Concurrent delivery of carmustine, irinotecan, and cisplatin to the cerebral cavity using biodegradable nanofibers: In vitro and in vivo studies

Exploring the vast potentials and probable limitations of novel and nanostructured implantable drug delivery systems for cancer treatment

Conventional cancer chemotherapy regimens, albeit successful to some extent, suffer from some significant drawbacks, such as high-dose requirements, limited bioavailability, low therapeutic indices, emergence of multiple drug resistance, off-target distribution, and adverse effects. The main goal of developing implantable drug delivery systems (IDDS) is to address these challenges and maintain anti-cancer drugs directly at the intended sites of therapeutic action while minimizing inevitable side effects. IDDS possess numerous advantages over conventional drug delivery, including controlled drug release patterns, one-time drug administration, as well as loading and stabilizing poorly water-soluble chemotherapy drugs. Here, we summarized conventional and novel (three-dimensional (3D) printing and microfluidic) preparation techniques of different IDDS, including nanofibers, films, hydrogels, wafers, sponges, and osmotic pumps. These systems could be designed with high biocompatibility and biodegradability features using a wide variety of natural and synthetic polymers. We also reviewed the published data on these systems in cancer therapy with a particular focus on their release behavior. Various release profiles could be attained in IDDS, which enable predictable, adjustable, and sustained drug releases. Furthermore, multi-step or stimuli-responsive drug release could be obtained in these systems. The studies mentioned in this article have proven the effectiveness of IDDS for treating different cancer types with high prevalence, including breast cancer, and aggressive cancer types, such as glioblastoma and liver cancer. Additionally, the challenges in applying IDDS for efficacious cancer therapy and their potential future developments are also discussed. Considering the high potential of IDDS for further advancements, such as programmable release and degradation features, further clinical trials are needed to ensure their efficiency. The overall goal of this review is to expand our understanding of the behavior of commonly investigated IDDS and to identify the barriers that should be addressed in the pursuit of more efficient therapies for cancer. See also the graphical abstract(Fig. 1).

Long-Acting Therapeutic Delivery Systems for the Treatment of Gliomas

Despite the emergence of cutting-edge therapeutic strategies and tremendous progress in research, a complete cure of glioma remains elusive. The heterogenous nature of tumor, immunosuppressive state and presence of blood brain barrier are few of the major obstacles in this regard. Long-acting depot formulations such as injectables and implantables are gaining attention for drug delivery to brain owing to their ease in administration and ability to elute drug locally for extended durations in a controlled manner with minimal toxicity. Hybrid matrices fabricated by incorporating nanoparticulates within such systems help to enhance pharmaceutical advantages. Utilization of long-acting depots as monotherapy or in conjunction with existing strategies rendered significant survival benefits in many preclinical studies and some clinical trials. The discovery of novel targets, immunotherapeutic strategies and alternative drug administration routes are now coupled with several long-acting systems with an ultimate aim to enhance patient survival and prevent glioma recurrences.

A novel combination for the treatment of small cell lung cancer: Active targeted irinotecan and stattic co-loaded PLGA nanoparticles

Polymeric nanoparticles are widely used drug delivery systems for cancer treatment due to their properties such as ease of passing through biological membranes, opportunity to modify drug release, specifically targeting drugs to diseased areas, and potential of reducing side effects. Here, we formulated irinotecan and Stattic co-loaded PLGA nanoparticles targeted to small cell lung cancer. Nanoparticles were successfully conjugated with CD56 antibody with a conjugation efficiency of 84.39 ± 1.01%, and characterization of formulated nanoparticles was conducted with in-vitro and in-vivo studies. Formulated particles had sizes in the range of 130-180 nm with PDI values smaller than 0.3. Encapsulation and active targeting of irinotecan and Stattic resulted in increased cytotoxicity and anti-cancer efficiency in-vitro. Furthermore, it was shown with ex-vivo biodistribution studies that conjugated nanoparticles were successfully targeted to CD56-expressing SCLC cells and distributed mainly to tumor tissue and lungs. Compliant with our hypothesis and literature, the STAT3 pathway was successfully inhibited with Stattic solution and Stattic loaded nanoparticles. Additionally, intravenous injection of conjugated co-loaded nanoparticles resulted in decreased side effects and better anti-tumor activity than individual solutions of drugs in SCLC tumor-bearing mice. These results may indicate a new treatment option for clinically aggressive small cell lung cancer.

