Pep-1&borneol-Bifunctionalized Carmustine-Loaded Micelles Enhance Anti-Glioma Efficacy Through Tumor-Targeting and BBB-Penetrating

Dual fluorescence images, transport pathway, and blood-brain barrier penetration of B-Met-W/O/W SE

Borneol is an aromatic traditional Chinese medicine that can improve the permeability of the blood-brain barrier (BBB), enter the brain, and promote the brain tissue distribution of many other drugs. In our previous study, borneol-metformin hydrochloride water/oil/water composite submicron emulsion (B-Met-W/O/W SE) was prepared using borneol and SE to promote BBB penetration, which significantly increased the brain distribution of Met. However, the dynamic images, transport pathway (uptake and efflux), promotion of BBB permeability, and mechanisms of B-Met-W/O/W SE before and after entering cells have not been clarified. In this study, rhodamine B and coumarin-6 were selected as water-soluble and oil-soluble fluorescent probes to prepare B-Met-W/O/W dual-fluorescent SE (B-Met-W/O/W DFSE) with concentric circle imaging. B-Met-W/O/W SE can be well taken up by brain microvascular endothelial cells (BMECs). The addition of three inhibitors (chlorpromazine hydrochloride, methyl-β-cyclodextrin, and amiloride hydrochloride) indicated that its main pathway may be clathrin-mediated and fossa protein-mediated endocytosis. Meanwhile, B-Met-W/O/W SE was obviously shown to inhibit the efflux of BMECs. Next, BMECs were cultured in the Transwell chamber to establish a BBB model, and Western blot was employed to detect the protein expressions of Occludin, Zona Occludens 1 (ZO-1), and p-glycoprotein (P-gp) after B-Met-W/O/W SE treatment. The results showed that B-Met-W/O/W SE significantly down-regulated the expression of Occludin, ZO-1, and P-gp, which increased the permeability of BBB, promoted drug entry into the brain through BBB, and inhibited BBB efflux. Furthermore, 11 differentially expressed genes (DEGs) and 7 related signaling pathways in BMECs treated with B-W/O/W SE were detected by transcriptome sequencing and verified by quantitative real-time polymerase chain reaction (qRT-PCR). These results provide a scientific experimental basis for the dynamic monitoring, transmembrane transport mode, and permeation-promoting mechanism of B-Met-W/O/W SE as a new brain-targeting drug delivery system.

Investigation of cytotoxic antiproliferative and antiapoptotic effects of nanosized boron phosphate filled sodium alginate composite on glioblastoma cancer cells

BACKGROUND

The effects of nanosized boron phosphate-filled sodium alginate composite gel (SA/BP) on the biological characteristics of three types of glioblastoma multiforme (GBM) cells (C6, U87MG and T98G) were examined in this study. MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) assay was used to determine the cytotoxicity of the composite gel on GBM, which was then compared to L929 healthy cells. Furthermore, wound healing, apoptosis, and colony formation capacities were evaluated. The investigation revealed that the SA/BP composite gel was successful in all GBM cells and could be used as a treatment agent for GBM and/or other invasive cancer types.

METHODS AND RESULTS

According to the results, the SA/BP composite gel had no effect on healthy fibroblast cells but had a lethal effect on all glioblastoma cells. Additionally, the wound healing method was used to examine the effect of the SA/BP composite gel on cell migration. It was discovered that the wound closed in 24 h in untreated control group cells, while the SA/BP composite gel closed up to 29.62%, 26.77% and 11.31% of the wound for C6, U87MG and T98G cell lines respectively. SA/BP significantly reduced cell migration in cancer cells. The effect of the generated SA/BP composite gel on cell colony development was assessed using a colony formation assay, and the cells reduced colony formation for all GBMs. It was roughly 45% for 24 h and 30% for 48 h when compared to the control group for C6 cells, 33%(24 h) and 40%(48 h) for U87MG cells, 40%(24 h) and 43%(48 h) for T98G cells. DAPI(4',6-Diamidino-2-phenylindole) and JC-1(5,5',6,6'-Tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine, iodide) staining to evaluate apoptosis revealed that the SA/BP composite gel dramatically enhanced the frequency of all GBMs undergoing apoptosis.

