In vivo imaging of DNA lipid nanocapsules after systemic administration in a melanoma mouse model

Suicide gene strategies applied in ovarian cancer studies

Ovarian cancer represents the most lethal gynecological malignancy among women in developed countries. Despite the recent innovations, the improvements in the 5-year survival rate have been insufficient and the management of this disease still remains a challenge. The fact that the majority of patients experience recurrent or resistant disease have substantiated the necessity of an innovative treatment. Among various strategies investigated, the recent strides made in gene delivery techniques have made gene therapy, including suicide gene strategies, a potential alternative for treating ovarian cancer. Various suicide gene candidates, which are capable of promoting cancer cell apoptosis directly after its entry or indirectly by prodrug administration, can be separated into three systems using enzyme-coding, toxin or pro-apoptotic genes. With this review, we aim to provide an overview of different suicide genes depending on therapeutic strategies, the vectors used to deliver these transgenes specifically to malignant cells, and the combined treatments of these genes with various therapeutic regimens.

Lipid nanocapsules for intracellular delivery of microRNA: a first step towards intervertebral disc degeneration therapy

Approximately 40% of cases of lower back pain are caused by disc degeneration disease (DDD). It is well established that microRNA (miR) dysregulation is a key player in various diseases, and its impact on DDD has recently been highlighted. RNAi (miR in particular) is increasingly being considered as a novel therapeutic tool. However, free miR is degraded rapidly in vivo, and its protection is thus a prerequisite. Nanoparticular platforms, such as lipid nanocapsules (LNC), could be specifically adapted for miR delivery, allowing the transfer and release of miR in the cell cytoplasm. The objective of the current study was to formulate and characterize miR-loaded LNC to establish their in vitro potential (cell internalization, bioactivity) as well as to determine the safety and feasibility of in situ intervertebral disc (IVD) injection of miR LNC in a healthy sheep model. Using a miR library, miR-155 was clearly identified as being involved in the DDD process and was selected for further assessment. miR-155-loaded LNC (miR-155 LNC) were successfully formulated using a phase inversion process, with the addition of lipoplexes in the cooling step. Following purification, miR-155 LNC were fully characterized, and the optimized formulation had an average diameter of 75 nm, a polydispersity index below 0.1, and a positive zeta potential. By fluorescence spectroscopy, an encapsulation efficiency (EE) of 75.6% and a drug loading (DL) of 0.6% were obtained, corresponding to a sufficient amount of miR per mL of LNC to potentially have a biological effect. The sustained release of miR-155 from LNC was demonstrated compared with free miR-155: only 22% was released after 2 h and 58% after 24 h. miR-155 protection against endonuclease degradation by LNC was confirmed by gel electrophoresis, a sine qua non condition for it to be administered in vivo. Cell viability assays were performed on human adipose stromal cells (hASCs) and ovine Nucleus pulposus cells (oNP), and a cytotoxicity of less than 30% was obtained at the considered concentrations. Additionally, miR-155 LNC cell internalization was demonstrated by flow cytometry and confocal imaging. Moreover, downregulation of total ERK1/2 in hASCs and oNP cells, after miR-155 LNC treatment, was demonstrated by Western blot and quantitative reverse-transcription PCR (qRT-PCR), thus confirming maintenance of its bioactivity after formulation and internalization. Finally, the feasibility and safety of miR-155 LNC in situ injection (compared to control groups: blank LNC and sham condition) was demonstrated in healthy sheep by imaging (MRI and T2wsi measurement) and histology (Boos' scoring) analysis. T2wsi was measured, and no significant difference was observed three months after the injection between the different conditions. No histological impact was observed, with no significant difference in Boos' scoring between the different conditions. All these results suggest LNC may be a potent strategy for the encapsulation and delivery of miR (particularly miR-155) and can be considered as a first step towards IVD regenerative medicine.

Ferrocifen Loaded Lipid Nanocapsules: A Promising Anticancer Medication against Multidrug Resistant Tumors

Resistance of cancer cells to current chemotherapeutic drugs has obliged the scientific community to seek innovative compounds. Ferrocifens, lipophilic organometallic compounds composed of a tamoxifen scaffold covalently bound to a ferrocene moiety, have shown very interesting antiproliferative, cytotoxic and immunologic effects. The formation of ferrocenyl quinone methide plays a crucial role in the multifaceted activity of ferrocifens. Lipid nanocapsules (LNCs), meanwhile, are nanoparticles obtained by a free organic solvent process. LNCs consist of an oily core surrounded by amphiphilic surfactants and are perfectly adapted to encapsulate these hydrophobic compounds. The different in vitro and in vivo experiments performed with this ferrocifen-loaded nanocarrier have revealed promising results in several multidrug-resistant cancer cell lines such as glioblastoma, breast cancer and metastatic melanoma, alone or in combination with other therapies. This review provides an exhaustive summary of the use of ferrocifen-loaded LNCs as a promising nanomedicine, outlining the ferrocifen mechanisms of action on cancer cells, the nanocarrier formulation process and the in vivo results obtained over the last two decades.