A Review of the Release Profiles and Efficacies of Chemotherapy Drug-Loaded Electrospun Membranes

Electrospun fibrous membranes loaded with chemotherapy drugs have been broadly studied, many of which have had promising data demonstrating therapeutic effects on cancer cell inhibition, tumor size reduction, the life extension of tumor-bearing animals, and more. Nevertheless, their drug release profiles are difficult to predict since their degradation pattern varies with crystalline polymers. In addition, there is room for improving their release performances, optimizing the release patterns, and achieving better therapeutic outcomes. In this review, the key factors affecting electrospun membrane drug release profiles have been systematically reviewed. Case studies of the release profiles of typical chemotherapy drugs are carried out to determine the preferred polymer choices and techniques to achieve the expected prolonged or enhanced release profiles. The therapeutic effects of these electrospun, chemo-drug-loaded membranes are also discussed. This review aims to assist in the design of future drug-loaded electrospun materials to achieve preferred release profiles with enhanced therapeutic efficacies.

Electrospun nanofibers for 3-D cancer models, diagnostics, and therapy

As one of the leading causes of global mortality, cancer has prompted extensive research and development to advance efficacious drug discovery, sustained drug delivery and improved sensitivity in diagnosis. Towards these applications, nanofibers synthesized by electrospinning have exhibited great clinical potential as a biomimetic tumor microenvironment model for drug screening, a controllable platform for localized, prolonged drug release for cancer therapy, and a highly sensitive cancer diagnostic tool for capture and isolation of circulating tumor cells in the bloodstream and for detection of cancer-associated biomarkers. This review provides an overview of applied nanofiber design with focus on versatile electrospinning fabrication techniques. The influence of topographical, physical, and biochemical properties on the function of nanofiber assemblies is discussed, as well as current and foreseeable barriers to the clinical translation of applied nanofibers in the field of oncology.

Nek1-inhibitor and temozolomide-loaded microfibers as a co-therapy strategy for glioblastoma treatment

Malignant glioblastoma (GB) is the predominant primary brain tumour in adults, but despite the efforts towards novel therapies, the median survival of GB patients has not significantly improved in the last decades. Therefore, localised approaches that treat GB straight into the tumour site provide an alternative to enhance chemotherapy bioavailability and efficacy, reducing systemic toxicity. Likewise, the discovery of protein targets, such as the NIMA-related kinase 1 (Nek1), which was previously shown to be associated with temozolomide (TMZ) resistance in GB, has stimulated the clinical development of target therapy approaches to treat GB patients. In this study, we report an electrospun polyvinyl alcohol (PVA) microfiber (MF) brain-implant prepared for the controlled release of Nek1 protein inhibitor (iNek1) and TMZ or TMZ-loaded nanoparticles. The formulations revealed adequate stability and drug loading, which prolonged the drugs' release allowing a sustained exposure of the GB cells to the treatment and enhancing the drugs' therapeutic effects. TMZ-loaded MF provided the highest concentration of TMZ within the brain of tumour-bearing rats, and it was statistically significant when compared to TMZ via intraperitoneal (IP). All animals treated with either co-therapy formulation (TMZ + iNek1 MF or TMZ nanoparticles + iNek1 MF) survived until the endpoint (60 days), whereas the Blank MF (drug-unloaded), TMZ MF and TMZ IP-treated rats' median survival was found to be 16, 31 and 25 days, respectively. The tumour/brain area ratio of the rats implanted with either MF co-therapy was found to be reduced by 5-fold when compared to Blank MF-implanted rats. Taken together, our results strongly suggest that Nek1 is an important GB oncotarget and the inhibition of Nek1's activity significantly decreases GB cells' viability and tumour size when combined with TMZ treatment.

