The MAPK Kinase Kinase GmMEKK1 Regulates Cell Death and Defense Responses.

MAPK signaling pathways play critical roles in plant immunity. Here, we silenced multiple genes encoding MAPKs using virus-induced gene silencing mediated by Bean pod mottle virus to identify MAPK genes involved in soybean (Glycine max) immunity. Surprisingly, a strong hypersensitive response (HR) cell death was observed when soybean MAPK KINASE KINASE1 (GmMEKK1), a homolog of Arabidopsis (Arabidopsis thaliana) MEKK1, was silenced. The HR was accompanied by the overaccumulation of defense signaling molecules, salicylic acid (SA) and hydrogen peroxide. Genes involved in primary metabolism, translation/transcription, photosynthesis, and growth/development were down-regulated in GmMEKK1-silenced plants, while the expression of defense-related genes was activated. Accordingly, GmMEKK1-silenced plants were more resistant to downy mildew (Peronospora manshurica) and Soybean mosaic virus compared with control plants. Silencing GmMEKK1 reduced the activation of GmMPK6 but enhanced the activation of GmMPK3 in response to flg22 peptide. Unlike Arabidopsis MPK4, GmMPK4 was not activated by either flg22 or SA. Interestingly, transient overexpression of GmMEKK1 in Nicotiana benthamiana also induced HR. Our results indicate that GmMEKK1 plays both positive and negative roles in immunity and appears to differentially activate downstream MPKs by promoting GmMPK6 activation but suppressing GmMPK3 activation in response to flg22. The involvement of GmMPK4 kinase activity in cell death and in flg22- or SA-triggered defense responses in soybean requires further investigation.

[Expression of Aquaporin 4 in Diffuse Brain Injury of Rats].

OBJECTIVE: To observe the expression of aquaporin 4 (AQP4) in diffuse brain injury (DBI) of rats and to explore the corresponding effect of AQP4 for brain edema. METHODS: The rat model of DBI was established using Marmarou's impact-compression trauma model. Brain water content was measured by dry-wet weight method. Blood-brain barrier permeability was evaluated by Evans blue (EB) staining. Immunohistochemical method was used to observe the expression of AQP4. RESULTS: Brain water content increased after 3 h and peaked at 24 h after DBI. Brain EB content significantly increased and peaked at 12 h after DBI. The expression of AQP4 significantly increased after 3 h and peaked at 24 h after DBI, and the number of AQP4 positive astrocytes increased. CONCLUSION: The increment of the permeability of blood-brain barrier and the expression of AQP4 may contribute to the development of brain edema in rat DBI. The change of AQP4 expression in astrocytes may also contribute to determine DBI.

Formation mechanism, environmental sensitivity and functional characteristics of succinylated ovalbumin/ε-polylysine electrostatic complexes: The roles of succinylation modification and ε-polylysine combination.

Biocomplex materials formed by oppositely charged biopolymers (proteins) tend to be sensitive to environmental conditions and may lose part functional properties of original proteins, and one of the approaches to address these weaknesses is protein modification. This study established an electrostatic composite system using succinylated ovalbumin (SOVA) and ε-polylysine (ε-PL) and investigated the impact of varying degrees of succinylation and ε-PL addition on microstructure, environmental responsiveness and functional properties. Molecular docking illustrated that the most favorable binding conformation was that ε-PL binds to OVA groove, which was contributed by the multi­hydrogen bonding and hydrophobic interactions. Transmission electron microscopy observed that SOVA/ε-PL had a compact spherical structure with 100 nm. High-degree succinylation reduced complex sensitivity to heat, ionic strength, and pH changes. ε-PL improved the gel strength and antibacterial properties of SOVA. The study suggests possible uses of SOVA/ε-PL complex as multifunctional protein complex systems in the field of food additives.

Effectiveness and safety of Moluodan in the treatment of precancerous lesions of gastric cancer: A randomized clinical trial.

