Angiopep-2 Research Articles

A multifunctional targeted nano-delivery system with radiosensitization and immune activation in glioblastoma

Glioblastoma (GBM), the most common primary brain malignancy in adults, is notoriously difficult to treat due to several factors: tendency to be radiation resistant, the presence of the blood brain barrier (BBB) which limits drug delivery and immune-privileged status which hampers effective immune responses. Traditionally, high-dose irradiation (8 Gy) is known to effectively enhance anti-tumor immune responses, but its application is limited by the risk of severe brain damage. Currently, conventional dose segmentation (2 Gy) is the standard radiotherapy method, which does not fully exploit the potential of high-dose irradiation for immune activation. The hypothesis of our study posits that instead of directly applying high doses of radiation, which is risky, a strategy could be developed to harness the immune-stimulating benefits of high-dose irradiation indirectly. This involves using nanoparticles to enhance antigen presentation and immune responses in a safer manner. Angiopep-2 (A2) was proved a satisfactory BBB and brain targeting and Dbait is a small molecule that hijack DNA double strand break damage (DSB) repair proteins to make cancer cells more sensitive to radiation. In view of that, the following two nanoparticles were designed to combine immunity of GBM, radiation resistance and BBB innovatively. One is cationic liposome nanoparticle interacting with Dbait (A2-CL/Dbait NPs) for radiosensitization effect; the other is PLGA-PEG-Mal nanoparticle conjugated with OX40 antibody (A2-PLGA-PEG-Mal/anti-OX40 NPs) for tumor-derived protein antigens capture and optimistic immunoregulatory effect of anti-OX40 (which is known to enhance the activation and proliferation T cells). Both types of nanoparticles showed favorable targeting and low toxicity in experimental models. Specifically, the combination of A2-CL/Dbait NPs and A2-PLGA-PEG-Mal/anti-OX40 NPs led to a significant extension in the survival time and a significant tumor shrinkage of mice with GBM. The study demonstrates that combining these innovative nanoparticles with conventional radiotherapy can effectively address key challenges in GBM treatment. It represents a significant step toward more effective and safer therapeutic options for GBM patients.

Improving treatment for Parkinson's disease: Harnessing photothermal and phagocytosis-driven delivery of levodopa nanocarriers across the blood-brain barrier

Parkinson's disease (PD) poses a significant therapeutic challenge, mainly due to the limited ability of drugs to cross the blood-brain barrier (BBB) without undergoing metabolic transformations. Levodopa, a key component of dopamine replacement therapy, effectively enhances dopaminergic activity. However, it encounters obstacles from peripheral decarboxylase, hindering its passage through the BBB. Furthermore, levodopa metabolism generates reactive oxygen species (ROS), exacerbating neuronal damage. Systemic pulsatile dosing further disrupts natural physiological buffering mechanisms. In this investigation, we devised a ROS-responsive levodopa prodrug system capable of releasing the drug and reducing ROS levels in the central nervous system. The prodrug was incorporated within second near-infrared region (NIR-II) gold nanorods (AuNRs) and utilized angiopep-2 (ANG) for targeted delivery across the BBB. The processes of tight junction opening and endocytosis facilitated improved levodopa transport. ROS scavenging helped alleviate neuronal oxidative stress, leading to enhanced behavioral outcomes and reduced oxidative stress levels in a mouse model of PD. Following treatment, the PD mouse model exhibited enhanced flexibility, balance, and spontaneous exploratory activity. This approach successfully alleviated the motor impairments associated with the disease model. Consequently, our strategy, utilizing NIR-Ⅱ AuNRs and ANG-mediated BBB penetration, coupled with the responsive release of levodopa, offers a promising approach for dopamine supplementation and microenvironmental regulation. This system holds substantial potential as an efficient platform for delivering neuroprotective drugs and advancing PD therapy.

