靶向抗肿瘤药物甲氨喋呤-琥珀酰壳聚糖缀合物的制备及其体外稳定性的初步探讨

报道了甲氨喋呤-琥珀酰壳聚糖缀合物的合成方法,并通过紫外光谱、红外光谱及核磁共振谱进行了结构验证.流式细胞仪的检测结果表明,N-琥珀酰壳聚糖对K562白血病肿瘤细胞具有较强的亲和性;溶解性实验结果表明,甲氨喋呤-琥珀酰壳聚糖缀合物的水溶性较好(pH=1～14);体外释放实验结果表明,缀合物性质稳定,能明显延缓甲氨喋呤的释放,为抗肿瘤药物的靶向及缓控释给药体系的研究提供了初步参考.     

新型壳聚糖荧光纳米粒的制备及pH敏感性能研究

以合成的具有羧基官能团的萘酰亚胺类化合物为荧光团,通过酰氯化法活化其中的羧基,并选用生物相容性较好的水溶性高分子聚合物——羧甲基壳聚糖(CMCS)为基质材料,以化学键合的方式将荧光团引入到CMCS基体中,得到新型荧光材料萘酰亚胺修饰羧甲基壳聚糖CMCS3N.通过红外光谱、紫外光谱及透射电子显微镜对CMCS3N的结构和形...     

硒化壳聚糖抗K562细胞的实验研究

用MTT法和AO/EB荧光染色法观察了硒化壳聚糖对K 562肿瘤细胞株生长的影响。结果发现,硒化壳聚糖可有效地抑制K 562细胞生长,并呈量效、时效关系。经硒化壳聚糖作用后的细胞可明显出现核固缩、碎裂等凋亡形态改变。硒化壳聚糖可诱导K 562细胞凋亡,抑制其生长。     

N,O-羧甲基壳聚糖的合成和性质研究

采用多段升温法将壳聚糖改性,合成了取代度为1.84、平均分子量为3.08×105、等电点为7.28的N,O-羧甲基壳聚糖(CMC),分别用紫外光谱、红外光谱、荧光光谱对其结构进行了表征,并对其水溶液的Zeta电位、电导率、表面张力以及水分散体系中羧甲基壳聚糖微粒的粒径分布进行了研究.结果表明, N,O-羧甲基壳聚糖具有表面活性;介质的pH值和浓度对羧甲基壳聚糖溶液的稳定性有很大的影响.     

低分子量N-羧丁酰壳聚糖的合成及其吸湿保湿性

低分子量N-羧丁酰壳聚糖的合成及其吸湿保湿性;低分子量壳聚糖;低分子量N-羧丁酰壳聚糖;吸湿性;保湿性     

N-琥珀酰壳聚糖的合成和性能研究

通过控制反应时间，制备了一系列取代度不同的N-琥珀酰壳聚糖。测定了产物的取代度、特性粘数、吸湿与保湿性，并用IR进行了结构表征。结果表明：壳聚糖在C2位上引入了琥珀酰基后可溶于水，其吸湿性与保湿性随取代度的增加而增强，且优于壳聚糖和透明质酸。     

低分子量N,O-羧甲基壳聚糖的合成及吸湿保湿性能

采用不同反应温度、反应时间和低分子量壳聚糖与氯乙酸摩尔比,在非均相反应体系中合成了不同取代度的低分子量N,O-羧甲基壳聚糖。当反应温度为60°C,反应时间为4h,低分子量壳聚糖与氯乙酸投料比为1∶1.5时,目标产物的取代度可达71%。吸湿保湿性能测定表明:取代度越大,低分子量N,O-羧甲基壳聚糖的吸湿保湿性越好,在相对湿度为81%,取代度从27%增大到71%时,其吸湿性从32.14%增大到37.27%,保湿性从310.72%增大到348.69%。     

