Local delivery of ferrociphenol lipid nanocapsules followed by external radiotherapy as a synergistic treatment against intracranial 9L glioma xenograft

Diversely substituted poly(N-vinyl amide) derivatives towards non-toxic, stealth and pH-responsive lipid nanocapsules

Surface modification of lipid nanocapsules (LNC) is necessary to impart stealth properties to these drug carriers and enhance their accumulation into the tumor microenvironment. While pegylation is commonly used to prolong the circulation time of LNC, the increased presence of anti-PEG antibodies in the human population and the internalization issues associated to the PEG shell are strong incentives to search alternatives. This work describes the development of amphiphilic poly(N-vinyl amide)-based (co)polymers, including pH-responsive ones, and their use as LNC modifiers towards improved drug delivery systems. RAFT polymerization gave access to a series of LNC modifiers composed of poly(N-methyl-N-vinyl acetamide), poly(N-vinyl pyrrolidone) or pH-responsive vinylimidazole-based sequence bearing a variety of lipophilic end-groups, namely octadecyl, dioctadecyl or phospholipid groups, for anchoring to the LNC. Decoration of the LNC with these families of poly(N-vinyl amide) derivatives was achieved via both post-insertion and per-formulation methods. This offered valuable and non-toxic LNC protection from opsonization by complement activation, emphasized the benefit of dioctadecyl in the per-formulation approach and highlighted the great potential of poly(N-methyl-N-vinyl acetamide) as PEG alternative. Moreover, incorporation of imidazole moieties in the shell of the carrier imparted pH-responsiveness to the LNC likely to increase the cellular uptake in the acidic tumor microenvironment, opening up new possibilities in the field of active targeting.

Thioredoxin Reductase and Organometallic Complexes: A Pivotal System to Tackle Multidrug Resistant Tumors?

Cancers classified as multidrug-resistant (MDR) are a family of diseases with poor prognosis despite access to increasingly sophisticated treatments. Several mechanisms explain these resistances involving both tumor cells and their microenvironment. It is now recognized that a multi-targeting approach offers a promising strategy to treat these MDR tumors. Inhibition of thioredoxin reductase (TrxR), a key enzyme in maintaining redox balance in cells, is a well-identified target for this approach. Auranofin was the first inorganic gold complex to be described as a powerful inhibitor of TrxR. In this review, we will first recall the main results obtained with this metallodrug. Then, we will focus on organometallic complexes reported as TrxR inhibitors. These include gold(I), gold(III) complexes and metallocifens, i.e., organometallic complexes of Fe and Os derived from tamoxifen. In these families of complexes, similarities and differences in the molecular mechanisms of TrxR inhibition will be highlighted. Finally, the possible relationship between TrxR inhibition and cytotoxicity will be discussed and put into perspective with their mode of action.

Ferrocene-Based Drugs, Delivery Nanomaterials and Fenton Mechanism: State of the Art, Recent Developments and Prospects

Ferrocene has been the most used organometallic moiety introduced in organic and bioinorganic drugs to cure cancers and various other diseases. Following several pioneering studies, two real breakthroughs occurred in 1996 and 1997. In 1996, Jaouen et al. reported ferrocifens, ferrocene analogs of tamoxifen, the chemotherapeutic for hormone-dependent breast cancer. Several ferrocifens are now in preclinical evaluation. Independently, in 1997, ferroquine, an analog of the antimalarial drug chloroquine upon the introduction of a ferrocenyl substituent in the carbon chain, was reported by the Biot-Brocard group and found to be active against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum. Ferroquine, in combination with artefenomel, completed phase IIb clinical evaluation in 2019. More than 1000 studies have been published on ferrocenyl-containing pharmacophores against infectious diseases, including parasitic, bacterial, fungal, and viral infections, but the relationship between structure and biological activity has been scarcely demonstrated, unlike for ferrocifens and ferroquines. In a majority of ferrocene-containing drugs, however, the production of reactive oxygen species (ROS), in particular the OH. radical, produced by Fenton catalysis, plays a key role and is scrutinized in this mini-review, together with the supramolecular approach utilizing drug delivery nanosystems, such as micelles, metal-organic frameworks (MOFs), polymers, and dendrimers.