Optical and Optoacoustic Imaging

The spatiotemporal determination of molecular events and cells is important for understanding disease processes, especially in oncology, and thus for the development of novel treatments. Equally important is the knowledge of the biodistribution, localization, and targeted accumulation of novel therapies as well as monitoring of tumor growth and therapeutic response. Optical imaging provides an ideal versatile platform for imaging of all these problems and questions.

Model Affitin and PEG modifications onto siRNA lipid nanocapsules: cell uptake and in vivo biodistribution improvements

Malignant melanoma is an aggressive tumor, associated with the presence of local and/or distant metastases. The development of gene therapy by the use of small interfering RNA (siRNA) represents a promising new treatment. However, the protection of this biomolecule is necessary in order for it to be intravenously administrated, for example via its incorporation into nanomedicines. In parallel to the passive targeting usually obtained by pegylation, various studies have aimed at developing “smart” nanomedicines to efficiently deliver the drug to tumor sites. In this work, siRNA loaded lipid nanocapsules (LNCs) were modified with DSPE-polyethylene glycol (DSPE-PEG), tetraether-PEG (TE-PEG) and/or with an Affitin model, to assay multiple targeting strategies. The uptake of fluorescently labelled LNCs, nanocarrier integrity and siRNA release into human SK-Mel28 melanoma cells were studied by flow cytometry, conventional confocal microscopy and by confocal spectral imaging in a Förster Resonance Energy Transfer (FRET) mode. Surface modified siRNA LNCs were followed after human plasma incubation and after intravenous injection, in order to compare the stealth properties. Finally, the biodistribution of the different siRNA LNCs in healthy and melanoma tumor bearing mice models was assessed by in vivo biofluorescence imaging (BFI), to evaluate the potential tumor targeting ability. The post-insertion of DSPE-PEG induced a strong decrease of the internalization into melanoma cells compared to TE-PEG modification. Both PEG polymer decorations induced a great plasma protection of siRNA but only DSPE-PEG led to stealth properties, even at low concentration (5 mM). The Affitin grafting by thiolation of DSPE-PEG was validated on siRNA LNCs. DSPE-PEG-Affitin LNCs were not detected in this melanoma tumor model but did not show unspecific accumulation in organs. DSPE-PEG and TE-PEG LNCs induced a significant intratumoral accumulation of modified LNCs.

Surface modifications of siRNA LNCs were assessed with innovative TE-PEG polymers and an Affitin model, in comparison to classic DSPE-PEG LNCs, in order to evaluate the potential tumor targeting of siRNA after intravenous administration.

A non-coding function of TYRP1 mRNA promotes melanoma growth

Competition among RNAs to bind miRNA is proposed to influence biological systems. However, the role of this competition in disease onset is unclear. Here, we report that TYRP1 mRNA, in addition to encoding tyrosinase-related protein 1 (TYRP1), indirectly promotes cell proliferation by sequestering miR-16 on non-canonical miRNA response elements. Consequently, the sequestered miR-16 is no longer able to repress its mRNA targets, such as RAB17, which is involved in melanoma cell proliferation and tumour growth. Restoration of miR-16 tumour-suppressor function can be achieved in vitro by silencing TYRP1 or increasing miR-16 expression. Importantly, TYRP1-dependent miR-16 sequestration can also be overcome in vivo by using small oligonucleotides that mask miR-16-binding sites on TYRP1 mRNA. Together, our findings assign a pathogenic non-coding function to TYRP1 mRNA and highlight miRNA displacement as a promising targeted therapeutic approach for melanoma.

Evaluation of New Fluorescent Lipophosphoramidates for Gene Transfer and Biodistribution Studies after Systemic Administration

The objective of lung gene therapy is to reach the respiratory epithelial cells in order to deliver a functional nucleic acid sequence. To improve the synthetic carrier's efficacy, knowledge of their biodistribution and elimination pathways, as well as cellular barriers faced, depending on the administration route, is necessary. Indeed, the in vivo fate guides the adaptation of their chemical structure and formulation to increase their transfection capacity while maintaining their tolerance. With this goal, lipidic fluorescent probes were synthesized and formulated with cationic lipophosphoramidate KLN47 (KLN: Karine Le Ny). We found that such formulations present constant compaction properties and similar transfection results without inducing additional cytotoxicity. Next, biodistribution profiles of pegylated and unpegylated lipoplexes were compared after systemic injection in mice. Pegylation of complexes led to a prolonged circulation in the bloodstream, whereas their in vivo bioluminescent expression profiles were similar. Moreover, systemic administration of pegylated lipoplexes resulted in a transient liver toxicity. These results indicate that these new fluorescent compounds could be added into lipoplexes in small amounts without perturbing the transfection capacities of the formulations. Such additional properties allow exploration of the in vivo biodistribution profiles of synthetic carriers as well as the expression intensity of the reporter gene.

