonstrate the successful application of protein corona-mediated brain-targeted nanomicelles in the treatment of glioma, loading them with paclitaxel (PTX), and decorating them with amyloid β-protein (Aβ)-CN peptide (PTX/Aβ-CN-PMs). Aβ-CN peptide, like the Aβ_1–42 peptide, specifically binds to the lipid-binding domain of apolipoprotein E (ApoE) in vivo to form the ApoE-enriched protein corona surrounding Aβ-CN-PMs (ApoE/PTX/Aβ-CN-PMs). The receptor-binding domain of the ApoE then combines with low-density lipoprotein receptor (LDLr) and LDLr-related protein 1 receptor (LRP1r) expressed in the blood–brain barrier and glioma, effectively mediating brain-targeted delivery.

Methods

PTX/Aβ-CN-PMs were prepared using a film hydration method with sonication, which was simple and feasible. The specific formation of the ApoE-enriched protein corona around nanoparticles was characterized by Western blotting analysis and LC–MS/MS. The in vitro physicochemical properties and in vivo anti-glioma effects of PTX/Aβ-CN-PMs were also well studied.

Results

The average size and zeta potential of PTX/Aβ-CN-PMs and ApoE/PTX/Aβ-CN-PMs were 103.1 nm, 172.3 nm, 7.23 mV, and 0.715 mV, respectively. PTX was efficiently loaded into PTX/Aβ-CN-PMs, and the PTX release from rhApoE/PTX/Aβ-CN-PMs exhibited a sustained-release pattern in vitro. The formation of the ApoE-enriched protein corona significantly improved the cellular uptake of Aβ-CN-PMs on C6 cells and human umbilical vein endothelial cells (HUVECs) and enhanced permeability to the blood–brain tumor barrier in vitro. Meanwhile, PTX/Aβ-CN-PMs with ApoE-enriched protein corona had a greater ability to inhibit cell proliferation and induce cell apoptosis than taxol. Importantly, PTX/Aβ-CN-PMs exhibited better anti-glioma effects and tissue distribution profile with rapid accumulation in glioma tissues in vivo and prolonged median survival of glioma-bearing mice compared to those associated with PMs without the ApoE protein corona.

Conclusions

The designed PTX/Aβ-CN-PMs exhibited significantly enhanced anti-glioma efficacy. Importantly, this study provided a strategy for the rational design of a protein corona-based brain-targeted drug delivery system. More crucially, we utilized the unfavorable side of the protein corona and converted it into an advantage to achieve brain-targeted drug delivery.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01097-8.

Lidocaine liposome modified with folic acid suppresses the proliferation and motility of glioma cells via targeting the PI3K/AKT pathway

Glioma is life-threatening tumor of the central nervous system. Although lidocaine is usually used as local anesthetic, it also has antitumor effects. However, its clinical application in glioma is hampered by limited distribution to the brain. The aim of the present study was to enhance the ability of lidocaine to penetrate the blood-brain barrier (BBB) to target glioma and investigate its antitumor mechanism. A folic acid (FA)-modified lidocaine-carrying liposome (Lid-FA-Lip) was prepared, and its particle size, ζ potential, encapsulation efficiency, release profile stability and hemolytic effect were characterized in vitro. The targeting capacity and antitumor activities of Lid-FA-Lip were also investigated in vitro and in vivo. The results indicated that the modification of liposomes with FA significantly improved the ability of lidocaine to cross the BBB in an in vitro model and increased its uptake by U87 cells. Additionally, Lid-FA-Lip significantly suppressed the motility of U87 glioma cells and stimulated apoptosis. Furthermore, the results confirmed that Lid-FA-Lip targeted the PI3K/AKT pathway and suppressed the growth of glioma xenografts in mice. In summary, the study demonstrated that Lid-FA-Lip is a promising liposomal formulation of lidocaine that may provide improved therapeutic effects on glioma, mediated via the PI3K/AKT pathway.

Nanocarriers for Biomedicine: From Lipid Formulations to Inorganic and Hybrid Nanoparticles

Encapsulation of cargoes in nanocontainers is widely used in different fields to solve the problems of their solubility, homogeneity, stability, protection from unwanted chemical and biological destructive effects, and functional activity improvement. This approach is of special importance in biomedicine, since this makes it possible to reduce the limitations of drug delivery related to the toxicity and side effects of therapeutics, their low bioavailability and biocompatibility. This review highlights current progress in the use of lipid systems to deliver active substances to the human body. Various lipid compositions modified with amphiphilic open-chain and macrocyclic compounds, peptide molecules and alternative target ligands are discussed. Liposome modification also evolves by creating new hybrid structures consisting of organic and inorganic parts. Such nanohybrid platforms include cerasomes, which are considered as alternative nanocarriers allowing to reduce inherent limitations of lipid nanoparticles. Compositions based on mesoporous silica are beginning to acquire no less relevance due to their unique features, such as advanced porous properties, well-proven drug delivery efficiency and their versatility for creating highly efficient nanomaterials. The types of silica nanoparticles, their efficacy in biomedical applications and hybrid inorganic-polymer platforms are the subject of discussion in this review, with current challenges emphasized.

A pentapeptide enabled AL3810 liposome-based glioma-targeted therapy with immune opsonic effect attenuated

AL3810, a molecular dual inhibitor of the vascular endothelial growth factor receptor (VEGFR) and fibroblast growth factor receptor (FGFR), has earned the permission of phase II clinical trial for tumor treatment by China FDA. As a reversible ATP-competitive inhibitor, AL3810 targets ATP-binding site on intracellular region of VEGFR and FGFR, whereas, AL3810 lacking interplay with extracellular region of receptors rendered deficient blood–brain tumor barrier (BBTB) recognition, poor brain penetration and unsatisfactory anti-glioma efficacy. Integrin αvβ3 overexpressed on capillary endothelial cells of BBTB as well as glioma cells illuminated ligand-modified liposomes for pinpoint spatial delivery into glioma. The widely accepted peptide c(RGDyK)-modified liposome loading AL3810 of multiple dosing caused hypothermia, activated anti-c(RGDyK)-liposome IgG and IgM antibody and pertinent complements C3b and C5b-9, and experienced complement-dependent opsonization. We newly proposed a pentapeptide mn with superb αvβ3-binding affinity and tailored AL3810-loaded mn-modified liposome that afforded impervious blood circulation, targeting ability, and glioma therapeutic expertise as vastly alleviated immune opsonization on the underpinning of the finite antibodies and complements assembly. Stemming from attenuated immunogenicity, peptide mn strengthened liposome functions as a promising nanocarrier platform for molecular targeting agents.