Injectable local drug delivery systems for glioblastoma: a systematic review and meta-analysis of progress to date

Glioblastoma (GBM) is an aggressive malignant cancer associated with bleak prognosis and high mortality. The current standard of care for GBM is maximum surgical resection plus radiotherapy and temozolomide (TMZ) chemotherapy. The blood brain barrier (BBB) remains the main obstacle for chemotherapy and severely limits the choice of therapeutic agents. Local treatment allows drugs to circumvent the BBB and reduces systemic side effects. Despite much research effort, to date, no drug delivery system (DDS) designed to be directly injected into brain tumors has been clinically approved, and a systematic overview of the progress in this field, or lack thereof, is missing. In this review, a systematic search of pre-clinical literature was conducted which resulted in 36 original articles on injectable DDS for local treatment of GBM which met the inclusion criteria. A wide range of injectable DDS have been developed and tested pre-clinically which include nanoparticles, liposomes, microspheres, hydrogels and others. meta-Analyses of the included studies showed that, overall, local administration of injectable DDS was beneficial to increase the animal's survival time. Finally, this review summarized the therapeutic effect after local treatment and discussed the shortcomings of the experimental setting in in vivo studies.

Physicochemical Characterization of Ferrocifen Lipid Nanocapsules: Customized Drug Delivery Systems Guided by the Molecular Structure

Ferrocifens, lipophilic organometallic complexes, comprise a biologically active redox motif [ferrocenyl-ene-p-phenol] which confers very interesting cytotoxic properties to this family. However, because of their highly lipophilic nature, a formulation stage is required before being administered in vivo. In recent decades, ferrocifen lipid nanocapsules (LNCs) have been successfully formulated and have demonstrated anticancer activity on multidrug-resistant cancers in several mice and rat models (glioblastoma, breast cancer, and metastatic melanoma). A recent family of ferrocifens (succinimidoalkyl-ferrociphenols, including P722) appears to be most efficacious on several resistant cancer cell lines, with IC₅₀ values in the nanomolar range together with promising in vivo results on murine ovarian cancer models. As LNCs are composed of an oily core (caprylic/capric triglycerides), modulation of the succinimido-ferrociphenol lipophilicity could be a valuable approach toward improving the drug loading in LNCs. As the drug loading of the diphenol P722 in LNCs was low, it was structurally modified to increase its lipophilicity and thereby the payload in LNCs. Chemical modification led to a series of five succinimido-ferrocifens. Results confirmed that these slight structural modifications led to increased drug loading in LNCs for all ferrocifens, with no reduction of their cytotoxicity on the SKOV3 ovarian cancer cell line. Interestingly, encapsulation of two of the ferrocifens, diester P769 and monophenolic ester (E)-P998, led to the formation of a gel. This was unprecedented behavior, a phenomenon that could be rationalized in terms of the positioning of ferrocifens in LNCs as shown by the decrease of interfacial tension measurements at the water/oil interface. Moreover, these results highlighted the importance of obtaining a gel of this particular motif, in which the acetylated phenolic ring and the succinimidoalkyl moieties are mutually cis relative to the central double bond. Promising perspectives to use these ferrocifen-loaded LNCs to treat glioblastoma could be readily envisaged by local application of the gel in the cavity after tumor resection.

