Non-aggregated protamine-coated poly(lactide-co-glycolide) nanoparticles of cisplatin crossed blood-brain barrier, enhanced drug delivery and improved therapeutic index in glioblastoma cells: in vitro studies

QbD-based co-loading of paclitaxel and imatinib mesylate by protamine-coated PLGA nanoparticles effective on breast cancer cells

Aim: Paclitaxel and imatinib mesylate are drugs used in the treatment of breast cancer. Conventional drug-delivery systems have limitations in the effective treatment of breast cancer using the drugs. Materials & methods: Combination index studies were used to identify the optimum ratio of both drugs showing maximum synergistic effect. Using a systematic quality-by-design approach, protamine-coated PLGA nanoparticles co-loaded with paclitaxel and imatinib mesylate were formulated. Further characterization and cell line evaluations were performed. Results: Encapsulation efficiency obtained was 92.54% for paclitaxel and 75.12% for imatinib mesylate. A sustained (24 h) and controlled zero-order drug release was obtained. Conclusion: Formulated nanoparticles had a low IC50 value and enhanced cellular uptake.

Overcoming colloidal nanoparticle aggregation in biological milieu for cancer therapeutic delivery: Perspectives of materials and particle design

Nanoparticles as cancer therapeutic carrier fail in clinical translation due to complex biological environments in vivo consisting of electrolytes and proteins which render nanoparticle aggregation and unable to reach action site. This review identifies the desirable characteristics of nanoparticles and their constituent materials that prevent aggregation from site of administration (oral, lung, injection) to target site. Oral nanoparticles should ideally be 75-100 nm whereas the size of pulmonary nanoparticles minimally affects their aggregation. Nanoparticles generally should carry excess negative surface charges particularly in fasting state and exert steric hindrance through surface decoration with citrate, anionic surfactants and large polymeric chains (polyethylene glycol and polyvinylpyrrolidone) to prevent aggregation. Anionic as well as cationic nanoparticles are both predisposed to protein corona formation as a function of biological protein isoelectric points. Their nanoparticulate surface composition as such should confer hydrophilicity or steric hindrance to evade protein corona formation or its formation should translate into steric hindrance or surface negative charges to prevent further aggregation. Unexpectedly, smaller and cationic nanoparticles are less prone to aggregation at cancer cell interface favoring endocytosis whereas aggregation is essential to enable nanoparticles retention and subsequent cancer cell uptake in tumor microenvironment. Present studies are largely conducted in vitro with simplified simulated biological media. Future aggregation assessment of nanoparticles in biological fluids that mimic that of patients is imperative to address conflicting materials and designs required as a function of body sites in order to realize the future clinical benefits.

Platinum-Based Nanoformulations for Glioblastoma Treatment: The Resurgence of Platinum Drugs?

Current therapies for treating Glioblastoma (GB), and brain tumours in general, are inefficient and represent numerous challenges. In addition to surgical resection, chemotherapy and radiotherapy are presently used as standards of care. However, treated patients still face a dismal prognosis with a median survival below 15-18 months. Temozolomide (TMZ) is the main chemotherapeutic agent administered; however, intrinsic or acquired resistance to TMZ contributes to the limited efficacy of this drug. To circumvent the current drawbacks in GB treatment, a large number of classical and non-classical platinum complexes have been prepared and tested for anticancer activity, especially platinum (IV)-based prodrugs. Platinum complexes, used as alkylating agents in the anticancer chemotherapy of some malignancies, are though often associated with severe systemic toxicity (i.e., neurotoxicity), especially after long-term treatments. The objective of the current developments is to produce novel nanoformulations with improved lipophilicity and passive diffusion, promoting intracellular accumulation, while reducing toxicity and optimizing the concomitant treatment of chemo-/radiotherapy. Moreover, the blood-brain barrier (BBB) prevents the access of the drugs to the brain and accumulation in tumour cells, so it represents a key challenge for GB management. The development of novel nanomedicines with the ability to (i) encapsulate Pt-based drugs and pro-drugs, (ii) cross the BBB, and (iii) specifically target cancer cells represents a promising approach to increase the therapeutic effect of the anticancer drugs and reduce undesired side effects. In this review, a critical discussion is presented concerning different families of nanoparticles able to encapsulate platinum anticancer drugs and their application for GB treatment, emphasizing their potential for increasing the effectiveness of platinum-based drugs.

