Dissecting stromal-epithelial interactions in a 3D in vitro cellularized intestinal model for permeability studies

Absorption evaluation plays an increasingly important role at the early stage of drug discovery due to its potential to scan the ADME (absorption, distribution, metabolism and excretion) properties of new drug candidates. Therefore, a new three-dimensional (3D) in vitro model replicating the intestinal functioning is herein proposed aiming to dissect the stromal-epithelial interactions and evaluate the permeation of a model drug, insulin. Inspired on the intestinal mucosal architecture, the present model comprises intestinal myofibroblasts (CCD18-Co cells) embedded in Matrigel, onto which epithelial enterocytes (Caco-2 cells) and mucus-producing cells (HT29-MTX cells) were seeded. CCD18-Co myofibroblasts showed to have a central role in the remodeling of the surrounding matrix confirmed by the production of fibronectin. Subsequently, this matrix revealed to be essential to the maintenance of the model architecture by supporting the overlying epithelial cells. In terms of functionality, this model allowed the efficient prediction of insulin permeability in which the presence of mucus, the less tight character between Caco-2 and HT29-MTX epithelial cells and the 3D assembly were critical factors. Concluding, this model constitutes a robust tool in the drug development field with potential to bridge the traditional 2D cell culture models and in vivo animal models.     

Near-infrared fluorescence imaging using organic dye nanoparticles

Near-infrared (NIR) fluorescence imaging in the 700–1000 nm wavelength range has been very attractive for early detection of cancers. Conventional NIR dyes often suffer from limitation of low brightness due to self-quenching, insufficient photo- and bioenvironmental stability, and small Stokes shift. Herein, we present a strategy of using small-molecule organic dye nanoparticles (ONPs) to encapsulate NIR dyes to enable efficient fluorescence resonance energy transfer to obtain NIR probes with remarkably enhanced performance for in vitro and in vivo imaging. In our design, host ONPs are used as not only carriers to trap and stabilize NIR dyes, but also light-harvesting agent to transfer energy to NIR dyes to enhance their brightness. In comparison with pure NIR dyes, our organic dye nanoparticles possess almost 50-fold increased brightness, large Stokes shifts (∼250 nm) and dramatically enhanced photostability. With surface modification, these NIR-emissive organic nanoparticles have water-dispersity and size- and fluorescence- stability over pH values from 2 to 10 for almost 60 days. With these superior advantages, these NIR-emissive organic nanoparticles can be used for highly efficient folic-acid aided specific targeting in vivo and ex vivo cellular imaging. Finally, during in vivo imaging, the nanoparticles show negligible toxicity. Overall, the results clearly display a potential application of using the NIR-emissive organic nanoparticles for in vitro and in vivo imaging.     

Intestinal mucosa permeability following oral insulin delivery using core shell corona nanolipoparticles

Chitosan nanoparticles (NC) have excellent capacity for protein entrapment, favorable epithelial permeability, and are regarded as promising nanocarriers for oral protein delivery. Herein, we designed and evaluated a class of core shell corona nanolipoparticles (CSC) to further improve the absorption through enhanced intestinal mucus penetration. CSC contains chitosan nanoparticles as a core component and pluronic F127-lipid vesicles as a shell with hydrophilic chain and polyethylene oxide PEO as a corona. These particles were developed by hydration of a dry pluronic F127-lipid film with NC suspensions followed by extrusion. Insulin nested inside CSC was well protected from enzymatic degradation. Compared with NC, CSC exhibited significantly higher efficiency of mucosal penetration and, consequently, higher cellular internalization of insulin in mucus secreting E12 cells. The cellular level of insulin after CSC treatment was 36-fold higher compared to treatment with free insulin, and 10-fold higher compared to NC. CSC significantly facilitated the permeation of insulin across the ileum epithelia, as demonstrated in an ex vivo study and an in vivo absorption study. CSC pharmacological studies in diabetic rats showed that the hypoglycemic effects of orally administrated CSC were 2.5-fold higher compared to NC. In conclusion, CSC is a promising oral protein delivery system to enhance the stability, intestinal mucosal permeability, and oral absorption of insulin.     