OBJECTIVE: To investigate the clinical potential and safety of Moluodan to reverse gastric precancerous lesions. METHODS: Patients aged 18-70 years diagnosed with moderate-to-severe atrophy and/or moderate-to-severe intestinal metaplasia, with or without low-grade dysplasia, and negative for Helicobacter pylori were recruited in this randomized, double-blind, parallel-controlled trial. The primary outcome was the improvement of global histological diagnosis at 1-year follow-up endoscopy using the operative link for gastritis assessment, the operative link for gastric intestinal metaplasia assessment, and the disappearance rate of dysplasia. RESULTS: Between November 3, 2017 and January 27, 2021, 166 subjects were randomly assigned to the Moluodan group, 168 to the folic acid group, 84 to the combination group, and 84 to the high-dose Moluodan group. The improvement in global histological diagnosis was achieved in 60 (39.5%) subjects receiving Moluodan, 59 (37.8%) receiving folic acid, 26 (32.1%) receiving the combined drugs, and 36 (47.4%) receiving high-dose Moluodan. Moluodan was non-inferior to folic acid (95% confidence interval: -9.2 to 12.5; P = 0.02). High-dose Moluodan had a trend for better protective efficacy, though there was no statistical significance. The disappearance rate of dysplasia was 82.8% in the Moluodan group, which was superior to folic acid (53.9%; P = 0.006). No drug-related serious adverse events were observed. CONCLUSIONS: One pack of Moluodan three times daily for 1 year was safe and effective in reversing gastric precancerous lesions, especially dysplasia. Doubling its dose showed a better efficacy trend.

Degradation and toxicity change of 4-chlorophenol in aqueous solution during CGDE treatment.

This study focused on the degradation and toxicity change of 4-chlorophenol (4-CP) in aqueous solution by contact glow discharge electrolysis (CGDE) with and without Fe(2+). It was found that the addition of Fe(2+) increased the degradation rate of 4-CP and decreased the toxicity of the solution. After 90 min CGDE treatment, only 28.0% 4-CP was removed and EC50 increased from 33.8 to 63.1 mg/L. With 25.0 mg/L Fe(2+) in solution, the degradation rate of 4-CP reached 93.3% and EC50 changed from 35.9 to 93.9 mg/L after 90 min CGDE treatment.

SmDXS5, acting as a molecular valve, plays a key regulatory role in the primary and secondary metabolism of tanshinones in Salvia miltiorrhiza.

Red sage, the dry root and rhizome of the herbaceous plant Salvia miltiorrhiza Bunge, is widely used for treating various diseases. The low content of tanshinones (terpenoids) has always restricted development of the S. miltiorrhiza industry. Here, we found that SmDXS5, a rate-limiting enzyme-coding gene located at the intersection of primary and secondary metabolism, can effectively change the transcription level and secondary metabolome profile of hairy roots of S. miltiorrhiza, and significantly increase the content of tanshinones. Agrobacterium rhizogenes was used to infuse S. miltiorrhiza explants, and hairy roots of S. miltiorrhiza expressing the SmDXS5 gene were obtained successfully. We identified 39 differentially accumulated metabolites (DAMs) by metabolomics based on ultra-high performance liquid chromatography quadrupole exactive mass spectrometry and multivariate statistics. These DAMs might be key metabolites of SmDXS5 gene regulation. RNA sequencing was used to compare gene expression between the hairy roots of the SmDXS5 overexpressing group and the blank control (BC) group. Compared with the BC group, 18,646 differentially expressed genes were obtained: 8994 were upregulated and 9,652 downregulated. The combined transcriptome and metabolome analyses revealed that the mevalonate and methylerythritol phosphate pathways and synthase gene expression levels in the SmDXS5 overexpressing group were upregulated significantly, and the accumulation of tanshinone components was increased significantly, which promoted the process of glycolysis and promoted the transformation of carbohydrates to secondary metabolism. Moreover, the expression of SmPAL, the first rate-limiting enzyme gene of the phenylpropane pathway, decreased, reducing the accumulation of phenolic acid, another secondary metabolite. Therefore, SmDXS5 can be defined as a 'valve' gene, mainly responsible for regulating the distribution of primary and secondary metabolic flow of tanshinones in S. miltiorrhiza, and for other secondary metabolic pathways. The discovery of SmDXS5 and its molecular valve function in regulating primary and secondary metabolism will provide a basis for the industrial production of tanshinone components, and cultivation of high quality S. miltiorrhiza.