Efficient in vitro gene therapy with PEG siRNA lipid nanocapsules for passive targeting strategy in melanoma

Small interfering RNA (siRNA)-mediated gene therapy is a promising strategy to temporarily inhibit the expression of proteins implicated in carcinogenesis or chemotherapy resistance. Although intra-tumoral administration can be envisaged, studies currently focus on formulating nanomedicines for intravenous injection to target tumor sites as well as metastases. The development of synthetic nanoparticles and liposomes has advanced greatly during the last decade. The objective of this work consists in formulating and optimizing the encapsulation of siRNA into lipid nanocapsules (LNCs) for efficient gene therapy to target melanoma cells. SiRNA LNCs were prepared from DOTAP/DOPE lipoplexes, and the siRNA amount and lipid/siRNA charge ratio were assayed to improve the stability and the encapsulation yield. Cryo-TEM imaging of the siRNA lipoplexes and LNC morphology revealed specific organization of the siRNA DOTAP/DOPE lipoplexes as well as specific lipid microstructures that can be eliminated by purification. No cytotoxicity of the siRNA LNCs against the melanoma SK-Mel28 cell line was observed at concentrations of up to 500 ng/mL siRNA. In vitro siRNA transfection experiments, compared to Oligofectamine™, demonstrated interesting targeted gene silencing effects. Finally, complement activation assays confirmed the feasibility of the PEGylation of siRNA LNCs as part of a passive targeting strategy for future in vivo melanoma- and metastasis-targeting experiments.

Treatment efficacy of DNA lipid nanocapsules and DNA multimodular systems after systemic administration in a human glioma model

BACKGROUND

We previously developed different types of DNA nanocarriers for systemic administration. Recently, the biodistribution profiles of these intravenously administered nanocarriers, DNA lipid nanocapsules (LNCs) and different multimodular systems (MMS), were analysed in healthy mice using in vivo biofluorescence imaging.

METHODS

In the present study, the experiments were performed in an ectopic human U87MG glioma model in nude mice. First, the biodistribution profiles of intravenously administered multimodular systems delivering a plasmid DNA with a luciferase cassette were analysed using in vivo biofluorescence imaging. Afterwards, a systemic treatment with two long circulating DNA nanocarriers, poly(ethylene glycol) (PEG) DNA LNCs and galactose (GAL) DNA MMS dioleylamin-succinyl paromomycin (DOSP) was performed on this glioma model using a plasmid encoding the herpes simplex virus thymidine kinase (HSV-tk) and subsequent ganciclovir (GCV) treatment.

RESULTS

The biodistribution profiles of the different DNA nanocarriers on this glioma model were similar to those observed on healthy animals and varied in function of their cationic lipid composition and their surface characteristics. Furthermore, PEG DNA LNCs and GAL DNA MMS DOSP showed a specific accumulation and some luciferase expression in the tumour tissue. The systemic treatment using the HSV-tk/GCV approach showed a tumour growth reduction compared to the nontreated mice cohort.

CONCLUSIONS

These results are in good accordance with those obtained previously with PEG DNA LNCs in a human melanoma mouse model and highlight the potential use of GAL DNA MMS DOSP and PEG DNA LNCs as future therapeutics in glioma and other cancers.

Intelligent design of multifunctional lipid-coated nanoparticle platforms for cancer therapy

Nanotechnology is rapidly evolving and dramatically changing the paradigms of drug delivery. The small sizes, unique chemical properties, large surface areas, structural diversity and multifunctionality of nanoparticles prove to be greatly advantageous for combating notoriously therapeutically evasive diseases such as cancer. Multifunctional nanoparticles have been designed to enhance tumor uptake through either passive or active targeting, while also avoiding reticuloendothelial system uptake through the incorporation of PEG onto the surface. First-generation nanoparticle systems, such as liposomes, are good carriers for drugs and nucleic acid therapeutics, although they have some limitations. These lipid bilayers are now being utilized as excellent carriers for drug-loaded, solid core particles such as iron oxide, mesoporus silica and calcium phosphate. In this article, their design, as well as their multifunctional role in cancer therapy are discussed.

