RESUMO
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.
Assuntos
Dextranos , Peróxido de Hidrogênio , Ácidos Láuricos , Micelas , Osteossarcoma , Animais , Humanos , Osteossarcoma/tratamento farmacológico , Osteossarcoma/patologia , Linhagem Celular Tumoral , Dextranos/química , Camundongos , Ácidos Láuricos/química , Ácidos Láuricos/farmacologia , Apoptose/efeitos dos fármacos , Polímeros/química , Polímeros/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/patologia , Camundongos Nus , Antineoplásicos/farmacologia , Antineoplásicos/química , Camundongos Endogâmicos BALB C , Masculino , Serina-Treonina Quinases TOR/metabolismoRESUMO
Osteoporosis is an osteolytic disease with a disrupted balance between the resorption and formation of bone as well as bone microstructure degeneration, leading to bone loss and increased fracture risk, which greatly affects patients' quality of life. Currently, inhibition of osteoclast bone resorption remains the mainstream treatment for osteoporosis. Onc201, a new compound, induces the gene expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and has an efficient anticancer effect in clinical trials. However, its effects on osteolytic disease and the mechanism of action are unclear. We examined the effect of Onc201 on nuclear factor κB ligand-receptor activator (RANKL)-induced osteoclasts via Cell Counting Kit-8, bone resorption assay, luciferase reporter assay, immunofluorescence staining, calcium ion intensity assay and employed an ovariectomy model to investigate the effect of Onc201 on osteoporosis in the mice. Results showed that Onc201 inhibited the function and formation of osteoclasts induced by RANKL in a manner that was dependent on time and concentration, and did not cause cytotoxicity. Mechanistically, Onc201 inhibited osteoclast-relevant genes and NFATc1 expression, the main transcriptional regulatory factor of the formation of osteoclasts induced by RANKL; meanwhile, downregulating the expressions of the osteoclast cytoskeleton key signal molecules integrin αvß3, focal adhesion kinase (FAK), c-Src, and spleen-associated tyrosine kinase (SYK). In addition, Onc201 had a protective effect on the mouse model of bone loss caused by ovariectomy-induced estrogen deficiency, which is consistent with the in vitro results. Our findings suggest that the new small-molecular compound Onc201 has the potential to prevent osteoclast-related osteolytic diseases.
Assuntos
Reabsorção Óssea , Osteoporose , Animais , Reabsorção Óssea/metabolismo , Reabsorção Óssea/prevenção & controle , Diferenciação Celular , Feminino , Humanos , Integrinas/metabolismo , Ligantes , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Transcrição NFATC/metabolismo , Osteoclastos , Osteogênese , Osteoporose/etiologia , Osteoporose/metabolismo , Osteoporose/prevenção & controle , Ovariectomia/efeitos adversos , Qualidade de Vida , Ligante RANK/metabolismo , Ligante RANK/farmacologia , Receptor Ativador de Fator Nuclear kappa-B , Transdução de SinaisRESUMO
Osteoclasts with elevated bone resorption are commonly present in postmenopausal osteoporosis, and other osteolytic pathologies. Therefore, suppressing osteoclast generation and function has been the main focus of osteoporosis treatment. Betulinic acid (BA) represents a triterpenoid mainly purified from the bark of Betulaceae. BA shows multiple biological activities, including antitumor and anti-HIV properties, but its effect on osteolytic conditions is unknown. Here, BA suppressed receptor activator of nuclear factor-κB ligand (RANKL)-associated osteoclastogenesis and bone resorptive function, as assessed by tartrate-resistant acid phosphatase (TRAP) staining, fibrous actin ring generation, and hydroxyapatite resorption assays. Mechanistically, BA downregulated the expression of osteoclastic-specific genes. Western blot analysis revealed that BA significantly interrupted ERK, JNK and p38 MAPK activation as well as intracellular reactive oxygen species (ROS) production, thus altering c-Fos and NFATc1 activation. Corroborating the above findings in cell-based assays, BA prevented ovariectomy-associated bone loss in an animal model. In conclusion, these findings suggest that BA can inhibit osteoclast generation and function as well as the RANKL signaling pathway, and might be used for treating osteoclast-related osteoporosis.
RESUMO
Visible improvements: Owing to the plasmon resonance of silver nanoparticles deposited on the surface of AgBr, the newly-prepared plasmonic photocatalyst Ag section signAgBr has a strong absorption in the visible region (see picture) and shows high efficiency in the photodegradation of organic pollutants under visible light.
RESUMO
Mn/C-codoped GaN nanostructures were synthesized by carbothermal nitridation with active charcoal as the carbon source. Nanostructures such as zigzag nanowires and nanoscrews were observed by varying the reaction time and the C/Ga molar ratio of the starting material used for the synthesis. The structures and morphologies of the as-grown samples were characterized by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy measurements. The doping of both Mn and C in the GaN matrix was confirmed by X-ray photoelectron spectroscopy measurements, and the ferromagnetic properties of Mn/C-codoped GaN samples were confirmed by room-temperature magnetization measurements. The saturation magnetization of Mn/C-codoped GaN increases steadily with increasing C/Ga molar ratio of the starting material at a rate of approximately 0.023 emu/g per C/Ga molar ratio, and the ferromagnetism of Mn/C-codoped GaN can be stronger than that of Mn-doped GaN by a factor of approximately 40. A plausible growth mechanism was proposed, and the role of carbon codoping in tuning the morphology and ferromagnetic property was discussed. Our work suggests that carbon doping in the GaN matrix favors the N sites over the Ga sites, Mn/C-codoping in the GaN matrix is energetically favorable, and the C-codoping strongly enhances the preference of the FM coupling to the AFM coupling between the two doped Mn sites. These suggestions were probed on the basis of first-principles density functional theory electronic structure calculations for a number of model doped structures constructed with a 32-atom 2 x 2 x 2 supercell.