Multi-targeting Peptide-Functionalized Nanoparticles Recognized Vasculogenic Mimicry, Tumor Neovasculature, and Glioma Cells for Enhanced Anti-glioma Therapy

Integration of an LPAR1 Antagonist into Liposomes Enhances Their Internalization and Tumor Accumulation in an Animal Model of Human Metastatic Breast Cancer

Lysophosphatidic acid receptor 1 (LPAR1) is elevated in breast cancer. The deregulation of LPAR1, including the function and level of expression, is linked to cancer initiation, progression, and metastasis. LPAR1 antagonists, AM095 or Ki16425, may be effective therapeutic molecules, yet their limited water solubility hinders in vivo delivery. In this study, we report on the synthesis of two liposomal formulations incorporating AM095 or Ki16425, embedded within the lipid bilayer, as targeted nanocarriers for metastatic breast cancer (MBC). The data show that the Ki16425 liposomal formulation exhibited a 50% increase in internalization by MBC mouse epithelial cells (4T1) and a 100% increase in tumor accumulation in a mouse model of MBC compared with that of a blank liposomal formulation (control). At the same time, normal mouse epithelial cells (EpH-4Ev) internalized the Ki16425 liposomal formulation 25% lesser than the control formulation. Molecular dynamics simulations show that the integration of AM095 or Ki16425 modified the physical and mechanical properties of the lipid bilayer, making it more flexible in these liposomal formulations compared with liposomes without drug. The incorporation of an LPAR1 antagonist within a liposomal drug delivery system represents a viable therapeutic approach for targeting the LPA-LPAR1 axis, which may hinder the progression of MBC.

Antibody-conjugated nanoparticles for target-specific drug delivery of chemotherapeutics

Nanotechnology provides effective methods for precisely delivering chemotherapeutics to cancer cells, thereby improving efficacy and reducing off-target side effects. The targeted delivery of nanoscale chemotherapeutics is accomplished by two different approaches, namely the exploitation of leaky tumor vasculature (EPR effect) and the surface modification of nanoparticles (NPs) with various tumor-homing peptides, aptamers, oligonucleotides, and monoclonal antibodies (mAbs). Because of higher binding affinity and specificity, mAbs have received a lot of attention for the detection of selective cancer biomarkers and also for the treatment of various types of cancer. Antibody-conjugated nanoparticles (ACNPs) are an effective targeted therapy for the efficient delivery of chemotherapeutics specifically to the targeted cancer cells. ACNPs combine the benefits of NPs and mAbs to provide high drug loads at the tumor site with better selectivity and delivery efficiency. The mAbs on the NP surfaces recognize their specific receptors expressed on the target cells and release the chemotherapeutic agent in a controlled manner. Appropriately designed and synthesized ACNPs are essential to fully realize their therapeutic benefits. In blood stream, ACNPs instantly interact with biological molecules, and a protein corona is formed. Protein corona formation triggers an immune response and affects the targeting ability of the nanoformulation. In this review, we provide recent findings to highlight several antibody conjugation methods such as adsorption, covalent conjugation, and biotin-avidin interaction. This review also provides an overview of the many effects of the protein corona and the theranostic applications of ACNPs for the treatment of cancer.

The driving mechanism and targeting value of mimicry between vascular endothelial cells and tumor cells in tumor progression

The difficulty and poor prognosis of malignant tumor have always been a difficult problem to be solved. The internal components of solid tumor are complex, including tumor cells, stromal cells and immune cells, which play an important role in tumor proliferation, migration, metastasis and drug resistance. Hence, targeting of only the tumor cells will not likely improve survival. Various studies have reported that tumor cells and endothelial cells have high plasticity, which is reflected in the fact that they can simulate each other's characteristics by endothelial-mesenchymal transition (EndMT) and vasculogenic mimicry (VM). In this paper, this mutual mimicry concept was integrated and reviewed for the first time, and their similarities and implications for tumor development are discussed. At the same time, possible therapeutic methods are proposed to provide new directions and ideas for clinical targeted therapy and immunotherapy of tumor.

Advances in antibody-based drugs and their delivery through the blood-brain barrier for targeted therapy and immunotherapy of gliomas

Gliomas are highly invasive and are the most common type of primary malignant brain tumor. The routine treatments for glioma include surgical resection, radiotherapy, and chemotherapy. However, glioma recurrence and patient survival remain unsatisfactory after employing these traditional treatment approaches. With the rapid development of molecular immunology, significant breakthroughs have been made in targeted glioma therapy and immunotherapy. Antibody-based therapy has excellent advantages in treating gliomas due to its high specificity and sensitivity. This article reviewed various targeted antibody drugs for gliomas, including anti-glioma surface marker antibodies, anti-angiogenesis antibodies, and anti-immunosuppressive signal antibodies. Notably, many antibodies have been validated clinically, such as bevacizumab, cetuximab, panitumumab, and anti-PD-1 antibodies. These antibodies can improve the targeting of glioma therapy, enhance anti-tumor immunity, reduce the proliferation and invasion of glioma, and thus prolong the survival time of patients. However, the existence of the blood-brain barrier (BBB) has caused significant difficulties in drug delivery for gliomas. Therefore, this paper also summarized drug delivery methods through the BBB, including receptor-mediated transportation, nano-based carriers, and some physical and chemical methods for drug delivery. With these exciting advancements, more antibody-based therapies will likely enter clinical practice and allow more successful control of malignant gliomas.

The Role of Nanotechnologies in Brain Tumors

The treatment of glioma remains one of the most interesting topics in neurooncology. Glioblastoma multiforme is the most aggressive and prevalent malignant brain tumor. Nowadays, technologies and new tools are helping the neurosurgeons to define a tailored surgery. However, there are few pharmaceutical strategies in operated and nonoperated patients. There are still few anticancer drugs approved by FDA and EMA. Moreover, these drugs are not so effective and have a lot of side effects due to their toxicity. Nanoparticles are a new strategy which could help to create and carry new drugs. In fact, NPs improve the pharmacokinetic properties of anticancer drugs, reduce side-effects, and increase drug half-life and its selectivity. Nanoparticle drug delivery system has been studied for targeting different molecular biomarkers and signaling pathways. Furthermore, the first problem of anticancer drugs in the treatment of gliomas is penetrating the blood brain barrier which represents an insurmountable wall for most of synthetic and natural particles. In the last 15 years, a lot of researches tried to design a perfect nanoparticle both able to cross blood-brain barrier and to selectively target glioma cells, unfortunately, without great results. In vivo human trials are still ongoing and many of them have already failed. In this chapter we evaluate the effectiveness of nanotechnologies in the treatment of brain tumors. There is not yet, currently, a nanoparticle drug designed for the treatment of gliomas approved by FDA and EMA. Advancements in discovery of molecular characteristics of tumors lead to the development of targeted nanoparticles that are tested in numerous in vitro and in vivo studies on gliomas. Novel and repurposed drugs, as well as novel drug combinations, have also been already studied but those are not included in this chapter because the carried drugs (active substances) are not included among the approved anticancer drug used in the treatment of gliomas.

