Chiara Bastiancich

Anticancer drug-loaded hydrogels as drug delivery systems for the local treatment of glioblastoma.

Among central nervous system tumors, Glioblastoma (GBM) is the most common, aggressive and neurological destructive primary brain tumor in adults. Standard care therapy for GBM consists in surgical resection of the accessible tumor (without causing neurological damage) followed by chemoradiation. However, several obstacles limit the assessment of tumor response and the delivery of cytotoxic agents at the tumor site, leading to a lack of effectiveness of conventional treatments against GBM and fatal outcome. Despite the efforts of the scientific community to increase the long-term benefits of GBM therapy, at the moment GBM remains incurable. Among the strategies that have been adopted in the last two decades to find new and efficacious therapies for the treatment of GBM, the local delivery of chemotherapeutic drugs in the tumor resection cavity emerged. In this review, our aim is to provide an overview on hydrogels loaded with anticancer drugs for the treatment of GBM recently used in preclinical and clinical studies, their advantages and major limitations for clinical translation. This review is divided in three parts: the first one describes the context of GBM and its current treatments, with a highlight on the role of local delivery in GBM treatment and the development of GBM resection murine models. Then, recent developments in the use of anticancer drug-loaded hydrogels for the treatment of GBM will be detailed. The final section will be focused on the limitations for in vivo studies, clinical translation and the clinical perspectives to the development of hydrogels.

Lauroyl-gemcitabine-loaded lipid nanocapsule hydrogel for the treatment of glioblastoma

The local delivery of chemotherapeutic agents is a very promising strategy for the treatment of glioblastoma (GBM). Gemcitabine is a chemotherapeutic agent that has a different mechanism of action compared to alkylating agents and shows excellent radio-sensitizing properties. So, we developed an injectable gel-like nanodelivery system consisting in lipid nanocapsules loaded with anticancer prodrug lauroyl-gemcitabine (GemC12-LNC) in order to obtain a sustained and local delivery of this drug in the brain. In this study, the GemC12-LNC has been formulated and characterized and the viscoelastic properties of the hydrogel were evaluated after extrusion from 30G needles. This system showed a sustained and prolonged in vitro release of the drug over one month. GemC12 and the GemC12-LNC have shown increased in vitro cytotoxic activity on U-87 MG glioma cells compared to the parent hydrophilic drug. The GemC12-LNC hydrogel reduced significantly the size of a subcutaneous human GBM tumor model compared to the drug and short-term tolerability studies showed that this system is suitable for local treatment in the brain. In conclusion, this proof-of-concept study demonstrated the feasibility, safety and efficiency of the injectable GemC12-LNC hydrogel for the local treatment of GBM.

Injectable nanomedicine hydrogel for local chemotherapy of glioblastoma after surgical resection

&NA; Glioblastoma (GBM) treatment includes, when possible, surgical resection of the tumor followed by radiotherapy and oral chemotherapy with temozolomide, however recurrences quickly develop around the resection cavity borders leading to patient death. We hypothesize that the local delivery of Lauroyl‐gemcitabine lipid nanocapsule based hydrogel (GemC12‐LNC) in the tumor resection cavity of GBM is a promising strategy as it would allow to bypass the blood brain barrier, thus reaching high local concentrations of the drug. The cytotoxicity and internalization pathways of GemC12‐LNC were studied on different GBM cell lines (U251, T98‐G, 9L‐LacZ, U‐87 MG). The GemC12‐LNC hydrogel was well tolerated when injected in mouse brain. In an orthotopic xenograft model, after intratumoral administration, GemC12‐LNC significantly increased mice survival compared to the controls. Moreover, its ability to delay tumor recurrences was demonstrated after perisurgical administration in the GBM resection cavity. In conclusion, we demonstrate that GemC12‐LNC hydrogel could be considered as a promising tool for the post‐resection management of GBM, prior to the standard of care chemo‐radiation. Graphical abstract Figure. No caption available.

Novel model of orthotopic U-87 MG glioblastoma resection in athymic nude mice.

In vitro and in vivo models of experimental glioma are useful tools to gain a better understanding of glioblastoma (GBM) and to investigate novel treatment strategies. However, the majority of preclinical models focus on treating solid intracranial tumours, despite surgical resection being the mainstay in the standard care of patients with GBM today. The lack of resection and recurrence models therefore has undermined efforts in finding a treatment for this disease. Here we present a novel orthotopic tumour resection and recurrence model that has potential for the investigation of local delivery strategies in the treatment of GBM. The model presented is simple to achieve through the use of a biopsy punch, is reproducible, does not require specific or expensive equipment, and results in a resection cavity suitable for local drug delivery systems, such as the implantation or injection of hydrogels. We show that tumour resection is well tolerated, does not induce deleterious neurological deficits, and significantly prolongs survival of mice bearing U-87 MG GBM tumours. In addition, the resulting cavity could accommodate adequate amounts of hydrogels for local delivery of chemotherapeutic agents to eliminate residual tumour cells that can induce tumour recurrence.