CONCLUSIONS

In line with experimental findings, it was observed that the SA/BP composite gel system did not affect healthy fibroblast cells but had a cytotoxic effect on glioblastoma cells, significantly reduced cell migration and colony-forming capacity of cells, and significantly increased apoptosis and depolarization of cell membranes. Based on all these findings, it can be said that SA/BP composite gel has cytotoxic, antiproliferative and antiapoptotic effects on different glioblastoma cells.

Recent Advances in Nanotechnology-Based Targeted Delivery Systems of Active Constituents in Natural Medicines for Cancer Treatment

Owing to high efficacy and safety, natural medicines have found their way into the field of cancer therapy over the past few decades. However, the effective ingredients of natural medicines have shortcomings of poor solubility and low bioavailability. Nanoparticles can not only solve the problems above but also have outstanding targeting ability. Targeting preparations can be classified into three levels, which are target tissues, cells, and organelles. On the premise of clarifying the therapeutic purpose of drugs, one or more targeting methods can be selected to achieve more accurate drug delivery and consequently to improve the anti-tumor effects of drugs and reduce toxicity and side effects. The aim of this review is to summarize the research status of natural medicines' nano-preparations in tumor-targeting therapies to provide some references for further accurate and effective cancer treatments.

Enhancing the stability, BBB permeability and neuroprotective activity of verbascoside in vitro using lipid nanocapsules in combination with menthol

Verbascoside (VER) shows promising neuroprotective activity. However, the instability and low permeability in crossing the blood-brain barrier (BBB) greatly hinder its application. In the present study, verbascoside was encapsulated into lipid nanocapsules (LNC) by reverse micelle (RM) to increase its stability. Besides, we used VER-RM-LNC combined with an envoy drug, menthol, to improve its BBB permeability and neuroprotective activity. VER-RM-LNC was prepared by the phase inversion temperature method, resulting in an encapsulation efficiency of nearly 85 %. The formulated VER-RM-LNC was stable for 6 months at 4 °C. VER encapsulated into LNC possessed enhanced stability and a reduced release profile. Menthol increased the cellular uptake and the permeability of VER-RM-LNC in the BBB model in vitro. In addition, the improved neuroprotective activity of VER through incubation with menthol and VER-RM-LNC was verified in the neurotoxic human brain microvascular endothelial cells model induced by Aβ_25-35.

Functionalized nanoparticles crossing the brain-blood barrier to target glioma cells

Glioma is the most common tumor of the central nervous system (CNS), with a 5-year survival rate of <35%. Drug therapy, such as chemotherapeutic and immunotherapeutic agents, remains one of the main treatment modalities for glioma, including temozolomide, doxorubicin, bortezomib, cabazitaxel, dihydroartemisinin, immune checkpoint inhibitors, as well as other approaches such as siRNA, ferroptosis induction, etc. However, the filter function of the blood-brain barrier (BBB) reduces the amount of drugs needed to effectively target CNS tumors, making it one of the main reasons for poor drug efficacies in glioma. Thus, finding a suitable drug delivery platform that can cross the BBB, increase drug aggregation and retainment in tumoral areas and avoid accumulation in non-targeted areas remains an unsolved challenge in glioma drug therapy. An ideal drug delivery system for glioma therapy should have the following features: (1) prolonged drug life in circulation and effective penetration through the BBB; (2) adequate accumulation within the tumor (3) controlled-drug release modulation; (4) good clearance from the body without significant toxicity and immunogenicity, etc. In this regard, due to their unique structural features, nanocarriers can effectively span the BBB and target glioma cells through surface functionalization, providing a new and effective strategy for drug delivery. In this article, we discuss the characteristics and pathways of different nanocarriers for crossing the BBB and targeting glioma by listing different materials for drug delivery platforms, including lipid materials, polymers, nanocrystals, inorganic nanomaterials, etc.