Stability, pharmacokinetics, and biodistribution in mice of the EPAC1 inhibitor (R)-CE3F4 entrapped in liposomes and lipid nanocapsules

(R)-CE3F4, a specific inhibitor of EPAC1 (exchange protein directly activated by cAMP type 1), has been demonstrated in vitro and in vivo to reduce hypertrophic signaling contributing to heart failure or to control arrhythmia and has shown promise as a drug candidate. However, (R)-CE3F4 exhibits poor solubility in aqueous media and has shown sensitivity to enzyme hydrolysis in plasma. To overcome these issues, the drug was entrapped in liposomes and lipid nanocapsules. Both systems considerably increased the drug apparent solubility in aqueous media. Among these nanocarriers, lipid nanocapsules offered significant protection in vitro against enzymatic degradation by increasing the (R)-CE3F4 apparent half-life from around 40 min to 6 h. Pharmacokinetics and biodistribution of (R)-CE3F4 radiolabeled or not were studied in healthy C57BL/6 mice. The non-encapsulated ³H-CE3F4 showed a very rapid distribution outside the blood compartment. Similar results were observed when using nanocarriers together with a fast dissociation of ³H-CE3F4 from nanocapsules simultaneously labeled with ¹⁴C. Thus, essential preclinical information on CE3F4 fate has been obtained, as well as the impact of its formulation using lipid-based nanocarriers.

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.

pH-Responsive Lipid Nanocapsules: A Promising Strategy for Improved Resistant Melanoma Cell Internalization

Despite significant advances in melanoma therapy, low response rates and multidrug resistance (MDR) have been described, reducing the anticancer efficacy of the administered molecules. Among the causes to explain these resistances, the decreased intratumoral pH is known to potentiate MDR and to reduce the sensitivity to anticancer molecules. Nanomedicines have been widely exploited as the carriers of MDR reversing molecules. Lipid nanocapsules (LNC) are nanoparticles that have already demonstrated their ability to improve cancer treatment. Here, LNC were modified with novel copolymers that combine N-vinylpyrrolidone (NVP) to impart stealth properties and vinyl imidazole (Vim), providing pH-responsive ability to address classical chemoresistance by improving tumor cell entry. These copolymers could be post-inserted at the LNC surface, leading to the property of going from neutral charge under physiological pH to positive charge under acidic conditions. LNC modified with polymer P5 (C18H37-P(NVP21-co-Vim15)) showed in vitro pH-responsive properties characterized by an enhanced cellular uptake under acidic conditions. Moreover, P5 surface modification led to an increased biological effect by protecting the nanocarrier from opsonization by complement activation. These data suggest that pH-sensitive LNC responds to what is expected from a promising nanocarrier to target metastatic melanoma.

Polymeric Nanoparticles for the Treatment of Malignant Gliomas

Malignant gliomas are one of the deadliest forms of brain cancer and despite advancements in treatment, patient prognosis remains poor, with an average survival of 15 months. Treatment using conventional chemotherapy does not deliver the required drug dose to the tumour site, owing to insufficient blood brain barrier (BBB) penetration, especially by hydrophilic drugs. Additionally, low molecular weight drugs cannot achieve specific accumulation in cancerous tissues and are characterized by a short circulation half-life. Nanoparticles can be designed to cross the BBB and deliver their drugs within the brain, thus improving their effectiveness for treatment when compared to administration of the free drug. The efficacy of nanoparticles can be enhanced by surface PEGylation to allow more specificity towards tumour receptors. This review will provide an overview of the different therapeutic strategies for the treatment of malignant gliomas, risk factors entailing them as well as the latest developments for brain drug delivery. It will also address the potential of polymeric nanoparticles in the treatment of malignant gliomas, including the importance of their coating and functionalization on their ability to cross the BBB and the chemistry underlying that.