Rationally designed drug delivery systems for the local treatment of resected glioblastoma

Glioblastoma (GBM) is a particularly aggressive brain cancer associated with high recurrence and poor prognosis. The standard of care, surgical resection followed by concomitant radio- and chemotherapy, leads to low survival rates. The local delivery of active agents within the tumor resection cavity has emerged as an attractive means to initiate oncological treatment immediately post-surgery. This complementary approach bypasses the blood-brain barrier, increases the local concentration at the tumor site while reducing or avoiding systemic side effects. This review will provide a global overview on the local treatment for GBM with an emphasis on the lessons learned from past clinical trials. The main parameters to be considered to rationally design fit-of-purpose biomaterials and develop drug delivery systems for local administration in the GBM resection cavity to prevent the tumor recurrence will be described. The intracavitary local treatment of GBM should i) use materials that facilitate translation to the clinic; ii) be characterized by easy GMP effective scaling up and easy-handling application by the neurosurgeons; iii) be adaptable to fill the tumor-resected niche, mold to the resection cavity or adhere to the exposed brain parenchyma; iv) be biocompatible and possess mechanical properties compatible with the brain; v) deliver a therapeutic dose of rationally-designed or repurposed drug compound(s) into the GBM infiltrative margin. Proof of concept with high translational potential will be provided. Finally, future perspectives to facilitate the clinical translation of the local perisurgical treatment of GBM will be discussed.

A review on allopathic and herbal nanofibrous drug delivery vehicles for cancer treatments

Drug delivery empowered with nanotechnology manifests to be a superior therapy to cancer. Electrospun nanofibers cocooning anti-cancerous drugs have shown tremendous cytotoxicity towards various tumor cells, including breast, brain, liver, and lung cancer cells. This pristine drug delivery system, according to literature, desists showing any undesirable effects on other parts of the body and bestows several other benefits. From nature-derived Curcumin to laboratory-made Doxorubicin, literature proclaims many such drugs used in nanofibrous drug delivery. Also, multi-drug delivery has been reported to exhibit enhanced properties. The present review exhibits the unrealized potential of nanofibrous drug delivery in chemotherapy.

Role of Polymeric Local Drug Delivery in Multimodal Treatment of Malignant Glioma: A Review

Malignant gliomas (MGs) are the most common and devastating primary brain tumor. At present, surgical interventions, radiotherapy, and chemotherapy are only marginally effective in prolonging the life expectancy of patients with MGs. Inherent heterogeneity, aggressive invasion and infiltration, intact physical barriers, and the numerous mechanisms underlying chemotherapy and radiotherapy resistance contribute to the poor prognosis for patients with MGs. Various studies have investigated methods to overcome these obstacles in MG treatment. In this review, we address difficulties in MG treatment and focus on promising polymeric local drug delivery systems. In contrast to most local delivery systems, which are directly implanted into the residual cavity after intratumoral injection or the surgical removal of a tumor, some rapidly developing and promising nanotechnological methods—including surface-decorated nanoparticles, magnetic nanoparticles, and focused ultrasound assist transport—are administered through (systemic) intravascular injection. We also discuss further synergistic and multimodal strategies for heightening therapeutic efficacy. Finally, we outline the challenges and therapeutic potential of these polymeric drug delivery systems.

Revisiting Platinum-Based Anticancer Drugs to Overcome Gliomas

Although there are many patients with brain tumors worldwide, there are numerous difficulties in overcoming brain tumors. Among brain tumors, glioblastoma, with a 5-year survival rate of 5.1%, is the most malignant. In addition to surgical operations, chemotherapy and radiotherapy are generally performed, but the patients have very limited options. Temozolomide is the most commonly prescribed drug for patients with glioblastoma. However, it is difficult to completely remove the tumor with this drug alone. Therefore, it is necessary to discuss the potential of anticancer drugs, other than temozolomide, against glioblastomas. Since the discovery of cisplatin, platinum-based drugs have become one of the leading chemotherapeutic drugs. Although many studies have reported the efficacy of platinum-based anticancer drugs against various carcinomas, studies on their effectiveness against brain tumors are insufficient. In this review, we elucidated the anticancer effects and advantages of platinum-based drugs used in brain tumors. In addition, the cases and limitations of the clinical application of platinum-based drugs are summarized. As a solution to overcome these obstacles, we emphasized the potential of a novel approach to increase the effectiveness of platinum-based drugs.

