Antitumor efficacy of a novel CLA-PTX microemulsion against brain tumors: in vitro and in vivo findings

Targeted nano-delivery of chemotherapy via intranasal route suppresses in vivo glioblastoma growth and prolongs survival in the intracranial mouse model

Nanotechnology-based drug delivery platforms have shown great potential in overcoming the limitations of conventional therapy for glioblastoma (GBM). However, permeation across the blood-brain barrier (BBB), physiological complexity of the brain, and glioma targeting strategies cannot entirely meet the challenging requirements of distinctive therapeutic delivery stages. The objective of this research is to fabricate lipid nanoparticles (LNPs) for the co-delivery of paclitaxel (PTX) and miltefosine (HePc) a proapoptotic agent decorated with transferrin (Tf-PTX-LNPs) and investigate its anti-glioma activity both in vitro and in vivo orthotopic NOD/SCID GBM mouse model. The present study demonstrates the anti-glioma effect of the dual drug combination of PTX and proapoptotic HePc lipid-based transferrin receptor (TfR) targeted alternative delivery (direct nose to brain transportation) of the nanoparticulate system (Tf-PTX-LNPs, 364 ± 5 nm, -43 ± 9 mV) to overcome the O⁶-methylguanine-DNA methyltransferase induce drug-resistant for improving the effectiveness of GBM therapy. The resulting nasally targeted LNPs present good biocompatibility, stability, high BBB transcytosis through selective TfR-mediated uptake by tumor cells, and effective tumor penetration in the brain of GBM induced mice. We observed markedly enhanced anti-proliferative efficacy of the targeted LNPs in U87MG cells compared to free drug. Nasal targeted LNPs had shown significantly improved brain concentration (C_max fivefold and AUC_0-24 4.9 fold) with early t_max (0.5 h) than the free drug. In vivo intracranial GBM-bearing targeted LNPs treated mice exhibited significantly prolonged survival with improved anti-tumor efficacy accompanied by reduced toxicity compared to systemic Taxol^® and nasal free drug. These findings indicate that the nasal delivery of targeted synergistic nanocarrier holds great promise as a non-invasive adjuvant chemotherapy therapy of GBM.

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

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

Hydrophilic Fluorescent Nanoprodrug of Paclitaxel for Glioblastoma Chemotherapy

Highly water-soluble, nontoxic organic nanoparticles on which paclitaxel (PTX), a hydrophobic anticancer drug, has been covalently bound via an ester linkage (4.5% of total weight) have been prepared for the treatment of glioblastoma. These soft fluorescent organic nanoparticles (FONPs), obtained from citric acid and diethylenetriamine by microwave-assisted condensation, show suitable size (Ø = 17-30 nm), remarkable solubility in water, softness as well as strong blue fluorescence in an aqueous environment that are fully retained in cell culture medium. Moreover, these FONPs were demonstrated to show in vitro safety and preferential internalization in glioblastoma cells through caveolin/lipid raft-mediated endocytosis. The PTX-conjugated FONPs retain excellent solubility in water and remain stable in water (no leaching), while they showed anticancer activity against glioblastoma cells in two-dimensional and three-dimensional culture. PTX-specific effects on microtubules reveal that PTX is intracellularly released from the nanocarriers in its active form, in relation with an intracellular-promoted lysis of the ester linkage. As such, these hydrophilic prodrug formulations hold major promise as biocompatible nanotools for drug delivery.

Magnetic targeting of paclitaxel-loaded poly(lactic-co-glycolic acid)-based nanoparticles for the treatment of glioblastoma

Introduction

Glioblastoma (GBM) therapy is highly challenging, as the tumors are very aggressive due to infiltration into the surrounding normal brain tissue. Even a combination of the available therapeutic regimens may not debulk the tumor completely. GBM tumors are also known for recurrence, resulting in survival rates averaging <18 months. In addition, systemic chemotherapy for GBM has been challenged for its minimal desired therapeutic effects and unwanted side effects.

Purpose

We hypothesized that paclitaxel (PTX) and superparamagnetic iron oxide (SPIO)-loaded PEGylated poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles (NPs; PTX/SPIO-NPs) can serve as an effective nanocarrier system for magnetic targeting purposes, and we aimed to demonstrate the therapeutic efficacy of this system in an orthotopic murine GBM model.

Materials and methods

PTX/SPIO-NPs were prepared by emulsion–diffusion–evaporation method and characterized for physicochemical properties. In vitro cellular uptake of PTX/SPIO-NPs was evaluated by fluorescence microscopy and Prussian blue staining. Orthotopic U87MG tumor model was used to evaluate blood–brain barrier disruption using T₁ contrast agent, ex vivo biodistribution, in vivo toxicity and in vivo antitumor efficacy of PTX/SPIO-NPs.