Advances in anti-invasive fungal drug delivery systems

Currently, the first-line drugs for invasive fungal infections (IFI), such as amphotericin B, fluconazole and itraconazole, have drawbacks including poor water solubility, low bioavailability, and severe side effects. Using drug delivery systems is a promising strategy to improve the efficacy and safety of traditional antifungal therapy. Synthetic and biomimetic carriers have greatly facilitated the development of targeted delivery systems for antifungal drugs. Synthetic carrier drug delivery systems, such as liposomes, nanoparticles, polymer micelles, and microspheres, can improve the physicochemical properties of antifungal drugs, prolong their circulation time, enhance targeting capabilities, and reduce toxic side effects. Cell membrane biomimetic drug delivery systems, such as macrophage or red blood cell membrane-coated drug delivery systems, retain the membrane structure of somatic cells and confer various biological functions and specific targeting abilities to the loaded antifungal drugs, exhibiting better biocompatibility and lower toxicity. This article reviews the development of antifungal drug delivery systems and their application in the treatment of IFI, and also discusses the prospects of novel biomimetic carriers in antifungal drug delivery.

Formation of a traditional Chinese medicine self-assembly nanostrategy and its application in cancer: a promising treatment

Traditional Chinese medicine (TCM) has been used for centuries to prevent and treat a variety of illnesses, and its popularity is increasing worldwide. However, the clinical applications of natural active components in TCM are hindered by the poor solubility and low bioavailability of these compounds. To address these issues, Chinese medicine self-assembly nanostrategy (CSAN) is being developed. Many active components of TCM possess self-assembly properties, allowing them to form nanoparticles (NPs) through various noncovalent forces. Self-assembled NPs (SANs) are also present in TCM decoctions, and they are closely linked to the therapeutic effects of these remedies. SAN is gaining popularity in the nano research field due to its simplicity, eco-friendliness, and enhanced biodegradability and biocompatibility compared to traditional nano preparation methods. The self-assembly of active ingredients from TCM that exhibit antitumour effects or are combined with other antitumour drugs has generated considerable interest in the field of cancer therapeutics. This paper provides a review of the principles and forms of CSAN, as well as an overview of recent reports on TCM that can be used for self-assembly. Additionally, the application of CSAN in various cancer diseases is summarized, and finally, a concluding summary and thoughts are proposed. We strongly believe that CSAN has the potential to offer fresh strategies and perspectives for the modernization of TCM.

Polydopamine-based loaded temozolomide nanoparticles conjugated by peptide-1 for glioblastoma chemotherapy and photothermal therapy

Purpose: Nanoparticles (NPs) of the polydopamine (PDA)-based,loaded with temozolomide (TMZ) and conjugated with Pep-1 (Peptide-1) as a feasible nano-drug delivery system were constructed and utilized for chemotherapy (CT) and photothermal therapy (PTT) of glioblastoma (GBM). Method: PDA NPs were synthesized from dopamine (DA) hydrochloride and reacted with TMZ to obtain the PDA-TMZ NPs and then the PDA NPs and the PDA-TMZ NPs were conjugated and modified by Pep-1 to obtain the Pep-1@PDA NPs and Pep-1@PDA-TMZ NPs via the Schiff base reaction (SBR), respectively.Their dimensions, charge, and shape were characterized by dynamic light scattering (DLS) and scanning electron microscope (SEM). The assembly of TMZ was verified by Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet and visible spectroscopy (UV-Vis). The biostability of both the nanocarrier and the synthetic NPs were validated using water and fetal bovine serum (FBS). The antitumor activities of the PDA-TMZ NPs and Pep-1@PDA-TMZ NPs were verified in U87 cells and tumor-bearing nude mice. Results: The prepared PDA NPs, PDA-TMZ NPs, Pep-1@PDA NPs, and Pep-1@PDA-TMZ NPs were regular and spherical, with dimension of approximately 122, 131, 136, and 140 nm, respectively. The synthetic nanoparticles possessed good dispersity, stability,solubility, and biocompatibility. No obvious toxic side effects were observed, and the loading rate of TMZ was approximately 50%.In vitro research indicated that the inhibition ratio of the Pep-1@PDA-TMZ NPs combined with 808 nm laser was approximately 94% for U87 cells and in vivo research was approximately 77.13%, which was higher than the ratio of the other groups (p < 0.05). Conclusion: Pep-1 was conjugated and modified to PDA-TMZ NPs, which can serve as a new targeted drug nano-delivery system and can offer a CT and PTT integration therapy against GBM. Thus, Pep-1@PDA-TMZ NPs could be a feasible approach for efficient GBM therapy, and further provide some evidence and data for clinical transformation so that gradually conquer GBM.

