Shijie Cao

Angiopep-2 and Activatable Cell-Penetrating Peptide Dual-Functionalized Nanoparticles for Systemic Glioma-Targeting Delivery

Gliomas are hard to treat because of the two barriers involved: the blood-brain barrier and blood-tumor barrier. In this study, a dual-targeting ligand, angiopep-2, and an activatable cell-penetrating peptide (ACP) were functionalized onto nanoparticles for glioma-targeting delivery. The ACP was constructed by conjugating RRRRRRRR (R8) with EEEEEEEE through a matrix metalloproteinase-2 (MMP-2)-sensitive linker. ACP modification effectively enhanced the C6 cellular uptake because of the high expression of MMP-2 on C6 cells. The uptake was inhibited by batimastat, an MMP-2 inhibitor, suggesting that the cell-penetrating property of the ACP was activated by MMP-2. By combining the dual-targeting delivery effect of angiopep-2 and activatable cell-penetrating property of the ACP, the dual-modified nanoparticles (AnACNPs) displayed higher glioma localization than that of single ligand-modified nanoparticles. After loading with docetaxel, a common chemotherapeutic, AnACNPs showed the most favorable antiglioma effect both in vitro and in vivo. In conclusion, a novel drug delivery system was developed for glioma dual targeting and glioma penetrating. The results demonstrated that the system effectively targeted gliomas and provided the most favorable antiglioma effect.

Tumor cells and neovasculature dual targeting delivery for glioblastoma treatment

Glioblastoma multiforme (GBM), one of the most common primary malignant brain tumors, was characterized by angiogenesis and tumor cells proliferation. Antiangiogenesis and antitumor combination treatment gained much attention because of the potency in dual inhibition of both the tumor proliferation and the tumor invasion. In this study, a neovasculature and tumor cell dual targeting delivery system was developed through modification of nanoparticles with interleukin-13 peptide and RGD (IRNPs), in which interleukin-13 peptide was targeting GBM cells and RGD was targeting neovasculature. To evaluate the potency in GBM treatment, docetaxel was loaded into IRNPs. In vitro, interleukin-13 peptide and RGD could enhance the corresponding cells (C6 and human umbilical vein endothelial cells) uptake and cytotoxicity. In combination, IRNPs showed high uptake in both cells and increased the cytotoxicity on both cells. In vivo, IRNPs could effectively deliver cargoes to GBM with higher intensity than mono-modified nanoparticles. Correspondingly, docetaxel-IRNPs displayed best anti-tumor effect with a median survival time of 35 days, which was significantly longer than that of mono-modified and unmodified nanoparticles. Importantly, treatment with docetaxel-IRNPs could avoid the accumulation of HIF1α in GBM site, which was crucial for the tumor invasion. After the treatment, there was no obvious change in normal organs of mice.

Glioma-homing peptide with a cell-penetrating effect for targeting delivery with enhanced glioma localization, penetration and suppression of glioma growth.

Tumor-targeted delivery systems are useful in enhancing drug delivery and increasing anti-tumor effects. Cell-penetrating peptides have been widely used for this purpose but have been hampered by the poor selectivity between neoplastic and non-neoplastic cells. As a peptide derived from interleukin-13, interleukin-13 peptide (IL-13p) is specifically targeted to IL13Rα2, a tumor-restricted receptor. More interestingly, IL-13p possesses cell-penetrating properties that can specifically enhance the uptake by tumor cells compared with endothelial cells. Thus, we anchored IL-13p onto nanoparticles (ILNPs) for glioma-targeting delivery. The uptake of ILNPs by U87 cells was higher than that of unmodified nanoparticles (NPs). However, there was no significant difference in the uptake by human umbilical vein endothelial cells. In addition, free IL-13p could also enhance the uptake of both NPs and ILNPs by U87 cells. Anchoring with IL-13p could enhance the penetration of particles into the core of spheroids. In vivo, the fluorescence intensity of ILNPs in tumors was 2.96-fold higher than that of NPs. The modification with IL-13p also significantly improved the speed and rate of penetration from vessels to tumor cells. The enhanced tumor localization of ILNPs was mostly attributable to the elevated tumor cell internalization of ILNPs, whereas most NPs were colocalized with microvessels or macrophages. Correspondingly, docetaxel-loaded NPs effectively suppressed the growth of subcutaneous U87 tumors. The average tumor volume of the ILNP group was only 31.4% that of the control, which was significantly smaller than that of the docetaxel and NP groups. In conclusion, the modification of IL-13p selectively enhanced tumor cell uptake, improved the penetration effect of NPs and improved the glioma localization ability, which led to a better tumor-suppression effect.