Results

PTX/SPIO-NPs were in the size of 250 nm with negative zeta potential. Qualitative cellular uptake studies showed that the internalization of NPs was concentration dependent. Through magnetic resonance imaging, we observed that the blood–brain barrier was disrupted in the GBM area. An ex vivo biodistribution study showed enhanced accumulation of NPs in the brain of GBM-bearing mice with magnetic targeting. Short-term in vivo safety evaluation showed that the NPs did not induce any systemic toxicity compared with Taxol^® (PTX). When tested for in vivo efficacy, the magnetic targeting treatment significantly prolonged the median survival time compared with the passive targeting and control treatments.

Conclusion

Overall, PTX/SPIO-NPs with magnetic targeting could be considered as an effective anticancer targeting strategy for GBM chemotherapy.

Synthetic low-density lipoprotein (sLDL) selectively delivers paclitaxel to tumor with low systemic toxicity

Low density lipoprotein (LDL), which is a principal carrier for the delivery of cholesterol, has been used as a great candidate for the delivery of drugs to tumor based on the great requirements for cholesterol of many cancer cells. Mimicking the structure and composition of LDL, we designed a synthetic low-density lipoprotein (sLDL) to encapsulate paclitaxel-alpha linolenic acid (PALA) for tumor therapy. The PALA loaded sLDL (PALA-sLDL) and PALA-loaded microemulsion (PALA-ME, without the binding domain for LDLR) displayed uniform sizes with high drug loading efficiency (> 90%). In vitro studies demonstrated PALA-sLDL exhibited enhanced cellular uptake capacity and better cytotoxicity to LDLR over-expressed U87 MG cells as compared to PALA-ME. The uptake mechanisms of PALA-sLDL were involved in a receptor mediated endocytosis and macropinocytosis. Furthermore, the in vivo biodistribution and tumor growth inhibition studies of PALA-sLDL were investigated in xenograft U87 MG tumor-bearing mice. The results showed that PALA-sLDL exhibited higher tumor accumulation than PALA-ME and superior tumor inhibition efficiency (72.1%) compared to Taxol^® (51.2%) and PALA-ME (58.8%) but with lower toxicity. These studies suggested that sLDL is potential to be used as a valuable carrier for the selective delivery of anticancer drugs to tumor with low systemic toxicity.

A self-assembling nanomedicine of conjugated linoleic acid-paclitaxel conjugate (CLA-PTX) with higher drug loading and carrier-free characteristic

The main objective of this study was to demonstrate the proof-of-principle for the hypothesis that conjugated linoleic acid-paclitaxel conjugate (CLA-PTX), a novel fatty acid modified anti-cancer drug conjugate, could self-assemble forming nanoparticles. The results indicated that a novel self-assembling nanomedicine, CLA-PTX@PEG NPs (about 105 nm), with Cremophor EL (CrEL)-free and organic solvent-free characteristics, was prepared by a simple precipitation method. Being the ratio of CLA-PTX:DSPE-PEG was only 1:0.1 (w/w), the higher drug loading CLA-PTX@PEG NPs (about 90%) possessed carrier-free characteristic. The stability results indicated that CLA-PTX@PEG NPs could be stored for at least 9 months. The safety of CLA-PTX@PEG NPs was demonstrated by the MTD results. The anti-tumor activity and cellular uptake were also confirmed in the in vitro experiments. The lower crystallinity, polarity and solubility of CLA-PTX compared with that of paclitaxel (PTX) might be the possible reason for CLA-PTX self-assembling forming nanoparticles, indicating a relationship between PTX modification and nanoparticles self-assembly. Overall, the data presented here confirm that this drug self-delivery strategy based on self-assembly of a CLA-PTX conjugate may offer a new way to prepare nanomedicine products for cancer therapy involving the relationship between anticancer drug modification and self-assembly into nanoparticles.

c9, t11- conjugated linoleic acid induces HCC cell apoptosis and correlation with PPAR-γ signaling pathway

OBJECTIVE

Cis9, trans11 conjugated linoleic acid (c9, t11-CLA.) is one of the most important isomers of conjugated linoleic acid, which have a strong anti-tumor effects. Based on previous studies, we further explored the molecular mechanism of inducing cells apoptosis in human hepatocellular carcinoma cell line HepG2 and Hep3B.

METHODS

Cell Counting Kit 8 (CCK-8) assay was used to investigate the effects of c9, t11-CLA on cell viability and cell proliferation ability; The effects of c9, t11-CLA on cell apoptosis was analyzed by DNA ladder assay, immuno-fluorescence and flow cytometry, respectively. Apoptotic related gene (Bcl-2, Bcl-XL, Bcl-w, Mcl-1, Bax, Bak, Bad, Bid and Bim), PPAR family member (PPAR-α, PPAR-β and PPAR-γ), and Cox2 mRNA and protein expression were analyzed by RT-PCR and western blotting. ELISA assay was used to detect the content of Caspase-3.

RESULTS

Our data were confirmed that c9, t11-CLA could inhibit the HCC cells proliferation ability and decrease the cells viability. RT-PCR and western blotting assay verified that c9, t11-CLA obviously increased the transcription and protein expression levels of PPAR-γ. The synchronism and correlation between PPAR-γ and apoptotic proteins Bcl-2, Bax and Caspase-3 were found with a dose- and time-dependent manner. PPAR-γ inhibitor GW9662 and activator Rosilitazone were further verified that there was cooperative relation between them.

