Antibody-drug conjugates:design and clinical progress / 药学学报

Antibody-drug conjugates, constructed with monoclonal antibodies, linker and cytotoxins, have distinctive advantages over chemotherapy drugs and antibody drugs in cancer therapy. In this review, the strategy of developing ADCs, and the important progress in past decade are well summarized. The representative ADCs in the pipeline are introduced and characterized with their new features. While, perspective for future directions of ADCs is proposed.

The correlation of asymmetrical dimethylarginine level and oxidative stress to the onset of Alzheimer's disease / 药学学报

This study is to investigate the influence and mechanism of action of asymmetrical dimethylarginine (ADMA) and the induced oxidative stress level on Alzheimer's disease (AD) incidence. ADMA concentration, nitric oxide, Abeta(40)/Abeta(42) ratio, inducible NO synthase (iNOS) activity and the concentrations of the induced free radicals including malondialdehyde (MDA), 3-nitrotyrosine (3-NT) and peroxynitrite (ONOO-) in the cerebrospinal fluid (CSF) from 34 neurologically normal controls and 37 AD patients were quantitatively determined and statistically compared. The results showed that the ADMA concentration significantly decreased in AD patients, and it showed negative correlation with the NO, iNOS activity, and showed positive correlation with MMSE score. ADMA concentration was negatively correlated with Abeta(40)/Abeta(42) ratio (P<0.01) with the observation that Abeta(40)/Abeta(42) ratio increased while ADMA level decreased in CSF in AD patients. The concentration levels of MDA, 3-NT and ROS significantly increased compared with the control with all the P values less than 0.05. These findings suggested that the ADMA disorder and the oxidative damage effect of the induced free radicals in CSF of AD patients are an important mechanism of AD incidence, and their joint regulation may provide new idea for the prevention and clinical treatment of AD.

Screening, Identifying and Function Analysis of Polyketide Synthase I Cluster from the Environmental Strain X-2 Which Produce Macrolactins / 微生物学通报

Macrolactins are 24-membered macrolides produced by unidentified marine bacterium, Actinomadura sp. and Bacillus sp., which exhibit both antibacterial and antitumor activities in vitro. The environmental strain X-2 which was isolated from the sediment of the East China Sea produce Macrolatin A, B and O. In this study, a set of degenerate oligonucleotide primers, designed for amplification ketosynthase(KS) domains, had been employed to identify KS gene fragments of the X-2 DNA samples. One 645 bp KS fragment(GenBank accession no. EF486351)had been cloned and used as a probe to screen the genome DNA fosmid library of X-2. Three positive clones were selected and sequenced, Homologous analysis and the function prediction of the obtained PKS gene fragments suggested that macrolactin is the Polyketide Biosynthesis Product of the gene cluster obtained in the environmental strain X-2.

Research and development of marine bio-active substances and drugs / 第二军医大学学报

The ocean is a huge resource of organisms and about 80% of the world species live in it. Marine organisms synthesize various structurally-unique and pharmacologically-active metabolites which differ from those derived from the land organisms and serve as lead compounds for drug development. More than 15 000 new compounds have been isolated and identified from marine animals, plants and microorganisms since decades ago, and drugs like cephalosporins, ziconotide (Prialt), cytarabine (AraC) and vidarabine (AraA) were developed using these compounds as precursors.

High-cell density cultivation of recombinant Escherichia coli for production of TRAIL by using a 2-stage feeding strategy / 生物工程学报