Stepwise-targeting and hypoxia-responsive liposome AMVY@NPs carrying siYAP and verteporfin for glioblastoma therapy

BackgroundThe Hippo pathway is a conserved tumour suppressor signalling pathway, and its dysregulation is often associated with abnormal cell growth and tumorigenesis. We previously revealed that the transcriptional coactivator Yes-associated protein (YAP), the key effector of the Hippo pathway, is a molecular target for glioblastoma (GBM), the most common malignant brain tumour. Inhibiting YAP with small interfering RNA (siYAP) or the specific inhibitor verteporfin (VP) can diminish GBM growth to a certain degree.ResultsIn this study, to enhance the anti-GBM effect of siYAP and VP, we designed stepwise-targeting and hypoxia-responsive liposomes (AMVY@NPs), which encapsulate hypoxia-responsive polymetronidazole-coated VP and DOTAP adsorbed siYAP, with angiopep-2 (A2) modification on the surface. AMVY@NPs exhibited excellent blood‒brain barrier crossing, GBM targeting, and hypoxia-responsive and efficient siYAP and VP release properties. By inhibiting the expression and function of YAP, AMVY@NPs synergistically inhibited both the growth and stemness of GBM in vitro. Moreover, AMVY@NPs strongly inhibited the growth of orthotopic U87 xenografts and improved the survival of tumour-bearing mice without adverse effects.ConclusionSpecific targeting of YAP with stepwise-targeting and hypoxia-responsive liposome AMVY@NPs carrying siYAP and VP efficiently inhibited GBM progression. This study provides a valuable drug delivery platform and creative insights for molecular targeted treatment of GBM in the future.

Key Lipoprotein Receptor Targeted Echinacoside-Liposomes Effective Against Parkinson's Disease in Mice Model.

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the degeneration of dopaminergic neurons in the substantia nigra. The precise molecular mechanisms underlying neuronal loss in PD remain unknown, and there are currently no effective treatments for PD-associated neurodegeneration. Echinacoside (ECH) is known for its neuroprotective effects, which include scavenging cellular reactive oxygen species and promoting mitochondrial fusion. However, the blood-brain barrier (BBB) limits the bioavailability of ECH in the brain, posing a significant challenge to its use in PD treatment. We synthesized and characterized PEGylated ECH liposomes (ECH@Lip) and peptide angiopep-2 (ANG) modified liposomes (ECH@ANG-Lip). The density of ANG in ANG-Lip was optimized using bEnd.3 cells. The brain-targeting ability of the liposomes was assessed in vitro using a transwell BBB model and in vivo using an imaging system and LC-MS. We evaluated the enhanced neuroprotective properties of this formulation in a the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD model. The ECH@ANG-Lip demonstrated significantly higher whole-brain uptake compared to ECH@Lip and free ECH. Furthermore, ECH@ANG-Lip was more effective in mitigating MPTP-induced behavioral impairment, oxidative stress, dopamine depletion, and dopaminergic neuron death than both ECH@Lip and free ECH. The formulation used in our study significantly enhanced the neuroprotective efficacy of ECH in the MPTP-induced PD model. Thus, ECH@ANG-Lip shows considerable potential for improving the bioavailability of ECH and providing neuroprotective effects in the brain.

HMGB1/TREM2 positive feedback loop drives the development of radioresistance and immune escape of glioblastoma by regulating TLR4/Akt signaling