EGFR siRNA lipid nanocapsules efficiently transfect glioma cells in vitro

Glioma are the most common malignant tumors of the central nervous system and remain associated with poor prognosis, despite the combination of chemotherapy and radiotherapy. EGFR targeting represents an interesting strategy to treat glioma. Indeed, a high level of endothelial growth factor receptors expression (EGFR), involved in the malignancy of the tumor, has been observed in glioma. Our strategy consisted in using EGFR siRNA entrapped into lipid nanocapsules (LNCs) via cationic liposomes. In vitro analyses on U87MG human glioma cells were performed to evaluate firstly the capacity of LNCs to efficiently deliver the siRNA and secondly the effect of EGFR siRNA targeting on U87MG proliferation. Then, the complement protein consumption was evaluated by CH50 assays to verify the suitability of the siRNA LNCs for systemic administration. The EGFR siRNA LNCs exhibited an adequate size lower than 150 nm as well as a neutral surface charge. The IC50 profile together with the 63% of protein extinction demonstrated the significant action of EGFR siRNA LNCs compared to scrambled LNCs. Dose and time-dependent survival assays showed a decrease of U87MG growth evaluated at 38%. Finally, low complement consumption demonstrated the suitability of EGFR siRNA LNCs for intravenous injection. In conclusion, EGFR siRNA LNCs demonstrated their capacity to efficiently encapsulate and deliver siRNA into U87MG human glioma cells, and will therefore be usable in the future for in vivo evaluation.

Gene therapy for advanced melanoma: selective targeting and therapeutic nucleic acids

Despite recent advances, the treatment of malignant melanoma still results in the relapse of the disease, and second line treatment mostly fails due to the occurrence of resistance. A wide range of mutations are known to prevent effective treatment with chemotherapeutic drugs. Hence, approaches with biopharmaceuticals including proteins, like antibodies or cytokines, are applied. As an alternative, regimens with therapeutically active nucleic acids offer the possibility for highly selective cancer treatment whilst avoiding unwanted and toxic side effects. This paper gives a brief introduction into the mechanism of this devastating disease, discusses the shortcoming of current therapy approaches, and pinpoints anchor points which could be harnessed for therapeutic intervention with nucleic acids. We bring the delivery of nucleic acid nanopharmaceutics into perspective as a novel antimelanoma therapeutic approach and discuss the possibilities for melanoma specific targeting. The latest reports on preclinical and already clinical application of nucleic acids in melanoma are discussed.

Nanoemulsions and nanoparticles for non-melanoma skin cancer: effects of lipid materials

Basal cell carcinomas and squamous cell carcinomas are non-melanoma skin cancers reported to be among the most common malignancies, being responsible for high human morbidity. Conventional chemotherapy applied to these conditions shows non-specific targeting, thus severe adverse side effects are also commonly reported. New therapeutic strategies based on nanoparticulates technology have emerged as alternatives for site specific chemotherapy. Among the different types of nanoparticulates, lipid nanoemulsions and nanoparticles have several advantages for topical delivery of poorly soluble chemotherapeutics. These particles show sustained drug release and protection of loaded drugs from chemical degradation. This technology is promising to enhance the intracellular concentration of drugs and consequently reduce the cytotoxicity of skin chemotherapy.

DNA nanocarriers for systemic administration: characterization and in vivo bioimaging in healthy mice

We hereby present different DNA nanocarriers consisting of new multimodular systems (MMS), containing the cationic lipid dioleylaminesuccinylparomomycin (DNA MMS DOSP), or bis (guanidinium)-tren-cholesterol (DNA MMS BGTC), and DNA lipid nanocapsules (DNA LNCs). Active targeting of the asialoglycoprotein receptor (ASGP-R) using galactose as a ligand for DNA MMS (GAL DNA MMS) and passive targeting using a polyethylene glycol coating for DNA LNCs (PEG DNA LNCs) should improve the properties of these DNA nanocarriers. All systems were characterized via physicochemical methods and the DNA payload of DNA LNCs was quantified for the first time. Afterwards, their biodistribution in healthy mice was analyzed after encapsulation of a fluorescent dye via in vivo biofluorescence imaging (BFI), revealing various distribution profiles depending on the cationic lipid used and their surface characteristics. Furthermore, the two vectors with the best prolonged circulation profile were administered twice in healthy mice revealing that the new DNA MMS DOSP vectors showed no toxicity and the same distribution profile for both injections, contrary to PEG DNA LNCs which showed a rapid clearance after the second injection, certainly due to the accelerated blood clearance phenomenon.