Cysteine modified rare-earth up-converting nanoparticles for in vitro and in vivo bioimaging

Cysteine, as a small organic molecule and amino acid, is a basic building block for proteins and has special physiological functions in vivo. Cysteine has strong affinity for cells, which can be taken advantage for various applications. A new and facile surface modification method has been developed for rare-earth doped upconversion nanoparticles (UCNs) using cysteine. Compared with unmodified samples, the water-solubility and biocompatibility of the cysteine modified NaYF₄:Yb,Er and NaYF₄:Yb,Tm UCNs (termed as UCN-Er-Cys and UCN-Tm-Cys, respectively) have been significantly improved, while their particle size and emission properties did not change substantially. Due to the low cytotoxicity as revealed by methyl thiazolyl tetrazolium assay, the cysteine modified UCNs were successfully applied to imaging of Hela cells in vitro and nude mouse in vivo. Most significant is that the method offers the advantages of ease of synthesis and handling as well as potentially low cost for biomedical emerging applications.     

The impact of nanoparticles on the mucosal translocation and transport of GLP-1 across the intestinal epithelium

Glucagon like peptide-1 (GLP-1) is an incretin hormone that is in the pipeline for type 2 diabetes mellitus (T2DM) therapy. However, oral administration of GLP-1 is hindered by the harsh conditions of the gastrointestinal tract and poor bioavailability. In this study, three nanosystems composed by three different biomaterials (poly(lactide-co-glycolide) polymer (PLGA), Witepsol E85 lipid (solid lipid nanoparticles, SLN) and porous silicon (PSi) were developed and loaded with GLP-1 to study their permeability in vitro. All the nanoparticles presented a size of approximately 200 nm. The nanoparticles' interaction with the mucus and the intestinal cells were enhanced after coating with chitosan (CS). PSi nanosystems presented the best association efficiency (AE) and loading degree (LD), even though a high AE was also observed for PLGA nanoparticles and SLN. Among all the nanosystems, PLGA and PSi were the only nanoparticles able to sustain the release of GLP-1 in biological fluids when coated with CS. This characteristic was also maintained when the nanosystems were in contact with the intestinal Caco-2 and HT29-MTX cell monolayers. The CS-coated PSi nanoparticles showed the highest GLP-1 permeation across the intestinal in vitro models. In conclusion, PLGA + CS and PSi + CS are promising nanocarriers for the oral delivery of GLP-1.     

Targeting fibronectins of glioma extracellular matrix by CLT1 peptide-conjugated nanoparticles

The abundant extracellular matrix (ECM) in the glioma microenvironment play a critical role in the maintenance of glioma morphology, glioma cells differentiation and proliferation, but little has been done to understand the feasibility of ECM as the therapeutic target for glioma therapy. In this study, a drug delivery system targeting fibronectins (FNs), a prevailing component in the ECM of many solid tumors, was constructed for glioma therapy based on the interaction between the abundant FNs in glioma tissues and the FNs-targeting moiety CLT1 peptide. CLT1 peptide was successfully conjugated to PEG-PLA nanoparticles (CNP). FNs were demonstrated to be highly expressed in the ECM of glioma spheroids in vitro and glioma tissues in vivo. CLT1 modification favored targeting nanoparticles penetration into the core of glioma spheroids and consequently induced more severe inhibitive effects on glioma spheroids growth than traditional NP. In vivo imaging, ex vivo imaging and glioma tissue slides showed that CNP enhanced nanoparticles retention in glioma site, distributed more extensively and more deeply into glioma tissues than that of conventional NP, and mainly located in glioma cells rather than in extracellular matrix as conventional NP. Pharmacodynamics outcomes revealed that the median survival time of glioma-bearing mice models treated with paclitaxel-loaded CNP (CNP-PTX) was significantly prolonged when compared with that of any other group. TUNEL assay demonstrated that more extensive cell apoptosis was induced by CNP-PTX treatment compared with other treatments. Altogether, these promising results indicated that this ECM-targeting drug delivery system enhanced retention and glioma cell uptake of nanoparticles and might have a great potential for glioma therapy in clinical applications.     