BackgroundRadioresistance and immune escape are crucial reasons for unsatisfactory therapeutic effects of glioblastoma (GBM). Although triggering receptor expressed on myeloid cells-2 (TREM2) involved in forming immunosuppressive microenvironment, but the underlying mechanism and its roles in mediating cancer radioresistance remain unclear, moreover, the efficient delivery of drugs targeting TREM2 to GBM encounters serious challenges. Hence, this study aimed to elucidate the effect and mechanisms of targeted TREM2 silencing on reversing the radioresistance and immune escape of GBM aided by a glutathione-responsive biomimetic nanoparticle (NP) platform.MethodsRadioresistant GBM cell lines and TREM2 stable knockdown GBM cell lines were firstly established. RNA sequencing, colony formation assay, western blot, enzyme-linked immunosorbent assay and co-immunoprecipitation assay were used to detect the molecular mechanisms of TREM2 in regulating the radioresistance and immune escape of GBM. The glutathione-responsive biomimetic NP, angiopep-2 (A2)- cell membrane (CM)-NP/siTREM2/spam1, was then constructed to triply and targeted inhibit TREM2 for in vivo study. Orthotopic GBM-bearing mouse models were established to evaluate the anti-GBM effect of TREM2 inhibition, multiplex immunofluorescence assay was conducted to detect the infiltration of immune cells.ResultsTREM2 was a regulator in accelerating the radioresistance and immune escape of GBM through participating in DNA damage repair and forming a positive feedback loop with high mobility group box 1 (HMGB1) to cascade the activation of Toll-like receptor 4 (TLR4)/protein kinase B (Akt) signaling. A2-CM-NP/siTREM2/spam1 was successfully synthesized with excellent passive targeting, active targeting and homologous targeting, and the in vivo results exhibited its remarkable anti-GBM therapeutic effect through promoting the infiltration of type 1 helper T cells and CD8+T cells, reducing the infiltration of type 2 helper T cells and regulatory T cells, repolarizing macrophages to M1-type, and decreasing the secretion of pro-tumor and immunosuppressive cytokines.ConclusionsTargeting TREM2 therapy is a promising avenue for optimizing radiotherapy and immunotherapy to improve the prognosis of GBM patients.

Framework nucleic acid-based nanoparticles enhance temozolomide sensitivity in glioblastoma

O6-methylguanine DNA methyltransferase (MGMT) is a crucial determinant of temozolomide (TMZ) sensitivity in patients with glioblastoma (GBM). The therapeutic potential of small interfering RNA (siRNA) targeting MGMT to enhance TMZ sensitivity has been hampered by serum nuclease degradation, off-target effects, poor accumulation at tumor sites, and low circulation in blood stream. In this study, we developed a framework nucleic acid-based nanoparticles (FNN), which is constructed from a six-helix DNA bundle, to encapsulate and protect siMGMT for improving TMZ sensitivity in GBM treatment. For better blood-brain barrier (BBB) penetration and GBM targeting, we conjugated Angiopep-2 (ANG) targeting modules to each end of the FNN. Nucleolin (NCL)-responsive locks were engineered along the sides of the six-helix DNA bundle, which safeguard siMGMT before tumor entry. Upon interaction with tumor-overexpressed NCL, these locks unlock, exposing siMGMT, this allows for effective suppression of MGMT, resulting in a significant improvement of TMZ therapeutic efficacy in GBM. This innovative strategy has the potential to transform the current treatment landscape for GBM.

Chemical engineering of zein with polyethylene glycol and Angiopep-2 to manufacture a brain-targeted docetaxel nanomedicine for glioblastoma treatment.

Glioblastoma (GBM) is the deadliest adult brain cancer. The current standard-of-care chemotherapy using orally administered temozolomide (TMZ) presents poor improvement in patient survival, emphasizing the compelling need for new therapies. A possible chemotherapeutic alternative is docetaxel (DTX), which possesses higher tumoricidal potency against GBM cells. However, its limited blood-brain barrier (BBB) permeability poses a constraint on its application. Nonetheless, nanomedicine offers promising avenues for overcoming this challenge. Angiopep-2 (ANG2) is a peptide that targets the BBB-overexpressed low-density lipoprotein receptor (LDLR). In this work, we managed, for the first time, to employ a pioneering approach of covalently linking zein protein with polyethylene glycol (PEG) and ANG2 prior to its formulation into nanoparticles (ZNPs) with enhanced stability and LDLR-mediated brain targetability, respectively. Carbodiimide and click chemistry approaches were optimized, resulting in functional modification of zein with around 25% PEG, followed by functional modification of PEG with nearly 100% ANG2. DTX-loaded ZNPs presented 100nm average size, indicating high suitability for BBB crossing through receptor-mediated transcytosis. ZNPs maintained the cytotoxic effect of the loaded DTX against GBM cells, while demonstrating a safe matrix against BBB cells. Importantly, these brain-targeted ZNPs showcased up to fourfold enhancement in blood-to-brain permeability in a BBB in vitro model, highlighting the potential of this novel approach of BBB targeting in significantly improving therapeutic outcomes for GBM patients. The versatility of the system and the possibility of significantly increasing drug concentration in the brain open the door to its future application in a wide range of other brain-related diseases.

