Reversal of P-glycoprotein-mediated multidrug resistance in SGC7901/VCR cells by PPARgamma activation by troglitazone / 华中科技大学学报（医学）（英德文版）

Over-expression of P-glycoprotein (P-gp), an ATP-dependent drug efflux pump, represents one of the major mechanisms that contribute to multidrug resistance (MDR) in cancer cells. This study examined the effects of troglitazone, a ligand of peroxisome proliferator-activated receptor gamma (PPARgamma), on P-gp-mediated MDR in SGC7901/VCR cells (a vincristine-resistant human gastric cancer cell line). The expression of P-gp was detected by RT-PCR and Western blotting, respectively. The SGC7901/VCR cells were treated with 0.1 mg/L vincristine (VCR) alone or in combination with 1, 5, 10 mumol/L troglitazone for 24 h. PPARgamma was measured by electrophoretic mobility shift assay (EMSA). The intracellular concentration of Rhodamine123 (Rh123, a fluorescent P-gp substrate) was assayed to evaluate the activity of P-gp. The cell cycle and apoptosis were measured by flow cytometry. The results showed that the P-gp was increasingly expressed in SGC7901, BGC823 and SGC7901/VCR cells in turn, suggesting that MDR in the SGC7901/VCR cells was mediated by the increased expression of P-gp. In the SGC7901/VCR cells, the expression level of total PPARgamma was increased, however, the protein level and activity of PPARgamma in the nuclei of cells decreased significantly. Troglitazone elevated the PPARgamma activity in SGC7901/VCR cells in a dose-dependent manner. Troglitazone decreased the P-gp expression and markedly enhanced the accumulation of Rh123 in SGC7901/VCR cells in a dose-dependent manner. We also found that troglitazone significantly increased the percentage of SGC7901/VCR cells in the G(2)/M phase and decreased the cell percentage in G(1) and S phase in a dose-dependent manner. Troglitazone significantly increased the apoptotic rate of SGC7901/VCR cells treated by VCR or ADR in a dose-dependent manner. It was concluded that P-gp-overexpressed SGC7901/VCR cells have minor endogenous PPARgamma activity. Elevation of the PPARgamma activity by troglitazone can reverse P-gp-mediated MDR via down-regulating the expression and activity of P-gp in SGC7901/VCR cells. It was suggested that troglitazone can dramatically enhance the sensitivity of P-gp-mediated MDR cancer cells to chemotherapeutic agents.

The role of endothelial cell derived toll-like receptor 4 acute lung injury / 中华急诊医学杂志

Objective To investigate the role of toll-like receptor 4 (TLR4) of endothelium or bone marrow derived cells in the acute lung injury (ALI) induced by lipopolyscccharide (LPS) in mice with reciprocal bone marrow transplantation. Method Chimeric mice were produced by reciprocal bone marrow transplantation between TLR4mut/mut and TLR4+/+ mice and divided into 4 groups: WT/WT (recipient/donor),WT/Mutant, Mutant/WT and Mutant/Mutant group. Six to eight weeks following transplantation, LPS was injected inot mice's tail vein in order to produce ALI model,and mice were sacrificed five hours later on.Samples of lung tissues were taken for the following analysis of wet/dry weight (W/D), lung permeabifity index (LPI), myeloperoxidase (MPO),levels of cytokines (TNF-α, IL-1β) and adhesion molecules (ICAM-1). Results Lung injury in the Mutant/Mutant mice was the mildest in the 4 groups. And lung injury in WT/Mutant mice was more serious than that in Mutant/WT mice. levels of MPO and ICAM-1 in WT/Mutant mice were much higher than those of Mutant/WT. In addition,the expression of ICAM-1 in WT/Mutant mice is comarable to that in WT/WT mice. Mutant/WT mice expressed higher levels of TNF-α and IL-1β than WT/Mutant mice. Conclusions Endothelial cell derived TLR4 plays ker-nel role in ALI induced by LPS via lung PMN recruitment,although bone marrow cells derived TLR4 are more im-portant for the release of cytokines.