Nanoparticle toxicity assessment using an in vitro 3-D kidney organoid culture model

Nanocarriers and nanoparticles remain an intense pharmaceutical and medical imaging technology interest. Their entry into clinical use is hampered by the lack of reliable in vitro models that accurately predict in vivo toxicity. This study evaluates a 3-D kidney organoid proximal tubule culture to assess in vitro toxicity of the hydroxylated generation-5 PAMAM dendrimer (G5-OH) compared to previously published preclinical in vivo rodent nephrotoxicity data. 3-D kidney proximal tubule cultures were created using isolated murine proximal tubule fractions suspended in a biomedical grade hyaluronic acid-based hydrogel. Toxicity in these cultures to neutral G5-OH dendrimer nanoparticles and gold nanoparticles in vitro was assessed using clinical biomarker generation. Neutral PAMAM nanoparticle dendrimers elicit in vivo-relevant kidney biomarkers and cell viability in a 3-D kidney organoid culture that closely reflect toxicity markers reported in vivo in rodent nephrotoxicity models exposed to this same nanoparticle.     

Systematic in vitro and in vivo study on porous silicon to improve the oral bioavailability of celecoxib

Mesoporous materials are promising candidates for improving dissolution rate of poorly water-soluble drugs in vitro and their bioavailability in vivo. In the present study, sixteen batches of celecoxib-loaded PSi particles with pore sizes ranging from 17 to 58 nm and celecoxib content from 5 to 36 w-% were prepared and a detailed physicochemical characterization of the drug was performed by several methods. Interaction between co-culture of Caco-2/HT29-MTX cells and unloaded PSi particles was tested in toxicity assays, and increased toxicity for particles with large pore size was observed. Dissolution rate of celecoxib was improved in vitro by lowering the drug loading degree which hindered the recrystallization of celecoxib on the external surface of the particles. The fastest permeation of loaded celecoxib through the co-culture monolayer as well as the highest bioavailability in rats was observed with the particles with small pore size and low loading degree. New insights were obtained on how various parameters of the mesoporous delivery system affect the state of the drug inside the pores and its release in vitro and in vivo.     

Choline transporter-targeting and co-delivery system for glioma therapy

Combination of gene therapy and chemotherapy is a promising approach for glioma therapy. In this study, a co-delivery system of plasmid encoding human tumor necrosis factor-related apoptosis-inducing ligand (pORF-hTRAIL, Trail) and doxorubicin (DOX) has been simply constructed in two steps. Firstly, DOX was intercalated into Trail to form a stable complex. Secondly, DOX-Trail complex was condensed by Dendrigraft poly-l-lysine (DGL) to form a nanoscaled co-delivery system. Choline transporters are both expressed on blood–brain barrier (BBB) and glioma, Herein, a choline derivate with high choline transporter affinity was chosen as BBB and glioma dual targeting ligand. Choline-derivate modified co-delivery system showed higher cellular uptake efficiency and cytotoxicity than unmodified co-delivery system in U87 MG cells. In comparison with single medication or unmodified delivery system, Choline-derivate modified co-delivery system induced more apoptosis both in vitro and in vivo. The therapeutic efficacy on U87 MG bearing xenografts further confirmed the predominance of this dual targeting and co-delivery system.     

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.     

Specific photothermal therapy to the tumors with high EphB4 receptor expression

Photothermal therapy (PTT) employs photo-absorbing agents to generate heat from optical energy, leading to the ‘burning’ of tumor cells. Real-time imaging of in vivo distribution of photothermal agents and monitoring of post-treatment therapeutic outcomes are very important to design and optimize personalized PTT treatment. In this work, we used chitosan-stearic acid copolymer (CSO-SA) to encapsulate hollow gold nanospheres (HAuNS) and near-infrared (NIR) fluorescent tracer, DiR. Then, the surface of nanoparticles was further conjugated with a peptide (TNYL), which facilitates EphB4-positive tumor targeting delivery. Using a paired tumor mode in vivo and a double tumor-cell co-culture strategy in vitro, we demonstrated the feasibility of increasing the accumulation of our nanoparticles (DiR loaded and TNYL-CSO-SA coated HAuNS (DTCSH)) into EphB4-positive tumors through interaction between TNYL-peptide on the nanoparticles and EpHB4 receptors on tumor cells. When combined with NIR laser irradiation, our nanoparticles induced more EphB4-positive tumor cells death in vitro. We further developed optical imaging to temporally and spatially monitor the biodistribution of DTCSH. Under NIR laser irradiation, PTT exhibited dramatically stronger antitumor effect against EphB4-positive tumors than EphB4-negative tumors. This was attributed to enhanced accumulation of our nanoparticles in EphB4-positive tumors.     