[Resveratrol improves coronary collateral circulation in pigs with experimental acute coronary occlusion].

OBJECTIVE: To evaluate the impact of resveratrol on coronary collateral circulation in pigs suffered from experimental acute coronary occlusion. METHODS: Eighteen healthy pigs were randomly divided into 3 groups: resveratrol group, nitroglycerin group and control group. Animal model of acute coronary occlusion was established through PTCA method, and the blood flow spectrum in the left circumflex artery (LCX) was detected using intracoronary Doppler ultrasound. RESULTS: The average peak velocity (APV) in infarction correlation artery (IRA) was significantly decreased immediately after coronary occlusion [(0.85 ± 0.25) cm/s vs. (24.83 ± 3.43) cm/s, P < 0.05]. The APV remained unchanged during 0, 30 and 60 minutes after the occlusion. Reversed or bidirectional blood flow was observed and the APV increased significantly [(9.22 ± 0.80) cm/s vs. (0.84 ± 0.21) cm/s, (8.93 ± 1.28) cm/s vs. (0.86 ± 0.26) cm/s respectively, P < 0.05] after the coronary injection of resveratrol (2 mg) or nitroglycerin (0.3 mg). There was no significant difference in peak APV between the resveratrol and nitroglycerin groups. The duration of increased APV was significantly longer in resveratrol group than that in nitroglycerin group [(58.83 ± 6.15) min vs. (21.80 ± 5.79) min, P < 0.05]. CONCLUSIONS: The collateral circulation after acute coronary occlusion was obviously insufficient in pigs. Resveratrol could significantly improve the blood flow in coronary collateral circulation after acute occlusion in this model.

Cortactin in Epithelial-Mesenchymal Transition.

Cortactin, a member of the actin-binding protein family, plays an important role in cell movement involving the cytoskeleton, as cell movement mediated by cortactin may induce the epithelial-mesenchymal transition. Cortactin participates in tumor proliferation, migration, and invasion and other related disease processes by binding to different proteins and participating in different pathways and mechanisms that induce the occurrence of these disease processes. Therefore, this article reviews the correlations between cortactin, the actin cytoskeleton, and the epithelial-mesenchymal transition and discusses its clinical importance in tumor therapy.

Negative regulation of quinone reductase 2 by resveratrol in cultured vascular smooth muscle cells.

1. Resveratrol, a polyphenol in red wine, has a cardioprotective effect. Resveratrol-targeting protein (RTP) has been purified using a resveratrol affinity column (RAC) and has been identified as quinone reductase type 2 (NQO2). We hypothesize that NQO2 is the target protein of resveratrol in vascular smooth muscle cells (VSMC) and that resveratrol inhibits proliferation of VSMC through its action on NQO2. In the present study, we investigated the correlation between NQO2 regulation and cell proliferation in VSMC in response to resveratrol treatment. 2. The RTP was purified using RAC and was detected with a NQO2 polyclonal antibody. The VSMC were incubated with resveratrol (1, 10 and 50 micromol/L) for 24, 48 and 72 h. Cell proliferation was detected by cell counting and bromodeoxyuridine (BrdU) assay. A lentiviral vector incorporating NQO2 short interference (si) RNA of short hairpin design was constructed and transduced into VSMC. Real-time quantitative polymerase chain reaction was used to measure NQO2 mRNA levels; NQO2 expression was determined by western blot analysis. 3. Using RAC, we extracted a 26 kDa protein from aortic smooth muscle, which was referred to as RTP-26. Proliferation of VSMC was inhibited by resveratrol in a concentration- and time-dependent manner. The mRNA and protein expression of NQO2 was also repressed by resveratrol in a concentration- and time-dependent manner. A similar pattern of inhibition was observed for cells treated with resveratrol (25 micromol/L) as for cells transduced with a lentiviral vector containing siRNA sequences against NQO2. 4. Collectively, these data indicate that the suppression of VSMC proliferation mediated by resveratrol correlates with NQO2 downregulation.