Management of Glioblastoma Multiforme by Phytochemicals: Applications of Nanoparticle-Based Targeted Drug Delivery System

The Glioblastoma Multiforme (GBM; grade IV astrocytoma) exhorts tumors of star-shaped glial cells in the brain. It is a fast-growing tumor that spreads to nearby brain regions specifically to cerebral hemispheres in frontal and temporal lobes. The etiology of GBM is unknown, but major risk factors are genetic disorders like neurofibromatosis and schwannomatosis, which develop the tumor in the nervous system. The management of GBM with chemo-radiotherapy leads to resistance, and current drug regimen like Temozolomide (TMZ) is less efficacious. The reasons behind the failure of drugs are due to DNA alkylation in the cell cycle by enzyme DNA guanidase and mitochondrial dysfunction. Naturally occurring bioactive compounds from plants referred as phytochemicals, serve as vital sources for anti-cancer drugs. Some prototypical examples include taxol analogs, vinca alkaloids (vincristine, vinblastine), podophyllotoxin analogs, camptothecin, curcumin, aloe-emodin, quercetin, berberine etc. These phytochemicals often regulate diverse molecular pathways, which are implicated in the growth and progression of cancers. However, the challenges posed by the presence of BBB/BBTB to restrict the passage of these phytochemicals, culminates in their low bioavailability and relative toxicity. In this review, we integrated nanotech as a novel drug delivery system to deliver phytochemicals from traditional medicine to the specific site within the brain for the management of GBM.

Green synthesis of methoxy-poly(ethylene glycol)-block-poly(l-lactide-co-glycolide) copolymer using zinc proline as a biocompatible initiator for irinotecan delivery to colon cancer in vivo

Poly(lactic-co-glycolic acid) (PLGA) is the most commonly described biocompatible copolymer used in biomedical applications. In this work, a green synthetic approach based on the biocompatible zinc proline complex, as an initiator for PLGA synthesis, is reported for the first time for the synthesis of methoxy-poly(ethylene glycol)-block-poly(l-lactic-co-glycolic acid) (mPEG-PLGA). mPEG-PLGA with controlled molecular weight and narrow polydispersity was synthesised. Its potential for delivery of irinotecan (Ir), a poorly water-soluble chemotherapeutic drug used for the treatment of colon and pancreatic cancer, was studied. Nanoparticles of controlled size (140-160 nm), surface charge (∼-10 mV), release properties and cytotoxicity against CT-26 (colon) and BxPC-3 (pancreatic) cancer cells, were prepared. Tumor accumulation was confirmed by optical imaging of fluorescently labelled nanoparticles. Unlike Tween® 80 coated NP-Ir, the Pluronic® F-127 coated NP-Ir exhibits significant tumor growth delay compared to untreated and blank formulation treated groups in the CT-26 subcutaneous tumor model, after 4 treatments of 30 mg irinotecan per kg dose. Overall, this proof-of-concept study demonstrates that the newly synthesized copolymer, via a green route, is proven to be nontoxic, requires fewer purification steps and has potential applications in drug delivery.

The Delivery Materials with Chemotherapy Drugs for Treatment of the Positive Margin in Solid Tumors

The positive surgical margins in solid tumors has been a disturbing issue for clinicians. Chemotherapy is an important method to deal with the positive margin. However, systemic chemotherapy is required for long-term administration and has great side effects on health, which cause great pain to the patients. Local administration of slow-release materials provides an opportunity to improve the situation. In this study, we utilized electrospinning technology to create the drug sustained-release materials with nanofibrous structure, which were made from polylactic acid and a certain proportion of chemotherapy drugs (gemcitabine and cisplatin). In vitro release behavior of the drug sustained-release materials were explored by the high-performance liquid chromatography. The antitumor efficacy of the drug sustained-release materials was preliminarily verified in prostate cancer and breast cancer in vitro. Through animal models of breast cancer, the drug sustained-release materials in the treatment of the positive margin has been well documented in vivo, and we also found that the drug sustained-release materials could definitely reduce the liver damage and myelosuppression compared with systemic chemotherapy. In summary, the experimental results showed that the local administration of the drug sustained-release materials could effectively inhibit the growth of the positive incision margins and definitely reduce the partial side effects associated with systemic chemotherapy.

