Background and purpose:Regulation of MMR activity under hypoxia may play an important role in genetic instability of cancer,but the mechanism is still unclear.We investigated the expression of DNA mismatch repair genes MLH1 and MSH2 in human SCLC cell line H446 under hypoxic condition and explore the role of promoter methylation of genes in hypoxia.Methods:RT-PCR and Western blot were applied to detect MLH1 and MSH2 expression in human SCLC cell line H446 at the mRNA and the protein level,respectively,under either hypoxic condition or after 5-Aza-CdR treatment.Meanwhile,methylation-specific PCR(MSP)was used to determine promoter methylation of MLH1 and MSH2.Results:The expression of MLH1 and MSH2 in H446 cells significantly decreased both at the mRNA and the protein level under hypoxic condition.5-Aza-CdR treatment led to the restoration of MLH1 and MSH2 expression,while,both MLH1 and MSH2 were down-regulated again after removing 5-Aza-CdR.Conclusions:The promoter methylation of MLH1 and MSH2 may play an important role in its defective expression in H446 cells under hypoxic condition.And 5-Aza-CdR could restore MLH1 and MSH2 expression.

Objective: To explore the mechanisms of the effect of isoflavone in reducing prostate cancer incidence throught studying the effects of isoflavone on apoptosis in PC-3 cell. Methods: Prostate cancer cell PC-3 was grown in RPMI 1640 medium supplemented with 10% bovine serum and 10 000 U/ml of penicillin/streptomycin in an incubator maintained at 5% CO 2 95% air and 100% humidity at 37 ℃. The respective test compound was added in fresh medium and the control cell received only the vehicle (MDSO). Apoptosis of PC-3 cells was analyzed by cell morphology under light microscope, agarose gel electrophoresis and flow cytometry. Results: Exposure of PC-3 cell to 50 ?mol/L GS, 75 ?mol/L DA and 75 ?mol/L GL after 72 h, the cell morphology indicated typical features commonly used to define apoptosis; agarose gel electrophoresis demonstrated laddered electrophoretic profiles of oligonucleosomal DNA fragments indicative of apoptosis, and flow cytometric analysis revealed a hyperdiploid population in the tested cells. Conclusion: Isoflavones could induce apoptosis in prostate cancer cells PC-3 and it may be the main cause of their role in cancer inhibition.

Objective To investigate the role of methylated DNA mismatch repair gene MLH1 and MSH2 in the acquired multidrug-resistance of human small cell lung cancer cells H446.Methods The reverse transcription polymerase chain reaction(RT-PCR)and Western blot were applied to measure MLH1 and MSH2 mRNA and protein expressions of the multidrug-resistant cells H446/DDP and its parental cells H446.The promoter methylation status of the genes was assessed by methylation-specific PCR(MSP).Results The expressions of MLH1 and MSH2 significantly decreased both in mRNA level and protein level.Promoter methylation of MLH1 was observed in H446/DDP cells but not in H446 cells.Promoter semi-methylation of MSH2 in H446 cells was transformed to methylation in H446/DDP cells.Conclusion The downregulation of DNA mismatch repair gene MLH1 and MSH2 induced by its promoter methylation may play an important role in the acquired multidrug resistance of human small cell lung cancer.

Vascular birthmarks are the most common disease.The morbidity is about 2.5%,most of the lesions occur in oral and maxillofacial regions which accounts for 40%-60% of the total lesions.In 1982,Mulliken and Glowacki proposed a biologic classification of vascular birthmarks on the basis of their clinical manifestations,histopathological features,and natural history.They defined hemangiomas as vascular tumors with a growth phase,marked by endothelial proliferation and hypercellularity,and an involutional phase.They recognized that many entities referred to as hemangiomas are actually structural malformations of the vasculature,derived from capillaries,veins,lymph vessels,or arteries or from a combination of these sources.The classification was confirmed and issued by International Society for the study of vascular anomality(ISSVA) in 1988.Waner and Suen amended the above category in 1995.This paper presents the new classification of vascular birthmarks and the developments in this field in re-cent years,including the pathology,clinical features and the therapy.For example,the classification of venular malformation categorized by Waner in 1989;the classification of lymphous malformation by Waner and Suen in 1995;and the treatments according to above classifications.

With Jingkang No.5 (PiA), calli of the PiA induced for 10-15 days were transferred into amino acid liquid culture medium, to establish excellent rice suspension cell lines successfully in a relative short time. The growth characteristics and differentiation conditions of suspension cells were measured at different phases. Results revealed that the optimal subculture time was 7-10 days, and the cells cultured for 30-120 days had the best differentiation ability (57.1%) and regeneration ability (20%). This study is promising in further using the suspension cell for genetic transformation and protoplasm isolation.
Cell Culture Techniques ; Cell Differentiation ; physiology ; Cell Line ; Culture Media ; Oryza ; cytology

Formation of the endoplasmic reticulum (ER) network requires homotypic membrane fusion, which involves a class of atlastin (ATL) GTPases. Purified Drosophila ATL is capable of mediating vesicle fusion in vitro, but such activity has not been reported for any other ATLs. Here, we determined the preliminary crystal structure of the cytosolic segment of Drosophila ATL in a GDP-bound state. The structure reveals a GTPase domain dimer with the subsequent three-helix bundles associating with their own GTPase domains and pointing in opposite directions. This conformation is similar to that of human ATL1, to which GDP and high concentrations of inorganic phosphate, but not GDP only, were included. Drosophila ATL restored ER morphology defects in mammalian cells lacking ATLs, and measurements of nucleotide-dependent dimerization and GTPase activity were comparable for Drosophila ATL and human ATL1. However, purified and reconstituted human ATL1 exhibited no in vitro fusion activity. When the cytosolic segment of human ATL1 was connected to the transmembrane (TM) region and C-terminal tail (CT) of Drosophila ATL, the chimera still exhibited no fusion activity, though its GTPase activity was normal. These results suggest that GDP-bound ATLs may adopt multiple conformations and the in vitro fusion activity of ATL cannot be achieved by a simple collection of functional domains.
Animals ; Dimerization ; Drosophila ; Drosophila Proteins ; chemistry ; genetics ; Endoplasmic Reticulum ; chemistry ; GTP Phosphohydrolases ; chemistry ; genetics ; GTP-Binding Proteins ; chemistry ; genetics ; Guanosine Diphosphate ; chemistry ; metabolism ; Humans ; Membrane Proteins ; chemistry ; genetics ; Mutation ; Protein Conformation ; Protein Structure, Secondary

Animals ; COS Cells ; Cercopithecus aethiops ; Endoplasmic Reticulum ; GTP Phosphohydrolases ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; GTP-Binding Proteins ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; Gene Expression ; Genetic Complementation Test ; HeLa Cells ; Humans ; Kinetics ; Membrane Fusion ; genetics ; Membrane Proteins ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; Protein Multimerization ; RNA, Small Interfering ; genetics ; metabolism ; Recombinant Proteins ; chemistry ; genetics ; metabolism ; Saccharomyces cerevisiae ; genetics ; metabolism ; Saccharomyces cerevisiae Proteins ; genetics ; metabolism ; Vesicular Transport Proteins ; genetics ; metabolism