Impairing proliferation of glioblastoma multiforme with CD44+ selective conjugated polymer nanoparticles

Glioblastoma is one of the most aggressive types of cancer with success of therapy being hampered by the existence of treatment resistant populations of stem-like Tumour Initiating Cells (TICs) and poor blood-brain barrier drug penetration. Therapies capable of effectively targeting the TIC population are in high demand. Here, we synthesize spherical diketopyrrolopyrrole-based Conjugated Polymer Nanoparticles (CPNs) with an average diameter of 109 nm. CPNs were designed to include fluorescein-conjugated Hyaluronic Acid (HA), a ligand for the CD44 receptor present on one population of TICs. We demonstrate blood-brain barrier permeability of this system and concentration and cell cycle phase-dependent selective uptake of HA-CPNs in CD44 positive GBM-patient derived cultures. Interestingly, we found that uptake alone regulated the levels and signaling activity of the CD44 receptor, decreasing stemness, invasive properties and proliferation of the CD44-TIC populations in vitro and in a patient-derived xenograft zebrafish model. This work proposes a novel, CPN- based, and surface moiety-driven selective way of targeting of TIC populations in brain cancer.

Hedgehog signaling regulates the development and treatment of glioblastoma (Review)

Glioblastoma (GBM) is the most common and fatal malignant tumor type of the central nervous system. GBM affects public health and it is important to identify biomarkers to improve diagnosis, reduce drug resistance and improve prognosis (e.g., personalized targeted therapies). Hedgehog (HH) signaling has an important role in embryonic development, tissue regeneration and stem cell renewal. A large amount of evidence indicates that both normative and non-normative HH signals have an important role in GBM. The present study reviewed the role of the HH signaling pathway in the occurrence and progression of GBM. Furthermore, the effectiveness of drugs that target different components of the HH pathway was also examined. The HH pathway has an important role in reversing drug resistance after GBM conventional treatment. The present review highlighted the relevance of HH signaling in GBM and outlined that this pathway has a key role in the occurrence, development and treatment of GBM.

Neutrophil-Biomimetic "Nanobuffer" for Remodeling the Microenvironment in the Infarct Core and Protecting Neurons in the Penumbra via Neutralization of Detrimental Factors to Treat Ischemic Stroke

High level of detrimental factors including reactive oxygen species (ROS) and inflammatory cytokines accumulated in the infarct core and their erosion to salvageable penumbra are key pathological cascades of ischemia-reperfusion injury in stroke. Few neuroprotectants can remodel the hostile microenvironment of the infarct core for the failure to interfere with dead or biofunctionally inactive dying cells. Even ischemia-reperfusion injury is temporarily attenuated in the penumbra by medications; insults of detrimental factors from the core still erode the penumbra continuously along with drug metabolism and clearance. Herein, a strategy named "nanobuffer" is proposed to neutralize detrimental factors and buffer destructive erosion to the penumbra. Inspired by neutrophils' tropism to the infarct core and affinity to inflammatory cytokines, poly(lactic-co-glycolic acid) (PLGA) nanoparticles are coated with neutrophil membrane to target the infarct core and absorb inflammatory cytokines; α-lipoic acid is decorated on the surface and cannabidiol is loaded for ROS scavenging and neuroprotection, respectively, to construct the basic unit of the nanobuffer. Such a nanobuffer exerts a comprehensive effect on the infarct area via detrimental factor neutralization and cannabidiol-induced neuroprotection. Besides, the nanobuffer can possibly be enhanced by dynamic ROP (ring-opening-polymerization)-induced membrane cross-fusion among closely adjacent units in vivo. Systematic evaluations show significant decrease of detrimental factors in the core and the penumbra, reduced infarct volume, and improved neurological recovery compared to the untreated group of stroke rats.

Combination of chemotherapy and immune checkpoint therapy by the immunoconjugates-based nanocomplexes synergistically improves therapeutic efficacy in SCLC

Although the etoposide and carboplatin (EP) combination strategy has been the first-line chemotherapy, patients with extensive-stage disease small-cell lung cancer (SCLC) still have poor survival outcomes. Our retrospective analysis revealed that 46 patients with SCLC only achieved medium overall survival (OS) of 11.6 months after treated by EP. Recently, it was demonstrated that combination therapy of PD1/PD-L1 immune checkpoint blocker and EP could significantly improve the OS of SCLC patients. However, the serious treatment-related toxicity leaded to a high rate of treatment-discontinuation or even death. In the present study, we have developed a novel TPP1-conjugated nanocomplex, abbreviated as TPP1NP-EP, which was co-loaded with carboplatin (CBP) and etoposide (VP16). The TPP1 was a PD-L1 targeting peptide and conjugated on the surface of nanocomplex by a matrix metalloproteinase (MMP-2/9)-cleavable peptide linker sequence PLGLAG. For dual-loading of CBP and VP16, the CBP was chemically conjugated with poly(ethylene glycol) (PEG)-poly(caprolactone) (PCL) by pH-sensitive hydrazone bond and the VP16 was physically encapsulated by emulsion-solvent evaporation method. In vitro and in vivo experiments demonstrated an excellent anti-tumor effect of TPP1NP-EP on SCLC and improved safety. In conclusion, the present study has provided a promising strategy for treatment of malignant SCLC.

Emerging Nanotherapeutic Approaches to Overcome Drug Resistance in Cancers with Update on Clinical Trials

A key issue with modern cancer treatments is the emergence of resistance to conventional chemotherapy and molecularly targeted medicines. Cancer nanotherapeutics were created in order to overcome the inherent limitations of traditional chemotherapeutics. Over the last few decades, cancer nanotherapeutics provided unparalleled opportunities to understand and overcome drug resistance through clinical assessment of rationally designed nanoparticulate delivery systems. In this context, various design strategies such as passive targeting, active targeting, nano-drug, and multimodal nano-drug combination therapy provided effective cancer treatment. Even though cancer nanotherapy has made great technological progress, tumor biology complexity and heterogeneity and a lack of comprehensive knowledge of nano-bio interactions remain important roadblocks to future clinical translation and commercialization. The current developments and advancements in cancer nanotherapeutics employing a wide variety of nanomaterial-based platforms to overcome cancer treatment resistance are discussed in this article. There is also a review of various nanotherapeutics-based approaches to cancer therapy, including targeting strategies for the tumor microenvironment and its components, advanced delivery systems for specific targeting of cancer stem cells (CSC), as well as exosomes for delivery strategies, and an update on clinical trials. Finally, challenges and the future perspective of the cancer nanotherapeutics to reverse cancer drug resistance are discussed.