Polydopamine-based loaded temozolomide nanoparticles conjugated by peptide-1 for glioblastoma chemotherapy and photothermal therapy

Purpose: Nanoparticles (NPs) of the polydopamine (PDA)-based,loaded with temozolomide (TMZ) and conjugated with Pep-1 (Peptide-1) as a feasible nano-drug delivery system were constructed and utilized for chemotherapy (CT) and photothermal therapy (PTT) of glioblastoma (GBM).

Method: PDA NPs were synthesized from dopamine (DA) hydrochloride and reacted with TMZ to obtain the PDA-TMZ NPs and then the PDA NPs and the PDA-TMZ NPs were conjugated and modified by Pep-1 to obtain the Pep-1@PDA NPs and Pep-1@PDA-TMZ NPs via the Schiff base reaction (SBR), respectively.Their dimensions, charge, and shape were characterized by dynamic light scattering (DLS) and scanning electron microscope (SEM). The assembly of TMZ was verified by Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet and visible spectroscopy (UV-Vis). The biostability of both the nanocarrier and the synthetic NPs were validated using water and fetal bovine serum (FBS). The antitumor activities of the PDA-TMZ NPs and Pep-1@PDA-TMZ NPs were verified in U87 cells and tumor-bearing nude mice.

Results: The prepared PDA NPs, PDA-TMZ NPs, Pep-1@PDA NPs, and Pep-1@PDA-TMZ NPs were regular and spherical, with dimension of approximately 122, 131, 136, and 140 nm, respectively. The synthetic nanoparticles possessed good dispersity, stability,solubility, and biocompatibility. No obvious toxic side effects were observed, and the loading rate of TMZ was approximately 50%.In vitro research indicated that the inhibition ratio of the Pep-1@PDA-TMZ NPs combined with 808 nm laser was approximately 94% for U87 cells and in vivo research was approximately 77.13%, which was higher than the ratio of the other groups (p &lt; 0.05).

Conclusion: Pep-1 was conjugated and modified to PDA-TMZ NPs, which can serve as a new targeted drug nano-delivery system and can offer a CT and PTT integration therapy against GBM. Thus, Pep-1@PDA-TMZ NPs could be a feasible approach for efficient GBM therapy, and further provide some evidence and data for clinical transformation so that gradually conquer GBM.

Norbornene and Related Structures as Scaffolds in the Search for New Cancer Treatments

The norbornene scaffold has arisen as a promising structure in medicinal chemistry due to its possible therapeutic application in cancer treatment. The development of norbornene-based derivatives as potential chemotherapeutic agents is attracting significant attention. Here, we report an unprecedented review on the recent advances of investigations into the antitumoral efficacy of different compounds, including the abovementioned bicyclic scaffold in their structure, in combination with chemotherapeutic agents or forming metal complexes. The impact that structural modifications to these bicyclic compounds have on the antitumoral properties and the mechanisms by which these norbornene derivatives act are discussed in this review. In addition, the use of norbornene, and its related compounds, encapsulation in nanosystems for its use in cancer therapies is here detailed.

Advances in Preclinical/Clinical Glioblastoma Treatment: Can Nanoparticles Be of Help?

Simple Summary

As one of the most lethal human cancers, glioblastoma treatment is a real challenge because of several resistance mechanisms, including limited drug entry into the central nervous system through the blood–brain barrier and the vast heterogeneity of this family of tumors. In the development of precision medicine, various nanoconstructs are being proposed to cross the BBB, specifically target GB tumors, release the therapeutic cargo in a controlled manner, and reduce therapeutic resistance. This review summarizes the different families of nanoparticles and approaches followed so far pursuing these aims.