Exogenous PTEN gene induces apoptosis in breast carcinoma cell line MDA468 / 华中科技大学学报（医学）（英德文版）

The effects and mechanisms of exogenous phosphatase and tensin homolog deleted from chromosome ten (PTEN) gene on phosphatase activity-dependent apoptosis of breast cancer cell line MDA468 were investigated. PTEN gene packaged with lipofectin was transferred into breast cancer cell line MDA468 and parental MDA468 cells served as controls. RT-PCR and Western blot were done to detect the expression of target genes. The expression of phosphospecific protein kinase B (PKB/Akt) and focal adhesion kinase (FAK) protein stimulated by epidermal growth factor (EGF) was also detected. Apoptosis was determined by flow cytometry with a double-staining method using FITC-conjugated annexin V and PI. MDA468 cells transfected with PTEN gene could express PTEN mRNA and protein. PTEN decreased the phosphorylation level of AKT protein and down-regulated FAK protein expression in MDA468 stimulated by EGF. The apoptosis rate was 21.68%. PTEN induced breast cancer apoptosis phosphatase activity-dependently. The mechanism is possibly related with phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB)/AKT signaling pathway. Those results may provide new clues on the gene therapy in breast cancer.

Exogenous PTEN Gene Induces Apoptosis in Breast Carcinoma Cell Line MDA468 / 华中科技大学学报（医学）（英德文版）

The effects and mechanisms of exogenous phosphatase and tensin homolog deleted from chromosome ten (PTEN) gene on phosphatase activity-dependent apoptosis of breast cancer cell line MDA468 were investigated. PTEN gene packaged with lipofectin was transferred into breast cancer cell line MDA468 and parental MDA468 cells served as controls. RT-PCR and Western blot were done to detect the expression of target genes. The expression of phosphospecific protein kinase B (PKB/Akt) and focal adhesion kinase (FAK) protein stimulated by epidermal growth factor (EGF) was also detected. Apoptosis was determined by flow cytometry with a double-staining method using FITC-conjugated annexin V and PI. MDA468 cells transfected with PTEN gene could express PTEN mRNA and protein. PTEN decreased the phosphorylation level of AKT protein and down-regulated FAK protein expression in MDA468 stimulated by EGF. The apoptosis rate was 21.68%. PTEN induced breast cancer apoptosis phosphatase activity-dependently. The mechanism is possibly relatedwith phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB)/AKT signaling pathway. Those results may provide new clues on the gene therapy in breast cancer.

Inhibition of RAW264.7 Macrophage Inflammatory Cytokines Release by Small Haparin RNAi Targeting TLR4 / 华中科技大学学报（医学）（英德文版）

In order to construct an expression vector carrying small hairpin (sh) RNA (shRNA) for toll-like receptor 4 mRNA and a reporter gene of enhanced green fluorescence protein (EGFP) and study the inhibition of cytokine release by RAW264.7 cell induced by lipopolysaccharide (LPS)stimulation through transfection and expression of shRNA targeting TLR4 gene via the RNAi mechanism, the reporter gene plasmid pEGFP-C1 (4.7 kb) and psiRNA-hHlneo (2979 bp) were used. The H1 promotor and double Bbs Ⅰ restrict endoenzyme site were cloned from plasmid psiRNA-hHlneo and reconstructed them into plasmid pEGFP-C1 in the Mlu Ⅰ restrict endoenzymic site, forming plasmid pEGFP-H1/siRNA, which contained Bbs site and reporter EGFP gene. Then an oligonuclear hairpin sequence targeting TLR4 gene was designed by internet tool and inserted into the plasmid pEGFP-H 1/siRNA forming plasmid pEGFP-H 1/TLR4-siRNA. After transfection of pEGFP-H1/TLR4-siRNA into RAW264.7 cells, tumor necrosis factor-alpha (TNF-α) release by the cells after stimulation by LPS was detected. The results showed that the constructed pEGFP-H1/TLR4-siRNA carrying hairpin RNA for TLR4 gene and reporter EGFP gene were proven to be right by restriction endonuclease analysis. The expression of EGFP gene was (50.37±8.23) %and after transfection of the plasmid pEGFP-H1/ TLR4-siRNA the level of TNF-α released by RAW264.7 cell was down regulated. It was concluded that shRNA targeting TLR4 gene could inhibit the TNF-α release by RAW264.7 cells evoked by LPS.