Nanoparticles modified with vasculature-homing peptides for targeted cancer therapy and angiogenesis imaging

The two major challenges in cancer treatment include lack of early detection and ineffective therapies with various side effects. Angiogenesis is the key process in the growth, survival, invasiveness, and metastasis of many of cancerous tumors. Imaging of the angiogenesis could lead to diagnosis of tumors in the early stage and evaluation of the therapeutic responses. Angiogenic blood vessels express specific molecular markers different from normal blood vessels (in level or kind). This fact would make the tumor vasculature a suitable site to target therapeutics and imaging agents within the tumor. Surface modified nanoparticles using peptide ligands with high binding affinity to the vasculature markers, provide efficient delivery of therapeutic and imaging agents, while avoiding undesirable side effects. In this review, we discuss discoveries of various tumor targeting peptides useful for tumor angiogenesis imaging and targeted therapy with emphasis on surface modified nanomedicines using vasculature targeting peptides.

Highlights in targeted nanoparticles as a delivery strategy for glioma treatment

Glioma is the most common type of Central Nervous System (CNS) neoplasia and it arises from glial cells. As glial cells are formed by different types of cells, glioma can be classified according to the cells that originate it or the malignancy grade. Glioblastoma multiforme is the most common and aggressive glioma. The high lethality of this tumor is related to the difficulty in performing surgical removal, chemotherapy, and radiotherapy in the CNS. To improve glioma treatment, a wide range of chemotherapeutics have been encapsulated in nanosystems to increase their ability to overcome the blood-brain barrier (BBB) and specifically reach the tumoral cells, reducing side effects and improving drug concentration in the tumor microenvironment. Several studies have investigated nanosystems covered with targeting ligands (e.g., proteins, peptides, aptamers, folate, and glucose) to increase the ability of drugs to cross the BBB and enhance their specificity to glioma through specific recognition by receptors on BBB and glioma cells. This review addresses the main targeting ligands used in nanosystems to overcome the BBB and promote the active targeting of drugs for glioma. Furthermore, the advantages of using these molecules in glioma treatment are discussed.

Nano drug delivery system reconstruct tumour vasculature for the tumour vascular normalisation

The abnormal structure and function of blood vessels in the TME are obvious characteristics of the tumour. Abnormal blood vessels with high leakage support the occurrence of malignant tumours and increase the possibility of tumour cell invasion and metastasis. The formation of abnormal vascular also enhances immunosuppression and prevents the delivery of chemotherapy drugs to deeper tumours. Therefore, the normalisation of tumour blood vessels is a very promising approach to improve anti-tumour efficacy, aiming to restore the structural integrity of vessels and improve drug delivery efficiency and anti-tumour immunity. In this review, we have summarised strategies to improve cancer treatment that via nano drug delivery technology regulates the normalisation of tumour blood vessels. The treatment strategies related to the structure and function of tumour blood vessels such as angiogenesis factors, tumour-associated macrophages, tumour vascular endothelial cells, tumour-associated fibroblasts and immune checkpoints in the TME were mainly discussed. The normalisation of tumour blood vessels presents new opportunities and challenges for the more efficient delivery of nanoparticles to tumour tissues and cells and an innovative combination of treatments for cancer.

Redox-responsive amphiphilic camptothecin prodrug nanoparticles for targeted liver tumor therapy

Tumor cell-targeting drug delivery systems are of great importance to anti-tumor therapy in clinics. Owing to the overexpression of the asialoglycoprotein receptor (ASGPR) on the membrane of hepatoma carcinoma cells, the conjugation of lactose on the surface of drug delivery systems has already shown significant advantages for targeting tumor cells. In this study, a disulfide bond-conjugated prodrug targeting delivery system consisting of camptothecin (CPT) and lactose (LA) was synthesized, which was denoted as CPT-S-S-LA. Camptothecin and lactose act as the chemotherapy drug and targeting ligand in the drug delivery system, respectively. Since CPT-S-S-LA is an amphiphilic compound, it can self-assemble into nanoparticles with a diameter of around 110 nm. The CPT-S-S-LA nanoparticles displayed controllable drug release behavior in the physiological environment. Unlike the free CPT, the CPT-S-S-LA nanoparticles firstly assembled at the tumor sites via the enhanced permeability and retention (EPR) effect, and then were phagocytized by the tumor cells with ASGP receptor-mediated endocytosis. Finally, the antitumor agent CPT was released for killing tumor cells, which have a high glutathione (GSH) concentration environment. The nanoparticles displayed favorable ability to target hepatoma carcinoma cells rather than the normal HUVEC cells in vitro. Both the in vitro and in vivo studies demonstrated that the CPT-S-S-LA nanoparticles display enhanced antitumor ability and reduced side effects. Thus, active targeting prodrug delivery systems should be a promising strategy for liver tumor therapy.

The enhanced treatment efficacy of invasive brain glioma by dual-targeted artemether plus paclitaxel micelles

High grade-gliomas are highly invasive and prone to metastasis, leading to poor survival and prognosis. Currently, we urgently need a new treatment strategy to effectively inhibit glioma. In this study, artemether and paclitaxel were used as two agents for tumour suppression. Two functional materials were synthesised and modified on the surface of the micelle as targeting molecules. The addition of two functional materials confers the ability of the micelles to effectively cross the blood-brain barrier (BBB) and then target the glioma cells. Thus, this dual-targeted delivery system allows the drug to play a better role in inhibiting tumour invasion and vasculogenic mimicry (VM) channels. In this paper, the anticancer effects of dual-targeted artemether plus paclitaxel micelles on glioma U87 cells were studied in three aspects: (I) In vitro and in vivo targeting assessment, including the role of penetrating BBB and targeting glioma; (II) In vitro regulation of invasion-associated proteins; (III) Inhibition of VM channels formation and invasion in vitro; (IV) The study of pharmacodynamics in tumour-bearing mice. These results suggest that dual-targeted artemether plus paclitaxel micelle may provide a new strategy to treat glioma via inhibiting invasive and VM channels.

Enhancement of Therapies for Glioblastoma (GBM) Using Nanoparticle-based Delivery Systems

Glioblastoma multiforme (GBM) is the most aggressive type of malignant brain tumor. Current FDA-approved treatments include surgical resection, radiation, and chemotherapy, while hyperthermia, immunotherapy, and most relevantly, nanoparticle (NP)-mediated delivery systems or combinations thereof have shown promise in preclinical studies. Drug-carrying NPs are a promising approach to brain delivery as a result of their potential to facilitate the crossing of the blood-brain barrier (BBB) via two main types of transcytosis mechanisms: adsorptive-mediated transcytosis (AMT) and receptor-mediated transcytosis (RMT). Their ability to accumulate in the brain can thus provide local sustained release of tumoricidal drugs at or near the site of GBM tumors. NP-based drug delivery has the potential to significantly reduce drug-related toxicity, increase specificity, and consequently improve the lifespan and quality of life of patients with GBM. Due to significant advances in the understanding of the molecular etiology and pathology of GBM, the efficacy of drugs loaded into vectors targeting this disease has increased in both preclinical and clinical settings. Multitargeting NPs, such as those incorporating multiple specific targeting ligands, are an innovative technology that can lead to decreased off-target effects while simultaneously having increased accumulation and action specifically at the tumor site. Targeting ligands can include antibodies, or fragments thereof, and peptides or small molecules, which can result in a more controlled drug delivery system compared to conventional drug treatments. This review focuses on GBM treatment strategies, summarizing current options and providing a detailed account of preclinical findings with prospective NP-based approaches aimed at improving tumor targeting and enhancing therapeutic outcomes for GBM patients.