CONCLUSION

In our study, we first report that c9, t11-CLA induces apoptosis in HCC cells by activation of PPARγ-Bcl-2-Caspase-3 signal pathway. These results indicated that c9, t11-CLA will be useful for clinic therapy of anti-tumor and as a new regulator of PPAR-γ in the future.

Micheliolide derivative DMAMCL inhibits glioma cell growth in vitro and in vivo

Background

There is no highly effective chemotherapy for malignant gliomas to date. We found that dimethylaminomicheliolide (DMAMCL), a selective inhibitor of acute myeloid leukemia (AML) stem/progenitor cells, inhibited the growth of glioma cells.

Methods

The distribution of DMAMCL in brain was analyzed by an ultraperformance liquid chromatography-mass spectrometry (UPLC-MS/MS) system. The anti-tumor evaluations of DMAMCL in vitro were performed by MTT, FACS and RT-PCR. In vivo, the mixture of C6 cells and matrigel was injected into caudatum, and the anti-tumor activity of DMAMCL was evaluated by tumor growth and rat survival. The toxicity of DMAMCL was evaluated by body weight, daily food intake, hematological or serum biochemical analyses, and histological appearance of tissues.

Results

The IC₅₀ values of DMAMCL against the C6 and U-87MG cell lines in vitro were 27.18 ± 1.89 μM and 20.58 ± 1.61 μM, respectively. DAMMCL down-regulated the anti-apoptosis gene Bcl-2 and increased apoptosis in C6 and U-87MG cells in a dose-dependent manner. In a C6 rat tumor model, daily administration of DMAMCL for 21 days reduced the burden of C6 tumors by 60% to 88% compared to controls, and more than doubled the mean lifespan of tumor-bearing rats. Distribution analysis showed that the DMAMCL concentration was higher in the brain than in plasma. Evaluations for toxicity revealed that oral administration of DMAMCL at 200 or 300 mg/kg once a day for 21 days did not result in toxicity.

Conclusions

These results suggest that DMAMCL is highly promising for the treatment of glioma.

Antitumor effect of iRGD-modified liposomes containing conjugated linoleic acid-paclitaxel (CLA-PTX) on B16-F10 melanoma

In the present study, we prepared a novel delivery system of iRGD (CRGDK/RGPD/EC)-modified sterically stabilized liposomes (SSLs) containing conjugated linoleic acid–paclitaxel (CLA-PTX). The anti-tumor effect of iRGD-SSL-CLA-PTX was investigated on B16-F10 melanoma in vitro and in vivo. The in vitro targeting effect of iRGD-modified SSLs was investigated in a real-time confocal microscopic analysis experiment. An endocytosis-inhibition assay was used to evaluate the endocytosis pathways of the iRGD-modified SSLs. In addition, the in vitro cellular uptake and in vitro cytotoxicity of iRGD-SSL-CLA-PTX were evaluated in B16-F10 melanoma cells. In vivo biodistribution and in vivo antitumor effects of iRGD-SSL-CLA-PTX were investigated in B16-F10 tumor-bearing mice. The induction of apoptosis by iRGD-SSL-CLA-PTX was evaluated in tumor-tissue sections. Real-time confocal microscopic analysis results indicated that the iRGD-modified SSLs internalized into B16-F10 cells faster than SSLs. The identified endocytosis pathway of iRGD-modified SSLs indicated that energy- and lipid raft-mediated endocytosis played a key role in the liposomes’ cellular uptake. The results of the cellular uptake experiment indicated that the increased cellular uptake of CLA-PTX in the iRGD-SSL-CLA-PTX-treated group was 1.9-, 2.4-, or 2.1-fold compared with that in the CLA-PTX group after a 2-, 4-, or 6-hour incubation, respectively. In the biodistribution test, the CLA-PTX level in tumor tissues from iRGD-SSL-CLA-PTX-treated mice at 1 hour (1.84±0.17 μg/g) and 4 hours (1.17±0.28 μg/g) was 2.3- and 2.0-fold higher than that of CLA-PTX solution at 1 hour (0.79±0.06 μg/g) and 4 hours (0.58±0.04 μg/g). The value of the area under the curve for the first 24 hours in the tumors of iRGD-SSL-CLA-PTX-treated mice was significantly higher than that in the SSL-CLA-PTX and CLA-PTX solution-treated groups (P<0.01). The in vivo antitumor results indicated that iRGD-SSL-CLA-PTX significantly inhibited the growth of B16-F10 tumors compared with the SSL-CLA-PTX or CLA-PTX solution-treatment groups (P<0.01). The results of tumor-cell apoptosis showed that tumors from the iRGD-SSL-CLA-PTX-treated group exhibited more advanced cell apoptosis compared with the control, CLA-PTX solution-, and SSL-CLA-PTX-treated groups. In conclusion, the antitumor effect of iRGD-SSL-CLA-PTX was confirmed on B16-F10 melanoma in vitro and in vivo.