Angiopep-2-conjugated FeTi@Au core-shell nanoparticles for tumor targeted dual-mode magnetic resonance imaging and hyperthermic glioma therapy

Herein, we fabricated gold surface-coated iron titanium core-shell (FeTi@Au) nanoparticles (NPs) with conjugation of angiopep-2 (ANG) (FeTi@Au-ANG) NPs for targeted delivery and improved NPs penetration by receptor-mediated endocytosis to achieve hyperthermic treatment of gliomas. The synthesized “core-shell” FeTi@Au-ANG NPs exhibited spherical in shape with around 16 nm particle size and increased temperature upon alternating magnetic field (AMF) stimulation, rendering them effective for localized hyperthermic therapy of cancer cells. Effective targeted delivery of FeTi@Au-ANG NPs was demonstrated in vitro by improved transport and cellular uptake, and increased apoptosis in glioma cells (C6) compared with normal fibroblast cells (L929). FeTi@Au-ANG NPs exhibited higher deposition in brain tissues and a superior therapeutic effect in an orthotopic intracranial xenograft mouse model. Taken together, our data indicate that FeTi@Au-ANG NPs hold significant promise as a targeted delivery strategy for glioma treatment using hyperthermia.

Low-dose pleiotropic radiosensitive nanoformulations for three-pronged radiochemotherapy of hypoxic brain glioblastoma under BOLD/DWI monitoring

BackgroundHypoxia-mediated radioresistance is the main obstacle to the successful treatment of glioblastoma (GBM). Enhancing hypoxic radiosensitivity and alleviating tumor hypoxia are both effective means to improve therapeutic efficacy, and the combination of the two is highly desirable and meaningful.ResultsHerein, we construct a low-dose pleiotropic radiosensitive nanoformulation consisting of a high-Z atomic nanocrystal core and mesoporous silica shell, surface-modified with angiopep-2 (ANG) peptide and loaded with nitric oxide (NO) donor and hypoxia-activated prodrug (AQ4N). Benefiting from ANG-mediated transcytosis, this nanoformulation can efficiently cross the BBB and accumulate preferentially in the brain. Low-dose radiation triggers this nanoformulation to exert a three-pronged synergistic therapeutic effect through high-Z-atom-dependent dose deposition enhancement, NO-mediated hypoxia relief, and AQ4N-induced hypoxia-selective killing, thereby significantly inhibiting GBM in situ growth while prolonging survival and maintaining stable body weight in the glioma-bearing mice. Meanwhile, the proposed in vivo 9.4 T BOLD/DWI can realize real-time dynamic assessment of local oxygen supply and radiosensitivity to monitor the therapeutic response of GBM.ConclusionsThis work provides a promising alternative for hypoxia-specific GBM-targeted comprehensive therapy, noninvasive monitoring, and precise prognosis.Graphical

The nanoprodrug of polytemozolomide combines with MGMT siRNA to enhance the effect of temozolomide in glioma

Temozolomide (TMZ) is a conventional chemotherapeutic drug for glioma, however, its clinical application and efficacy is severely restricted by its drug resistance properties. O6-methylguanine-DNA methyltransferase (MGMT) is a DNA repair enzyme, which can repair the DNA damage caused by TMZ. A large number of clinical data show that reducing the expression of MGMT can enhance the chemotherapeutic efficacy of TMZ. Therefore, in order to improve the resistance of glioma to TMZ, an angiopep-2 (A2) modified nanoprodrug of polytemozolomide (P(TMZ)n) that combines with MGMT siRNA (siMGMT) targeting MGMT was developed (A2/T/D/siMGMT). It not only increased the amount of TMZ within tumor lesion site, but also reduced MGMT expression in glioma. The in vitro experiments indicated that the A2/T/D/siMGMT effectively enhanced the cellular uptake of TMZ and siMGMT, and resulted in a significant cell apoptosis and cytotoxicity in the glioma cells. The in vivo experiments showed that glioma growth was inhibited and the survival time of animals were prolonged remarkably after A2/T/D/siMGMT was injected via tail vein. The results showed that the therapeutic effect of A2/T/D/siMGMT in the treatment of glioma was significantly improved.