Development and characterization of sorafenib-loaded lipid nanocapsules for the treatment of glioblastoma

Anticancer agents that target both tumor cells and angiogenesis are of potential interest for glioblastoma (GB) therapy. One such agent is sorafenib (SFN), a tyrosine kinase inhibitor. However, poor aqueous solubility and undesirable side effects limit its clinical application, including local treatment. We encapsulated SFN in lipid nanocapsules (LNCs) to overcome these drawbacks. LNCs are nanocarriers formulated according to a solvent-free process, using only components that have received regulatory approval. SFN-LNCs had a diameter of 54 ± 1 nm, high encapsulation efficiency (>90%), and a drug payload of 2.11 ± 0.03 mg/g of LNC dispersion. They inhibited in vitro angiogenesis and decreased human U87MG GB cell viability similarly to free SFN. In vivo studies showed that the intratumoral administration of SFN-LNCs or free SFN in nude mice bearing an orthotopic U87MG human GB xenograft decreased the proportion of proliferating cells in the tumor relative to control groups. SFN-LNCs were more effective than free SFN for inducing early tumor vascular normalization, characterized by increases in tumor blood flow and decreases in tumor vessel area. These results highlight the potential of LNCs as delivery systems for SFN. The vascular normalization induced by SFN-LNCs could be used to improve the efficacy of chemotherapy or radiotherapy for treating GB.

Iron Compounds as Anticancer Agents

Many ferrocene complexes have been prepared for their oncological potential. Some derive from molecules with known biological effects (taxanes, podophyllotoxine, artemisine, SAHA, etc.) while others are synthetic molecules selected for their cytotoxic effects (N-alkylaminoferrocenes and ferrocenyl alkylpyridinium). Although these complexes have received a great deal of attention, the field of iron metallodrugs is not limited to them. A number of inorganic complexes of iron(ii) and iron(iii) with possible anticancer effects have also been published, although research into their biological effects is often only at an early stage. This chapter also includes iron chelators, molecules that are administered in non-metallic form but whose cytotoxic species are their coordination complexes of iron generated in vivo. The most emblematic molecule of this family is bleomycin, used as an anticancer agent in many chemotherapies. To these can be added the iron chelates originally synthesized to treat iron overload, some of which have been shown to possess interesting anticancer properties. They have been, and continue to be, the subject of many clinical trials, whether alone or in combination. Thus, the area of iron metallodrugs includes molecules with very different structures and reactivity, studied from a number of different perspectives, but focused on increasing the number of molecules at our disposal for combatting cancer.

Nanoalginates via Inverse-Micelle Synthesis: Doxorubicin-Encapsulation and Breast Cancer Cytotoxicity

Crosslinked-biopolymer nanoparticles provide a convenient platform for therapeutic encapsulation and delivery. Here, we present a robust inverse-micelle process to load water-soluble drugs into a calcium-crosslinked alginate matrix. The utility of the resulting nanoalginate (NALG) carriers was assessed by a doxorubicin (DOX) formulation (NALG-DOX) and evaluating its potency on breast cancer cells (4T1). This facile synthesis process produced doxorubicin-containing particles of ~ 83 nm by hydrodynamic size and zeta potential ~ 7.2 mV. The cyclohexane/dodecylamine microemulsion yielded uniform and spherical nanoparticles as observed by electron microscopy. The uptake of the drug from the NALG-DOX formulation in 4T1 cells was observed by fluorescence microscopy employing doxorubicin's inherent fluorescence. Therapeutic efficacy of the NALG-DOX against 4T1 cells was demonstrated qualitatively through a LIVE/DEAD fluorescence assay and quantitatively via cell viability assay (Alamar Blue). In addition, IC50 values were determined, with encapsulated doxorubicin having a slightly higher value. No toxicity of the empty NALG carrier was observed. Overall, these results demonstrate the utility of this synthesis process for encapsulation of hydrophilic therapeutics and NALG to function as a drug carrier.