Antibacterial Constituents of Hainan Morinda citrifolia (Noni) Leaves.

Noni (Morinda citrifolia L.) is an edible and medicinal plant distributed in Hainan, China. The antibacterial activities of the extracts of water (WE), petroleum ether (PEE), ethyl acetate (EAE), chloroform (CE), and n-butanol (BE) were assayed by the disk diffusion method. The results showed that the extracts from Noni leaves possessed antibacterial effects against Bacillus subtilis, Escherichia coli, Proteus vulgaris, and Staphylococcus aureus. Among 5 different extracts, the BE produced the best antibacterial activity. The samples were first extracted by ethanol, and the primary compounds in the BE fraction of ethanol extract was further isolated and identified. Six phenolic compounds, including 5, 15-dimethylmorindol, ferulic acid, p-hydroxycinamic acid, methyl 4-hydroxybenzoate, methyl ferulate, and methyl 4-hydroxycinnamate, were identifiedby NMR. The results indicated that the phenolic compounds might significantly contribute to antibacterial activities of Noni leaves.

SIRT6 suppresses mitochondrial defects and cell death via the NF-κB pathway in myocardial hypoxia/reoxygenation induced injury.

The present study explored changes of the SIRT6/NF-κB pathway in myocardial hypoxia/reoxygenation induced injury and the effects on mitochondrial damage and myocardial damage by regulating SIRT6. SIRT6 expression decreased and NF-κB expression increased in H9c2 cells during hypoxic injury. Cell death and mitochondrial defects paralleled mPTP opening, and a decrease in ΔΨm occurred in hypoxic myocytes compared with normoxic control cells in annexin V and propidium iodide staining and TUNEL results. These effects were suppressed in cells overexpressing SIRT6, but reemerged in cells expressing the SIRT6 mutant. We also found that NF-κB p65 increased in both the cytoplasm and nuclei, which could be repressed by SIRT6 overexpression. The expression level of NF-κB was significantly and negatively correlated with the SIRT6 mRNA level. Our data demonstrated that SIRT6/NF-κB changed during hypoxic injury and SIRT6 overexpression averted mitochondrial defects through inhibition of NF-κB in hypoxic H9c2 cells. Activation of SIRT6 may be a potential method for hypoxia/reoxygenation injury therapy.

Effect of red wine and wine polyphenol resveratrol on endothelial function in hypercholesterolemic rabbits.

The effect of red wine and wine polyphenol resveratrol on endothelial function was investigated in experimental hypercholesterolemic rabbits. Endothelial function as measured by flow-mediated dilation (FMD) in the femoral artery was 19.28+/-2.81% in control animals fed a regular diet. In contrast, rabbits fed a high-cholesterol (1.5%) diet showed a reduced endothelial function, as revealed by a 25% reduction in the measured FMD. Intragastric feeding of resveratrol (3 mg/kg/day), red wine (4 ml/kg/day), dealcoholized red wine (4 ml/kg/day), for 12 weeks in hypercholesterolemic rabbits significantly mitigated the reduction in endothelial function, and resulted in FMD values of 14.52+/-0.60, 18.95+/-2.30, 17.58+/-1.43, and 18.80+/-3.94%, respectively. Measurement of plasma endothelin 1 (ET-1) and nitric oxide (NO) levels showed that feeding a high-cholesterol diet significantly increased plasma ET-1 levels (from 51.4+/-17.6 to 96.9+/-24.3 pg/ml), and decreased plasma NO concentration (from 104.6+/-18.5 to 67.7+/-16.1 pg/ml). With administration of resveratrol, red wine, or dealcoholized red wine, plasma ET-1 levels statistically decreased, in parallel with a significant elevation in NO levels. These results provide in vivo evidence suggesting that resveratrol and red wine improve endothelial function, which may be one of the mechanisms by which this red wine polyphenol exerts its alcohol-independent cardioprotective effects.