Dual functional nanoparticles efficiently across the blood-brain barrier to combat glioblastoma via simultaneously inhibit the PI3K pathway and NKG2A axis

The blood-brain barrier (BBB) and complex tumour immunosuppressive micro-environment posed austere challenges for combatting brain tumours such as the glioblastoma. In this study, we have developed a novel dual functional dendrimer drug delivery system (DDS) by the PAMAM and loaded with siLSINCT5 (NP- siRNA) for efficiently across the BBB to inhibit glioblastoma. To achieve the goal of BBB crossing, on the surface of NP-siRNA was decorated with the cell penetrating peptides tLyp-1 (tLypNP-siRNA). Moreover, to overcome the immunosuppressive microenvironment within the glioblastoma (GBM) tissues, a checkpoint inhibitor named as anti-NKG2A monoclonal antibody (aNKG2A), which was able of promoting anti-tumour immunity by unleashing both T and NK Cells, was further conjugated on the surface of siLSINCT5-loaded nanoparticles via the pH-sensitive linkage. Therefore, the developed dual functional and siLSINCT5-loaded dendrimer nanoparticles (tLyp/aNKNP-siRNA) was supposed to have the ability to efficiently cross the BBB and inhibit GBM by simultaneously inhibit the LSINCT5-activated signalling pathways and activate the anti-tumour immunity. The hypothesis was thoroughly confirmed by in vitro cellular and in vivo animal experiments, and provided a novel strategy for combating glioblastoma.

Advances and Prospects of Vasculogenic Mimicry in Glioma: A Potential New Therapeutic Target?

Vasculogenic mimicry (VM) is the formation of a “vessel-like” structure without endothelial cells. VM exists in vascular-dependent solid tumors and is a special blood supply source involved in the highly invasive tumor progression. VM is observed in a variety of human malignant tumors and is closely related to tumor proliferation, invasion, and recurrence. Here, we review the mechanism, related signaling pathways, and molecular regulation of VM in glioma and discuss current research problems and the potential future applications of VM in glioma treatment. This review may provide a new viewpoint for glioma therapy.

Nanoparticle Drug Delivery System for Glioma and Its Efficacy Improvement Strategies: A Comprehensive Review

Gliomas are the most common tumor of the central nervous system. However, the presence of the brain barrier blocks the effective delivery of drugs and leads to the treatment failure of various drugs. The development of a nanoparticle drug delivery system (NDDS) can solve this problem. In this review, we summarized the brain barrier (including blood-brain barrier (BBB), blood-brain tumor barriers (BBTB), brain-cerebrospinal fluid barrier (BCB), and nose-to-brain barrier), NDDS of glioma (such as passive targeting systems, active targeting systems, and environmental responsive targeting systems), and NDDS efficacy improvement strategies and deficiencies. The research prospect of drug-targeted delivery systems for glioma is also discussed.

Exploring Novel Molecular Targets for the Treatment of High-Grade Astrocytomas Using Peptide Therapeutics: An Overview

Diffuse astrocytomas are the most aggressive and lethal glial tumors of the central nervous system (CNS). Their high cellular heterogeneity and the presence of specific barriers, i.e., blood–brain barrier (BBB) and tumor barrier, make these cancers poorly responsive to all kinds of currently available therapies. Standard therapeutic approaches developed to prevent astrocytoma progression, such as chemotherapy and radiotherapy, do not improve the average survival of patients. However, the recent identification of key genetic alterations and molecular signatures specific for astrocytomas has allowed the advent of novel targeted therapies, potentially more efficient and characterized by fewer side effects. Among others, peptides have emerged as promising therapeutic agents, due to their numerous advantages when compared to standard chemotherapeutics. They can be employed as (i) pharmacologically active agents, which promote the reduction of tumor growth; or (ii) carriers, either to facilitate the translocation of drugs through brain, tumor, and cellular barriers, or to target tumor-specific receptors. Since several pathways are normally altered in malignant gliomas, better outcomes may result from combining multi-target strategies rather than targeting a single effector. In the last years, several preclinical studies with different types of peptides moved in this direction, providing promising results in murine models of disease and opening new perspectives for peptide applications in the treatment of high-grade brain tumors.

An iRGD-conjugated prodrug micelle with blood-brain-barrier penetrability for anti-glioma therapy

Various obstacles impede the chemotherapy efficiency of glioma in clinic, such as blood brain barrier (BBB) and blood brain tumor barrier (BBTB). Ligand-mediated polymeric micelles have shown great potential for improving the efficiency of glioma treatment. Herein, we developed a disulfide bond-conjugated prodrug polymer consisted of camptothecin (CPT) and polyethylene glycol (PEG) with further modification of iRGD peptide. The polymer of CPT-S-S-PEG-COOH could self-assemble into nanosized polymeric micelles with diameter around 100 nm, and loaded with photosensitizer IR780 for combination therapy. The micelles displayed good stability with controlled drug release under physiological environment. Importantly, the iRGD modified polymeric micelles demonstrated favorable ability to cross the BBB and target glioma cells via αv β integrin and neuropilin-1-mediated ligand transportation in vitro and in vivo. The whole synthesis process is simple and the drug loading content of CPT in the CPT-S-S-PEG-iRGD@IR780 micelles was higher than 10%. Moreover, CPT-S-S-PEG-iRGD@IR780 micelles combined chemotherapy with photodynamic therapy (PDT) displayed more excellent tumor-killing capability than the other groups. Thus, both in vitro and in vivo studies suggested that the targeting prodrug system could not only effectively cross various barriers to reach at glioma site, but also significantly enhance the antitumor effect with laser irradiation. Our findings consequently suggested that CPT-S-S-PEG-iRGD@IR780 micelles with laser irradiation are a promising drug delivery system for glioma therapy.