Core-Shell type lipid/rPAA-Chol polymer hybrid nanoparticles for in vivo siRNA delivery

Our previous study had reported that cholesterol-grafted poly(amidoamine) (rPAA-Chol polymer) was able to self-assemble into cationic nanoparticles and act as a potential carrier for siRNA transfection. In this study, the core–shell type lipid/rPAA-Chol hybrid nanoparticles (PEG-LP/siRNA NPs and T7-LP/siRNA NPs) were developed for improving in vivo siRNA delivery by modifying the surface of rPAA-Chol/siRNA nanoplex core with a lipid shell, followed by post-insertion of polyethylene glycol phospholipid (DSPE-PEG) and/or peptide (HAIYPRH, named as T7) modified DSPE-PEG-T7. The integrative hybrid nanostructures of LP/siRNA NPs were evidenced by dynamic light scattering (DLS), confocal laser scanning microscope (CLSM), cryo-transmission electron microscope (Cryo-TEM) and surface plasmon resonance (SPR) assay. It was demonstrated that the T7 peptide modified LP/siRNA NPs (T7-LP/siRNA NPs) exhibited uniform and spherical structures with particle size of 99.39 ± 0.65 nm and surface potential of 42.53 ± 1.03 mV, and showed high cellular uptake efficiency and rapid endosomal/lysosomal escape ability in MCF-7 cells. Importantly, in vitro gene silencing experiment demonstrated that both of pegylated and targeted LP/siEGFR NPs exhibited significantly stronger downregulation of EGFR protein expression level in MCF-7 cells, compared to that of the physical mixture of siRNA lipoplexes and rPAA-Chol/siRNA nanoplexes. In vivo tumor therapy on nude mice bearing MCF-7 tumors further confirmed that the targeted T7-LP/siEGFR NPs exhibited the greatest inhibition on tumor growth via transferrin receptor-mediated targeting delivery, without any activation of immune responses and significant body weight loss following systemic administration. These findings indicated that the core-shell type T7-LP/siRNA nanoparticles would be promising siRNA delivery systems for in vivo tumor-targeted therapy.     

PEGylated NaLuF4: Yb/Er upconversion nanophosphors for in vivo synergistic fluorescence/X-ray bioimaging and long-lasting,real-time tracking

Simultaneous in vivo luminescence and X-ray bioimaging in a tissue or animal integrates the advantages of each single-modal imaging technology, and will find widespread application in biological and clinical fields. However, synergistic dual-modal bioimaging that utilizes a new generation of upconversion nanoprobes is still limited. In addition, investigations concentrated on in vivo biodistribution of these nanoprobes may contribute to diagnosis and treatment, but long-term in vivo tracking based on these nanoprobes is rarely reported. In this work, water-soluble NaLuF₄: Yb/Er nanophosphors were prepared through modified one-pot simultaneous synthesis and surface modification method. Owing to the outstanding upconverting emissions and large X-ray absorption coefficient/K-edge value of Lu and doped Yb ions, the obtained nanoprobes were successfully used as luminescent nanoprobes and X-ray contrast agents for in vivo synergistic upconversion luminescence and X-ray bioimaging. The in vivo biodistribution of these nanoprobes were observed, and the results based on long-term tracking reveal that the as-prepared nanoprobes first aggregated in the lung of the mouse, transferred to the liver, and finally moved to the spleen.     

Drug permeability and mucoadhesion properties of thiolated trimethyl chitosan nanoparticles in oral insulin delivery

Trimethyl chitosan-cysteine conjugate (TMC-Cys) was synthesized in an attempt to combine the mucoadhesion and the permeation enhancing effects of TMC and thiolated polymers related to different mechanisms for oral absorption. TMC-Cys with various molecular weights (30, 200, and 500 kDa) and quaternization degrees (15 and 30%) was allowed to form polyelectrolyte nanoparticles with insulin through self-assembly, which demonstrated particle size of 100–200 nm, zeta potential of +12 to +18 mV, and high encapsulation efficiency. TMC-Cys/insulin nanoparticles (TMC-Cys NP) showed a 2.1–4.7-fold increase in mucoadhesion compared to TMC/insulin nanoparticles (TMC NP), which might be partly attributed to disulfide formation between TMC-Cys and mucin as evidenced by DSC measurement. Compared to insulin solution and TMC NP, TMC-Cys NP induced increased insulin transport through rat intestine by 3.3–11.7 and 1.7–2.6 folds, promoted Caco-2 cell internalization by 7.5–12.7 and 1.7–3.0 folds, and augmented uptake in Peyer's patches by 14.7–20.9 and 1.7–5.0 folds, respectively. Such results were further confirmed by in vivo experiment with the optimal TMC-Cys NP. Biocompatibility assessment revealed lack of toxicity of TMC-Cys NP. Therefore, self-assembled nanoparticles between TMC-Cys and protein drugs could be an effective and safe oral delivery system.     

