To determine whether interferon-gamma (IFN-gamma)inhibit the expression of vascular endothelial growth factor (VEGF) in ovarian cancer cell line SKOV3 with the level of mRNA and protein.

HDL receptor plays a very important role in reverse cholesterol transport, and it represents a novel therapeutic target for atherosclerosis. For construction of an in vitro high-throughput drug screening model based on competitive receptor--ligand binding, the extracellular domain of HDL receptor was expressed in the methylotropic yeast Pichia pastoris. The DNA fragment encoding for extracellular domain of HDL receptor was cloned by RT-PCR from Hepatoma Bel-7402 total RNA and the nucleotide sequence of the cloned cDNA was verified by inserting it into pGEM-T vector. Then the cDNA was subcloned into pPIC9K, the integrative secretory expression plasmid of Pichia pastoris was constructed, with the methanol-inducible alcohol oxidase promoter and alpha-signal peptide. The recombinant plasmid was transformed into Pichia pastoris GS115 (His- strain) by electroporation. PCR was used to confirm the insertion of HDLR gene into the genome of Mut+ transformants. During cultivation the recombinant strain was induced by 1% methanol and supernatant was analyzed by SDS-PAGE and Western blot. The result showed a specific protein band at approximately 64.5 kDa after 5 days of induction. Then the ligand binding activity was confirmed using the DiI-AcLDL as ligand.

Streptomyces are Gram-positive, filamentous soil bacteria, which produce a wide variety of metabolites that are currently being exploited in both medicine and agriculture. Moreover, Streptomyces lividans is used as a host strain to effectively express and secrete heterologous proteins to culture media. Genes encoding Sec proteins responsible for the translocation of preproteins have been identified in S. lividans. SecYEG, a complex of integral membrane proteins SecY, SecE, and SecG in the cytoplasmic membrane, constitutes a pathway for polypeptide movement. SecA plays a central role in translocation as it is the site of preprotein entry into the translocase and it is the only ATPase essential for preprotein translocation. The role of SecD and SecF is to regulate the movement of the translocating protein. A better understanding of their regulatory mechanism could help to develop S. lividans strains with hyper-secretory capacity. In this study, a reporter system was used to investigate the regulatory mechanism of secE promoter. Upstream sequence (496 bp) of secE of S. lividans TK24 was cloned and characterized in a promoter probe vector pIJ4083 upstream of promoterless xylE. Sequencing analysis revealed that secE upstream sequence of S. lividans shares 99.8% homology with the secE promoter of S. coelicolor. The transcriptive activity of this fragment approximates vsi promoter in CMI medium, a strong promoter from S. venezuelae. The activity of secE promoter was observed in different growth phase, culture temperature and culture media. The expression level of secE was higher during the log phase, but decreased at the beginning of the stationary phase. At growth temperature of 28 degrees C, the expression level was much higher than that at 37 degrees C. When the bacteria were incubated in NB, Phage, and CM medium respectively, the expression level of secE promoter was different at a certain fermentation time, but all reached the highest level at log phase. Further analysis revealed that glucose may repress secE promoter expression.

Gene amplification is a common mechanism that contributes to the drug resistance. To explore the molecular genetic background related to the MTX resistance in the mouse MTX-resistant cells, differential PCR was used to determine the amplification and overexpression of DHFR gene. In addition, the correlations between c-myc, p53 status and dhfr amplification were studied. Amplification and overexpression of dhfr suggested its role in MTX-resistant cells. However, no amplification and overexpression of c-myc were detected. On the other hand, no alteration of p53 copy number was found. The increased mRNA level of p53 suggested the normal function of p53. These results implicated the status of c-myc and p53 had no correlation with dhfr amplification, therefore some other molecular genetic alterations may exist to permit the dhfr amplification in MTX-resistant cells.

To investigate the expression of cyclins related gene in HL60 cells before and after arsenic trioxide treatment by gene chip.

To elucidate the molecular mechanism of realgar-induced apoptosis and differentiation of acute promyelocytic leukemia(APL) cell line NB4.

To study the specific expression of the antisense RNA against hepatitis B virus X (HBX) gene in hepatoblastoma cell line and its anti -HBV activity.

The objective of this study was to explore tissue factor (TF) expression induced by TNF-alpha in cultured human umbilical vien endothelial cells (HUVEC) and its molecular mechanism. TF expression on the surface of HUVEC, TF mRNA and nuclear factor kappaB (NF-kappaB) in HUVEC were detected by flow cytometry, RT-PCR and Western blot respectively. The results showed that TNF-alpha could enhance TF expression on the surface of HUVEC, the TF expression increase was highly consistent with the increased synthesis of TF mRNA, and the increase of TF expression was lately appeared for several hours. It was also found activation of NF kappaB at the time TF mRNA increase. In conclusion, NF-kappaB could be activated promptly after HUVEC incubated with TNF-alpha, then it was bound to TF promotor to start the TF transcription, TF mRNA expression was upregulated, that leaded to the increase of TF expression on the HUVEC surface and activated the coagulation cascade.