Co-delivery of plantamajoside and sorafenib by a multi-functional nanoparticle to combat the drug resistance of hepatocellular carcinoma through reprograming the tumor hypoxic microenvironment

Sorafenib (SOR) is a multi-kinase inhibitor that was approved as the first-line systematic treatment agent of hepatocellular carcinoma (HCC). However, the anti-cancerous effect of SOR is dramatically impaired by the drug resistance, insufficient accumulation at tumor tissues, and limited tumor inner penetration. To combat the above issues, the PLA-based nanoparticles were first fabricated and co-loaded with SOR and plantamajoside (PMS), natural herbal medicines that possess excellent anti-cancerous effect on many types of drug resistant cancers. Then, the polypeptide CT, which is tumor-homing and cell membrane penetrable, was further decorated on the dual-agents loaded nanoparticles (CTNP-PMS/SOR) to enhance tumor accumulation of drugs. Importantly, the CT peptide is a conjugate derived from the covalent conjugation of CVNHPAFAC peptide, a tumor-homing peptide, on the fourth lysine of TAT, namely cell membrane penetrating peptide, through a pH-sensitive hydrazone bond. By this way, the cell penetrating ability of TAT was dramatically sealed under the normal condition and immediately recovered once the nanoparticles reached tumor sites. Both in vivo and in vitro experiments demonstrated that the anti-cancerous effect of SOR on malignant HCC was significantly enhanced after co-loaded with PMS. Mechanisms studies revealed that the PMS is capable of reprograming the tumor hypoxic microenvironment, which represents the main cause of drug-resistance of tumor cells. Besides, functionalization of the NP-PMS/SOR with CT peptides signally improved the accumulation of drugs at tumor sites and penetration of agents into tumor cells, which in turn resulted in stronger capacity of tumor growth inhibition.

Dual and multi-targeted nanoparticles for site-specific brain drug delivery

In recent years, nanomedicines have emerged as a promising method for central nervous system drug delivery, enabling the drugs to overcome the blood-brain barrier and accumulate preferentially in the brain. Despite the current success of brain-targeted nanomedicines, limitations still exist in terms of the targeting specificity. Based on the molecular mechanism, the exact cell populations and subcellular organelles where the injury occurs and the drugs take effect have been increasingly accepted as a more specific target for the next generation of nanomedicines. Dual and multi-targeted nanoparticles integrate different targeting functionalities and have provided a paradigm for precisely delivering the drug to the pathological site inside the brain. The targeting process often involves the sequential or synchronized navigation of the targeting moieties, which allows highly controlled drug delivery compared to conventional targeting strategies. Herein, we focus on the up-to-date design of pathological site-specific nanoparticles for brain drug delivery, highlighting the dual and multi-targeting strategies that were employed and their impact on improving targeting specificity and therapeutic effects. Furthermore, the background discussion of the basic properties of a brain-targeted nanoparticle and the common lesion features classified by neurological pathology are systematically summarized.

pH sensitive peptide functionalized nanoparticles for co-delivery of erlotinib and DAPT to restrict the progress of triple negative breast cancer

Although a variety of drug delivery strategies have been designed for enhancing the treatment of Triple negative breast cancer (TNBC), combating with TNBCs is still dramatically challenged by the selection of appropriate therapeutic targets and insufficient tumor accumulation or inner penetration of chemotherapeutics. To address these issues, the classical EGFR-inhibitor, erlotinib (EB), was selected as the model drug here and PLA-based nano-platform (NP-EB) was prepared for tumor site drug delivery. Given the significant role of Notch-EGFR interplay in raising severe resistance to EGFR inhibition of EB, gamma secretase inhibitor (GSI)-DAPT was further entrapped into the core of nanoparticles to inhibit the activation of Notch signaling (NP-EB/DART). For achieving the goal of tumor targeting drug delivery, we developed a new peptide CF and decorating it on the surface of EB/DART-dual loaded nanoparticles (CF-NP-EB/DART). Such CF peptide was designed by conjugating two separated peptide CREKA, tumor-homing peptide, and F3, cell penetrating peptide, to together via a pH-sensitive hydrazone bond. By this way, the tumor unspecific property of F3 was sealed and significantly reduced the site effects. However, after the nanoparticles reach the tumor site, the pH-sensitive linkage can be broken down by the unique acidic environment of tumor, and subsequently discovered the F3 peptide to penetrate into tumor cells.

Peptide-Conjugated Nanoparticles as Targeted Anti-angiogenesis Therapeutic and Diagnostic in Cancer

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Targeting angiogenesis in the microenvironment of a tumor can enable suppression of tumor angiogenesis and delivery of anticancer drugs into the tumor. Anti-angiogenesis targeted delivery systems utilizing passive targeting such as Enhanced Permeability and Retention (EPR) and specific receptor-mediated targeting (active targeting) should result in tumor-specific targeting. One targeted anti-angiogenesis approach uses peptides conjugated to nanoparticles, which can be loaded with anticancer agents. Anti-angiogenesis agents can suppress tumor angiogenesis and thereby affect tumor growth progression (tumor growth arrest), which may be further reduced with the targetdelivered anticancer agent. This review provides an update of tumor vascular targeting for therapeutic and diagnostic applications, with conventional or long-circulating nanoparticles decorated with peptides that target neovascularization (anti-angiogenesis) in the tumor microenvironment.

Breakthroughs in medicine and bioimaging with up-conversion nanoparticles

Nanomedicine is a medical application of biochemistry incorporated with materials chemistry at the scale of nanometer for the purpose of diagnosis, prevention, and treatment. New models and approaches are typically associated with nanomedicine for precise multifunctional diagnostic systems at molecular level. Hence, employing nanoparticles (NPs) has unveiled new opportunities for efficient therapies and remedy of difficult-to-cure diseases. Among all types of inorganic NPs, lanthanide-doped up-conversion nanoparticles (UCNPs) have shown excellent potential for biomedical applications, especially for multimodal bioimaging including fluorescence and electron microscopy. Association of these visualization techniques plus the capability for transporting biomaterials and drugs make them superior agents in the field of nanomedicine. Accordingly, in this review, we firstly presented a fundamental understanding of physical and optical properties of UCNPs and secondly, we illustrated some of the prominent associations with bioimaging, theranostics, cancer therapy, and optogenetics.

Salidroside enhances the anti-cancerous effect of imatinib on human acute monocytic leukemia via the induction of autophagy-related apoptosis through AMPK activation

As the typical tyrosine kinase inhibitor, imatinib has been the first-line antineoplastic agent for both chronic myeloid leukemia and acute lymphoblastic leukemia. However, a large number of patients are still resistant to the benefits of imatinib, and they have a dissatisfactory prognosis. Salidroside, a compound that is extracted from natural plants, has been reported to have an excellent anticancer effect and few side effects. In the present study, we have developed a new combination therapy strategy of salidroside and imatinib for combating the growth of acute lymphoblastic leukemia. As demonstrated by the anti-proliferation assay, salidroside exhibited excellent cytotoxicity against myeloid leukemia cells. Moreover, cells treated by the combination therapy of salidroside and imatinib displayed a clear lower growth rate than cells only treated by imatinib, indicating that salidroside has a positive effect on enhancing the cytotoxicity of imatinib against leukemia cells. Subsequently, the underlying mechanisms were investigated. The results revealed that autophagy marker proteins in leukemia cells, including LC3, p62, and Beclin1, displayed a significant expression change after treating them with salidroside plus imatinib, with the levels of LC3 and Beclin1 dramatically increasing while the expression of p62 was significantly decreased. Moreover, an obvious down-regulation of p-PI3K, p-AKT and p-mTOR expression levels in leukemia cells after treatment with salidroside plus imatinib suggested that the PI3K/mTOR pathway plays an important role in the process of cell apoptosis induced by salidroside or imatinib. Further studies showed that pre-incubating the cells with an autophagy inhibitor dramatically inhibited the ability of imatinib to induce autophagy, but did not inhibit the ability of salidroside. The underlying causes were subsequently explored and the results showed that silencing AMPKα1, the most important regulator of autophagy, dramatically attenuates the ability of salidroside to induce cell apoptosis. These results together indicated that salidroside enhances the cytotoxicity of imatinib on acute monocytic leukemia via the induction of autophagy-related apoptosis through AMPK activation. The unique advantages of combination therapy were further confirmed by in vivo experiments, with the tumor-bearing cells treated with salidroside plus imatinib achieving the best anti-tumor effect.

