Study on apoptosis of breast cancer cells induced by green tea / 中国基层医药

Objective To study the apoptosis of breast cancer cells induced by green tea and the preventive effect of green tea on cancer.Methods Catecholamine,the main components of green tea was added into human breast cancer cell line(MDA-MB-231) with different concentrations,and then human breast cancer cell line was measured by MTT assay,comet assay,flow cytometry and caspase-3 activity assay respectively.Results After treatment with 0.2mmol/L EGCG for 48 h,the cell proliferation was inhibited in the experimental group in MTT assay[minimum absorbance value (0.391±0.041),t=4.223 P<0.01].In comet assay,cells treated with 0.2mmol/L EGCG for 48 h in the experimental group showed a fairly long tail[control group average value (4.92±0.64)μm,the experimental group average value (18.76±1.37)μm,P=0.003].The rate of cell apoptosis increased significantly by testing MDA-MB-231 exposed to EGCG with flow cytometry.The apoptotic rate of the cells exposed to 0.2mmol/L EGCG for 48 h in the experimental group was (29.370±1.485)(t=11.125,P<0.01).EGCG induced apoptosis and caspase-3 activity rate was dependent on time and dose.The OD value of caspase-3 observed by the colorimetric method in cells exposed to 0.2mmol/L EGCG for 48 h in the experimental group was (0.144±0.045)(t=5.321,P<0.01).Conclusion EGCG may play a role in the treatment and prevention of breast cancer by affecting apoptosis.

Cellular ESCRT complex and its roles in enveloped viruses budding / 生物工程学报

In eukaryotic cells, multivesicular bodies (MVBs) are required for trafficking of membrane proteins to lysosomes for selective destruction. The sorting of ubiquitylated membrane proteins into multivesicular bodies and the biogenesis of MVBs are mediated by the endosomal sorting complex required for transport (ESCRT). Topologically equivalent to the budding of intralumenal vesicles from the limiting membrane of the MVBs, the ESCRT complex is also involved in cytokinetic abscission, phagophore formation, and enveloped virus budding. Many retroviruses and RNA viruses encode "late-domain" motifs that are able to interact with the components of the ESCRT complex, and the interactions recruit ESCRT-III and VPS4 to the viral assembly and budding sites. Recently, few studies revealed that the ESCRT complex is also required for efficient egress of some DNA viruses, including Hepatitis B, Herpes simplex virus type-1, and Autographa californica multiple nucleopolyhedrovirus. Further examination of virus-ESCRT interactions should shed light on the detailed mechanism of virus assembly and budding.

Correlation between drug resistance of leukemic cells and Caspase-3 / 西安交通大学学报(医学版)

Objective To explore the relationship between drug resistance of leukemic cells and Caspase-3,this study took adriamycin(ADR)-resistant human chronic granulocytic leukemic cell strain K562/AO_2 as research subject,observing the cell survival and the morphological change of cell apoptosis under the action of ADR and arsenic sulfide and the Caspase-3 activity before and after putting in the Caspase-3 inhibitor.Methods ① The 3-(4,5-dimethylthiazo-2-yl)-2,5-diphenyl-tetrazolium bromide(MTT) method was used to determine the cell survival(A value) of K562/AO_(2)cell strain under the action of ADR and arsenic sulfide.② DNA agarose gel electrophoresis was performed to observe the DNA cleavage of apoptotic cells.③ The enzyme colorimetric activity assay(CAA) method was used to measure the change of the Caspase-3 activity of K562/AO_(2) cell strain.Results ① The A value of K562/AO_(2) cells had a time and dosage dependent relation with arsenic sulfide.② Apoptosis occurred in the K562/AO_(2) cell strain affected by arsenic sulfide.③ Compared with the cell strains with the Caspase-3 inhibitor added,the Caspase-3 activity of those without the Caspase-3 inhibitor increased remarkably(P