To study the biological role of human cultured bone marrow mesenchymal stem cell (BM-MSC) in hematopoiesis by investigation of its expression of multiple hematopoietic growth factors, RT-PCR was used to analyze the expression of SCF, Flt3-ligand, TPO, LIF, G-CSF, GM-CSF, IL-3, IL-6 and IL-11 at mRNA level for human BM-MSC from healthy donors and patients with leukemia and lymphoma. BM-MSC were incubated with or without hydrocortison (HC). The results clearly showed that the cultured BM-MSC expressed mRNA of SCF, Flt3-ligand, TPO, LIF, IL-6 and IL-11 at passages 3 up to 15, but did not express G-CSF, GM-CSF and IL-3. The same expression pattern of above cytokines was seen also for the patient's BM-MSC. HC was able to induce BM-MSC to express G-CSF but not to express GM-CSF. BM-MSC seemed not to change morphologically after incubation with HC for up to 21 days. In conclusion, both normal and patient BM-MSC should be potential to promote hematopoiesis according to their expression of multiple hematopoietic cytokines, and HC is able to induce hematopoietic growth factor expression.

This study was conducted to investigate the altered gene expression of MCF-7 cell before and after the treatment with beta-carotene using cDNA microarray and to investigate the mechanism which beta-carotene induce breast cancer cell apoptosis.

To explore the molecular elements responsible for the enhanced apoptotic susceptibility in U937 cells mediated by silencing atactic telangiectasis mutation (ATM) gene.

To study the in vitro antitumor activity of bcl-2 fully phosporothioated antisense oligodeoxynucleotide (bcl-2 ASODN) to malignant lymphoblastic cells.

To study the inhibition effect of HCV NS5A on p53 protein transactivity and its possible mechanism.

To investigate the effect of environmental risk factors on the development of stroke.

To investigate the mechanisms of arsenic trioxide (As(2)O(3)) induced demethylation.

The aim of this study was to investigate whether and how phosphodiesterase (PDE) inhibitors modulate the proliferation, cell cycle and apoptosis in lymphoma cells. The effects of aminophylline (AM), a non-specific PDE inhibitor, on Raji cells were explored in vitro. MTT assay, light and transmission electron microscopy and annexin V staining were used to observe cell proliferation, morphologic changes and apoptosis rate in AM-treated cells, and FCM and RT-PCR techniques were adopted to detect the effect on cell cycle, the expression of cyclin B1 and Bcl-2 and mitochondrial transmembrane potential in AM-treated cells. The results showed that AM inhibited the growth of Raji cells in a concentration-dependent manner. Morphologic observations showed apoptosis changes in AM-treated cells, including cytoplamic shrinkage, cytoplasmic bubbling, karyopyknosis and nuclear fragmentation. FCM and RT-PCR detection showed that AM intervention increased the fraction of annexin V(+) cells, reduced the value of mitochondrial transmembrane potential, induced S phase arrest, and down-regulated the expression of Bcl-2 at both mRNA and protein level and cyclin B1 protein in a concentration-dependent manner. It is concluded that PDE inhibitor aminophylline may induce Raji cell growth inhibition, S phase arrest, apoptosis via down-regulation of Bcl-2 and reduction of mitochondrial transmembrane potential.

The advanced technique of DNA microarray makes it possible to monitor the expression of thousands of genes simultaneously in one hybridization experiment. This technique accelerates demonstration of anti-tumor drug mechanisms and discovery of new drug targets. This study was designed to investigate the differential gene expression of K562 cells after cytochalasin B treatment using cDNA microarray.

This review introduces the structure, functions, tissue distribution, physiologic roles of estrogen receptor subtypes (ER alpha and ER beta) along with transcriptional activities of estrogen receptor ligands and the mechanism of the modulatory pathway and tissue specific property of selective estrogen receptor modulators (SERMs), and phytoestrogens. This article is to provide a systemic approach for increasing the selectivity of estrogenic drug and optimizing the clinically based strategy of drug design. Differences exist between ER alpha and ER beta in structure, function, tissue distribution, physiologic roles and response to ligands, as well as the regulating effect on gene transcription, which are mainly determined by different co-regulators they recruit respectively.

Objective. To investigate the mechanism of beating in cultured myocardiocytes through analyzing mPER1 expression and effect of melatonin on it. Method. Immunohistochemistry and melatonin interference test were employed. Result. mPER1 expression in cultured myocardiocytes showed circadian pattern, its acrophase was 15:20, its three consecutive daily average period length was approximately 23 h. Melatonin had little effects on its amplitude and period, but results in its phase delayed. The observation in this study was similar to those that we previously observed in cultured murine myocardiocytes beating. Conclusion. Oscillation of mPER1 gene is one of the important reasons which cause murine myocardiocytes circadian beating. Melatonin acts as "Zeitgeber" regulating mPER1 gene expression.