Investigation of imatinib loaded surface decorated biodegradable nanocarriers against glioblastoma cell lines: Intracellular uptake and cytotoxicity studies

Small Molecule Tyrosine Kinase Inhibitors (TKIs) for Glioblastoma Treatment

In the last decade, many small molecules, usually characterized by heterocyclic scaffolds, have been designed and synthesized as tyrosine kinase inhibitors (TKIs). Among them, several compounds have been tested at preclinical and clinical levels to treat glioblastoma multiforme (GBM). GBM is the most common and aggressive type of cancer originating in the brain and has an unfavorable prognosis, with a median survival of 15-16 months and a 5-year survival rate of 5%. Despite recent advances in treating GBM, it represents an incurable disease associated with treatment resistance and high recurrence rates. For these reasons, there is an urgent need for the development of new pharmacological agents to fight this malignancy. In this review, we reported the compounds published in the last five years, which showed promising activity in GBM preclinical models acting as TKIs. We grouped the compounds based on the targeted kinase: first, we reported receptor TKIs and then, cytoplasmic and peculiar kinase inhibitors. For each small molecule, we included the chemical structure, and we schematized the interaction with the target for some representative compounds with the aim of elucidating the mechanism of action. Finally, we cited the most relevant clinical trials.

A receptor-mediated landscape of druggable and targeted nanomaterials for gliomas

Gliomas are the most common type of brain cancer, and among them, glioblastoma multiforme (GBM) is the most prevalent (about 60% of cases) and the most aggressive type of primary brain tumor. The treatment of GBM is a major challenge due to the pathophysiological characteristics of the disease, such as the presence of the blood-brain barrier (BBB), which prevents and regulates the passage of substances from the bloodstream to the brain parenchyma, making many of the chemotherapeutics currently available not able to reach the brain in therapeutic concentrations, accumulating in non-target organs, and causing considerable adverse effects for the patient. In this scenario, nanocarriers emerge as tools capable of improving the brain bioavailability of chemotherapeutics, in addition to improving their biodistribution and enhancing their uptake in GBM cells. This is possible due to its nanometric size and surface modification strategies, which can actively target nanocarriers to elements overexpressed by GBM cells (such as transmembrane receptors) related to aggressive development, drug resistance, and poor prognosis. In this review, an overview of the most frequently overexpressed receptors in GBM cells and possible approaches to chemotherapeutic delivery and active targeting using nanocarriers will be presented.

Tyrosine Kinase Inhibitors for Glioblastoma Multiforme: Challenges and Opportunities for Drug Delivery

Glioblastoma multiforme (GBM) is an aggressive brain tumor with high mortality rates. Due to its invasiveness, heterogeneity, and incomplete resection, the treatment is very challenging. Targeted therapies such as tyrosine kinase inhibitors (TKIs) have great potential for GBM treatment, however, their efficacy is primarily limited by poor brain distribution due to the presence of the blood-brain barrier (BBB). This review focuses on the potential of TKIs in GBM therapy and provides an insight into the reasons behind unsuccessful clinical trials of TKIs in GBM despite the success in treating other cancer types. The main section is dedicated to the use of promising drug delivery strategies for targeted delivery to brain tumors. Use of brain targeted delivery strategies can help enhance the efficacy of TKIs in GBM. Among various drug delivery approaches used to bypass or cross BBB, utilizing nanocarriers is a promising strategy to augment the pharmacokinetic properties of TKIs and overcome their limitations. This is because of their advantages such as the ability to cross BBB, chemical stabilization of drug in circulation, passive or active targeting of tumor, modulation of drug release from the carrier, and the possibility to be delivered via non-invasive intranasal route.

Oral delivery of imatinib through galactosylated polymeric nanoparticles to explore the contribution of a saccharide ligand to absorption

Imatinib (IMT) is a selective tyrosine kinase inhibitor clinically used for treating chronic myeloid leukemia and malignant gastrointestinal stromal tumors. However, oral administration of IMT is challenged by its high oral dose, low intestinal solubility and adverse reactions. This work aimed to investigate the effect of galactose ligand on polymeric nanoparticles-facilitated oral absorption of IMT. N-oleoyl-D-galactosamine was synthesized for fabricating biomimetic galactose-modified nanoparticles (GNPs) in an attempt to improve the oral bioavailability of IMT. IMT-loaded GNPs (IMT-GNPs) were prepared using a solvent diffusion technique and characterized by particle size, morphology, and entrapment efficiency (EE). The in vitro release and in vivo oral bioavailability of IMT-GNPs were comparatively studied with bulk IMT and IMT-loaded nanoparticles (IMT-NPs), respectively. The resultant IMT-GNPs were 122.0 nm around in particle size with a polydispersity index (PDI) of 0.201. IMT-GNPs possessed a high EE (93.06%) and exhibited a sustained effect on drug release. After oral administration, IMT-GNPs significantly enhanced the oral bioavailability of IMT, up to 152.3% relative to IMT suspensions, whereas IMT-NPs merely resulted in an increase to 115.2%. Cellular uptake and ex vivo intestinal transport imaging demonstrated that GNPs were armed with higher cellular affinity and intestinal epithelial permeability compared with galactose-free IMT-NPs. These results provide solid evidence that galactose modification has great potential to ulteriorly promote the oral absorption of IMT on the base of nanoparticles, which may be conducive to achieve the synergy and attenuation of IMT.

Use of nanoparticles for glioblastoma treatment: a new approach

Glioblastoma (GBM) is a very aggressive CNS tumor with poor prognosis. Current treatment lacks efficacy indicating that new therapeutic approaches are needed. One of these new approaches is based on the use of nanoparticles (NPs) to deliver different cargos (antitumoral drugs or genetic materials) to tumoral cells. This review covers the signaling pathways altered in GBM cells to understand the rationale behind choosing new therapeutic targets and recent advances in the use of different NPs to deliver to GBM cells, both in vitro and in vivo, different therapeutic molecules. A special focus is placed on the effect of NPs on orthotopic brain tumors since this animal model represents the optimal model for translational purposes.