Synthesis, Characterization, and In Vitro Studies of an Reactive Oxygen Species (ROS)-Responsive Methoxy Polyethylene Glycol-Thioketal-Melphalan Prodrug for Glioblastoma Treatment

Glioblastoma (GBM) is the most frequent and aggressive primary tumor of the brain and averages a life expectancy in diagnosed patients of only 15 months. Hence, more effective therapies against this malignancy are urgently needed. Several diseases, including cancer, are featured by high levels of reactive oxygen species (ROS), which are possible GBM hallmarks to target or benefit from. Therefore, the covalent linkage of drugs to ROS-responsive molecules can be exploited aiming for a selective drug release within relevant pathological environments. In this work, we designed a new ROS-responsive prodrug by using Melphalan (MPH) covalently coupled with methoxy polyethylene glycol (mPEG) through a ROS-cleavable group thioketal (TK), demonstrating the capacity to self-assembly into nanosized micelles. Full chemical-physical characterization was conducted on the polymeric-prodrug and proper controls, along with in vitro cytotoxicity assayed on different GBM cell lines and “healthy” astrocyte cells confirming the absence of any cytotoxicity of the prodrug on healthy cells (i.e. astrocytes). These results were compared with the non-ROS responsive counterpart, underlining the anti-tumoral activity of ROS-responsive compared to the non-ROS-responsive prodrug on GBM cells expressing high levels of ROS. On the other hand, the combination treatment with this ROS-responsive prodrug and X-ray irradiation on human GBM cells resulted in an increase of the antitumoral effect, and this might be connected to radiotherapy. Hence, these results represent a starting point for a rationale design of innovative and tailored ROS-responsive prodrugs to be used in GBM therapy and in combination with radiotherapy.

Gold Nanoparticles in Glioma Theranostics

Despite many endeavors to treat malignant gliomas in the last decades, the median survival of patients has not significantly improved. The infiltrative nature of high-grade gliomas and the impermeability of the blood-brain barrier to the most therapeutic agents remain major hurdles, impeding an efficacious treatment. Theranostic platforms bridging diagnosis and therapeutic modalities aim to surmount the current limitations in diagnosis and therapy of glioma. Gold nanoparticles (AuNPs) due to their biocompatibility and tunable optical properties have widely been utilized for an assortment of theranostic purposes. In this Review, applications of AuNPs as imaging probes, drug/gene delivery systems, radiosensitizers, photothermal transducers, and multimodal theranostic agents in malignant gliomas are discussed. This Review also aims to provide a perspective on cancer theranostic applications of AuNPs in future clinical trials.

Nanocarriers and nonviral methods for delivering antiangiogenic factors for glioblastoma therapy: the story so far

Angiogenesis, the formation of new blood vessels, is an essential component of glioblastoma (GB) progression. The development of angiogenesis inhibitor therapy, including treatments targeting vascular endothelial growth factor (VEGF) in particular, raised new hopes for the treatment of GB, but no Phase III clinical trial to date has reported survival benefits relative to standard treatment. There are several possible reasons for this limited efficacy, including VEGF-independent angiogenesis, induction of tumor invasion, and inefficient antiangiogenic factor delivery to the tumor. Efforts have been made to overcome these limitations by identifying new angiogenesis inhibitors that target angiogenesis through different mechanisms of action without inducing tumor invasion, and through the development of viral and nonviral delivery methods to improve antiangiogenic activity. Herein, we describe the nonviral methods, including convection-enhanced delivery devices, implantable polymer devices, nanocarriers, and cellular vehicles, to deliver antiangiogenic factors. We focus on those evaluated in intracranial (orthotopic) animal models of GB, the most relevant models of this disease, as they reproduce the clinical scenario of tumor progression and therapy response encountered in GB patients.

Electrospun nanofibers for local anticancer therapy: Review of in vivo activity

Currently, chemotherapy is the most common treatment for oncological diseases. Systemic administration of chemotherapeutics provides an easy and effective distribution of the active agents throughout the patient's body, however organs may be severely impaired by serious life-threatening side effects. In many oncological diseases, particularly solid tumors, the local application of chemotherapeutics would be advantageous. Recently, nanofibrous materials as local drug delivery systems have attracted much attention. They have considerable potential in the treatment of various cancers as they can provide a high concentration of the drug at the target site for a prolonged time, thereby lowering total exposure and adverse effects. The present review describes the specifics of drug delivery to the tumor microenvironment, basic characteristics of nanofibrous materials and their preparation, and comprehensively summarizes recent scientific reports concerning in vivo experiments with drug-loaded electrospun nanofibrous systems designed for local anticancer therapy.