Local strategies and delivery systems for the treatment of malignant gliomas

Glioma is one of the most common type of malignant tumours with high morbidity and mortality rates. Due to the particular features of the brain, such as blood-brain barrier or blood-tumour barrier, therapeutic agents are ineffective by systemic administration. The tumour inevitably recurs and devitalises patients. Herein, an overview of the localised gliomas treatment strategies is provided, including direct intratumoural/intracerebral injection, convection-enhanced delivery, and the implant of biodegradable polymer systems. The advantages and disadvantages of each therapy are discussed. Subsequently, we have reviewed the recent developments of therapeutic delivery systems aimed at transporting sufficient amounts of antineoplastic drugs into the brain tumour sites while minimising the potential side effects. To treat gliomas, localised and controlled delivery of drugs at their desired site of action is preferred as it reduces toxicity and increases treatment efficiency. Simultaneously, various drug delivery systems (DDS) have been used to enhance drug delivery to the brain. Use of non-conventional DDS for localised therapy has greatly expanded the spectrum of drugs available for the treatment of malignant tumours. Use smart DDS via localised delivery strategies, in combination with radiotherapy and multiple drug loading would serve as a promising approach to treat gliomas.

Enhanced and preferential internalization of lipid nanocapsules into human glioblastoma cells: effect of a surface-functionalizing NFL peptide

Increasing intracellular drug concentration using nanocarriers can be a potential strategy to improve efficacy against glioblastoma (GBM). Here, the fluorescent-labelled NFL-TBS·40-63 peptide (fluoNFL) concentration on a lipid nanocapsule (LNC) was studied to enhance nanovector internalization into human GBM cells. LNC surface-functionalization with various fluoNFL concentrations was performed by adsorption. LNC size and surface charge altered gradually with increasing peptide concentration, but their complement protein consumption remained low. Desorption of fluoNFL from the LNC surface was found to be slow. Furthermore, it was observed that the rate and extent of LNC internalization in the U87MG human glioblastoma cells were dependent on the surface-functionalizing fluoNFL concentration. In addition, we showed that the uptake of fluoNFL-functionalized LNCs was preferential towards U87MG cells compared to healthy human astrocytes. The fluoNFL-functionalized LNC internalization into the U87MG cells was energy-dependent and occurred possibly by macropinocytosis and clathrin-mediated and caveolin-mediated endocytosis. A new ferrocifen-type molecule (FcTriOH), as a potent anticancer candidate, was then encapsulated in the LNCs and the functionalization improved its in vitro efficacy compared to other tested formulations against U87MG cells. In the preliminary study, on subcutaneous human GBM tumor model in nude mice, a significant reduction of relative tumor volume was observed at one week after the second intravenous injection with FcTriOH-loaded LNCs. These results showed that enhancing NFL peptide concentration on the LNC surface is a promising approach for increased and preferential nanocarrier internalization into human GBM cells, and the FcTriOH-loaded LNCs are a promising therapy approach for GBM.

A new generation of ferrociphenols leads to a great diversity of reactive metabolites, and exhibits remarkable antiproliferative properties

Organometallic compounds bearing the redox motif [ferrocenyl-ene-phenol] have very promising antiproliferative properties which have been further improved by incorporating pertinent substituents able to engender new mechanisms. Here we show that novel ferrociphenols bearing a hydroxypropyl chain exhibit strong antiproliferative effects, in most cases much better than those of cisplatin, tamoxifen, or of previously described ferrociphenols devoid of this terminal OH. This is illustrated, in the case of one of these compounds, by its IC50 values of 110 nM for MDA-MB-231 triple negative breast cancer cells and of 300 nM for cisplatin-resistant A2780cisR human ovarian cancer cells, and by its GI50 values lower than 100 nM towards a series of melanoma and renal cancer cell lines of the NCI-60 panel. Interestingly, oxidative metabolism of these hydroxypropyl-ferrociphenols yields two kinds of quinone methides (QMs) that readily react with various nucleophiles, such as glutathione, to give 1,6- and 1,8-adducts. Protonation of these quinone methides generates numerous reactive metabolites leading eventually to many rearrangement and cleavage products. This unprecedented and fully characterized metabolic profile involving a wide range of electrophilic metabolites that should react with cell macromolecules may be linked to the remarkable profile of antiproliferative activities of this new series. Indeed, the great diversity of unexpected reactive metabolites found upon oxidation will allow them to adapt to various situations present in the cancer cell. These data initiate a novel strategy for the rational design of anticancer molecules, thus opening the way to new organometallic potent anticancer drug candidates for the treatment of chemoresistant cancers.