Rhynchophylline-encapsulating core-shell nanoparticles to overcome blood-brain-barrier and inhibit drug efflux for efficient anti-Parkinson therapy

Parkinson's disease (PD), one of common neurodegenerative diseases, afflicts many elderly people lacking of effective treatment strategies. Rhynchophylline (RIN) is an anti-PD natural active compound. However, RIN can hardly cross the blood-brain barrier (BBB) and is easily excreted as a substrate of P-glycoprotein (P-gp), making it difficult to exert anti-PD efficacy in brain. Nanocarrier-based brain targeting strategies provide an attractive platform to address brain distribution problems of drugs. In this work, we designed a brain-targeting core-shell nanoparticle (RIN/TAR-A2-CSN) for the programmed co-delivery of RIN and P-gp inhibitor Tariquidar (TAR). It was composed of Angiopep-2 (A2) modified reduction-responsive PEG shell material and thiamine disulfide system (TDS) grafted polyglutamate core material. After entering the body, first RIN/TAR-A2-CSN crossed the BBB into the brain via A2-receptor-mediated transport. Subsequently, the shell material disintegrated under reducing conditions, and the TDS-grafted core material was reduced to become hydrophilic, thereby leading to the drugs "locked-in" the brain. Finally, the released TAR inhibits P-gp-mediated RIN efflux, increases the retention time of RIN in the brain, and fully exerts the anti-PD effect of RIN. The brain targeting efficiency of RIN/TAR-A2-CSN was improved to 5.8 times that of free RIN. In addition, the therapeutic effect on the MPTP-induced PD mice model was significantly improved. This work develops a novel brain targeting strategy for drugs to overcome BBB and inhibit efflux. RIN/TAR-A2-CSN nanoparticles show the potential to become PD therapeutics.

Revealing Angiopep-2/LRP1 Molecular Interaction for Optimal Delivery to Glioblastoma (GBM).

Background: The family of synthetic peptide angiopeps, and particularly angiopep-2 (ANG-2) demonstrated the ability preclinically and clinically to shuttle active molecules across the blood–brain barrier (BBB) and selectively toward brain tumor cells. The literature has also proved that the transport occurs through a specific receptor-mediated transcytosis of the peptide by LRP-1 receptors present both on BBB and tumor cell membranes. However, contradictory results about exploiting this promising mechanism to engineer complex delivery systems, such as nanoparticles, are being obtained. Methodology: For this reason, we applied a molecular docking (MD)-based strategy to investigate the molecular interaction of ANG-2 and the LRP-1 ligand-binding moieties (CR56 and CR17), clarifying the impact of peptide conjugation on its transport mechanism. Results: MD results proved that ANG-2/LRP-1 binding involves the majority of ANG-2 residues, is characterized by high binding energies, and that it is site-specific for CR56 where the binding to 929ASP recalls a transcytosis mechanism, resembling the binding of the receptor to the receptor-associated protein. On the other hand, ANG-2 binding to CR17 is less site-specific but, as proved for apolipoprotein internalization in physiological conditions, it involves the ANG-2 lysin residue. Conclusions: Overall, our results proved that ANG-2 energetic interaction with the LRP-1 receptor is not hindered if specific residues of the peptide are chemically crosslinked to simple or complex engineered delivery systems.

Signature Effects of Vector-Guided Systemic Nano Bioconjugate Delivery Across Blood-Brain Barrier of Normal, Alzheimer's, and Tumor Mouse Models.