Biodegradable hybrid-structured nanofibrous membrane supported chemoprotective gene therapy enhances chemotherapy tolerance and efficacy in malignant glioma rats

Chemotherapy is ineffective for treating malignant glioma (MG) because of the low therapeutic levels of pharmaceuticals in tumour tissues and the well-known tumour resistance. The resistance to alkylators is modulated by the DNA repair protein O⁶-alkylguanine-DNA alkyltransferase (AGT). O⁶-benzylguanine (O⁶-BG) can irreversibly inactivate AGT by competing with O⁶-methylguanine and has been confirmed to increase the therapeutic activity of alkylators. We developed hybrid-structured poly[(d,l)-lactide-co-glycolide] nanofibrous membranes (HSNMs) that enable the sequential and sustained release of O⁶-BG and two alkylators (carmustine and temozolomide [TMZ]). HSNMs were surgically instilled into the cerebral cavity of pathogen-free rats and F98 glioma-bearing rats. The release behaviours of loaded drugs were quantified by using high-performance liquid chromatography. The treatment results were compared with the rats treated with intraperitoneal injection of O⁶-BG combined with surgical implantation of carmustine wafer and oral TMZ. The HSNMs revealed a sequential drug release behaviour with the elution of high drug concentrations of O⁶-BG in the early phase, followed by high levels of two alkylators. All drug concentrations remained high for over 14 weeks. Tumour growth was slower and the mean survival time was significantly prolonged in the HSNM-treated group. Biodegradable HSNMs can enhance therapeutic efficacy and prevent toxic systemic effects.

Recent advances in brain tumor therapy: application of electrospun nanofibers

Despite much effort to treat glioblastoma multiforme (GBM), the median survival of patients has not significantly improved. The high rate of tumor recurrence after tumor resection and the blood-brain barrier (BBB) decrease the treatment efficacy. Local drug delivery at the surgical resection site via implantable electrospun nanofibers not only circumvents the BBB, but can also reduce the rate of tumor recurrence. Nanofibers can provide a sustained release and a high concentration of chemotherapeutics at the tumor vicinity, while decreasing their systemic exposure and toxicity. In another scenario, aligned nanofibers can mimic the topographical features of the brain extracellular matrix (ECM), which can be utilized for in vitro studies on GBM cell migration. This strategy is beneficial to investigate the interactions of tumor cells with the microenvironment which has a dominant role in regulating tumor formation, progression, and metastasis.

Advanced interstitial chemotherapy combined with targeted treatment of malignant glioma in rats by using drug-loaded nanofibrous membranes

Glioblastoma multiforme (GBM), the most prevalent and malignant form of a primary brain tumour, is resistant to chemotherapy. In this study, we concurrently loaded three chemotherapeutic agents [bis-chloroethylnitrosourea, irinotecan, and cisplatin; BIC] into 50:50 poly[(d,l)-lactide-co-glycolide] (PLGA) nanofibres and an antiangiogenic agent (combretastatin) into 75:25 PLGA nanofibres [BIC and combretastatin (BICC)/PLGA]. The BICC/PLGA nanofibrous membranes were surgically implanted onto the brain surfaces of healthy rats for conducting pharmacodynamic studies and onto C6 glioma-bearing rats for estimating the therapeutic efficacy.

The chemotherapeutic agents were rapidly released from the 50:50 PLGA nanofibres after implantation, followed by the release of combretastatin (approximately 2 weeks later) from the 75:25 PLGA nanofibres. All drug concentrations remained higher in brain tissues than in the blood for more than 8 weeks. The experimental results, including attenuated malignancy, retarded tumour growth, and prolonged survival in tumour-bearing rats, demonstrated the efficacy of the BICC/PLGA nanofibrous membranes. Furthermore, the efficacy of BIC/PLGA and BICC/PLGA nanofibrous membranes was compared. The BICC/PLGA nanofibrous membranes more efficiently retarded the tumour growth and attenuated the malignancy of C6 glioma-bearing rats. Moreover, the addition of combretastatin did not significantly change the drug release behaviour of the BIC/PLGA nanofibrous membranes. The present advanced and novel interstitial chemotherapy and targeted treatment provide a potential strategy and regimen for treating GBM.