Nanotherapeutic systems for local treatment of brain tumors

Malignant brain tumor, including the most common type glioblastoma, are histologically heterogeneous and invasive tumors known as the most devastating neoplasms with high morbidity and mortality. Despite multimodal treatment including surgery, radiotherapy, chemotherapy, and immunotherapy, the disease inevitably recurs and is fatal. This lack of curative options has motivated researchers to explore new treatment strategies and to develop new drug delivery systems (DDSs); however, the unique anatomical, physiological, and pathological features of brain tumors greatly limit the effectiveness of conventional chemotherapy. In this context, we review the recent progress in the development of nanoparticle-based DDSs aiming to address the key challenges in transporting sufficient amount of therapeutic agents into the brain tumor areas while minimizing the potential side effects. We first provide an overview of the standard treatments currently used in the clinic for the management of brain cancers, discussing the effectiveness and limitations of each therapy. We then provide an in-depth review of nanotherapeutic systems that are intended to bypass the blood-brain barrier, overcome multidrug resistance, infiltrate larger tumorous tissue areas, and/or release therapeutic agents in a controlled manner. WIREs Nanomed Nanobiotechnol 2018, 10:e1479. doi: 10.1002/wnan.1479 This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Efficient ferrocifen anticancer drug and Bcl-2 gene therapy using lipid nanocapsules on human melanoma xenograft in mouse

Metastatic melanoma has been described as a highly aggressive cancer with low sensibility to chemotherapeutic agents. New types of drug, such as metal-based drugs (ferrocifens) have emerged and could represent an alternative for melanoma treatment since they show interesting anticancer potential. Furthermore, molecular analysis has evidenced the role of apoptosis in the low sensibility of melanomas and especially of the key regulator, Bcl-2. The objective of this study was to combine two strategies in the same lipid nanocapsules (LNCs): i) gene therapy to modulate anti-apoptotic proteins by the use of Bcl-2 siRNA, and ii) ferrocifens as a new type of anticancer agent. The efficient gene silencing with LNCs was verified by the specific extinction of Bcl-2 in melanoma cells. The cellular toxicity of ferrocifens (ferrociphenol (FcDiOH) or Ansa-FcDiOH) was demonstrated, showing higher efficacy than dacarbazine. Interestingly, the association of siBcl-2 LNCs with Ansa-FcDiOH demonstrated a significant effect on melanoma cell viability. Moreover, the co-encapsulation of siRNA and ferrocifens was successfully performed into LNCs for animal experiments. A reduction of tumor volume and mass was proved after siBcl-2 LNC treatment and Ansa-FcDiOH LNC treatment, individually (around 25%). Finally, the association of both components into the same LNCs increased the reduction of tumor volume to about 50% compared to the control group. In conclusion, LNCs appeared to provide a promising tool for the co-encapsulation of a metal-based drug and siRNA.

Nano-structures mediated co-delivery of therapeutic agents for glioblastoma treatment: A review

Glioblastoma is a malignant brain tumor and leads to death in most patients. Chemotherapy is a common method for brain cancer in clinics. However, the recent advancements in the chemotherapy of brain tumors have not been efficient enough. With the advancement of nanotechnology, the used drugs can enhance chemotherapy efficiency and increase the access to brain cancers. Combination of therapeutic agents has been recently attracted great attention for glioblastoma chemotherapy. One of the early benefits of combination therapies is the high potential to provide synergistic effects and decrease adverse side effects associated with high doses of single anticancer drugs. Therefore, brain tumor treatments with combination drugs can be considered as a crucial approach for avoiding tumor growth. This review investigates current progress in nano-mediated co-delivery of therapeutic agents with focus on glioblastoma chemotherapy prognosis.