Construction and Expression of Human PTEN Tumor Suppressor Gene Recombinant Adenovirus Vector / 华中科技大学学报（医学）（英德文版）

The recombinant defective adenovirus vector carrying human PTEN tumor suppres sor gene was constructed by using AdEasy-1 system and its expression was detected in human breast cancer cell line MDA-MB-468. Human PTEN cDNA was cloned into adenovirus shuttle plasmid pAdTrack-CMV to generate a recombinant plasmid pAdTrack-CMV-PTEN, then homologeous recombination was carried out in the E. coli BJ5183 by contransforming linearized shuttle vector with adenovirus backbone plasmid pAdEasy-1. The newly recombined defective adenovirus vector AdPTEN containing green fluorescent protein (GFP) was packaged and propagated in 293 cells. After being purified by cesium chloride gradient centrifugation, the adenovirus was transfected into human breast cancer cell line MDA-MB-468 in vitro. The expression of PTEN mRNA and protein in infected human breast cancer cell line MDA-MB-468 was detected by RT-PCR and Western blot respectively. The recombinant defective adenovirus vector carrying PTEN gene was constructed successfully. The viral titer of purified adenovirus was 2.5×1010 pfu/mL, and about 70 % breast cancer cells were infected with Ad PTEN when multiplicity of infection (MOI) reached 50. The exogenous PTEN mRNA and protein were expressed in MDA-MB-468 cells infected with Ad-PTEN by RT-PCR and Western blot. The recombinant defective adenovirus vector of PTEN gene was constructed successfully using AdEasy-1 system rapidly, which paved a sound foundation for gene study of breast cancer.

Relationship between Carbachol Hyperstimulation-Induced Pancreatic Acinar Cellular Injury and Trypsinogen or NF-κB Activation in Rats in vitro / 华中科技大学学报（医学）（英德文版）

The relationship between M3 cholinergic receptor agonist (carbachol) hyperstimulationinduced pancreatic acinar cellular injury and trypsinogen activation or NF-κB activation in rats was studied in vitro. Rat pancreatic acinar cells were isolated, cultured and treated with carbachol, the active protease inhibitor (pefabloc), and NF-κB inhibitor (PDTC) in vitro. Intracellular trypsin activity was measured by using a fluorogenic substrate. The cellular injury was evaluated by measuring the leakage of LDH from pancreatic acinar cells. The results showed that as compared with control group, 10-3 mol/L carbachol induced a significant increase of the intracellular trypsin activity and the leakage of LDH from pancreatic acinar cells. Pretreatment with 2 mmol/L pefabloc could significantly decrease the activity of trypsin and the leakage of LDH from pancreatic acinar cells (P ＜0.01) following the treatment with a high concentration of carbachol (10-3 mol/L) in vitro. The addition of 10-2 mol/L PDTC didn't result in a significant decrease in the activity of trypsin and the leakage of LDH from pancreatic acinar cells treated with a high concentration of carbachol (10-3 mol/L) in vitro (P＞0.05). It was concluded that intracellular trypsinogen activation is likely involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro. NF-κB activation may not be involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro.

Inhibition of RAW264.7 macrophage inflammatory cytokines release by small haparin RNAi targeting TLR4 / 华中科技大学学报（医学）（英德文版）