Abstract

Glioblastoma multiforme (GB) is the most aggressive and frequent primary malignant tumor in the central nervous system (CNS), with unsatisfactory and challenging treatment nowadays. Current standard of care includes surgical resection followed by chemotherapy and radiotherapy. However, these treatments do not much improve the overall survival of GB patients, which is still below two years (the 5-year survival rate is below 7%). Despite various approaches having been followed to increase the release of anticancer drugs into the brain, few of them demonstrated a significant success, as the blood brain barrier (BBB) still restricts its uptake, thus limiting the therapeutic options. Therefore, enormous efforts are being devoted to the development of novel nanomedicines with the ability to cross the BBB and specifically target the cancer cells. In this context, the use of nanoparticles represents a promising non-invasive route, allowing to evade BBB and reducing systemic concentration of drugs and, hence, side effects. In this review, we revise with a critical view the different families of nanoparticles and approaches followed so far with this aim.

Peptides as Pharmacological Carriers to the Brain: Promises, Shortcomings and Challenges

Central nervous system (CNS) diseases are among the most difficult to treat, mainly because the vast majority of the drugs fail to cross the blood-brain barrier (BBB) or to reach the brain at concentrations adequate to exert a pharmacological activity. The obstacle posed by the BBB has led to the in-depth study of strategies allowing the brain delivery of CNS-active drugs. Among the most promising strategies is the use of peptides addressed to the BBB. Peptides are versatile molecules that can be used to decorate nanoparticles or can be conjugated to drugs, with either a stable link or as pro-drugs. They have been used to deliver to the brain both small molecules and proteins, with applications in diverse therapeutic areas such as brain cancers, neurodegenerative diseases and imaging. Peptides can be generally classified as receptor-targeted, recognizing membrane proteins expressed by the BBB microvessels (e.g., Angiopep2, CDX, and iRGD), "cell-penetrating peptides" (CPPs; e.g. TAT_47-57, SynB1/3, and Penetratin), undergoing transcytosis through unspecific mechanisms, or those exploiting a mixed approach. The advantages of peptides have been extensively pointed out, but so far few studies have focused on the potential negative aspects. Indeed, despite having a generally good safety profile, some peptide conjugates may display toxicological characteristics distinct from those of the peptide itself, causing for instance antigenicity, cardiovascular alterations or hemolysis. Other shortcomings are the often brief lifetime in vivo, caused by the presence of peptidases, the vulnerability to endosomal/lysosomal degradation, and the frequently still insufficient attainable increase of brain drug levels, which remain below the therapeutically useful concentrations. The aim of this review is to analyze not only the successful and promising aspects of the use of peptides in brain targeting but also the problems posed by this strategy for drug delivery.

Polymeric nanoparticles for drug delivery in glioblastoma: State of the art and future perspectives

Glioblastoma (GBM) is an aggressive, fatal and malignant primary brain tumor. Despite the current standard treatment for glioblastoma patients including neurosurgical resection, followed by concomitant radiation and chemotherapy, the median survival rate is only about 15 months. An unresolved challenge for current therapies is related to getting drugs through the blood-brain barrier (BBB), which hinders many chemotherapeutic agents from reaching tumors cells. Although a large amount of research has been done to circumvent the BBB and deliver drugs to the brain, with nanoparticles (NPs) taking the lead, the challenge is still high. In this regard, the BBB and how to transfer drug pathways through the BBB, especially using NPs, are introduced here. Afterwards, the latest advances in drug delivery, co-drug delivery, and combination modalities are described specifically for GBM treatments using natural and synthetic polymeric NPs and adjuvant therapies including hyperthermia, photodynamic therapy and also ketogenic regimens. In addition, receptor-mediated endocytosis agents that exist in endothelial capillary cells of the brain are explained. Lastly, future directions to finally deliver drugs through the BBB for GBM treatment are emphasized. It is the hope that this review can provide a number of practical pathways for the future development of BBB permeable nanochemotherapeutics against GBM.