Recent advances in iron complexes as potential anticancer agents

The iron complexes discussed in this review highlight their promising future as anticancer agents.

Targeting and treatment of glioblastomas with human mesenchymal stem cells carrying ferrociphenol lipid nanocapsules

Recently developed drug delivery nanosystems, such as lipid nanocapsules (LNCs), hold great promise for the treatment of glioblastomas (GBs). In this study, we used a subpopulation of human mesenchymal stem cells, “marrow-isolated adult multilineage inducible” (MIAMI) cells, which have endogenous tumor-homing activity, to deliver LNCs containing an organometallic complex (ferrociphenol or Fc-diOH), in the orthotopic U87MG GB model. We determined the optimal dose of Fc-diOH-LNCs that can be carried by MIAMI cells and compared the efficacy of Fc-diOH-LNC-loaded MIAMI cells with that of the free-standing Fc-diOH-LNC system. We showed that MIAMI cells entrapped an optimal dose of about 20 pg Fc-diOH per cell, with no effect on cell viability or migration capacity. The survival of U87MG-bearing mice was longer after the intratumoral injection of Fc-diOH-LNC-loaded MIAMI cells than after the injection of Fc-diOH-LNCs alone. The greater effect of the Fc-diOH-LNC-loaded MIAMI cells may be accounted for by their peritumoral distribution and a longer residence time of the drug within the tumor. These results confirm the potential of combinations of stem cell therapy and nanotechnology to improve the local tissue distribution of anticancer drugs in GB.

Drug-loaded nanoparticle systems and adult stem cells: a potential marriage for the treatment of malignant glioma?

Despite all recent advances in malignant glioma research, only modest progress has been achieved in improving patient prognosis and quality of life. Such a clinical scenario underscores the importance of investing in new therapeutic approaches that, when combined with conventional therapies, are able to effectively eradicate glioma infiltration and target distant tumor foci. Nanoparticle-loaded delivery systems have recently arisen as an exciting alternative to improve targeted anti-glioma drug delivery. As drug carriers, they are able to efficiently protect the therapeutic agent and allow for sustained drug release. In addition, their surface can be easily manipulated with the addition of special ligands, which are responsible for enhancing tumor-specific nanoparticle permeability. However, their inefficient intratumoral distribution and failure to target disseminated tumor burden still pose a big challenge for their implementation as a therapeutic option in the clinical setting. Stem cell-based delivery of drug-loaded nanoparticles offers an interesting option to overcome such issues. Their ability to incorporate nanoparticles and migrate throughout interstitial barriers, together with their inherent tumor-tropic properties and synergistic anti-tumor effects make these stem cell carriers a good fit for such combined therapy. In this review, we will describe the main nanoparticle delivery systems that are presently available in preclinical and clinical studies. We will discuss their mechanisms of targeting, current delivery methods, attractive features and pitfalls. We will also debate the potential applications of stem cell carriers loaded with therapeutic nanoparticles in anticancer therapy and why such an attractive combined approach has not yet reached clinical trials.

Developments in the use of nanocapsules in oncology

The application of nanotechnology to medicine can provide important benefits, especially in oncology, a fact that has resulted in the emergence of a new field called Nanooncology. Nanoparticles can be engineered to incorporate a wide variety of chemotherapeutic or diagnostic agents. A nanocapsule is a vesicular system that exhibits a typical core-shell structure in which active molecules are confined to a reservoir or within a cavity that is surrounded by a polymer membrane or coating. Delivery systems based on nanocapsules are usually transported to a targeted tumor site and then release their contents upon change in environmental conditions. An effective delivery of the therapeutic agent to the tumor site and to the infiltrating tumor cells is difficult to achieve in many cancer treatments. Therefore, new devices are being developed to facilitate intratumoral distribution, to protect the active agent from premature degradation and to allow its sustained and controlled release. This review focuses on recent studies on the use of nanocapsules for cancer therapy and diagnosis.