Precise glioma targeting of and penetration by aptamer and peptide dual-functioned nanoparticles.

The treatment of a brain glioma is still one of the most difficult challenges in oncology. To effectively treat brain glioma and reduce the side effects, drugs must be transported across the blood brain barrier (BBB) and then targeted to the brain cancer cells because most anti-tumor drugs are highly toxic to the normal brain tissue. A cascade delivery strategy was developed to perform these two aims and to achieve enhanced and precisely targeted delivery. Herein, we utilize a phage-displayed TGN peptide and an AS1411 aptamer, which are specific targeting ligands of the BBB and cancer cells, respectively and we conjugate them with nanoparticles to establish the brain glioma cascade delivery system (AsTNP). In vitro cell uptake and three-dimensional tumor spheroid penetration studies demonstrated that the system could not only target endothelial and tumor cells but also penetrate the endothelial monolayers and tumor cells to reach the core of the tumor spheroids, which was extremely important but mostly ignored in glioma therapy. In vivo imaging further demonstrated that the AsTNP provided the highest tumor distribution and tumor/normal brain ratio. The distribution was also reconfirmed by fluorescent images of the brain slides. As a result, the docetaxel-loaded AsTNP presents the best anti-glioma effect with improved glioma bearing survival. In conclusion, the AsTNP could precisely target to the brain glioma, which was a valuable target for glioma imaging and therapy.

In vitro and in vivo intracellular distribution and anti-glioblastoma effects of docetaxel-loaded nanoparticles functioned with IL-13 peptide.

An active targeting delivery system helps increase intracellular drug delivery, which is promising for the treatment of glioblastoma. Interleukin 13 (IL-13) peptide which was derived from IL-13 protein could specially bind with IL-13Rα2, a receptor highly expressed on glioblastoma cells but not on normal brain cells, suggesting IL-13 peptide is an optional ligand for glioblastoma targeted therapy. In this contribution, IL-13 peptide was functionalized to nanoparticles (ILNP) to form a glioblastoma targeted drug delivery system where docetaxel was used as a model drug. The cellular uptake and intracellular delivery of ILNP indicated that IL-13 peptide facilitated cellular uptake of nanoparticles and Golgi apparatus was involved in the sorting and trafficking of ILNP rather than NP in U87 cells. Transmission electron microscopy observation revealed that ILNP mainly distributed into endosomes, cytoplasm and Golgi apparatus. In vitro apoptosis assay indicated docetaxel-loaded ILNP could induce polymerization of microtubules and produce the highest early and late apoptosis of U87 cells. Growth inhibition results of tumor spheroids demonstrated ILNP displayed the best growth inhibition of tumor spheroids. In vivo imaging suggested that ILNP accumulated significantly more in the glioma site than NP while more NP was distributed in liver, lung and spleen than ILNP. Transmission electron microscopy further demonstrated ILNP could distribute into different organelles of cells in glioma site. Thus, docetaxel loaded ILNP could induce the most apoptosis of glioma cells which was demonstrated by TUNEL. In conclusion, we presented a glioblastoma-targeting drug delivery system ILNP, which could increase the intracellular delivery of nanoparticles as well as precisely target to glioblastoma cells, and significantly increase the anti-proliferation and anti-spheroid growth effect.

Whole-cell SELEX aptamer-functionalised poly(ethyleneglycol)-poly(ε-caprolactone) nanoparticles for enhanced targeted glioblastoma therapy.