低分子量壳聚糖的Sm3+配合物的合成和表征

壳聚糖经双氧水降解制得低分子量壳聚糖,低分子量壳聚糖与Sm3 反应制得配合物。分别用红外、紫外、荧光等测试手段对低分子量壳聚糖及其与Sm3 形成的配合物的结构和性能进行了表征。结果表明,低分子量壳聚糖与Sm3 发生了螯合作用,形成了较稳定的配合物。     

壳聚糖纳米粒子荧光探针的制备和表征

通过低分子量的壳聚糖(LCS)聚阳离子与三聚磷酸钠(TPP)的静电作用制备纳米级壳聚糖微球,并利用壳聚糖链上丰富的氨基与荧光素异硫氰酸酯(FITC)反应从而制备纳米壳聚糖微球荧光探针(NFCS)。结果表明,当壳聚糖分子量为60000,LCS与TPP的质量比为6∶1时,可得到粒度均一的球形纳米粒子,平均粒径为40±3 nm。荧光倒置显微镜观察证实FITC结合到壳聚糖微球上。荧光光谱分析显示NFCS的最大激发波长、最大发射波长与游离态FITC无显著差异。光漂白实验证实NFCS的稳定性比游离态FITC有显著提高。     

壳聚糖在水溶液中的辐射降解反应

研究了壳聚糖在CH3COOH/NaCl缓冲溶液均相体系下的辐射降解反应,给出了H2O2、异丙醇、pH、样品初始分子量等因素对壳聚糖降解的影响,探讨了实验条件下溶液中不同自由基对壳聚糖降解的作用,并对辐照前后壳聚糖的结构进行了表征.结果表明,酸性条件下,壳聚糖的降解主要由.H和.OH自由基共同作用引起,加入H2O2或者通入N2O都能够略微提高.OH自由基浓度,对壳聚糖的降解有促进作用.加入异丙醇后,由于同时降低了.H和.OH自由基浓度,导致壳聚糖降解缓慢.当溶液的pH接近中性后,对壳聚糖的降解起主要作用的为.OH自由基,加入H2O2或者通入N2O都会增加.OH自由基的浓度,从而明显提高壳聚糖的降解速率.此外,研究发现低分子量的壳聚糖具有较快的降解速率.样品的UV、FTIR分析表明,辐照后除在壳聚糖分子链端生成羰基外,壳聚糖主链结构未见变化,脱乙酰度也没有显著改变,显示出辐射降解是一种有效的控制壳聚糖分子量方法.     

The cellular labeling and pH-sensitive responsive-drug release of celastrol in cancer cells based on Cys-CdTe QDs

As one of the active compounds derived from Traditional Chinese Medicine,Celastrol(CSL)had cytotoxicity for human leukemia cancer cells K562 and its multidrug-resistant cell line K562/A02.Here,we introduced cysteamine-modified CdTe QDs as the labeling and drug carrier into CSL research and found that the self-assembly and conjugation of anticancer molecular CSL with the Cys-CdTe QDs could significantly increase the drug’s cytotoxicity for K562 cells.More important,these CSL-Cys-CdTe nanocomposites could overcome the multidrug resistance of K562/A02 cells and efficiently inhibit the cancer cell proliferation by realizing the pH-sensitive responsive release of CSL to cancer cells.The enhanced cytotoxicity was caused by the increase of the G2/M phase arrest for K562/A02 cells as well as for K562 cells.Cys-CdTe QDs can readily bind on the cell plasma membranes and be internalized into cancer cells to trace and detect human leukemia cancer cells in real time.In addition,these Cys-CdTe QDs can facilitate the inhibition of the multidrug resistance of K562/A02 cells and readily induce apoptosis.As a good photosensitizer for the therapy,labeling,and tracing of cancer cells,the combination of CSL with Cys-CdTe QDs can optimize the use of and a new potential therapy method for CSL and yield new tools to explore the mechanisms of active compounds from Traditional Chinese Medicine.     