Cerium oxide nanoparticles: influence of the high-Z component revealed on radioresistant 9L cell survival under X-ray irradiation

This article pioneers a study into the influence of the high-Z component of nanoparticles on the efficacy of radioprotection some nanoparticles offer to exposed cells irradiated with X-rays. We reveal a significant decrease in the radioprotection efficacy for cells exposed to CeO2 nanoparticles and irradiated with 10 MV and 150 kVp X-rays. In addition, analysis of the 150 kVp survival curve data indicates a change in radiation quality, becoming more lethal for irradiated cells exposed to CeO2 nanoparticles. We attribute the change in efficacy to an increase in high linear energy transfer Auger electron production at 150 kVp which counterbalances the CeO2 nanoparticle radioprotection capability and locally changes the radiation quality. This study highlights an interesting phenomenon that must be considered if radiation protection drugs for use in radiotherapy are developed based on CeO2 nanoparticles.

FROM THE CLINICAL EDITOR

CeO2 nanoparticles are thought to offer radioprotection; however, this study reveals significant decrease in the radioprotection efficacy for cells exposed to CeO2 nanoparticles and irradiated with 10 MV and 150 kVp X-rays. This phenomenon must be considered when developing radiation protection drugs based on CeO2 nanoparticles.

Administration-dependent efficacy of ferrociphenol lipid nanocapsules for the treatment of intracranial 9L rat gliosarcoma

The anti-tumour effect of ferrociphenol (FcdiOH)-loaded lipid nanocapsules (LNCs), with or without a DSPE-mPEG2000 coating, was evaluated on an orthotopic gliosarcoma model after administration by convection-enhanced delivery (CED) technique or by intra-carotid injection. No toxicity was observed by MRI nor by MRS in healthy rats receiving a CED injection of FcdiOH-LNCs (60μL, 0.36mg of FcdiOH/rat) when the pH and osmolarity had been adjusted to physiological values prior to injection. At this dose, the treatment by CED with FcdiOH-LNCs significantly increased the survival time of tumour-bearing rats in comparison with an untreated group (28.5 days vs 25 days, P=0.0009) whereas DSPE-mPEG2000-FcdiOH-LNCs did not exhibit any efficacy with a median survival time of 24 days. After intra-carotid injection (400μL, 2.4mg of FcdiOH/rat), hyperosmolar DSPE-mPEG2000-FcdiOH-LNCs markedly increased the median survival time (up to 30 days, P=0.0008) as compared to the control (20%). This was strengthened by their evidenced accumulation in the tumour zone and by the measure of the fluorescent brain surface obtained on brain slides for these DiI-labelled LNCs, being 3-fold higher than for the control. These results demonstrated that, depending upon the administration route used, the characteristics of LNC suspensions had to be carefully adapted.

External irradiation models for intracranial 9L glioma studies

PURPOSE

Radiotherapy has been shown to be an effective for the treatment human glioma and consists of 30 fractions of 2 Gy each for 6-7 weeks in the tumor volume with margins. However. in preclinical studies, many different radiation schedules are used. The main purpose of this work was to review the relevant literature and to propose an external whole-brain irradiation (WBI) protocol for a rat 9L glioma model.

MATERIALS AND METHODS

9L cells were implanted in the striatum of twenty 344-Fisher rats to induce a brain tumor. On day 8, animals were randomized in two groups: an untreated group and an irradiated group with three fractions of 6 Gy at day 8, 11 and 14. Survival and toxicity were assessed.

RESULTS

Irradiated rats had significantly a longer survival (p = 0.01). No deaths occurred due to the treatment. Toxicities of reduced weight and alopecia were increased during the radiation period but no serious morbidity or mortality was observed. Moreover, abnormalities disappeared the week following the end of the therapeutic schedule.

CONCLUSIONS

Delivering 18 Gy in 3 fractions of 6 Gy every 3 days, with mild anaesthesia, is safe, easy to reproduce and allows for standardisation in preclinical studies of different treatment regimens glioma rat model.