Detection of micrometastasis of gastric carcinoma in peripheral blood circulation.

AIM: To detect the micrometastasis of gastric carcinoma in peripheral blood circulation using immunomagnetic beads sorting technique and RT-PCR technique, and to discuss its significance and the difference between the two methods. METHODS: Density gradient centrifugation was used to isolate mononuclear cells from peripheral blood, immunomagnetic beads sorting technique and RT-PCR technique were used to detect the disseminated carcinoma cells. HE, immunocytochemical and immunofluorescence staining were also used to identify the characteristics of the cells separated with immunomagnetic beads sorting technique. RESULTS: Cells expressing cytokeratin were separated and enriched from the peripheral blood specimens of patients suffering from gastric carcinoma or chronic gastritis. After HE staining, two kinds of cells with little cytoplasm were found. Majority of these cells had small and round nuclei, even chromatins and the thickness of nuclear membrane was normal. Immunohistochemical staining indicated that there were CD34 and CD45 expression on the cell membrane of this kind of cells and these cells also showed expressed human telomerase reverse transcriptase by immunofluorescence staining, but the expression of carcinoembryonic antigen was absent. So, these cells might hematopoiesis precursors. Another kind of cells had larger and abnormal nuclei with thicker nuclear membranes. Massed chromatins and poly-nucleoli were found in the nuclei. These cells expressed human telomerase reverse transcriptase and carcinoembryonic antigen, but CD34 and CD45 were not found on the cell membrane. So, these cells were considered as gastric carcinoma cells escaping from the original focuses and existing in the peripheral blood circulation. Carcinoma cells were found in 25 of 60(41.7%) specimens of peripheral blood from patients with gastric carcinoma, while there were no such cells separated from the blood specimens of chronic gastritis patients. The difference of positive rates of disseminated carcinoma cells between two groups was markedly significant (P<0.005). The expressions of CK20 mRNA in peripheral blood specimens were examinated with RT-PCR. CK20 mRNA was detected from 32 of 60(53.3%) peripheral blood specimens in the group of gastric carcinoma patients, while none of the specimens from patients suffering from chronic gastritis had CK20 mRNA. Significant difference was also found between two groups (P<0.005). Statistic analyses also showed that there was a significant difference between the positive rates of two methods in detecting the disseminated carcinoma cells from the peripheral blood circulation of gastric carcinoma patients (P<0.05). CONCLUSION: The results demonstrated that there were disseminated carcinoma cells in the peripheral blood circulation of some patients with gastric carcinoma. Disseminated carcinoma cells can be detected from the peripheral blood samples with immunomagnetic beads sorting technique and RT-PCR technique. The positive rate of RT-PCR technique is higher than that of immunomagnetic beads sorting technique in detecting micrometastasis.

[Therapeutic effects of octreotide on hepatofibrosis-induced with carbon tetrachloride in rats].