The ability to cross the blood-brain barrier (BBB) is critical for targeted therapy of the central nerve system (CNS). Six peptide vectors were covalently attached to a 50 kDa poly(β-l-malic acid)-trileucine polymer forming P/LLL(40%)/vector conjugates. The vectors were Angiopep-2 (AP2), B6, Miniap-4 (M4), and d-configurated peptides D1, D3, and ACI-89, with specificity for transcytosis receptors low-density lipoprotein receptor-related protein-1 (LRP-1), transferrin receptor (TfR), bee venom-derived ion channel, and Aβ/LRP-1 related transcytosis complex, respectively. The BBB-permeation efficacies were substantially increased (“boosted”) in vector conjugates of P/LLL(40%). We have found that the copolymer group binds at the endothelial membrane and, by an allosterically membrane rearrangement, exposes the sites for vector–receptor complex formation. The specificity of vectors is indicated by competition experiments with nonconjugated vectors. P/LLL(40%) does not function as an inhibitor, suggesting that the copolymer binding site is eliminated after binding of the vector-nanoconjugate. The two-step mechanism, binding to endothelial membrane and allosteric exposure of transcytosis receptors, is supposed to be an integral feature of nanoconjugate-transcytosis pathways. In vivo brain delivery signatures of the nanoconjugates were recapitulated in mouse brains of normal, tumor (glioblastoma), and Alzheimer’s disease (AD) models. BBB permeation of the tumor was most efficient, followed by normal and then AD-like brain. In tumor-bearing and normal brains, AP2 was the top performing vector; however, in AD models, D3 and D1 peptides were superior ones. The TfR vector B6 was equally efficient in normal and AD-model brains. Cross-permeation efficacies are manifested through modulated vector coligation and dosage escalation such as supra-linear dose dependence and crossover transcytosis activities.

Low-Level Endothelial TRAIL-Receptor Expression Obstructs the CNS-Delivery of Angiopep-2 Functionalised TRAIL-Receptor Agonists for the Treatment of Glioblastoma.

Glioblastoma (GBM) is the most malignant and aggressive form of glioma and is associated with a poor survival rate. Latest generation Tumour Necrosis Factor Related Apoptosis-Inducing Ligand (TRAIL)-based therapeutics potently induce apoptosis in cancer cells, including GBM cells, by binding to death receptors. However, the blood–brain barrier (BBB) is a major obstacle for these biologics to enter the central nervous system (CNS). We therefore investigated if antibody-based fusion proteins that combine hexavalent TRAIL and angiopep-2 (ANG2) moieties can be developed, with ANG2 promoting receptor-mediated transcytosis (RMT) across the BBB. We demonstrate that these fusion proteins retain the potent apoptosis induction of hexavalent TRAIL-receptor agonists. Importantly, blood–brain barrier cells instead remained highly resistant to this fusion protein. Binding studies indicated that ANG2 is active in these constructs but that TRAIL-ANG2 fusion proteins bind preferentially to BBB endothelial cells via the TRAIL moiety. Consequently, transport studies indicated that TRAIL-ANG2 fusion proteins can, in principle, be shuttled across BBB endothelial cells, but that low TRAIL receptor expression on BBB endothelial cells interferes with efficient transport. Our work therefore demonstrates that TRAIL-ANG2 fusion proteins remain highly potent in inducing apoptosis, but that therapeutic avenues will require combinatorial strategies, such as TRAIL-R masking, to achieve effective CNS transport.

Rational Constructed Ultra-Small Iron Oxide Nanoprobes Manifesting High Performance for T1-Weighted Magnetic Resonance Imaging of Glioblastoma.

Precise diagnosis and monitoring of cancer depend on the development of advanced technologies for in vivo imaging. Owing to the merits of outstanding spatial resolution and excellent soft-tissue contrast, the application of magnetic resonance imaging (MRI) in biomedicine is of great importance. Herein, Angiopep-2 (ANG), which can simultaneously help to cross the blood-brain barrier and target the glioblastoma cells, was rationally combined with the 3.3 nm-sized ultra-small iron oxide (Fe3O4) to construct high-performance MRI nanoprobes (Fe3O4-ANG NPs) for glioblastoma diagnosis. The in vitro experiments show that the resultant Fe3O4-ANG NPs not only exhibit favorable relaxation properties and colloidal stability, but also have low toxicity and high specificity to glioblastoma cells, which provide critical prerequisites for the in vivo tumor imaging. Furthermore, in vivo imaging results show that the Fe3O4-ANG NPs exhibit good targeting ability toward subcutaneous and orthotopic glioblastoma model, manifesting an obvious contrast enhancement effect on the T1-weighted MR image, which demonstrates promising potential in clinical application.