Recent Progress on the Synergistic Antitumor Effect of a Borneol-Modified Nanocarrier Drug Delivery System

Borneol, a traditional Chinese medicine, can enhance therapeutic efficacy by guiding the active ingredients to the target site. Reportedly, borneol improves the penetration capacity of the nasal, cornea, transdermal, intestinal, and blood-brain barriers. Although nanotechnology dramatically changed the face of oncology by targeting tumor sites, the efficiency of nanoparticles delivered to tumor sites is very low, with only 0.7% of the total particles delivered. Thus, based on the penetration ability and the inhibition drug efflux of borneol, it was expected to increase the targeting and detention efficacy of drugs into tumor sites in nanocarriers with borneol modification. Borneol modified nanocarriers used to improve drug-targeting has become a research focus in recent years, but few studies in this area, especially in the antitumor application. Hence, this review summarizes the recent development of nanocarriers with borneol modification. We focus on the updated works of improving therapeutic efficacy, reducing toxicity, inhibiting tumor metastasis, reversing multidrug resistance, and enhancing brain targeting to expand their application and provide a reference for further exploration of targeting drug delivery systems for solid tumor treatment.

miR-9-5p Mediates ABCC1 to Elevate the Sensitivity of Glioma Cells to Temozolomide

Chemotherapy combined with surgery is an important clinical treatment for glioma, but endogenous or acquired temozolomide (TMZ) resistance can lead to poor prognosis. microRNA (miR)-9-5p acts in biological function of glioma, but the drug resistance of miR-9-5p in glioma is under exploration. The study intended to test the molecular mechanism of miR-9-5p in glioma cells. MTT assay was applied to investigate the chemosensitivity enhancement of miR-9-5p on TMZ in glioma cells U87-TMZ and U251-TMZ, and in vivo experiments confirmed its role on tumor growth in nude mice. The results of double luciferase reporter gene assay, qRT-PCR and WB indicated that miR-9-5p directly targeted ABCC1 (ATP binding cassette subfamily C member 1) to reduce its expressions. MTT and flow cytometry indicated that elevation of miR-9-5p or down-regulation of ABCC1 could inhibit proliferation-induced apoptosis of drug-resistant cells, and the decrease of miR-9-5p could reverse the reduction of ABCC1 on proliferation-induced apoptosis of drug-resistant cells. In vivo experiments showed that miR-9-5p could promote the anti-tumor role of TMZ. To sum up, the increase of miR-9-5p directly targets ABCC1 and may make glioma cells sensitive to TMZ.

Selenium-driven enhancement of synergistic cancer chemo-/radiotherapy by targeting nanotherapeutics

To overcome drug resistance in hypoxic tumors and the limitations of radiation impedance and radiation dose, we developed a nano-radiosensitizer to improve the efficacy of cancer radiotherapy. We used multifunctional mesoporous silica nanoparticles (MSNs) as the carriers for a novel anticancer selenadiazole derivative (SeD) and modified its surface with folic acid (FA) to enhance its cervical cancer-targeting effects, forming the nanosystem named SeD@MSNs-FA. Upon radiation, SeD@MSNs-FA inhibits the growth of cervical cancer cells by inducing apoptosis through the death receptor-mediated apoptosis pathway and S phase arrest, significantly improving the sensitivity of cervical cancer cells to X-ray radiation. The combined activity of SeD@MSN-FA and radiation can promote excessive production of intracellular reactive oxygen species (ROS) and induce cell apoptosis by affecting p53, protein kinase B (AKT), and mitogen-activated protein kinase (MAPK) pathways. Furthermore, SeD@MSNs-FA can effectively inhibit tumor growth of xenografted HeLa tumors in nude mice. The toxicity analysis of SeD@MSNs-FA nanoparticles in vivo and the histological analysis performed in the mouse model showed that under the current experimental conditions, the nanoparticles induced no significant damage to the heart, liver, spleen, lungs, kidneys, or other major organs. Taken together, this study provides a translational nanomedicine-based strategy for the simultaneous chemo- and radiotherapy of cervical cancer and sheds light on potential mechanisms that can be used to overcome radiotherapeutic resistance.

Borneol: a Promising Monoterpenoid in Enhancing Drug Delivery Across Various Physiological Barriers