OBJECTIVES: To investigate the therapeutic effects and mechanism of octreotide on experimental hepatic fibrosis in rats. METHODS: Hepatofibrotic rats models were established with carbon tetrachloride. All the experimental rats were divided into four groups: normal control group, pre-and post-treatment model group, and octreotide-treated group in which the rats were injected subcutaneously with octreotide at the dose of 50ng/100g, twice daily, for thirty days. Serum levels of hyaluronic acid (HA), laminin (LN) and pro-collagen type III peptide (PCIII) were detected by radioimmunoassay. Hepatic fibrosis scoring grade was assessed through Van-Gieson staining and observed under light microscope. Protein expression levels of alpha-smooth muscle actin (alpha-SMA) and transforming growth factor beta1 (TGFbeta1) were determined with immunohistochemical staining method. Messenger RNA (mRNA) levels of collagen type I and PCIII were detected by reverse transcription polymerase chain reaction. RESULTS: Serum levels of HA (ng/L), LN (microg/L) and PCIII (ng/L) in pre- and post-treatment model groups were higher than those in normal control group (121.8+/-9.5 and 110.3+/-13.4 vs. 33.1+/-3.7, 85.7+/-12.1 and 78.2+/-7.9 vs. 37.1+/-6.3, 35.9+/-3.5 and 33.7+/-2.6 vs. 15.6+/-2.8, respectively, t > or = 9.41, P<0.05), and there was no significant difference between the two model groups. Concentrations of HA (55.8ng/L+/-7.2ng/L), LN (43.1microg/L+/-3.4microg/L) and PCIII (27.8ng/L+/-3.4ng/L) decreased significantly in octreotide-treated group, compared with those in model groups (t >or=2.76, P<0.05). With histological analysis, fibrotic scoring grade in octreotide-treated group was obviously ameliorated, compared with that in model groups (chi2 > or = 3.97, P<0.05). Imaging analysis revealed that alpha-SMA and TGFbeta1 immunohistological staining areas were markedly shrinked in octreotide-treated group (t > or = 2.47, P < 0.05). In two model groups, PCIII and type I mRNA levels significantly up-regulated as compared with those in normal group (t > or = 9.27, P<0.001), and they were inhibited by octreotide markedly (t > or = 2.47, P<0.05). CONCLUSIONS: Octreotide can inhibit hepatic stellate cells transforming into myofibroblasts, down-regulate TGFbeta1, collagen type I and PCIII transcriptions, so that it has therapeutic effects on experimental hepatic fibrosis.

[The role of peroxisome proliferators-activated receptor gamma (PPARgamma) during activation of hepatic stellate cells].

OBJECTIVES: To observe the role of PPARgamma during the activation process of hepatic stellate cells (HSC). METHODS: By morphology and RT-PCR, we study the changes of expression of PPARgamma in culture-activated HSC or in vivo activated HSC induced by dimethylnitrosamine (DMN). RESULTS: In vitro, the expression level of PPARgamma in freshly isolated HSC (0.72+/-0.01) significantly reduced to 0.48+/-0.03 on the third day of culture (t = 19.8372, P<0.01), and reduced 70% on the seventh culture-day and could not be detected after the second passage. In vivo, HSC freshly isolated from normal control rats expressed PPARgamma (0.76+/-0.01). During the development of rat liver fibrosis induced by DMN, the expression level significantly reduced to 0.46+/-0.02 after the third injection of DMN (t = 29.5318, P<0.01), and reduced 66% on the end of first week and could not be detected on the end of second and third week. CONCLUSION: The expression of PPARgamma might play an important role on the maintenance of resting-form of HSC, and the reduction of expression of PPARgamma might be an early event during the activation process of HSC.

A meta-analysis of the risk of total cardiovascular events of isosmolar iodixanol compared with low-osmolar contrast media.

BACKGROUND: The iso-osmolar contrast agent iodixanol may be associated with a lower incidence of cardiac events than low-osmolar contrast media (LOCM), but previous trials have yielded mixed results. OBJECTIVE: To compare the risk of total cardiovascular events of the iso-osmolar contrast medium, iodixanol, to LOCM. METHODS: Medical literature databases were searched to identify comparisons between iodixanol and LOCM with cardiovascular events as a primary endpoint. A random-effects model was used to obtain pooled odds ratio (OR) for within-hospital and 30-day events. RESULTS: A total of 2 prospective cross-sectional studies and 11 randomized controlled trials (RCTs) (covering 6859 subjects) met our criteria. There was no significant difference in the incidence of within-hospital and 30-day cardiovascular events when iodixanol was compared with LOCM, with pooled OR of 0.72 (95%CI 0.49-1.06, p=0.09) and 1.19 (95%CI 0.70-2.02, p=0.53), respectively. Subgroup analysis showed no relative difference when iodixanol was compared with ioxaglate (OR=0.92, 95%CI 0.50-1.70, p=0.80) and iohexol (OR=0.75, 95%CI 0.48-1.17, p=0.21). However, a reduction in the within-hospital cardiovascular events was observed when iodixanol was compared with LOCM in the RCT subgroup (OR=0.65, 95%CI 0.44-0.96, p=0.03). Sensitivity analyses revealed that three studies had a strong impact on the association of within-hospital cardiovascular events between iodixanol and LOCM. Meta-regression analysis failed to account for heterogeneity. No publication bias was detected. CONCLUSIONS: This meta-analysis demonstrates that there is no conclusive evidence that iodixanol is superior to LOCM overall with regard to fewer cardiovascular events.