SYNTHESIS AND CHARACTERIZATION OF TEMOZOLOMIDE LOADED THERANOSTIC QUANTUM DOTS FOR THE TREATMENT OF BRAIN GLIOMA

In the present study, we have synthesized a multifunctional nano-carrier for the targeted delivery of temozolomide to brain glioma cells. The synthesis involved the surface modification of Ag2S quantum dots (QDs) with PEG2000. Silver sulphide quantum dots (Ag2S QDs) have gained a lot of attention as a theranostic agent because they have outstanding optical and chemical features that make diagnosis and therapy easier at the same time. PEGylation of QDs provides active binding sites for the conjugation of other bio-molecules while also stabilising the carrier in a biological environment. Angiopep-2 (ANG-2), a 19-aa oligopeptide, was incorporated as a targeting agent for the specific targeting of the nano-carrier to the brain glioma cells. LRP1 (low-density lipoprotein receptor-related protein 1) is abundantly expressed in both brain capillary endothelial cells and glioma cells. Angiopep-2 can bind to LRP1 and use receptor-mediated transport to cross the blood–brain barrier. As a result, ANG can be employed to deliver drugs to both the brain and the tumour locations. Fourier transform infrared, ultraviolet-visible, and fluorescence spectroscopy were used to extensively examine the structural features and optical qualities. The efficiency of entrapment was determined to be 71±0.8%. At the lysosomal pH (pH 5.0), the prepared TMZ-ANG-PEG-QDs formulations show a sustained release pattern of TMZ (68.6±0.2 percent in 24 hr). Drug-loaded QDs had higher cytotoxicity and cellular uptake, and were taken up preferentially by malignant cells through receptor-mediated endocytosis pathways. As a result, we postulated that the synthesised QDs could be a good choice for theranostic applications, particularly for targeted drug delivery and cellular imaging at the same time.

Angiopep-2-Modified Carboxymethyl Chitosan-Based pH/Reduction Dual-Stimuli-Responsive Nanogels for Enhanced Targeting Glioblastoma.

Glioblastoma (GBM) is a fatal brain tumor with poor prognosis. Blood-brain barrier (BBB) prevents the effective delivery of chemotherapeutic agents to GBM. Herein, we developed a pH/reduction-sensitive carboxymethyl chitosan nanogel (CMCSN) modified by targeting peptide angiopep-2 (ANG) and loaded with doxorubicin (DOX). The multifunctional nanogel (DOX-ANG-CMCSN) exhibited good pH and reduction sensitivity, ideal stability, and biocompatibility. Its hydrodynamic diameter was 190 nm, drug loading was 12.7%, and the cumulative release rate of 24 h was 82.3% under the simulated tumor microenvironment. More importantly, the modification of ANG significantly enhanced BBB penetration and tumor targeting ability both in vivo and in vitro. DOX-ANG-CMCSN achieved 2-3-fold higher uptake and an enhanced antitumor activity compared with nontargeted DOX-CMCSN. Therefore, the targeted nanogels with the pH/reduction dual-stimuli response may provide a promising platform for GBM-targeted chemotherapy.

Polylactic acid block copolymer grafted temozolomide targeted nano delivery in the treatment of glioma

Gliomas are tumors of the central nervous system; they can be invasive and are commonly treated by surgical resection, chemo, and radiotherapy. Removal of a glioma is dangerous and not always successful. Temozolomide (TMZ), the first-line chemotherapy drug for gliomas, inhibit tumor recurrence, and metastasis to some extent. TMZ is often accompanied by side effects such as anemia, fever, constipation, and more. Here using a double-targeted Kunitz domain Angiopep-2 (ANG) modified block copolymer poly(lactic acid)-polyethylene glycol (PEG-PLA) coated with TMZ, we constructed a nano-delivery system (ANG@PLA-PEG/TMZ) that crosses the blood-brain barrier (BBB) to treat gliomas.