Metformin and Docosahexaenoic Acid Hybrid Micelles for Premetastatic Niche Modulation and Tumor Metastasis Suppression

Metastasis is the major cause of high mortality in cancer patients; thus, blocking the metastatic process is of critical importance for cancer treatments. The premetastatic niche, a specialized microenvironment with aberrant changes related to inflammation, allows the colonization of circulating tumor cells (CTCs) and serves as a potential target for metastasis prevention. However, little effort has been dedicated to developing nanomedicine to amend the premetastatic niche. Here this study reports a premetastatic niche-targeting micelle for the modulation of premetastatic microenvironments and suppression of tumor metastasis. The micelles are self-assembled with the oleate carbon chain derivative of metformin and docosahexaenoic acid, two anti-inflammatory agents with low toxicity, and coated with fucoidan for premetastatic niche-targeting. The obtained functionalized micelles (FucOMDs) exhibit an excellent blood circulation profile and premetastatic site-targeting efficiency, inhibit CTC adhesion to activated endothelial cells, alleviate lung vascular permeability, and reverse the aberrant expression of key marker proteins in premetastatic niches. As a result, FucOMDs prevent metastasis formation and efficiently suppress both primary-tumor growth and metastasis formation when combined with targeted chemotherapy. Collectively, the findings here provide proof of concept that the modulation of the premetastatic niche with targeted anti-inflammatory agents provides a potent platform and a safe and clinical translational option for the suppression of tumor metastasis.

Sequential Targeting TGF-β Signaling and KRAS Mutation Increases Therapeutic Efficacy in Pancreatic Cancer

Pancreatic cancer is a highly aggressive malignancy that strongly resists extant treatments. The failure of existing therapies is majorly attributed to the tough tumor microenvironment (TME) limiting drug access and the undruggable targets of tumor cells. The formation of suppressive TME is regulated by transforming growth factor beta (TGF-β) signaling, while the poor response and short survival of almost 90% of pancreatic cancer patients results from the oncogenic KRAS mutation. Hence, simultaneously targeting both the TGF-β and KRAS pathways might dismantle the obstacles of pancreatic cancer therapy. Here, a novel sequential-targeting strategy is developed, in which antifibrotic fraxinellone-loaded CGKRK-modified nanoparticles (Frax-NP-CGKRK) are constructed to regulate TGF-β signaling and siRNA-loaded lipid-coated calcium phosphate (LCP) biomimetic nanoparticles (siKras-LCP-ApoE3) are applied to interfere with the oncogenic KRAS. Frax-NP-CGKRK successfully targets the tumor sites through the recognition of overexpressed heparan sulfate proteoglycan, reverses the activated cancer-associated fibroblasts (CAFs), attenuates the dense stroma barrier, and enhances tumor blood perfusion. Afterward, siKras-LCP-ApoE3 is efficiently internalized by the tumor cells through macropinocytosis and specifically silencing KRAS mutation. Compared with gemcitabine, this sequential-targeting strategy significantly elongates the lifespans of pancreatic tumor-bearing animals, hence providing a promising approach for pancreatic cancer therapy.

Vinorelbine cationic liposomes modified with wheat germ agglutinin for inhibiting tumor metastasis in treatment of brain glioma

Glioma is the most common primary malignant brain tumor with a poor prognosis. The application of chemotherapeutic drugs is limited due to the existence of blood-brain barrier and serious side effects. Liposomes have been proven to be a stable and useful drug delivery system for tumors. In this paper, WGA (wheat germ agglutinin) modified vinorelbine cationic liposomes had been successfully constructed for treating glioma. In the liposomes, WGA was modified on the liposomal surface for crossing the blood-brain barrier and increasing the targeting effects, 3-(N-(N', N'-dimethylaminoethane) carbamoyl) cholesterol (DC-Chol) was used as cationic material and vinorelbine was encapsulated in the aqueous core of liposomes to inhibit tumor metastasis and kill tumor cells. Studies were performed on C6 cells in vitro and were verified in brain glioma-bearing mice in vivo. Results in vitro demonstrated that the targeting liposomes could induce C6 cells apoptosis, promote drugs across the blood-brain barrier, inhibit the metastasis of tumor cells and increase targeting effects to tumor cells. Meanwhile, action mechanism studies showed that the targeting liposomes could down-regulate PI3K, MMP-2, MMP-9 and FAK to inhibit tumor metastasis. Results in vivo exhibited that the targeting liposomes displayed an obvious antitumor efficacy by accumulating selectively in tumor site and exhibited low toxicity to blood system and major organs. Hence, WGA modified vinorelbine cationic liposomes might provide a safe and efficient therapy strategy for glioma.

Targeted Theranostic Nanoparticles for Brain Tumor Treatment

The poor prognosis and rapid recurrence of glioblastoma (GB) are associated to its fast-growing process and invasive nature, which make difficult the complete removal of the cancer infiltrated tissues. Additionally, GB heterogeneity within and between patients demands a patient-focused method of treatment. Thus, the implementation of nanotechnology is an attractive approach considering all anatomic issues of GB, since it will potentially improve brain drug distribution, due to the interaction between the blood⁻brain barrier and nanoparticles (NPs). In recent years, theranostic techniques have also been proposed and regarded as promising. NPs are advantageous for this application, due to their respective size, easy surface modification and versatility to integrate multiple functional components in one system. The design of nanoparticles focused on therapeutic and diagnostic applications has increased exponentially for the treatment of cancer. This dual approach helps to understand the location of the tumor tissue, the biodistribution of nanoparticles, the progress and efficacy of the treatment, and is highly useful for personalized medicine-based therapeutic interventions. To improve theranostic approaches, different active strategies can be used to modulate the surface of the nanotheranostic particle, including surface markers, proteins, drugs or genes, and take advantage of the characteristics of the microenvironment using stimuli responsive triggers. This review focuses on the different strategies to improve the GB treatment, describing some cell surface markers and their ligands, and reports some strategies, and their efficacy, used in the current research.