Incorporation of permeation enhancers is one of the most widely employed approaches for delivering drugs across biological membranes. Permeation enhancers aid in delivering drugs across various physiological barriers such as brain capillary endothelium, stratum corneum, corneal epithelium, and mucosal membranes that pose resistance to the entry of a majority of drugs. Borneol is a natural, plant-derived, lipophilic, volatile, bicyclic monoterpenoid belonging to the class of camphene. It has been used under the names "Bing Pian" or "Long Nao" in Traditional Chinese Medicine for more than 1000 years. Borneol has been incorporated predominantly as an adjuvant in the traditional Chinese formulations of centrally acting drugs to improve drug delivery to the brain. This background knowledge and anecdotal evidence have led to extensive research in establishing borneol as a permeation enhancer across the blood-brain barrier. Alteration in cell membrane lipid structures and modulation of multiple ATP binding cassette transporters as well as tight junction proteins are the major contributing factors to blood-brain barrier opening functions of borneol. Owing to these mechanisms of altering membrane properties, borneol has also shown promising potential to improve drug delivery across other physiological barriers as well. The current review focuses on the role of borneol as a permeation enhancer across the blood-brain barrier, mucosal barriers including nasal and gastrointestinal linings, transdermal, transcorneal, and blood optic nerve barrier.

Borneol in cardio-cerebrovascular diseases: Pharmacological actions, mechanisms, and therapeutics

With the coming acceleration of global population aging, the incidence rate of cardio-cerebrovascular diseases (CVDs) is increasing. It has become the leading cause of human mortality. As a natural drug, borneol (BO) not only has anti-inflammatory, anti-oxidant, anti-apoptotic, anti-coagulant activities and improves energy metabolism but can also promote drugs to enter the target organs or tissues through various physiological barriers, such as the blood-brain barrier (BBB), mucous membrane, skin. Thus, it has a significant therapeutic effect on various CVDs, which has been confirmed in a large number of studies. However, the pharmacological actions and mechanisms of BO on CVDs have not been fully investigated. Hence, this review summarizes the pharmacological actions and possible mechanisms of BO, which provides novel ideas for the treatment of CVDs.

Blood-Brain Barrier Modulation to Improve Glioma Drug Delivery

The blood-brain barrier (BBB) is formed by brain microvascular endothelial cells that are sealed by tight junctions, making it a significant obstacle for most brain therapeutics. The poor BBB penetration of newly developed therapeutics has therefore played a major role in limiting their clinical success. A particularly challenging therapeutic target is glioma, which is the most frequently occurring malignant brain tumor. Thus, to enhance therapeutic uptake in tumors, researchers have been developing strategies to modulate BBB permeability. However, most conventional BBB opening strategies are difficult to apply in the clinical setting due to their broad, non-specific modulation of the BBB, which can result in damage to normal brain tissue. In this review, we have summarized strategies that could potentially be used to selectively and efficiently modulate the tumor BBB for more effective glioma treatment.

Recent Progress of Nanocarrier-Based Therapy for Solid Malignancies

Conventional chemotherapy is still an important option of cancer treatment, but it has poor cell selectivity, severe side effects, and drug resistance. Utilizing nanoparticles (NPs) to improve the therapeutic effect of chemotherapeutic drugs has been highlighted in recent years. Nanotechnology dramatically changed the face of oncology by high loading capacity, less toxicity, targeted delivery of drugs, increased uptake to target sites, and optimized pharmacokinetic patterns of traditional drugs. At present, research is being envisaged in the field of novel nano-pharmaceutical design, such as liposome, polymer NPs, bio-NPs, and inorganic NPs, so as to make chemotherapy effective and long-lasting. Till now, a number of studies have been conducted using a wide range of nanocarriers for the treatment of solid tumors including lung, breast, pancreas, brain, and liver. To provide a reference for the further application of chemodrug-loaded nanoformulations, this review gives an overview of the recent development of nanocarriers, and the updated status of their use in the treatment of several solid tumors.

Enhanced Anti-Glioma Efficacy by Borneol Combined With CGKRK-Modified Paclitaxel Self-Assembled Redox-Sensitive Nanoparticles