Gemcitabine and glioblastoma: challenges and current perspectives

Gemcitabine is a nucleoside analog currently used for the treatment of various solid tumors as a single agent or in combination with other chemotherapeutic drugs. Its use against highly aggressive brain tumors (glioblastoma) has been evaluated in preclinical and clinical trials leading to controversial results. Gemcitabine can inhibit DNA chain elongation, is a potent radiosensitizer and it can enhance antitumor immune activity, but it also presents some drawbacks (e.g., short half-life, side effects, chemoresistance). The aim of this review is to discuss the challenges related to the use of gemcitabine for glioblastoma and to report recent studies that suggest overcoming these obstacles opening new perspectives for its use in the field (e.g., gemcitabine derivatives and/or nanomedicines).

Evaluation of lauroyl-gemcitabine-loaded hydrogel efficacy in glioblastoma rat models

AIM Anticancer drug-loaded hydrogels are a promising strategy for the local treatment of incurable brain tumors such as glioblastoma (GBM). Recently, we demonstrated the efficacy of lauroyl-gemcitabine lipid nanocapsule hydrogel (GemC12-LNC) in a U-87 MG xenograft orthotopic mouse model. In this study, we developed a reliable and reproducible surgical procedure to resect orthotopic GBM tumors in rats. GemC12-LNC hydrogel integrity was tested after brain administration in rats and its anti-tumor efficacy was tested on a 9L syngeneic orthotopic model. RESULTS We demonstrated that LNC integrity is maintained at least for one week after local administration of GemC12-LNC. GemC12-LNC was able to delay the formation of recurrences in 9L tumor-bearing resected rats, demonstrating the efficacy of this nanomedicine hydrogel in this preclinical model. CONCLUSION Our results confirm that GemC12-LNC, a hydrogel uniquely formed by a nanocarrier and a cytotoxic drug, could be a promising and safe delivery tool for the local treatment of operable GBM tumors.

Repurposing cationic amphiphilic drugs as adjuvants to induce lysosomal siRNA escape in nanogel transfected cells

Abstract Cytosolic delivery remains a major bottleneck for siRNA therapeutics. To facilitate delivery, siRNAs are often enclosed in nanoparticles (NPs). However, upon endocytosis such NPs are mainly trafficked towards lysosomes. To avoid degradation, cytosolic release of siRNA should occur prior to fusion of endosomes with lysosomes, but current endosomal escape strategies remain inefficient. In contrast to this paradigm, we aim to exploit lysosomal accumulation by treating NP‐transfected cells with low molecular weight drugs that release the siRNA from the lysosomes into the cytosol. We show that FDA‐approved cationic amphiphilic drugs (CADs) significantly improved gene silencing by siRNA‐loaded nanogels in cancer cells through simple sequential incubation. CADs induced lysosomal phospholipidosis, leading to transient lysosomal membrane permeabilization and improved siRNA release without cytotoxicity. Of note, the lysosomes could be applied as an intracellular depot for triggered siRNA release by multiple CAD treatments. Graphical abstract Through functional inhibition of acid sphingomyelinase (ASM), cationic amphiphilic drugs (CADs) induce non‐lethal lysosomal membrane permeabilization (LMP), enhancing the cytosolic delivery of siRNA and improving target gene knockdown. Figure. No Caption available.

Post-resection treatment of glioblastoma with an injectable nanomedicine-loaded photopolymerizable hydrogel induces long-term survival

ABSTRACT Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor. Despite available therapeutic options, the prognosis for patients with GBM remains very poor. We hypothesized that the intra‐operative injection of a photopolymerizable hydrogel into the tumor resection cavity could sustain the release of the anti‐cancer drug paclitaxel (PTX) encapsulated in poly (lactic‐co‐glycolic acid) (PLGA) nanoparticles and prevent GBM recurrence. The tumor was resected 13days after implantation and a pre‐gel solution composed of polyethylene glycol dimethacrylate (PEG‐DMA) polymer, a photoinitiator and PTX‐loaded PLGA nanoparticles (PTX PLGA‐NPs) was injected into the tumor resection cavity. A solid gel filling the whole cavity was formed immediately by photopolymerization using a 400nm light. PTX in vitro release study showed a burst release (11%) in the first 8h and a sustained release of 29% over a week. In vitro, U87 MG cells were sensitive to PTX PLGA‐NPs with IC50 level of approximately 0.010&mgr;g/mL. The hydrogel was well‐tolerated when implanted in the brain of healthy mice for 2 and 4months. Administration of PTX PLGA‐NPs‐loaded hydrogel into the resection cavity of GBM orthotopic model lead to more than 50% long‐term survival mice (150days) compared to the control groups (mean survival time 52days). This significant delay of recurrence is very promising for the post‐resection treatment of GBM.

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.