Meta-analysis of broad-spectrum antibiotic therapy in patients with active inflammatory bowel disease.

Patients with Crohn's disease (CD) or ulcerative colitis (UC) undergo various therapies, including antibiotic therapy. This meta-analysis of controlled clinical trials was conducted to evaluate whether the use of antibacterial therapy improves the clinical symptoms of inflammatory bowel disease (IBD). The Medline and Scopus databases were searched and a systematic review was performed. Randomized, controlled trials in which antibiotic therapy was compared with placebo were investigated. A total of 10 randomized, placebo-controlled clinical trials for CD were included in the meta-analysis. The pooling of the data from these trials yielded an odds ratio (OR) of 1.35 [95% confidence interval (CI), 1.16-1.58] for antibiotic therapy compared with placebo in patients with CD. Furthermore, nine randomized placebo-controlled clinical trials for UC matched our criteria and were included in the analysis. The pooling of the data from these trials yielded an OR of 2.17 (95% CI, 1.54-3.05) in favor of antibiotic therapy. These results suggest that antibiotics improve clinical outcomes in patients with IBD.

Rofecoxib augments anticancer effects by reversing intrinsic multidrug resistance gene expression in BGC-823 gastric cancer cells.

OBJECTIVE: To investigate combined chemotherapeutic effects of rofecoxib in combination with 5-fluorouracil (5-FU), cisplatin (DDP) and etoposide (VP-16) in vitro, and to explore the potential mechanisms in modulating multidrug resistance (MDR) expression. METHODS: The BGC-823 gastric cancer cell line was incubated for 48 h with 0.1 micromol/L rofecoxib, 5-FU, DDP and VP-16 (1 microg/mL, 10 microg/mL and 100 microg/mL) alone, and combined with rofecoxib, respectively. Methyl-thiazolyl-tetrazolium and the terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-yriphosphate nick-end labeling assays were performed to calculate inhibitory rates and apoptotic index. Middle effects principles (CI values) were used to determine the interaction between rofecoxib and chemotherapeutic agents. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis were employed to determine expression of MDR1, multidrug resistance-associated protein 1 (MRP1), glutathione S-tranferase-pi (GST-pi) mRNA and protein in gastric cancer cells administered by rofecoxib, respectively. RESULTS: Both anticancer drugs such as 5-FU, DDP and VP-16 and rofecoxib inhibited the cells' proliferation and induced apoptosis in a dose-dependent manner, and a more significant inhibition was achieved when the cells were co-treated with anticancer drugs and rofecoxib. There was a synergetic role when different concentrations of chemotherapeutic agents were combined with rofecoxib (all CI < 1, P < 0.01 or 0.05). RT-PCR analyses of MDR gene families in BGC-823 gastric cancer cells revealed a strong expression in MRP1 and GST-pi mRNA, but MDR1 mRNA was undetectable. After administration with different concentrations of rofecoxib (0.1, 1.0, 10 micromol/L), significant downregulation of MRP1 and GST-pi mRNA was observed (MRP1: from 0.984 +/- 0.093-0.513 +/- 0.098; GST-pi: from 1.078 +/- 0.201-0.472 +/- 0.084, P < 0.01 or 0.05). In addition, MRP1 and GST-pi protein expression induced by rofecoxib were also reduced (P < 0.01 or 0.05). CONCLUSION: Rofecoxib, a specific cyclooxygenase-2 inhibitor, plays a chemotherapeutic sensitizer role in various anticancer agents on the BGC-823 gastric cancer cell line, which could be partly explained by its ability to reverse the intrinsic MRP1 and GST-piin vitro.