Inhibition of bcl-2 and cox-2 Protein Expression after Local Application of a New Carmustine-Loaded Clinoptilolite-Based Delivery System in a Chemically Induced Skin Cancer Model in Mice

Our research has focused on in vitro and in vivo evaluations of a new Carmustine (BCNU)-loaded clinoptilolite-based delivery system. Two clinoptilolite ionic forms-hydrogen form (HCLI) and sodium form (NaCLI)-were prepared, allowing a loading degree of about 5-6 mg BCNU/g of zeolite matrix due to the dual porous feature of clinoptilolite. Clinoptilolite-based delivery systems released 35.23% of the load in 12 h for the BCNU@HCLI system and only 10.82% for the BCNU@NaCLI system. The BCNU@HCLI system was chosen to develop gel and cream semisolid dosage forms. The cream (C_BCNU@HCLI) released 29.6% of the loaded BCNU after 12 h in the Nylon synthetic membrane test and 31.6% in the collagen membrane test, higher by comparison to the gel. The new cream was evaluated in vivo in a chemically induced model of skin cancer in mice. Quantitative immunohistochemistry analysis showed stronger inhibition of B-cell lymphoma-2 (bcl-2) and cyclooxygenase 2 (cox-2) protein expression, known markers for cancer survival and aggressiveness, after the treatment with C_BCNU@HCLI by comparison to all the control treatment types, including an off-label magistral formula commercially available Carmustine cream as reference, bringing evidence that a clinoptilolite-based delivery systems could be used as a cancer drug carriers and controlled release systems (skin-targeted topical delivery systems).

Self-assembled polypeptide nanoparticles for intracellular irinotecan delivery

In this research poly(l-lysine)-b-poly(l-leucine) (PLys-b-PLeu) polymersomes were developed. It was shown that the size of nanoparticles depended on pH of self-assembly process and varied from 180 to 650nm. The biodegradation of PLys-b-PLeu nanoparticles was evaluated using in vitro polypeptide hydrolysis in two model enzymatic systems, as well as in human blood plasma. The experiments on the visualization of cellular uptake of rhodamine 6g-loaded and fluorescein-labeled nanoparticles were carried out and the possibility of their penetration into the cells was approved. The cytotoxicity of polymersomes obtained was tested using three cell lines, namely, HEK, NIH-3T3 and A549. It was shown that tested nanoparticles did not demonstrate any cytotoxicity in the concentrations up to 2mg/mL. The encapsulation of specific to colorectal cancer anti-tumor drug irinotecan into developed nanocontainers was performed by means of pH gradient method. The dispersion of drug-loaded polymersomes in PBS was stable at 4°C for a long time (at least 1month) without considerable drug leakage. The kinetics of drug release was thoroughly studied using two model enzymatic systems, human blood serum and PBS solution. The approximation of irinotecan release profiles with different mathematical drug release models was carried out and allowed identification of the release mechanism, as well as the morphological peculiarities of developed particles. The dependence of encapsulation efficiency, as well as maximal loading capacity, on initial drug concentration was studied. The maximal drug loading was found as 320±55μg/mg of polymersomes. In vitro anti-tumoral activity of irinotecan-loaded polymersomes on a colon cancer cell line (Caco-2) was measured and compared to that for free drug.

Theranostic 3-Dimensional nano brain-implant for prolonged and localized treatment of recurrent glioma

Localized and controlled delivery of chemotherapeutics directly in brain-tumor for prolonged periods may radically improve the prognosis of recurrent glioblastoma. Here, we report a unique method of nanofiber by fiber controlled delivery of anti-cancer drug, Temozolomide, in orthotopic brain-tumor for one month using flexible polymeric nano-implant. A library of drug loaded (20 wt%) electrospun nanofiber of PLGA-PLA-PCL blends with distinct in vivo brain-release kinetics (hours to months) were numerically selected and a single nano-implant was formed by co-electrospinning of nano-fiber such that different set of fibres releases the drug for a specific periods from days to months by fiber-by-fiber switching. Orthotopic rat glioma implanted wafers showed constant drug release (116.6 μg/day) with negligible leakage into the peripheral blood (<100 ng) rendering ~1000 fold differential drug dosage in tumor versus peripheral blood. Most importantly, implant with one month release profile resulted in long-term (>4 month) survival of 85.7% animals whereas 07 day releasing implant showed tumor recurrence in 54.6% animals, rendering a median survival of only 74 days. In effect, we show that highly controlled drug delivery is possible for prolonged periods in orthotopic brain-tumor using combinatorial nanofibre libraries of bulk-eroding polymers, thereby controlling glioma recurrence.

