ABSTRACT
Osteosarcoma (OS) is a highly malignant primary bone neoplasm that is the leading cause of cancerassociated death in young people. GNE477 belongs to the second generation of mTOR inhibitors and possesses promising potential in the treatment of OS but dose tolerance and drug toxicity limit its development and utilization. The present study aimed to prepare a novel H2O2 stimulusresponsive dodecanoic acid (DA)phenylborate esterdextran (DABDEX) polymeric micelle delivery system for GNE477 and evaluate its efficacy. The polymer micelles were characterized by morphology, size and critical micelle concentration. The GNE477 loaded DABDEX (GNE477@DBD) tumortargeting drug delivery system was established and the release of GNE477 was measured. The cellular uptake of GNE477@DBD by three OS cell lines (MG63, U2OS and 143B cells) was analyzed utilizing a fluorescent tracer technique. The hydroxylated DAB was successfully grafted onto dextran at a grafting rate of 3%, suitable for forming amphiphilic micelles. Following exposure to H2O2, the DABDEX micelles ruptured and released the drug rapidly, leading to increased uptake of GNE477@DBD by cells with sustained release of GNE477. The in vitro experiments, including MTT assay, flow cytometry, western blotting and RTqPCR, demonstrated that GNE477@DBD inhibited tumor cell viability, arrested cell cycle in G1 phase, induced apoptosis and blocked the PI3K/Akt/mTOR cascade response. In vivo, through the observation of mice tumor growth and the results of H&E staining, the GNE477@DBD group exhibited more positive therapeutic outcomes than the free drug group with almost no adverse effects on other organs. In conclusion, H2O2responsive DABDEX presents a promising delivery system for hydrophobic antitumor drugs for OS therapy.
Subject(s)
Dextrans , Hydrogen Peroxide , Lauric Acids , Micelles , Osteosarcoma , Animals , Humans , Osteosarcoma/drug therapy , Osteosarcoma/pathology , Cell Line, Tumor , Dextrans/chemistry , Mice , Lauric Acids/chemistry , Lauric Acids/pharmacology , Apoptosis/drug effects , Polymers/chemistry , Polymers/pharmacology , Xenograft Model Antitumor Assays , Bone Neoplasms/drug therapy , Bone Neoplasms/pathology , Mice, Nude , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Mice, Inbred BALB C , Male , TOR Serine-Threonine Kinases/metabolismABSTRACT
Osteoarthritis is one of the major causes of disability in elderly adults. Chondrocytes are responsible for the formation and remodeling of articular cartilage in joint tissue. The dysfunction of chondrocytes is a significant factor in the development of osteoarthritis. In the current study, we found that theobromine, a constituent of the cacao plant, possesses a preventive effect against interleukin (IL)-1ß-induced chondrocyte dysfunction. Theobromine ameliorates IL-1ß-induced production of cellular reactive oxygen species (ROS) and inflammatory mediators including cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2). The presence of theobromine suppresses IL-1ß-induced inducible nitro oxide synthase (iNOS) expression and cellular nitro oxide (NO) production. Theobromine also suppresses IL-1ß-induced production of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein-1 (MCP-1), as well as matrix metalloproteinases (MMP)-3 and MMP-13. Additionally, theobromine mitigates IL-1ß-induced type II collagen degradation. Mechanistically, we show that theobromine inhibits IL-1ß-induced IκBα activation, nuclear factor-κB (NF-κB) protein p65 accumulation, and transfected NF-κB promoter activity, indicating that theobromine suppresses the NF-κB pathway in chondrocytes. Collectively, our study demonstrates that the natural molecule theobromine has a protective effect to counter cytokine-induced chondrocyte dysfunction, implying its beneficial effect in the prevention of osteoarthritis.