Hypoxia-Responsive Lipid-Polymer Nanoparticle-Combined Imaging-Guided Surgery and Multitherapy Strategies for Glioma.

Glioma is the most prevalent type of malignant brain tumor and is usually very aggressive. Because of the high invasiveness and aggressive proliferative growth of glioma, it is difficult to resect completely or cure with surgery. Residual glioma cells are a primary cause of postoperative recurrence. Herein, we describe a hypoxia-responsive lipid polymer nanoparticle (LN) for fluorescence-guided surgery, chemotherapy, photodynamic therapy (PDT), and photothermal therapy (PTT) combination multitherapy strategies targeting glioma. The hypoxia-responsive LN [LN (DOX + ICG)] contains a hypoxia-responsive component poly(nitroimidazole)25 [P-(Nis)25], the glioma-targeting peptide angiopep-2 (A2), indocyanine green (ICG), and doxorubicin (DOX). LN (DOX + ICG) comprises four distinct functional components: (1) A2: A2 modified nanoparticles effectively target gliomas, enhancing drug concentration in gliomas; (2) P-(Nis)25: (i) the hydrophobic component of LN (DOX + ICG) with hypoxia responsive ability to encapsulate DOX and ICG; (ii) allows rapid release of DOX from LN (DOX + ICG) after 808 nm laser irradiation; (3) ICG: (i) ICG allows imaging-guided surgery, combining PDT and PTT therapies; (ii) upon irradiation with an 808 nm laser, ICG creates a hypoxic environment; (4) DOX inhibits glioma growth. This work demonstrates that LN (DOX + ICG) might provide a novel clinical approach to preventing post-surgical recurrence of glioma.

NIMG-01. MRI VIRTUAL BIOPSY AND TREATMENT OF PRIMARY OR BRAIN METASTATIC TUMORS WITH TARGETED NANOBIOCONJUGATES

Abstract Differential diagnosis of brain magnetic resonance imaging (MRI) enhancement(s) remains a significant problem, which may be difficult to resolve without biopsy that can be often dangerous or even impossible. Such MRI enhancement(s) can result from metastasis of primary tumors such as lung or breast, radiation necrosis, infections or a new primary brain tumor (glioma, meningioma). Neurological symptoms are often the same on initial presentation. METHODS: We present a noninvasive tumor-specific imaging approach “MRI virtual biopsy” by engineering new nano imaging agents (NIA) on polymalic acid polymer (PMLA) scaffold containing linear-Gd-DOTA or star-Gd-DOTA moieties for differential diagnosis of brain tumors. The strategy is that after non-invasive MRI diagnosis recognizing the brain lesion on the basis of its molecular signatures, the primary cancer or brain metastasis (BM) is suppressed by tumor-specific molecular inhibitor(s), which is structurally similar to the used NIA. Anti-TfR antibody or Angiopep-2 (AP-2) peptide used to cross blood-brain barrier (BBB) by receptor-mediated transcytosis, and targeting antibody against EFGR- or HER2-overexpressing tumors were covalently attached to PMLA to recognize the tissues of interest. Delivery of contrast agents across BBB was studied by optical imaging. MRI signals in healthy brain and tumors were quantified using 9.4-Tesla MRI system. RESULTS: High specific signal values prevailed for 3 hours for NIA, in comparison with clinical Gd (MultiHance) that declined rapidly. In newly developed double tumor xenogeneic mouse models of brain metastasis this method allowed differential diagnosis of HER2- and EGFR-expressing brain tumors. After MRI diagnosis, breast and lung cancer brain metastases were successfully treated with similar tumor-targeted nanoconjugates carrying molecular inhibitors of EGFR or HER2 instead of imaging contrast agent. The treatment resulted in significant increase of animal survival and markedly reduced immunostaining for several cancer stem cell markers. Support: NIH grants: R01 CA188743, R01 CA206220, R01 CA209921