Loading cisplatin onto 6-mercaptopurine covalently modified MSNS: a nanomedicine strategy to improve the outcome of cisplatin therapy

In the treatment of cancer patients, cisplatin (CDDP) exhibits serious cardiac and renal toxicities, while classical combinations related to CDDP are unable to solve these problems and may result in worse prognosis. Alternately, this study covalently conjugated 6-mercaptopurine (6MP) onto the surface of mercapto-modified mesoporous silica nanoparticles (MSNS) to form MSNS-6MP and loaded CDDP into the holes on the surface of MSNS-6MP to form MSNS-6MP/CDDP, a tumor-targeting nano-releasing regime for CDDP and 6MP specifically. In the S180 mouse model, the anti-tumor activity and overall survival of MSNS-6MP/CDDP (50 mg·kg⁻¹·day⁻¹, corresponding to 1 mg·kg⁻¹·day⁻¹ of 6MP and 5 mg·kg⁻¹·day⁻¹ of CDDP) were significantly higher than those of CDDP alone (5 mg·kg⁻¹·day⁻¹) or CDDP (5 mg·kg⁻¹·day⁻¹) plus 6MP (1 mg·kg⁻¹·day⁻¹). The assays of serum alanine aminotransferase, aspartate aminotransferase and creatinine, as well as the images of myocardium and kidney histology, support that MSNS-6MP/CDDP is able to completely eliminate liver, kidney and heart toxicities induced by CDDP alone or CDDP plus 6MP.

Advances in drug delivery to high grade gliomas

If cancer is hard to be treated, brain cancer is even more, caused by the inability of many effective drugs given systemically to cross the blood brain and blood tumor barriers and reach adequate concentrations at the tumor sites. Effective delivery of drugs to brain cancer tissues is thus a necessary, albeit not sufficient, condition to effectively target the disease. In order to analyze the current status of research on drug delivery to high grade gliomas (HGG-WHO grades III and IV), the most frequent and aggressive brain cancers, a literature search was conducted in PubMed using the terms: "drug delivery and brain tumor" over the publication year 2015. Currently explored drug delivery techniques for HGG include the convection and permeabilization-enhanced deliveries, drug-releasing depots and Ommaya reservoirs. The efficacy/safety ratio widely varies among these techniques and the success of current efforts to increase this ratio widely varies as well.

Well-defined hydroxyethyl starch-10-hydroxy camptothecin super macromolecule conjugate: cytotoxicity, pharmacodynamics research, tissue distribution test and intravenous injection safety assessment

10-Hydroxy camptothecin (10-HCPT) is an antitumor agent effective in the treatment of several solid tumors but its use is hampered by poor water solubility, low lactone stability, short plasma half-life and dose-limiting toxicity. These limits of 10-HCPT had been overcome by our group through preparing super macromolecule prodrug: 10-HCPT-hydroxyethyl starch (HES) conjugate. In this study, we mainly evaluated in vitro and in vivo behavior of the prodrug, containing cytotoxicity assay, pharmacodynamics study, vascular irritation test, hemolysis experiment and tissue distribution test of rats. The irritation test results achieved much lower irritation than the commercial injection. The tissue distribution results showed that HES-10-HCPT conjugate increased significantly the 10-HCPT concentration in the tumor, liver and spleen site, whereas decreased the drug concentration in the heart and kidney. The hemolysis effect of the prepared conjugate was not obvious. The pharmacodynamics results indicated that HES-10-HCPT prodrug had a better antitumor efficiency against mice with H22 tumor than the commercial injection, and the inhibition ratio of tumor was 85.2% and 31.1%, respectively at the same dosage. These findings suggest that HES-10-HCPT prodrug is a promising drug delivery system providing improved good injection safety, greater tolerance and antitumor effect.