The serious therapeutic obstacles to glioma treatment include poor penetration across the blood-brain barrier (BBB) and low accumulation of therapeutic drugs at tumor sites. In this study, borneol combined with CGKRK peptide (a ligand of the heparan sulfate which overexpress on the glioma cells) modified paclitaxel prodrug self-assembled redox-responsive nanoparticles (CGKRK-PSNPs) were hypothesized to enhance the BBB penetration ability and active tumor targeting efficiency, respectively. The resulting CGKRK-PSNPs possessed a spherical shape with a small particle size (105.61 ± 1.53 nm) and high drug loading for PTX (54.18 ± 1.13%). The drug release behavior proved that CGKRK-PSNPs were highly sensitive to glutathione (GSH) redox environment. The in vitro cell experiments suggested that CGKRK-PSNPs significantly increased the cellular uptake and cytotoxicity of U87MG cells, meanwhile CGKRK-PSNPs showed the low cytotoxicity against BCEC cells. Combined with borneol, CGKRK-PSNPs exhibited enhanced transportation across in vitro BBB model. In intracranial U87MG glioma-bearing nude mice, the higher accumulation of CGKRK-PSNPs combined with borneol was observed through real-time fluorescence image. Moreover, the in vivo anti-glioma results confirmed that CGKRK-PSNPs combined with borneol could improve the anti-glioma efficacy with the prolonged medium survival time (39 days). In conclusion, the collaborative strategy of CGKRK-PSNPs combined with borneol provided a promising drug delivery routine for glioblastoma therapy.

Borneol and poly (ethylene glycol) dual modified BSA nanoparticles as an itraconazole vehicle for brain targeting

Itraconazole (ITZ) can be used for the treatment of cryptococcus neoformans meningitis and aspergillus brain abscess. While, the inherent hydrophobicity of ITZ and the existence of blood brain barrier (BBB) limit its applications as a central nervous system drug. In this study, a novel brain targeting drug delivery system based on bovine serum albumin (BSA) was constructed for enhancing ITZ distribution in brain. Firstly, ITZ was loaded into BSA nanoparticles (ITZ-NPs) with 11.6% of drug loading. Subsequently, the nanoparticles were modified with borneol (BO) and polyethylene glycol (PEG) (PEG/BO-ITZ-NPs). The resulting nanoparticles retained their nanosize (186.3 nm), uniform and spherical morphology, and negative surface charge (-21.03 mV). Cell uptake studies showed that compared with ITZ-NPs, PEG/BO-ITZ-NPs had significantly increased uptake in bEnd.3 cells, and the increase in BO concentration was beneficial for the cellular uptake of NPs. Moreover, PEG/BO-ITZ-NPs displayed an approximately 3.5-fold higher area under the curve in rats and about 2-fold higher brain distribution in mice than that of Sporanox®, i.e. ITZ solubilized by hydroxylpropyl-β-cyclodetrin, after i.v. administration. In a word, BO and PEG dual modified BSA nanoparticles may potentially serve as an ITZ vehicle for brain targeting.

AS1411 Aptamer/Hyaluronic Acid-Bifunctionalized Microemulsion Co-Loading Shikonin and Docetaxel for Enhanced Antiglioma Therapy

In this study, we developed an AS1411 aptamer/hyaluronic acid-bifunctionalized microemulsion co-loading shikonin and docetaxel (AS1411/SKN&DTX-M). Such microemulsion was capable of penetrating the blood-brain barrier (BBB), targeting CD44/nucleolin-overexpressed glioma, and inhibiting the orthotopic glioma growth. AS1411/SKN&DTX-M showed a spherical morphology with a diameter around 30 nm and rapidly released drugs in the presence of hyaluronidase and mild acid. In the U87 cellular studies, AS1411/SKN&DTX-M elevated the cytotoxicity, enhanced the cellular uptake, and induced the cell apoptosis. In the artificial blood-brain barrier model, the transepithelial electrical resistance was decreased after the treatment with AS1411/SKN&DTX-M and thereby of increasing the apparent permeability coefficient. Furthermore, AS1411/SKN&DTX-M showed a strong inhibition against the formation of cancer stem cell-enriched U87 cell spheroids, in which the expression of CD133 was downregulated significantly. In the biodistribution studies, AS1411/SKN&DTX-M could selectively accumulate in the brains of orthotopic luciferase-transfected U87 glioma tumor-bearing nude mice. Importantly, AS1411/SKN&DTX-M exhibited the overwhelming inhibition of glioma growth of orthotopic luciferase-transfected U87 glioma models and reached the longest survival period among all the treatments. In summary, the codelivery of shikonin and docetaxel using bifunctionalization with hyaluronic acid and AS1411 aptamer offers a promising strategy for dual drug-based combinational antiglioma treatment.