Analysis of the impact of extracellular acidity on the expression and activity of P-glycoprotein and on the P-glycoprotein-mediated cytotoxicity of daunorubicin in cancer cell by microfluidic chip technology / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the impact of extracellular acidic environment on the expression and activity of P-glycoprotein (P-gp) and on the P-gp-mediated cytotoxicity of daunomycin in cancer cells by using microfluidic chip technology.</p><p><b>METHODS</b>The A549 cells cultured on a microfluidic chip were divided into experiment group and control group. The experiment group was exposed to an acidic cell culture medium (pH 6.6), while the control group was treated with a neutral cell culture medium (pH 7.4). The expression of P-gp was detected by cell immunofluorescense analysis and the activity of P-gp was evaluated by Rhodamine 123 efflux experiment. Meanwhile, the cytotoxicity of daunomycin was analyzed by cell live/dead fluorescence staining method.</p><p><b>RESULTS</b>Microfluidic chip designed in this study could provide a suitable microenvironment for the growth of A549 cells and the A549 cells reached the confluence of 90% after inoculation for 72 h. Treatment of the acidic cell culture media on A549 cells did not make a significant difference on the expression level of P-gp. However, the activity of P-gp was significantly enhancement and peaked at 6 h after treatment with acidic cell culture media. Meanwhile, the cytotoxicity of daunomycin reduced significantly after treatment with acidic cell culture medium for 6 h,and a reversal effect was obtained when synergy with verapamil.</p><p><b>CONCLUSIONS</b>Microfluidic chip technology can shorten the analysis time and reduce the reagent consumption. It can be used as a new technology platform for understanding the mechanisms of multi-drug resistance and for screening highly efficient multi-drug resistance reversal agents.</p>

Neutrophil elastase inhibitor on proliferation and apoptosis of U937 cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To study and compare the effect of neutrophil elastase inhibitors (GW311616A and sivelestat) on the proliferation and apoptosis of U937 cells.</p><p><b>METHODS</b>Inhibitory effects of GW311616A and sivelestat on the proliferation of U937 cells were assayed by MTT assay. The morphologic changes of U937 cells were detected by transmission electron microscope, and apoptosis was observed by AnnexinV-FITC/PI staining. The changes of cell cycle and apoptosis were detected by flow cytometry. The expression of NE in U937 cells was observed by indirect immunofluorescence, the variations of content and activity of NE in U937 cells were measured through ELISA assay and colorimetric method.</p><p><b>RESULTS</b>MTT showed that both NE inhibitors could inhibit the proliferation of U937 cells in a dose dependent manner. The IC50 of GW311616A and sivelestat were 150 and 214 μmol/L respectively. The inhibition effect of GW311616A was significantly higher than of sivelestat (P<0.01). Typical apoptosis morphological changes of U937 cells was observed through electron microscope. AnnexinV-FITC/PI staining showed that U937 cells could be induced to undergo apoptosis by the two inhibitors, the apoptosis ratio of 150μmol/L GW311616A group (13.60%) was significantly higher than that of 150μmol/L sivelestat group (3.69%)(P<0.01). The result of flow cytometry indicated that the apoptosis ratio of 150 μmol/L GW311616A group was 14.61%, U937 cell cycle was mainly blocked in G2/M phase; meanwhile 150 μmol/L sivelestat group as 4.25% with cell cycle in S phase. The fluorescence intensity of GW311616A group obviously decreased than of sivelestat group. And the two inhibitors could reduce the content and activity of NE in U937 cells, but the effect of GW311616A was significantly higher than of sivelestat (P<0.01).</p><p><b>CONCLUSION</b>GW311616A and sivelestat could inhibit the proliferation and cause apoptosis of U937 cells. Furthermore, GW311616A was more effective and harmful to cells than sivelestat.</p>

Berberine and total base from rhizoma coptis chinensis attenuate brain injury in an aluminum-induced rat model of neurodegenerative disease

To investigate the protective effects of the total base from rhizoma coptis chinensis [CTB] and berberine [Ber] on neurodegeneration induced by aluminum overload in rats. The study took place in the Department of Pharmacology, Chongqing Medical University, Chongqing, China, between February 2005 and May 2007. Wistar rats were divided into control group, model group, Ber-treated group, CTB [55 mg/kg and 110 mg/kg]-treated group, and nimodipine-treated group [n=20]. A rat brain damage model was established via intragastric administration of 400 mg/kg element aluminum once a day, 5 days a week for 12 weeks. The CTB, Ber, and nimodipine were intragastrically administered 4 hours after each aluminum administration for 12 weeks. The morphological changes of the neurons of the rat hippocampus and the changes of rat learning and memory functions were observed. The superoxide dismutase [SOD], choline acetyltransferase [ChAT], acetylcholinesterase [AchE], and monoamine oxidase-B [MAO-B] activities and malondialdehyde [MDA] content, as well as the MAO-B expression in the rat brain were examined. The CTB, Ber, and nimodipine significantly improved the learning and memory ability impairment and hippocampal neuronal death. The CTB, Ber, and nimodipine also significantly blunted the decrease of SOD and ChAT activities, and the increase of MDA content, AchE activities, and MAO-B expressions and activity in the aluminum-overload rats. The CTB and Ber have protective effects on neurodegeneration induced by aluminum overload. The CTB [110 mg/kg] has more powerful neuroprotection than Ber

Screening and identification of proteins interacting with RAR alpha-V via yeast two-hybrid system / 中华血液学杂志

<p><b>OBJECTIVE</b>To screen the protein interacting with retinoic acid receptor variant protein (RAR alpha-V) via the yeast two-hybrid technique (YTHT) and to find out the targets protein and study its biological function.</p><p><b>METHODS</b>The bait vector of pGBKT7-RAR alpha-V was constructed for screening proteins interacting with RAR alpha-V in K562 cell cDNA expression library via YTHT. The protein-protein interaction was confirmed with re-transformation in yeast and GST pull-down in vitro.</p><p><b>RESULTS</b>The bait vector was successfully constructed without toxicity, leakage and self-activation. Sixteen proteins were screened by YTHT and eight positive clones were identified by re-transformation in yeast. The interaction between RAR alpha-V and JTV-1 was confirmed by GST pull-down in vitro.</p><p><b>CONCLUSIONS</b>There are some kinds of proteins interacting with RAR alpha-V in cell. The biological dysfunction caused by certain protein-protein interaction may be involved in the pathogenesis of leukemia.</p>