Though there has been substantial advancement in the knowledge about tumour development and treatment in the past 40 years, the prognosis of brain glioblastoma is still very grim due to the difficulty of targeting drugs to glioblastoma cells. An active targeting delivery system helps increase intracellular drug delivery, which is promising for the treatment of glioblastoma. For an active targeting delivery system, targeting ligands are crucial for efficient intracellular drug delivery. Current methods include systematic evolution of ligands by exponential enrichment (SELEX), which has been utilised for selecting specific ligands with better targeting effects. The GMT8 aptamer was a short DNA sequence selected by SELEX that could specifically bind with U87 cells. In this study, nanoparticles functionalised with GMT8 aptamers (ApNP) were utilised for glioblastoma therapy. In vitro cell uptake and U87 tumour spheroid uptake demonstrated that nanoparticles functionalised with GMT8 aptamer significantly enhanced intracellular drug delivery and tumour spheroid penetration. Assays for cell apoptosis and growth inhibition of tumour spheroids identified docetaxel-loaded ApNP to significantly induce cell apoptosis and inhibit tumour spheroid growth. In vivo imaging of glioblastoma-bearing mice demonstrated that ApNP could target glioblastoma and accumulate at the tumour site, which was further verified by fluorescence imaging of brain slices. Pharmacodynamic results indicated that docetaxel-loaded ApNP significantly prolonged the median survival time of glioblastoma-bearing mice compared to NP, DTX and control. In conclusion, GMT8 aptamer-functionalised nanoparticles enhanced tumour penetration and targeted glioblastoma therapy, which is promising for the prognosis of brain glioblastoma.

RGD and Interleukin-13 Peptide Functionalized Nanoparticles for Enhanced Glioblastoma Cells and Neovasculature Dual Targeting Delivery and Elevated Tumor Penetration

As the most common malignant brain tumors, glioblastoma multiforme (GBM) was characterized by angiogenesis and tumor cells proliferation. Dual targeting to neovasculature and GBM cells could deliver cargoes to these two kinds of cells, leading to a combination treatment. In this study, polymeric nanoparticles were functionalized with RGD and interleukin-13 peptide (IRNPs) to construct a neovasculature and tumor cell dual targeting delivery system in which RGD could target αvβ3 on neovasculature and interleukin-13 peptide could target IL13Rα2 on GBM cells. In vitro, interleukin-13 peptide and RGD could enhance the uptake by corresponding cells (C6 and human umbilical vein endothelial cells). Due to the expression of both receptors on C6 cells, RGD also could enhance the uptake by C6 cells. Through receptor labeling, it clearly showed that αvβ3 could mediate the internalization of RGD modified nanoparticles and IL13Rα2 could mediate the internalization of interleukin-13 peptide modified nanoparticles. The ligand functionalization also resulted in a modification on endocytosis pathways, which changed the main endocytosis pathways from macropinocytosis for unmodified nanoparticles to clathrin-mediated endocytosis for IRNPs. IRNPs also displayed the strongest penetration ability according to tumor spheroid analysis. In vivo, IRNPs could effectively deliver cargoes to GBM with higher intensity than monomodified nanoparticles. After CD31-staining, it demonstrated IRNPs could target both neovasculature and GBM cells. In conclusion, IRNPs showed promising ability in dual targeting both neovasculature and GBM cells.

Anti-glioma effect and safety of docetaxel-loaded nanoemulsion.

Docetaxel, an inhibitor of microtubule depolymerization, has been used for many malignancies. Due to its toxicity and the non-selective distribution of its commercial formulation, Taxotere®, new formulations with less toxicity and tumor targeting need to be explored. For its safety and ease of factory scale production, nanoemulsion, was selected to encapsulate docetaxel. The particle size of docetaxel loaded nanoemulsion (DNE) was 72.3 nm, the average zeta potential was −6.38 mV, the encapsulation efficiency was 93.1% and the drug loading capacity was 2.87%. Although DNE presented similar antiproliferation effects on both U87 cells and bEnd.3 cells, its in vivo toxicity was significantly lower than Taxotere®. In vivo fluorescent imaging suggested nanoemulsions loaded with a fluorescent probe could distribute to the brain and accumulate at the glioma site. The pharmacological experiments also confirmed that the DNE could target glioma sites and prolong the median survival time of mice with gliomas. In conclusion, DNE is a new, less toxic, drug formulation that is effective for brain glioma therapy.