Myristic Acid-Modified DA7R Peptide for Whole-Process Glioma-Targeted Drug Delivery

The clinical treatment of aggressive glioma has been a great challenge, mainly because of the complexity of the glioma microenvironment and the existence of the blood-brain tumor barrier (BBTB)/blood-brain barrier (BBB), which severely hampers the effective accumulation of most therapeutic agents in the glioma region. Additionally, vasculogenic mimicry (VM), angiogenesis, and glioma stem cells (GSC) in malignant glioma also lead to the failure of clinical therapy. To address the aforementioned issues, a whole-process glioma-targeted drug delivery strategy was proposed. The ^DA7R peptide has effective BBTB-penetrating and notable glioma-, angiogenesis-, and VM-targeting abilities. Herein, we designed a myristic acid modified ^DA7R ligand (MC-^DA7R), which combines tumor-homing ^DA7R with BBB-penetrable MC. MC-^DA7R was then immobilized to PEGylated liposomes (MC-^DA7R-LS) to form a whole-process glioma-targeting system. MC-^DA7R-LS exhibited exceptional internalization in glioma, tumor neovascular, and brain capillary endothelial cells. Enhanced BBTB- and BBB-traversing efficiencies were also observed on MC-^DA7R-LS. Ex vivo imaging on brain tumors also demonstrated the feasibility of MC-^DA7R-LS in intracranial glioma-homing, whereas the immunofluorescence studies demonstrated its GSC and angiogenesis homing. Furthermore, doxorubicin-loaded MC-^DA7R-LS accomplished a remarkable therapeutic outcome, as a result of a synergistic improvement on the glioma microenvironment. Our study highlights the potential of the MC-modified ^DA7R peptide as a great candidate for the whole-process glioma-targeted drug delivery.

K237-modified thermosensitive liposome enhanced the delivery efficiency and cytotoxicity of paclitaxel in vitro

This study aimed to develop novel temperature-sensitive liposomes loading paclitaxel (PTX-TSL) and evaluate them in vitro to improve the delivery efficiency and targeting of PTX. K237 peptide was conjugated to the terminal NHS of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[hydroxyl succinimidyl (polyethylene glycol)-(DSPE-PEG-NHS), and K237-modified PTX-TSL (K237-PTX-TSL) was prepared using a film dispersion method. K237-TSL encapsulation with calcein was synthesized and used to determine the cellular uptake of TSL. The morphology of K237-PTX-TSL was observed using a transmission electron microscope. The particle size and potential were measured using a laser particle size analyzer. The phase transition temperature was detected using the differential scanning calorimetry. The Cell Counting Kit-8 assay and flow cytometry were used to evaluate the effects of K237-PTX-TSL on the proliferation and cell cycle of cell lines SKOV-3 and human umbilical vein endothelial cell (HUVEC). The encapsulation efficiency of K237-PTX-TSL was 94.23% ± 0.76%. The particle diameter was 88.3 ± 4.7 nm. K237-PTX-TSL showed a fast release profile at 42 °C, while it was stable at 37 °C. PTX-TSL combined with hyperthermia significantly inhibited the cell proliferation of SKOV-3 cells and HUVECs due to increased cell arrest in the G2/M phase. The half-minimal inhibitory concentration value of K237-PTX-TSL on SKOV-3 cells and HUVECs was 13.61 ± 1.81 and 5.54 ± 0.95 nmol/L, respectively, which were significantly lower than those with PTX-TSL (p < 0.01). K237 modification could increase the targeting efficiency of TSL to cancer cells and vascular endothelial cells, thus resulting in higher cytotoxicities compared with PTX-TSL, which might be a potential formulation for targeting cancer therapy.

Multi-targeting NGR-modified liposomes recognizing glioma tumor cells and vasculogenic mimicry for improving anti-glioma therapy

Like the anti-angiogenic strategy, anti-vascular mimicry is considered as a novel targeting strategy for glioma. In the present study, we used NGR as a targeting ligand and prepared NGR-modified liposomes containing combretastatin A4 (NGR-SSL-CA4) in order to evaluate their potential targeting of glioma tumor cells and vasculogenic mimicry (VM) formed by glioma cells as well as their anti-VM activity in mice with glioma tumor cells. NGR-SSL-CA4 was prepared by a thin-film hydration method. The in vitro targeting of U87-MG (human glioma tumor cells) by NGR-modified liposomes was evaluated. The in vivo targeting activity of NGR-modified liposomes was tested in U87-MG orthotopic tumor-bearing nude mice. The anti-VM activity of NGR-SSL-CA4 was also investigated in vitro and in vivo. The targeting activity of the NGR-modified liposomes was demonstrated by in vitro flow cytometry and in vivo biodistribution. The in vitro anti-VM activity of NGR-SSL-CA4 was indicated in a series of cell migration and VM channel experiments. NGR-SSL-CA4 produced very marked anti-tumor and anti-VM activity in U87-MG orthotopic tumor-bearing mice in vivo. Overall, the NGR-SSL-CA4 has great potential in the multi-targeting therapy of glioma involving U87-MG cells, and the VM formed by U87-MG cells as well as endothelial cells producing anti-U87-MG cells, and anti-VM formed by U87-MG cells as well as anti-endothelial cell activity.

Matrix Metalloproteinase Cleavable Nanoparticles for Tumor Microenvironment and Tumor Cell Dual-Targeting Drug Delivery

Matrix metalloproteinases (MMPs), mostly abundant in the tumor extracellular matrix (ECM), tumor cells, and tumor vasculatures, are closely correlated with tumor progression and metastasis. In this case, making use of MMPs was supposed to achieve site-specific drug delivery and a satisfactory tumor treatment effect. Herein, we rationally developed a novel tumor microenvironment and tumor cell dual-targeting nanoparticle by integrating a chemotherapeutic-loaded drug-loaded carrier and a versatile polypeptide-LinTT1-PVGLIG-TAT (LPT) which is composed of a multitargeting peptide-LinTT1 and a cell-penetrating peptide-TAT. The functionalized nanoparticles exhibited a superior affinity to A549 lung-cancer cells and microenvironment including angiogenesis and tumor-associated macrophages (TAMs) in our study. In addition, cellular experiments demonstrated that the cell-penetrating ability of TAT was significantly shielded by the addition of LinTT1 to the fourth lysine of the TAT via an MMP cleavable linker PVGLIG and could be recovered under the catalysis of MMPs. This design was supposed to efficiently decrease the toxicological risk to normal tissues induced by the unselectivity of TAT. The finally treatment effect investigation showed that tumor-bearing mice treated with LPT-modified nanoparticles achieved an enhanced efficacy for inhibiting tumor growth and the longest survival time as compared to other groups. Collectively, this study provides a novel robust nanoplatform which could simultaneously target the tumor microenvironment and tumor cell drug delivery for increasing the efficacy of cancer therapy.