Water-dispersible magnetic carbon nanotubes as T2-weighted MRI contrast agents

An efficient MRI T₂-weighted contrast agent incorporating a potential liver targeting functionality was synthesized via the combination of superparamagnetic iron oxide (SPIO) nanoparticles with multiwalled carbon nanotubes (MWCNTs). Poly(diallyldimethylammonium chloride) (PDDA) was coated on the surface of acid treated MWCNTs via electrostatic interactions and SPIO nanoparticles modified with a potential targeting agent, lactose–glycine adduct (Lac–Gly), were subsequently immobilized on the surface of the PDDA–MWCNTs. A narrow magnetic hysteresis loop indicated that the product displayed superparamagnetism at room temperature which was further confirmed by ZFC (zero field cooling)/FC (field cooling) curves measured by SQUID. The multifunctional MWCNT-based magnetic nanocomposites showed low cytotoxicity in vitro to HEK293 and Huh7 cell lines. Enhanced T₂ relaxivities were observed for the hybrid material (186 mm⁻¹ s⁻¹) in comparison with the pure magnetic nanoparticles (92 mm⁻¹ s⁻¹) due to the capacity of the MWCNTs to “carry” more nanoparticles as clusters. More importantly, after administration of the composite material to an in vivo liver cancer model in mice, a significant increase in tumor to liver contrast ratio (277%) was observed in T₂ weighted magnetic resonance images.     

The brain targeting mechanism of Angiopep-conjugated poly(ethylene glycol)-co-poly(ε-caprolactone) nanoparticles

In order to evaluate the potential and mechanism of Angiopep-conjugated poly(ethylene glycol)-co-poly(?-caprolactone)nanoparticles (ANG-PEG-NP) as brain targeting drug delivery system, Rhodamine B isothiocyanate (RBITC) was used as a fluorescent probe molecule to label ANG-PEG-NP through covalent bonding. The brain transcytosis across the blood-brain barrier (BBB) and brain delivery in mice of RBITC labeled ANG-PEG-NP were investigated in this paper. Results showed that ANG-PEG-NP enhanced significantly the uptake by BCECs compared with that of PEG-NP through caveolae- and clathrin-mediated endocytosis, involving a time-dependent, concentration-dependent and energy-dependent mode. The transport of ANG-PEG-NP across the in vitro BBB model was significantly increased than that of PEG-NP. After injection a dose of 100 mg/kg RBITC labeled ANG-PEG-NP or PEG-NP in mouse caudal vein, the brain coronal section showed a higher accumulation of ANG-PEG-NP in the cortical layer, lateral ventricle, third ventricles and hippocampus than that of PEG-NP. By using an excess of free LRP ligand (Angiopep-2 and/or Aprotinin) as a specific receptor inhibitor, it was evidenced that the uptake by BCECs in vitro, transport across in vitro BBB model and penetration into brain tissue in vivo of RBITC labeled ANG-PEG-NP could be inhibited significantly, which demonstrated the brain targeting mechanism of Angiopep-conjugated poly(ethylene glycol)-co-poly(?-caprolactone)nanoparticles might be a LRP receptor mediated transcytosis process. Understanding these issues is important for the future development of ANG-PEG-NP as a brain targeting drug delivery system for neurodegenerative disorders including glioma and Alzheimer’s disease.     