Incorporation of lapatinib into lipoprotein-like nanoparticles with enhanced water solubility and anti-tumor effect in breast cancer

AIM The poor water solubility of many active compounds is a serious deterrent to their use as commercial drugs. Lapatinib is a dual inhibitor of the EGF receptor and EGF receptor 2 approved by the US FDA to treat advanced breast cancer. This study prepares lapatinib-incorporated lipoprotein-like nanoparticles (LTNPs) to enhance the water solubility and elevate the anti-tumor effect of lapatinib. MATERIALS & METHODS Bovine albumin was used to bind with lapatinib, and egg yolk lecithin was used to stabilize the conjugation of bovine albumin and lapatinib. The characteristics of LTNPs were evaluated by several experiments. Cell uptake and toxicity were performed on BT-474 cells. In vivo anti-tumor effect was performed on BT-474 xenograft-bearing mice. RESULTS LTNPs contained a lipid corona and a core of lapatinib and albumin. LTNPs could be effectively taken up by BT-474 cells and induced apoptosis. An in vivo study demonstrated that LTNPs could passively distribute into a tumor via the enhanced permeability and retention effect and induce anti-tumor activity in breast cancer. CONCLUSION The authors present a convenient nanoformulation with improved anti-tumor effect, which is a promising candidate for clinical trials.

Nanoparticle-Based ARV Drug Combinations for Synergistic Inhibition of Cell-Free and Cell–Cell HIV Transmission

Nanocarrier-based drug delivery systems are playing an emerging role in human immunodeficiency virus (HIV) chemoprophylaxis and treatment due to their ability to alter the pharmacokinetics and improve the therapeutic index of various antiretroviral (ARV) drug compounds used alone and in combination. Although several nanocarriers have been described for combination delivery of ARV drugs, measurement of drug-drug activities facilitated by the use of these nanotechnology platforms has not been fully investigated for topical prevention. Here, we show that physicochemically diverse ARV drugs can be encapsulated within polymeric nanoparticles to deliver multidrug combinations that provide potent HIV chemoprophylaxis in relevant models of cell-free, cell-cell, and mucosal tissue infection. In contrast to existing approaches that coformulate ARV drug combinations together in a single nanocarrier, we prepared single-drug-loaded nanoparticles that were subsequently combined upon administration. ARV drug-nanoparticles were prepared using emulsion-solvent evaporation techniques to incorporate maraviroc (MVC), etravirine (ETR), and raltegravir (RAL) into poly(lactic-co-glycolic acid) (PLGA) nanoparticles. We compared the antiviral potency of the free and formulated drug combinations for all pairwise and triple drug combinations against both cell-free and cell-associated HIV-1 infection in vitro. The efficacy of ARV-drug nanoparticle combinations was also assessed in a macaque cervicovaginal explant model using a chimeric simian-human immunodeficiency virus (SHIV) containing the reverse transcriptase (RT) of HIV-1. We observed that our ARV-NPs maintained potent HIV inhibition and were more effective when used in combinations. In particular, ARV-NP combinations involving ETR-NP exhibited significantly higher antiviral potency and dose-reduction against both cell-free and cell-associated HIV-1 BaL infection in vitro. Furthermore, ARV-NP combinations that showed large dose-reduction were identified to be synergistic, whereas the equivalent free-drug combinations were observed to be strictly additive. Higher intracellular drug concentration was measured for cells dosed with the triple ARV-NP combination compared to the equivalent unformulated drugs. Finally, as a first step toward evaluating challenge studies in animal models, we also show that our ARV-NP combinations inhibit RT-SHIV virus propagation in macaque cervicovaginal tissue and block virus transmission by migratory cells emigrating from the tissue. Our results demonstrate that ARV-NP combinations control HIV-1 transmission more efficiently than free-drug combinations. These studies provide a rationale to better understand the role of nanocarrier systems in facilitating multidrug effects in relevant cells and tissues associated with HIV infection.