ABSTRACT
The safe and effective delivery of drugs is a major obstacle in the treatment of ischemic stroke. Exosomes hold great promise as an endogenous drug delivery nanosystem for the treatment of cerebral ischemia given their unique properties, including low immunogenicity, innate stability, high delivery efficiency, and ability to cross the blood-brain barrier (BBB). However, exosome insufficient targeting capability limits their clinical applications. In this study, the c(RGDyK) peptide has been conjugated to the exosome surface by an easy, rapid, and bio-orthogonal chemistry. In the transient middle cerebral artery occlusion (MCAO) mice model, The engineered c(RGDyK)-conjugated exosomes (cRGD-Exo) target the lesion region of the ischemic brain after intravenous administration. Furthermore, curcumin has been loaded onto the cRGD-Exo, and administration of these exosomes has resulted in a strong suppression of the inflammatory response and cellular apoptosis in the lesion region. The results suggest a targeting delivery vehicle for ischemic brain based on exosomes and provide a strategy for the rapid and large-scale production of functionalized exosomes.
Subject(s)
Exosomes/chemistry , Pharmaceutical Vehicles , Stroke/drug therapy , Animals , Cell Line, Tumor , Curcumin/administration & dosage , Curcumin/chemistry , Disease Models, Animal , HeLa Cells , Humans , Infarction, Middle Cerebral Artery , Injections, Intravenous , Male , Mice , Mice, Inbred C57BL , Peptides/administration & dosage , Peptides/chemistryABSTRACT
Background: Glioblastoma (GBM) is the most common and most aggressive primary malignant brain tumor. Standard-of-care treatment involves maximal surgical resection of the tumor followed by radiation and chemotherapy (temozolomide [TMZ]). The 5-year survival rate of patients with GBM is <10%, a colossal failure that has been partially attributed to intrinsic and/or acquired resistance to TMZ through O6-methylguanine DNA methyltransferase (MGMT) promoter methylation status in the tumor. Methods: A drug screening aimed at evaluating the potential recycling and repurposing of known drugs was conducted in TMZ-resistant GBM cell lines and primary cultures of newly diagnosed GBM with different MGMT promoter methylation status, phenotypic/genotypic background and subtype, and validated with sphere formation, cell migration assays, and quantitative invasive orthotopic in vivo models. Results: We identified hydroxyurea (HU) to synergize with TMZ in GBM cells in culture and in vivo, irrespective of MGMT promoter methylation status, subtype, and/or stemness. HU acts specifically on the S-phase of the cell cycle by inhibiting the M2 unit of enzyme ribonucleotide reductase. Knockdown of this enzyme using RNA interference and other known chemical inhibitors exerted a similar effect to HU in combination with TMZ both in culture and in vivo. Conclusions: We demonstrate preclinical efficacy of repurposing hydroxyurea in combination with TMZ for adjuvant GBM therapy. This combination benefit is of direct clinical interest given the extensive use of TMZ and the associated problems with TMZ-related resistance and treatment failure.
Subject(s)
Brain Neoplasms/drug therapy , DNA Replication/drug effects , Drug Evaluation, Preclinical , Drug Resistance, Neoplasm/drug effects , Glioblastoma/drug therapy , Hydroxyurea/pharmacology , Temozolomide/pharmacology , Animals , Antineoplastic Agents, Alkylating/pharmacology , Apoptosis , Brain Neoplasms/classification , Brain Neoplasms/genetics , Brain Neoplasms/pathology , Cell Proliferation , Drug Repositioning , Glioblastoma/classification , Glioblastoma/genetics , Glioblastoma/pathology , Humans , Mice , Nucleic Acid Synthesis Inhibitors/pharmacology , Tumor Cells, Cultured , Xenograft Model Antitumor AssaysABSTRACT
The difference in light-emission kinetics between the Ca(2+)-triggered bioluminescent reaction of the photoprotein aequorin (AEQ) and the alkaline phosphatase (ALP)-catalyzed chemiluminescent hydrolysis of dioxetane aryl phosphate substrates was exploited for the analysis of both alleles of biallelic polymorphisms in a single microtiter well. The genotyping of the IVS-1-110 locus of the human beta-globin gene was chosen as a model. Genomic DNA, isolated from whole blood, was first subjected to polymerase chain reaction using primers flanking the polymorphic site. A single oligonucleotide-ligation reaction employing two allele-specific probes, labeled with biotin and digoxigenin, and a common probe carrying a characteristic tail was then performed. The ligation products were captured in a microtiter well through hybridization of the tail with an immobilized complementary oligonucleotide. The products were detected by adding a mixture of streptavidin-aequorin complex and antidigoxigenin-alkaline phosphatase conjugate. AEQ was measured first by adding Ca(2+) and integrating the signal for 3s followed by the addition of the substrate for ALP. The ratio of the luminescence signals obtained from ALP and AEQ gives the genotype of each sample. The coefficient of variation of the dual assay ranged from 7 to 11% for each allele. The reproducibility of the ALP/AEQ signal ratio was about 14%. The proposed assay allows for many samples to be screened in parallel in a single microtiter plate, for single-nucleotide polymorphisms.