Research progress on the role of platelet in mediating tumor metastasis by hematogenous spread and its mechanisms / 中国药理学通报

Tumor metastasis is one of the most important biologi-cal characteristics of malignant tumor, and it is also the main factors that cause treatment failure and poor prognosis. Clinical studies have shown that the number of platelets in patients with malignant tumor increased more significantly than that in benign tumor patients and healthy people, which indicate that platelet might be involved in the development process of tumor. Further study found that in the process of cancer spreading to blood, platelet could interact with tumor cells to form tumor emboli, helped tumor cells escape from immune surveillance, thus pro-moted the tumor metastasis. In recent years, related mechanisms on platelets in promoting tumor metastasis were revealed gradual-ly, and several targeted therapies based on platelets were also carried out. This paper reviews the role of platelet in mediating tumor metastasis by hematogenous spread and its mechanisms and discusses the therapy strategies that target platelet, which may provide references for follow-up research and clinical treat-ment.

Construction of pGL3-TNF-α3′UTR luciferase reporter gene and tanshinone compounds screening / 中国药理学通报

Aim To screen the potential inhibitors of post-transcriptional activity of pro-inflammatory media-tor TNF-α from the lipophilic constituents in Chinese Medicine Salvia miltiorrhiza Bunge ( Danshen) , we es-tablished dual luciferase reporter gene system pGL3-TNF-α3′UTR ( 3′untranslated region ) co-transfected with Renilla control gene. Methods Complementary DNA ( cDNA) template was obtained from human um-bilical vein endothelial cells ( HUVECs ) . The full length DNA of TNF-α 3′-UTR was amplified through PCR, and then connected the luciferase reporter vector pGL3-control after enzyme digestion. pGL3-TNF-α 3′UTR constructs were co-transfected with pSVRenilla into the mononuclear macrophages RAW264. 7 cells. The relative activity of reporter genes was measured by dual luciferase reporter ( DLR ) assay system after the stimulus of lipopolysaccharide ( LPS ) in presence or absence of tanshinones compounds. Results The pGL3-TNF-α3′UTR luciferase reporter gene was suc-cessfully constructed. The cloning DNA fragment and sequence were both consistent with the GENBANK da-tabase. LPS significantly induced the relative reporter activityof RAW264 . 7 cells transfected with pGL3-TNF-α 3′UTR. Among four tanshinones compounds, we found only cryptotanshinone could significantly de-crease LPS-induced relative reporter activity. Conclu-sion The pGL3-TNF-α 3′UTR construct combined with DLR assay system was successfully established, which can be used to discover the agents such as cryp-totanshinone that regulate the post-transcription of TNF-α in treatment of inflammatory and malignant dis-eases.

Bioassay of recombinant green fluorescent protein gene yeast cell for a high throughput to screen estrogenic compounds / 生物工程学报

We developed the recombinant green fluorescent protein gene yeast cell to screen estrogenic compounds based on two episomal vectors. In the expression vector the expression of human estrogen receptor alpha(hERalpha) was driven by 3-glyceraldehydephosphate dehydrogenase (GPD) promoter; in the reporter vector the expression of the yeast enhanced green fluorescent protein (yEGFP) gene was under the control of the estrogen response element (ERE). The vectors were transformed into yeast cell (W303-1A) to construct GFP recombinant yeast cell. Incubation of the yeast cell with various concentrations of the estrogenic compounds led to expression of the reporter gene product GFP in a dose dependent manner. Compared to other yeast bioassays, the yeast cell for environmental estrogen bioassay based on yEGFP reporter gene did not need cell wall disruption or the addition of a substrate or reagent. This yEGFP assay was performed completely in 96 well plates. So this test system can be used as a rapid and high throughput system for screening estrogenic chemical products, which has the characteristics of the sensitivity, reproducibility and cheapness.

Study on Estrogenic Effects of DDT-derivative Pesticides / 环境与健康杂志

Objective To study the estrogenic effects of DDT-derivative pesticides. Methods Using a recombinant human estrogen receptor gene yeast cell to estrogenic activity of DDT pesticides. The different concentrations of 17?-estradiol and individual DDT isomers and homologue such as p,p′-DDT, o,p′-DDT, p,p′-DDD and p,p′-DDE and their mixtures were added to yeast cultures, then estrogenic activity was measured by quantification of ?-galactosidase after 4 hours culture. Results DDT showed the ability to play the estrogenic effects like a ligand to bind hER and the dose dependent model existed between the estrogenic effects and the DDT concentration. The relative activity of o,p′-DDT, EC50=5.30?10-7mol/L, was higher and the estrogenic effects of isomers exhibited synergism, AI=1.5. The relative activity of p,p′-DDE , EC50=9.28?10-5mol/L, was lower and the antagonistical action between the homologues was found, AI=-1.38. DDT pesticides presented a synergism, the regression equation was =-2.600 6x2-28.079x-21.757,EC50 was 2.57?10-8mol/L, AI=0.83. Conclusion DDTs are ER mediated environmental estrogens, p,p′-DDT, o,p′-DDT, p,p′-DDD and p,p′-DDE show a synergic effect.