Nanomedicine based strategies for oligonucleotide traversion across the blood-brain barrier

Neurological disorders are considered the most prominent cause of disability worldwide. The major hurdle in the management of neurological disorders is the existence of the blood-brain barrier (BBB), which hinders the entry of several therapeutic moieties. In recent years, oligonucleotides have gained tremendous attention for their target specificity, diminished dose and adverse effects, thereby halting disease progression. However, enzymatic degradation, rapid clearance, limited circulation and availability at the bio-active site, etc., limit its clinical translation. Nanomedicine has opened up a breadth of opportunities in the delivery of oligonucleotides across the BBB. This review addresses the pitfalls associated with oligonucleotide delivery in traversing the BBB via nanotherapeutics for the management of brain disorders. Regulatory perspectives pertaining to hastening the clinical translation of oligonucleotide-loaded nanocarriers for brain delivery have been highlighted.

A Historical Review of Brain Drug Delivery

The history of brain drug delivery is reviewed beginning with the first demonstration, in 1914, that a drug for syphilis, salvarsan, did not enter the brain, due to the presence of a blood-brain barrier (BBB). Owing to restricted transport across the BBB, FDA-approved drugs for the CNS have been generally limited to lipid-soluble small molecules. Drugs that do not cross the BBB can be re-engineered for transport on endogenous BBB carrier-mediated transport and receptor-mediated transport systems, which were identified during the 1970s-1980s. By the 1990s, a multitude of brain drug delivery technologies emerged, including trans-cranial delivery, CSF delivery, BBB disruption, lipid carriers, prodrugs, stem cells, exosomes, nanoparticles, gene therapy, and biologics. The advantages and limitations of each of these brain drug delivery technologies are critically reviewed.

Co-Encapsulation of Fisetin and Cisplatin into Liposomes for Glioma Therapy: From Formulation to Cell Evaluation

(1) Background: Glioblastoma (GBM) is the most frequent cerebral tumor. It almost always relapses and there is no validated treatment for second-line GBM. We proposed the coencapsulation of fisetin and cisplatin into liposomes, aiming to (i) obtain a synergistic effect by combining the anti-angiogenic effect of fisetin with the cytotoxic effect of cisplatin, and (ii) administrate fisetin, highly insoluble in water. The design of a liposomal formulation able to encapsulate, retain and deliver both drugs appeared a challenge. (2) Methods: Liposomes with increasing ratios of cholesterol/DOPC were prepared and characterized in term of size, PDI and stability. The incorporation of fisetin was explored using DSC. The antiangiogneic and cytotoxic activities of the selected formulation were assayed in vitro. (3) Results: We successfully developed an optimized liposomal formulation incorporating both drugs, composed by DOPC/cholesterol/DODA-GLY-PEG2000 at a molar ratio of 75.3/20.8/3.9, with a diameter of 173 ± 8 nm (PDI = 0.12 ± 0.01) and a fisetin and cisplatin drug loading of 1.7 ± 0.3% and 0.8 ± 0.1%, respectively, with a relative stability over time. The maximum incorporation of fisetin into the bilayer was determined at 3.2% w/w. Then, the antiangiogenic activity of fisetin was maintained after encapsulation. The formulation showed an additive effect of cisplatin and fisetin on GBM cells; (4) Conclusions: The developed co-loaded formulation was able to retain the activity of fisetin, was effective against GBM cells and is promising for further in vivo experimentations.

Protamine sulphate coated poly (lactide-co-glycolide) nanoparticles of MUC-1 peptide improved cellular uptake and cytokine release in mouse antigen presenting cells

AIM

MUC-1-peptide (M-1-pep) loaded poly (lactide-co-glycolide) nanoparticles were coated with protamine sulphate (PS), M-1-pep-PS-P-NPs for targeting antigen presenting cells (APCs) to evoke cytokine release.