Preferential cytotoxicity for multidrug-resistant K562 cells using the combination of a photosensitizer and a cyanine dye

The cyanine dye 1,1',3,3,3',3'-hexamethylindodicarbocyanine iodide (HIDC) protects K562 leukemia cells from photodynamic membrane damage caused by cis-di(4-sulfonatophenyl)diphenylporphine (TPPS2) and 420 nm light. This wavelength of light is chosen because it is absorbed by TPPS2, but not by HIDC. The photodynamic system studied may be useful as a model for antineoplastic therapy. A subline of K562 leukemia (K562/DOX), expressing the multidrug-resistance (MDR) phenotype, is found to accumulate smaller amounts of HIDC than the parent cell line and thus has less photoprotection. In the absence of added HIDC, the K562/DOX cell line is more resistant to photodynamic cytotoxicity than the K562 cell line. The resistance of the K562/DOX cell line is not due to a smaller accumulation of TPPS2 than the K562 cell line. However, when both cell lines are incubated with HIDC and TPPS2, and then exposed to light, the K562/DOX cell line becomes more sensitive to photodynamic cell damage than the K562 cell line. The combination of a photosensitizer with a cationic or lysomorphotropic photoprotector represents a novel strategy for the eradication of malignant cells expressing the MDR phenotype.     

Cell differentiation inducers from a marine sponge Biemna sp.

Two pyridoacridines closely related to the known isocystodamine were isolated from the marine sponge Biemna sp. together with isocystodamine. Their structures were determined on the basis of spectroscopic data. They induce the erythroid differentiation of human leukemia K562 cells with an ED₅₀ value of 5 nM each.     

The formation of conjugates with PEG–chitosan improves the biocatalytic efficiency and antitumor activity of L-asparaginase from <Emphasis Type="Italic">Erwinia carotovora</Emphasis>

The ChitoPEGylation method, which is a novel approach to regulating the catalytic properties of enzymes that is based on the formation of a covalent conjugate of an enzyme with branched copolymers of chitosan, has been developed. The efficiency of this method has been demonstrated using a new recombinant preparation of L-asparaginase from Erwinia carotovora (EwA) as a model. The molecular architecture and composition of EwA conjugates with PEG–chitosans have been optimized. It has been shown that the decisive factors that affect the activity of the EwA conjugates are the molecular weight of and PEGylation degree of chitosan. It has been found that the EwA conjugation with PEG–chitosan increases, its cytostatic activity against human chronic myeloid leukemia K562 cells, Burkitt’s lymphoma Raji cells, and acute lymphoblastic leukemia Jurkat cells. These data provide new approaches to the synthesis of L-asparaginase preparations with improved biocatalytic properties.     

Detection and distinguishability of leukemia cancer cells based on Au nanoparticles modified electrodes

The Au nanoparticles (Au NPs) modified interface has been fabricated by multi-potential step electrodeposition in this study. Based on the nano-Au interface, we have proposed an electrochemical approach to detect the cancer cell numbers sensitively with a detection limit of about 500 cells. More interestingly, the drug sensitive leukemia K562 cells and drug resistant leukemia K562/adriamycin could be electrochemically distinguished on the interface by the oxidation potential, which did not show any evident differences on the bare electrode. These results indicate the promising application of this nano-interface for constructing the unlabeled potential-discriminative cell biosensors.     

A Simple Electrochemical Aptamer Cytosensor for Direct Detection of Chronic Myelogenous Leukemia K562 Cells

A simple and rapid electrochemical aptamer cytosensor has been developed for direct detection of chronic myelogenous leukemia (CML) K562 cells based on a specific aptamer and a biotin conjugated concanavalin A (bio‐ConA) detection probe. The K562 cell could be specifically recognized by T2‐KK1B10 capture aptamer pre‐immobilized on gold modified electrode surface. Then, bio‐ConA was added in the reaction to identify K562 cell surface mannose, resulting in an aptamer‐K562 cell‐bio‐ConA sandwich complex. Finally, streptavidin conjugated alkaline phosphatase (ST‐ALP) combined with the bio‐ConA to catalyze α‐naphthyl (α‐NP) phosphate to form α‐naphthol which is highly electroactive at an operating voltage of 180 mV (vs. Ag/AgCl). Under optimum conditions, the DPV signals were proportional to the logarithm of K562 cell from 1×10² to 1×10⁷ cells mL⁻¹ with a detection limit of 79 cells mL⁻¹. The cytosensor also exhibited high selectivity, stability and reproducibility. When applied to detect K562 cells in human blood samples, recoveries between 79.6 %–93.3 % were obtained, indicating the developed biosensor would be a potential alternative tool for CML K562 cell detection in real biological samples.     