A paclitaxel-conjugated adenovirus vector for targeted drug delivery for tumor therapy

Tumor-targeted drug delivery is an attractive strategy in cancer treatment. Our previous study demonstrated that modified adenovirus has strong tumor targeting ability and less toxicity to surrounding normal tissue. In this study, Paclitaxel (PTX), a widely used clinical anticancer drug, was conjugated to folate-modified adenovirus (Ad) nanoparticles by using succinic anhydride and Fmoc-Glu(OtBu)-OH linkers to form two prodrugs, FA-Ad-Suc-PTX and FA-Ad-ICG02-Glu-PTX. Near-infrared (NIR) fluorescent dye ICG-Der-02 was attached to -NH₂-Glu(OtBu)-PTX for in vivo optical imaging. In vitro and acute toxicity study demonstrates the low toxicity of the prodrug FA-Ad-Suc-PTX and FA-Ad-ICG02-Glu-PTX compared to the free drug. The dynamic behaviors and targeting ability of FA-Ad-ICG02-Glu-PTX on MDA-MB-231 tumor-bearing mice were investigated by NIR fluorescence imaging. The result show that PTX-conjugated Ad vector could enhance the targeting and residence time in tumor site. In vitro and in vivo studies demonstrate that Coxsackie adenovirus receptor (CAR) or foliate receptor (FR)-mediated uptake of FA-Ad-loaded PTX induced highly anti-tumor activity. The results support the potential of using chemically modified Ad vector as drug-loaded tumor-targeting delivery system.     

PEG-PLA nanoparticles modified with APTEDB peptide for enhanced anti-angiogenic and anti-glioma therapy

Tumor neovasculature and tumor cells dual-targeting chemotherapy can not only destroy the tumor neovasculature, cut off the supply of nutrition and starve the tumor cells, but also directly kill tumor cells, holding great potential in overcoming the drawbacks of anti-angiogenic therapy only and improving the anti-glioma efficacy. In the present study, by taking advantage of the specific expression of fibronectin extra domain B (EDB) on both glioma neovasculature endothelial cells and glioma cells, we constructed EDB-targeted peptide APT_EDB-modified PEG-PLA nanoparticles (APT-NP) for paclitaxel (PTX) loading to enable tumor neovasculature and tumor cells dual-targeting chemotherapy. PTX-loaded APT-NP showed satisfactory encapsulated efficiency, loading capacity and size distribution. In human umbilical vein endothelial cells, APT-NP exhibited significantly elevated cellular accumulation via energy-dependent, caveolae and lipid raft-involved endocytosis, and improved PTX-induced apoptosis therein. Both in vitro tube formation assay and in vivo matrigel angiogenesis analysis confirmed that APT-NP significantly improved the antiangiogenic ability of PTX. In U87MG cells, APT-NP showed elevated cellular internalization and also enhanced the cytotoxicity of the loaded PTX. Following intravenous administration, as shown by both in vivo live animal imaging and tissue distribution analysis, APT-NP achieved a much higher and specific accumulation within the glioma. As a result, APT-NP-PTX exhibited improved anti-glioma efficacy over unmodified nanoparticles and Taxol^® in both subcutaneous and intracranial U87MG xenograft models. These findings collectively indicated that APT_EDB-modified nanoparticles might serve as a promising nanocarrier for tumor cells and neovasculature dual-targeting chemotherapy and hold great potential in improving the efficacy anti-glioma therapy.     

Combined mTOR inhibitor rapamycin and doxorubicin-loaded cyclic octapeptide modified liposomes for targeting integrin α3 in triple-negative breast cancer

A novel therapeutic strategy combining mTOR inhibitor rapamycin (RAPA) and doxorubicin (DOX)-loaded cyclic octapeptide liposomes for targeting integrin α3 was expected to combat the triple-negative breast cancer (TNBC). RAPA was loaded into PEG–PCL polymer micelles (M-RAPA) to realize solubilization. Flow cytometry analysis and laser confocal microscopy were used to evaluate the in vitro cellular uptake. The in vivo tumor targeting and bio-distribution were investigated by living fluorescence imaging. As the results, LXY modification significantly enhanced the cellular uptake of liposomal DOX in integrin α3 overexpressed TNBC cells (MDA-MB-231) in vitro and accordingly improved the tumor accumulation of liposomes in vivo. When used alone or in combination with LXY-LS-DOX, M-RAPA could greatly inhibit the expression of HIF-1α protein, which is always highly expressed in malignant cancers and involved in tumor angiogenesis, proliferation, therapeutic resistance and poor prognosis. Meanwhile, the improved efficacy of combined targeted therapy with LXY-LS-DOX and M-RAPA was demonstrated by the in vitro cytotoxicity against model TNBC cells and in vivo anti-tumor activity against mouse bearing TNBC model. These results suggested that the targeted combinational therapy based on LXY-LS-DOX and M-RAPA systems may provide a rational strategy to improve therapeutic outcomes of TNBC.