METHODS AND RESULTS

M-1-pep-PS-P-NPs were tailored by emulsion-diffusion evaporation method and characterised in vitro under a set of rigorous parameters. The average particle size and zeta potential of optimised M-1-pep-PS-P-B-NPs was measured to be 132.21 ± 30.71 nm and 6.29 ± 0.71 mV, significantly (p < 0.01) higher than 71.24 ± 17.76-nm and -43.41 ± 3.37 mV of M-1-pep-P-NPs. Further, 50-μg/ml concentration of M-1-pep-PS-P-B-NPs displayed 82.4% cellular uptake in RAW 264.7 cells calculated in setting of fluorescence intensity significantly (p < 0.05) elevated than 63.1% of M-1-pep-P-NPs. Consistent to quantitative results, M-1-pep-PS-P-B-NPs also confirmed advanced cellular uptake (CU) in RAW 264.7 cells in contrast to M-1-pep-P-NPs suppose to be through multiple mechanisms including phagocytosis and clathrin mediated endocytosis.

CONCLUSION

M-1-pep-PS-P-B-NPs must be evaluated in vivo through inhalation route of administration for antitumor prospective in lung cancer xenograft model.

Development, In Vitro Characterization, and In Vivo Toxicity Evaluation of Chitosan-Alginate Nanoporous Carriers Loaded with Cisplatin for Lung Cancer Treatment

Polysaccharide-based aerogels are promising drug carriers. Being nanoporous with a high specific surface area allows their use as a drug vehicle for various delivery routes. Intratracheal and intravenous administration of free cisplatin causes toxicity in the rat liver, lungs, and kidneys. In this work, microspherical particles based on alginate-chitosan without a traditional crosslinker were evaluated for targeted delivery of cisplatin by intratracheal administration. The aerogel particles were prepared using the emulsion gelation method, followed by supercritical carbon dioxide extraction. Loading of cisplatin on the prepared porous particles was performed by impregnation using supercritical fluid technology. The prepared carrier and the loaded drug were evaluated for drug content, release, and in vivo acute and subacute toxicity. Cisplatin was successfully loaded (percent drug loading > 76%) on the prepared carrier (particle size = 0.433 ± 0.091 μm) without chemically interacting with the carrier and without losing its crystal form. Sixty percent of cisplatin was released within 2 h, and the rest was loaded inside the polymer pores and had a sustained first-order release over 6 h. Loading cisplatin on the carrier developed herein reduced the cisplatin lung toxicity but increased the liver toxicity after intratracheal administration with nephrotoxicity being proportional to cisplatin dose in case of carrier-loaded cisplatin. Moreover, loading cisplatin on the carrier significantly reduced mortality rate and prevented weight loss in rats as compared to free cisplatin in subacute studies after intratracheal administration. Thus, the developed carrier showed high potential for targeted delivery of cisplatin for lung cancer treatment by inhalation. Graphical abstract.

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.

Checkpoint inhibitors: 'raising the bar' also in brain metastases from non-small-cell lung cancer?

Despite efforts, brain metastases (BM) remain a critical issue in the management of patients affected by non-small-cell lung cancer (NSCLC). To date, radiotherapy is still considered the gold standard treatment; on the other hand, systemic chemotherapeutical agents are not so often an effective therapy for BM, whereas targeted agents in oncogene-addicted disease have shown a good activity also on BM. Anti-programmed death-1/programmed death ligand-1 agents represent a new valid therapeutic strategy for NSCLC as well as for several tumor types, but their efficacy on patients with BM is still unclear mainly due to the strict selection criteria adopted in clinical trials. The aim of the present article is to discuss the potential activity of checkpoint inhibitors in patients with BM from NSCLC.

Targeted brain delivery nanoparticles for malignant gliomas

Brain tumors display the highest mortality rates of all childhood cancers, and over the last decade its prevalence has steadily increased in elderly. To date, effective treatments for brain tumors and particularly for malignant gliomas remain a challenge mainly due to the low permeability and high selectivity of the blood-brain barrier (BBB) to conventional anticancer drugs. In recent years, the elucidation of the cellular mechanisms involved in the transport of substances into the brain has boosted the development of therapeutic-targeted nanoparticles (NPs) with the ability to cross the BBB. Here, we present a comprehensive overview of the available therapeutic strategies developed against malignant gliomas based on 'actively targeted' NPs, the challenges of crossing the BBB and blood-brain tumor barrier as well as its mechanisms and a critical assessment of clinical studies that have used targeted NPs for the treatment of malignant gliomas. Finally, we discuss the potential of actively targeted NP-based strategies in clinical settings, its possible side effects and future directions for therapeutic applications. First draft submitted: 4 October 2016; Accepted for publication: 14 October 2016; Published online: 23 November 2016.