Suchergebnisse

Shuang Jiang,1 Xiaobo Wang,1 Ronggang Xi,1 Yingge Zhang2 1210th Hospital of People Liberation Army, Dalian, People's Republic of China; 2Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing, People's Republic of China Abstract: Atomic force microscopy (AFM) was applied for obtaining structural information about acetylcholinesterase (AChE) tetramer (AChE G4) before and after reaction with S-acetylcholine iodide (S-ACh), in the presence or absence of propidium iodide (PI), an inhibitor for peripheral anionic sites (PAS). An iced-bath ultrasound was used to prepare the phospholipid membrane. Ves-fusion technique was applied for incorporating AChE G4 in a lipid layer on mica. Before reaction with substrates, the single AChE G4 particle was ellipsoid in shape with a clear border. It had a smooth surface with a central projection. The four subunits of a single enzyme particle were arranged tightly (no separated subunits being found, with an average size of 89 ± 7 nm in length, 68 ± 9 nm in width, and 6 ± 3 nm in height). After reaction with S-ACh in the absence of PI, the loose arrangement of subunits of AChE G4 was seen, with an average size of 104 ± 7 nm in length, 91 ± 5 nm in width, and 8 ± 2 nm in height. Also there was free-flowing space amongst the four subunits of the AChE G4. This was consistent with the results of the X-ray diffraction crystallography and molecular dynamics studies. The apparent free space was the central path of AChE G4, changing from small to big, to small, to lateral door appearance, with an average size of 60 ± 5 nm in length and 51 ± 9 nm in width. The size of lateral door was 52 ± 5 nm in width and 32 ± 3 nm in depth on average. In the presence of PI, S-ACh could not cause topological structure changes of AChE G4. AFM verified that the central path might govern the turnover of the enzyme morphologically, and the interactions between PI and S-ACh might gate the creation of a central path and the opening of ACG in monomer; and the combination of S-ACh with peripheral anionic sites is conducive to the opening of ACG while PI can inhibit this action. Resolution at the inframolecular level is favorable in providing substantial information on how the spatial structure is adapted to the high efficiency of AChE molecules. Keywords: AChE, AFM, ACG, Ves-fusion, phospholipid membrane

Shuang Jiang,1,2,* Xiaobo Wang,2,* Zhiran Zhang,2 Lan Sun,3 Yunzhu Pu,3 Hongjuan Yao,3 Jingcao Li,3 Yan Liu,3 Yingge Zhang,3 Weijing Zhang1,4 1Department of Lymphoma, Affiliated Hospital of the Military Medical Academy of Sciences, Beijing, 2Department of Pharmacy, 210th Hospital of the People's Liberation Army, Dalian, 3Key Laboratory of Nanopharmacology and Nanotoxicology, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, 4Department of Lymphoma, Beijing Shijitan Hospital of Capital Medical University, Beijing, People's Republic of China *These authors contributed equally to this work Abstract: A monoclonal antibody targeted nanoscale drug delivery system (NDDS) for chemotherapy was evaluated in CD20-positive Raji cells in vitro. Nanoparticles were formed by the assembly of an amphiphilic polymer consisting of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxypolyethyleneglycol-2000 (DSPE-PEG2000). Active carbon nanoparticles (ACNP) were conjugated to the chemotherapeutic agent, doxorubicin (DOX), and the nanoliposome carrier, DSPE-PEG2000 and DSPE-PEG2000-NH2 conjugated to the human anti-CD20 monoclonal antibody that targets B-lymphocytes. This monoclonal antibody targeted nanoparticle delivery system for chemotherapy formed the active NDDS complex, ACNP-DOX-DSPE-PEG2000-anti-CD20. This active NDDS was spherical in morphology and had good dispersion in the culture medium. When compared with the effects on CD20-negative YTS cells derived from natural killer/T-cell lymphoma, the active NDDS, ACNP-DOX-DSPE-PEG2000-anti-CD20, demonstrated DOX delivery to CD20-positive Raji cells derived from Burkitt's lymphoma (B cell lymphoma), resulting in increased cell killing in vitro. The intracellular targeting efficiency of the ACNP-DOX-DSPE-PEG2000-anti-CD20 complex was assessed by confocal laser microscopy and flow cytometry. The findings of this in vitro study have shown that the DSPE-PEG2000 polymeric liposome is an effective nanocarrier of both a monoclonal antibody and a chemotherapy agent and can be used to target chemotherapy to specific cells, in this case to CD20-positive B-cells. Future developments in this form of targeted therapy will depend on the development of monoclonal antibodies that are specific for malignant cells, including antibodies that can distinguish between lymphoma cells and normal lymphocyte subsets. Keywords: CD20, active carbon nanoparticles, doxorubicin, nanoscale drug delivery, targeted therapy, DSPE-NH2-anti-CD20 conjugate