Escherichia coli was genetically engineered to produce recombinant tumor necrosis factor-related apoptosis inducing ligand (Apo2L/TRAIL) using a temperature-inducible expression system. To create a fed-batch culture condition that allows efficient production of TRAIL, different feeding strategy including discontinuous, DO-stat and pH-stat feeding strategies were compared. Then, a special 2-stage feeding strategy was developed. High concentration of biomass (300g wet cell weight per liter of culture broth) and active soluble TRAIL protein (1.1g/L) was obtained by applying a high-cell-density cultivation procedure with the 2-stage feeding strategy. Cultivation of recombinant E. coli was started as a batch process at 30 degrees C and then followed by fed-batch culture when the dissolved oxygen concentration presented a steep increase resulted from the exhaustion of glucose in the medium. At the first phase of fermentation (batch phase), agitation rate was enhanced to control dissolved oxygen at 30 percent. When glucose in the medium was used up, indicated by a sudden rise in pH value and dissolved oxygen, the second phase (fed-batch phase) was started with glucose and nitrogen resource being supplied automatically. At the beginning of fed-batch operation, stirrer rate was cascaded with dissolved oxygen signals to keep it at 20 percent (DO-stat). During the fed-batch phase, glucose was limited to control the specific growth rate under the critical value microcrit, to avoid acetic acid excretion. When the stirrer speed arrived at its up-limit, the flow rate of feed was kept constant. In the inducing phase(42 degrees C for 4h) glucose was fed as a pH regulating agent (pH-stat) and the specific growth rate and dissolved oxygen decreased sharply. Aqueous ammonia was used for maintaining pH value at 7.0 throughout the first two phases. In the whole fermentation, acetic acid concentration didn't exceed 2.9 g/L. At the end of the high-cell-density cultivation process, no acetic acid could be detected in the medium. These results indicated that our fed-batch strategy was able to prevent acetate accumulation significantly. Although high cell density has been achieved, the induction process was not optimized satisfactorily and much work should be done further. Furthermore, since no special ways, like pure oxygen, pressure, has been used in our experiments, this efficient approaches would be useful not only in a pilot scale but also in an industry scale. Finally, simple purification procedure based on immobilized metal affinity column (IMAC) and CM-Sepharose column was implemented to isolate the TRAIL. Yields of more than 800mg TRAIL per liter of culture broth were obtained, the final purity reaching more than 95%. The purified TRAIL showed strong cytotoxity activity against human pancreatic 1990 tumor cells, with ED50 about 1.6 microg/mL.

Expression of recombined human endothelial monocyte-activating polypeptideⅡand determination of its activity / 中国肿瘤生物治疗杂志

Objective: To chine and express the recombinant human endothelial monocyte-activating polypeptide-Ⅱ(EMAP-Ⅱ)and identify its anti-tumor biological activities.Methods: EMAP-Ⅱ_(147-312)was expressed by the expression vector pMAL-p2x and E.coli BL-21 and the product was purified.The production of tissue factor(TF)in human umbili- cal vein endothelial cell ECV-304 mediated by the recombinant EMAP-Ⅱwas determined by chemiluminescence sub- strate.The promoting effect of recombinant EMAP-Ⅱon TNF?-induced ECV-304 cell.Apoptosis was determined by flow cytometry.Its inhibitory effect on human pancreaic cancer cell SW1990 proliferation was determined by MTT method. Results:DNA sequencing verified that EMAP-Ⅱwas correctly cloned.The molecular mass of the protein identified by SDS-PAGE was consistent with the theoretic value.The productivity of recombinant EMAP-Ⅱwas 500?g per 1 g bacteria (wet mass).The purified product induced expression of tissue factor(TF)in ECV-304 cells;it also enhanced the sensi- tivity of ECV-304 cells to the apoptotic effect of TNF?([16.6?2.5]% vs[25.6?2.3]%,P

The 16S rDNA Sequence Analysis and Phenotypical Study of Strain F12-11-1-2 / 微生物学通报

The strain F12-11-1-2 was isolated from the East China Sea,which had antimitosis activity using Pyricularia oryzae mode.Ac- cording to phenotypical study,salt-aggregation test and 16S rDNA sequence analysis,the strain F12-11-1-2 has been identified to be Bacillus subtilis.

Expression of Tumstatin_(183-230)-TRAIL fusion protein and identification of its biological functions / 第二军医大学学报

Objective:To express Tumstatin_(183-230)-TRAIL fusion protein and to observe its biological functions.Methods: SOE-ing PCR was employed to amplify the recombinant sequence of Tumstatin_(183-230)and TNF-related apoptosis-inducing ligand (TRAIL_(114-281)).An expression vector pMAL-Tu-T was constructed by inserting Tu-T sequence into pMAL-c_2;the vector was used to transfect E.coli BL21(DE3)and expression of MBP-Tu-T fusion protein was induced by IPTG.Amylose Resin columns were employed to purify the fusion protein.The biological functions of MBP-Tu-T protein was examined by inhibitory test of endothelial cell proliferation,standard tumor cell cytotoxic assay,in vitro tube formation inhibition,and electron microscopic observation(apoptosis).Results:The expression rate of MBP-Tu-T fusion protein in E.coli was about 20%. Purified recombinant protein obviously inhibited endothelial cell proliferation(IC_(50)12.5?g/ml),induced apoptosis of pancreatic cancer cells,and inhibited tube formation.Conclusion:Constructed MBP-Tu-T fusion protein is bifunctional,which lays a solid foundation for further investigation of antitumor effect of Tumstatin_(183-230)-TRAIL in vivo.