Cytotoxic and apoptotic activities of novel Pd(II) complexes against human leukemia cell lines in vitro

In the investigation for alternative chemotherapeutic strategies against leukemia, Pd(II) complexes were synthesized and investigated for cytotoxic and apoptotic properties on two human leukemia cell lines (HL-60 and K562). Pd(II) complexes (Pd-5a and Pd-6a) with 5a and 6a as ligands were synthesized and characterized by ¹H-NMR and F-TIR. The cytotoxicity of the compounds was quantified using MTT method. Bax, Bcl-2, and caspase 3 gene expression levels were estimated using RT-qPCR. Here we show that Pd(II) complexes have important cytotoxic activity on human leukemia cell lines. RT-qPCR indicated that Bax and caspase 3 gene expression levels were increased after 24 h treatment with Pd-5a and Pd-6a complexes in both HL-60 and K562 cells at some selected dose. Furthermore, Bcl-2 gene expression level decreased after 24 h treatment with Pd-5a and Pd-6a complexes in K562 cells at all selected dose. In HL-60 cells, only one selected Pd-5a dose (25 µM) decreased the gene expression level of Bcl-2. The results obtained in the present investigation indicate that these two newly synthesized Pd(II) complexes have apoptotic effects at appropriate doses through caspase 3 and Bax genes and might represent a novel potentially active agents for the management of human leukemia cell lines.     

聚异戊二烯基三胺的合成及生理活性评价

设计、合成了一系列聚异戊二烯基三胺化合物,目标化合物结构均经过核磁共振谱、质谱及元素分析确认;利用MTT法测试了目标化合物对人白血病细胞K562和人肝癌细胞Bel-7402的体外抗肿瘤活性.结果表明,目标化合物对两种肿瘤细胞的生长均有较强的抑制活性.     

Photodynamic treatment (ALA-PDT) suppresses the expression of the oncogenic Bcr-Abl kinase and affects the cytoskeleton organization in K562 cells

K562 is the chronic myelogenous leukemia (CML)-derived cell line that expresses high levels of chimeric oncoprotein Bcr-Abl. The deregulated (permanent) kinase activity of Bcr-Abl leads to continuous proliferation of K562 cells and their resistance to the apoptosis promotion by conventional drugs. The photodynamic treatment (PDT) based on the application of 5-aminolevulinic acid (ALA) and irradiation with blue light (ALA-PDT) resulted in the suppression of K562 cells proliferation. It was followed by a necrosis-like cell death [K. Kuzelová, D. Grebenová, M. Pluskalová, I. Marinov, Z. Hrkal, J. Photochem. Photobiol. B 73 (2004) 67-78]. ALA-PDT led to the perturbation of the Hsp90/p23 multichaperone complex of which the Bcr-Abl is the client protein. Bcr-Abl protein was suppressed whereas the bcr-abl mRNA level was not affected. Further on, we observed several changes in the cytoskeleton organization. We detected ALA-PDT-mediated disruption of filamental actin structure using FITC-Phalloidin staining. In connection with this we uncovered certain cytoskeleton organizing proteins involved in the cell response to the treatment. Among these proteins, Septin2, which plays a role in maintaining actin bundles, was suppressed. Another one, PDZ-LIM domain protein 1 (CLP36) was altered. This protein acts as an adaptor molecule for LIM-kinase which phosphorylates and thus inactivates cofilin. Cofilin was indeed dephosphorylated and could thus be activated and operate as an actin-depolymerizing factor. We propose the scheme of molecular response of K562 cells to ALA-PDT.