[Effects of selective cyclooxygenase-2 inhibitor on proliferation and apoptosis of human bladder cancer cell line T24].

BACKGROUND & OBJECTIVE: Cyclooxygenase-2 (COX-2) is related closely to the tumorigenesis of bladder cancer, and COX-2 inhibitor has potential antitumor effect. This study was to investigate the effects of selective COX-2 inhibitors on the proliferation and apoptosis of human bladder cancer cell line T24. METHODS: The effects of selective COX-2 inhibitors SC-58125 and celecoxib, and nonselective COX inhibitor indomethacin on the proliferation of T24 cells were evaluated by MTT assay. Cell apoptosis was determined by flow cytometry (FCM), DNA ladder electrophoresis, and fluorescent microscopy with Hoechst33258 staining. The expression of apoptosis-related genes Bcl-2 and Bax were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Within concentrations of 12.5-200 micromol/L, SC-58125, celecoxib, and indomethacin could inhibit the proliferation of T24 cells to different extents. SC-58125 tended to be more effective than the other two. The 50% inhibition concentration (IC50) of SC-58125 was determined to be 25-50 micromol/L. The apoptosis of T24 cells was enhanced after exposure to SC-58125. When treated with 100 micromol/L SC-58125 for 6 and 12 h, the apoptosis rates of T24 cells were (7.95+/-1.88)% and (12.5+/-2.42)%, respectively, which were significantly higher than that of control cells (P<0.05). But the expression of Bcl-2 and Bax genes did not change. CONCLUSIONS: Selective COX-2 inhibitor could inhibit the proliferation and induce the apoptosis of T24 cells.

Effects of AT1 receptor antagonist, losartan, on rat hepatic fibrosis induced by CCl(4).

AIM:To investigate effect of losartan, an AT1 receptor antagonist, on hepatic fibrosis induced by CCl(4); and to determine whether or not AT1 receptors are expressed on hepatic stellate cells. METHODS AND RESULTS:Fifty male Sprague-Dawley rats, weighing (180 plus minus20)g, were randomized into five groups (control group, model group, and three losartan treated groups), in which all rats were given the subcutaneous injection of 40% CCl(4)(every 3 days for 6 weeks) except for rats of control group. Rats of losartan-treated groups were treated with losartan (20 mg/kg, 10 mg/kg, 5 mg/kg, daily gavage). After 6 weeks liver tissue and serum samples of all rats were examined. Serum hyaluronic acid (HA), procollagen type III (PC III) were detected by radioimmunoassays. van Giesion collagen staining was used to evaluate the extracellular matrix of rats with liver fibrosis. The expression of AT1 receptors, transforming growth factor-beta (TGF-beta), and alpha-smooth muscle actinalpha-SMA) in liver tissue were determined by immunohistochemical techniques. Compared with model group, serum ALT and AST of losartan-treated groups were significantly reduced (italic>t = 4.20,P < 0.01 and italic>t = 4.57,P < 0.01). Serum HA and PC III also had significant differences (italic>t = 3.53,P<0.01 and t=2.20, P<0.05). The degree of fibrosis was improved by losartan and correlated with the expressions of AT1 receptors, TGF-beta, and alpha-SMA in liver tissue.CONCLUSION:AT1 receptor antagonist, losartan, could limit the progression of the hepatic fibrosis induced by CCl(4). The mechanism may be related to the decrease in the expression of AT1 receptors and TGF-beta, ameliorating the injury of hepatocytes; activation of local renin-angiotensin system might relate to hepatic fibrosis; and during progression of fibrosis, activated hepatic stellate cells might express AT1 receptors.