Seek & Destroy, use of targeting peptides for cancer detection and drug delivery

Accounting for 16 million new cases and 9 million deaths annually, cancer leaves a great number of patients helpless. It is a complex disease and still a major challenge for the scientific and medical communities. The efficacy of conventional chemotherapies is often poor and patients suffer from off-target effects. Each neoplasm exhibits molecular signatures - sometimes in a patient specific manner - that may completely differ from the organ of origin, may be expressed in markedly higher amounts and/or in different location compared to the normal tissue. Although adding layers of complexity in the understanding of cancer biology, this cancer-specific signature provides an opportunity to develop targeting agents for early detection, diagnosis, and therapeutics. Chimeric antibodies, recombinant proteins or synthetic polypeptides have emerged as excellent candidates for specific homing to peripheral and central nervous system cancers. Specifically, peptide ligands benefit from their small size, easy and affordable production, high specificity, and remarkable flexibility regarding their sequence and conjugation possibilities. Coupled to imaging agents, chemotherapies and/or nanocarriers they have shown to increase the on-site delivery, thus allowing better tumor mass contouring in imaging and increased efficacy of the chemotherapies associated with reduced adverse effects. Therefore, some of the peptides alone or in combination have been tested in clinical trials to treat patients. Peptides have been well-tolerated and shown absence of toxicity. This review aims to offer a view on tumor targeting peptides that are either derived from natural peptide ligands or identified using phage display screening. We also include examples of peptides targeting the high-grade malignant tumors of the central nervous system as an example of the complex therapeutic management due to the tumor's location. Peptide vaccines are outside of the scope of this review.

EGFR/EGFRvIII Dual-Targeting Peptide-Mediated Drug Delivery for Enhanced Glioma Therapy

Tumor-homing peptides have been widely used to mediate active targeted drug delivery. l-AE is a reported targeting peptide demonstrating high binding affinity to epidermal growth factor receptor (EGFR) and mutation variant III (EGFRvIII) overexpressed on neovasculature, vasculogenic mimicry, tumor cells, and tumor stem cells. To improve its proteolytic stability, a d-peptide ligand (termed d-AE, the enantiomer of l-AE) was developed. d-AE was confirmed to bind receptors EGFR and EGFRvIII with targeting capability comparable to l-AE. In vivo biodistribution demonstrated the superiority of d-AE in prolonged circulation and enhanced intratumoral accumulation. Furthermore, stabilized peptide modification endowed micelles higher transcytosis efficiency and penetrating capability on blood-brain tumor barrier/U87 tumor spheroids coculture model. When paclitaxel (PTX) was loaded, d-AE-micelle/PTX demonstrated excellent antitumor effect in comparison to Taxol, micelle/PTX, and l-AE-micelle/PTX. These findings indicated that the multitargeted drug delivery system enabled by d-AE ligand provides a promising way for glioma therapy.

Application of dual targeting drug delivery system for the improvement of anti-glioma efficacy of doxorubicin

Chemotherapy of glioma is always hampered by the unsatisfactory tumor accumulation of drugs, of which the most noticeable obstacle is the limited drug permeability from vessels into tumor inner. In the present study, we developed a novel nanocarrier for the delivery of doxorubicin to brain tumor. Such novel drug delivery system was mainly composed of a tumor homing peptide and DOX-loaded PLA nanoparticles (AP1-NP-DOX). CRKRLDRNC peptide, named as AP1, was a newly glioma affinity peptide which could specifically binds to interleukin-4 receptor (IL-4R), highly expressing on both glioma cells and angiogenesis. Our findings showed that the peptide-functionalized nanoparticles had a high affinity with both tumor cells and vascular endothelial cells. Besides, tumor targeting assay exhibited that AP1 decorated nanoparticles accumulated more in tumor site than the unmodified ones. Moreover, the results of tumor uptake experiments indicated that AP1-NP-DOX might own the ability of blood brain barrier (BBB) penetration. In the anti-glioma study, AP1-NP-DOX exhibited the highest therapeutic effect on tumor-bearing mice compared with the unmodified nanoparticles and free doxorubicin. These results together indicated that AP1-functionalized nanoparticles could represent a promising way to expand the treatment horizons of onco-therapy.

Dual-functional drug liposomes in treatment of resistant cancers

Efficacy of regular chemotherapy is significantly hampered by multidrug resistance (MDR) and severe systemic toxicity. The reduced toxicity has been evidenced after administration of drug liposomes, consisting of the first generation of regular drug liposomes, the second generation of long-circulation drug liposomes, and the third generation of targeting drug liposomes. However, MDR of cancers remains as an unsolved issue. The objective of this article is to review the dual-functional drug liposomes, which demonstrate the potential in overcoming MDR. Herein, dual-functional drug liposomes are referring to the drug-containing phospholipid bilayer vesicles that possess a dual-function of providing the basic efficacy of drug and the extended effect of the drug carrier. They exhibit unique roles in treatment of resistant cancer via circumventing drug efflux caused by adenosine triphosphate binding cassette (ABC) transporters, eliminating cancer stem cells, destroying mitochondria, initiating apoptosis, regulating autophagy, destroying supply channels, utilizing microenvironment, and silencing genes of the resistant cancer. As the prospect of an estimation, dual-functional drug liposomes would exhibit more strength in their extended function, hence deserving further investigation for clinical validation.

Multifunctional targeted liposomal drug delivery for efficient glioblastoma treatment

Glioblastoma multiforme (GBM) has been considered to be the most malignant brain tumors. Due to the existence of various barriers including the blood–brain barrier (BBB) and blood–brain tumor barrier (BBTB) greatly hinder the accumulation and deep penetration of chemotherapeutics, the treatment of glioma remains to be the most challenging task in clinic. In order to circumvent these hurdles, we developed a multifunctional liposomal glioma-targeted drug delivery system (c(RGDyK)/pHA-LS) modified with cyclic RGD (c(RGDyK)) and p-hydroxybenzoic acid (pHA) in which c(RGDyK) could target integrin α_vβ₃ overexpressed on the BBTB and glioma cells and pHA could target dopamine receptors on the BBB. In vitro, c(RGDyK)/pHA-LS could target glioblastoma cells (U87), brain capillary endothelial cells (bEnd.3) and umbilical vein endothelial cells (HUVECs) through a comprehensive pathway. Besides, c(RGDyK)/pHA-LS could also increase the cytotoxicity of doxorubicin encapsulated in liposomes on glioblastoma cells, and was able to penetrate inside the glioma spheroids after traversing the in vitro BBB and BBTB. In vivo, we demonstrated the targeting ability of c(RGDyK)/pHA-LS to intracranial glioma. As expected, c(RGDyK)/pHA-LS/DOX showed a median survival time of 35 days, which was 2.31-, 1.76- and 1.5-fold higher than that of LS/DOX, c(RGDyK)-LS/DOX, and pHA-LS/DOX, respectively. The findings here suggested that the multifunctional glioma-targeted drug delivery system modified with both c(RGDyK) and pHA displayed strong antiglioma efficiency in vitro and in vivo, representing a promising platform for glioma therapy.