In order to construct an expression vector carrying small hairpin (sh) RNA (shRNA) for toll-like receptor 4 mRNA and a reporter gene of enhanced green fluorescence protein (EGFP) and study the inhibition of cytokine release by RAW264.7 cell induced by lipopolysaccharide (LPS) stimulation through transfection and expression of shRNA targeting TLR4 gene via the RNAi mechanism, the reporter gene plasmid pEGFP-C1 (4.7 kb) and psiRNA-hHlneo (2979 bp) were used. The H1 promotor and double Bbs I restrict endoenzyme site were cloned from plasmid psiRNA-hH1neo and reconstructed them into plasmid pEGFP-C1 in the Mlu I restrict endoenzymic site, forming plasmid pEGFP-H1/siRNA, which contained Bbs site and reporter EGFP gene. Then an oligonuclear hairpin sequence targeting TLR4 gene was designed by internet tool and inserted into the plasmid pEGFP-H1/siRNA forming plasmid pEGFP-H1/TLR4-siRNA. After transfection of pEGFP-H1/TLR4-siRNA into RAW264.7 cells, tumor necrosis factor-alpha (TNF-alpha) release by the cells after stimulation by LPS was detected. The results showed that the constructed pEGFP-H1/TLR4-siRNA carrying hairpin RNA for TLR4 gene and reporter EGFP gene were proven to be right by restriction endonuclease analysis. The expression of EGFP gene was (50.37+/-8.23) % and after transfection of the plasmid pEGFP-H1/ TLR4-siRNA the level of TNF-alpha released by RAW264.7 cell was down regulated. It was concluded that shRNA targeting TLR4 gene could inhibit the TNF-alpha release by RAW264.7 cells evoked by LPS.

Construction and expression of human PTEN tumor suppressor gene recombinant adenovirus vector / 华中科技大学学报（医学）（英德文版）

The recombinant defective adenovirus vector carrying human PTEN tumor suppressor gene was constructed by using AdEasy-1 system and its expression was detected in human breast cancer cell line MDA-MB-468. Human PTEN cDNA was cloned into adenovirus shuttle plasmid pAdTrack-CMV to generate a recombinant plasmid pAdTrack-CMV-PTEN, then homologeous recombination was carried out in the E. coli BJ5183 by contransforming linearized shuttle vector with adenovirus backbone plasmid pAdEasy-1. The newly recombined defective adenovirus vector Ad-PTEN containing green fluorescent protein (GFP) was packaged and propagated in 293 cells. After being purified by cesium chloride gradient centrifugation, the adenovirus was transfected into human breast cancer cell line MDA-MB-468 in vitro. The expression of PTEN mRNA and protein in infected human breast cancer cell line MDA-MB-468 was detected by RT-PCR and Western blot respectively. The recombinant defective adenovirus vector carrying PTEN gene was constructed successfully. The viral titer of purified adenovirus was 2. 5 X 10(10) pfu/mL, and about 70% breast cancer cells were infected with Ad-PTEN when multiplicity of infection (MOI) reached 50. The exogenous PTEN mRNA and protein were expressed in MDA-MB-468 cells infected with Ad-PTEN by RT-PCR and Western blot. The recombinant defective adenovirus vector of PTEN gene was constructed successfully using AdEasy-1 system rapidly, which paved a sound foundation for gene study of breast cancer.

Relationship between carbachol hyperstimulation-induced pancreatic acinar cellular injury and trypsinogen or NF-kappaB activation in rats in vitro / 华中科技大学学报（医学）（英德文版）

The relationship between M3 cholinergic receptor agonist (carbachol) hyperstimulation-induced pancreatic acinar cellular injury and trypsinogen activation or NF-kappaB activation in rats was studied in vitro. Rat pancreatic acinar cells were isolated, cultured and treated with carbachol, the active protease inhibitor (pefabloc), and NF-kappaB inhibitor (PDTC) in vitro. Intracellular trypsin activity was measured by using a fluorogenic substrate. The cellular injury was evaluated by measuring the leakage of LDH from pancreatic acinar cells. The results showed that as compared with control group, 10(-3) mol/L carbachol induced a significant increase of the intracellular trypsin activity and the leakage of LDH from pancreatic acinar cells. Pretreatment with 2 mmol/L pefabloc could significantly decrease the activity of trypsin and the leakage of LDH from pancreatic acinar cells (P 0.05). It was concluded that intracellular trypsinogen activation is likely involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro. NF-kappaB activation may not be involved in pancreatic acinar cellular injury induced by carbachol hyperstimulation in vitro.

Effects of Toll-like receptor 4 in lipopolysaccharide induced acute lung injury / 中华急诊医学杂志

Objective To observe the difference of lung injury between toll-like receptor 4 (TLR4) mutant mice and wild type mice in a model of lipopolysaccharide (LPS) induced acute lung injury (ALI),discuss the role of TLR4 in ALI.Methods Different doses of LPS solution (1,5mg?kg~(-1)) were injected in vein tail to reproduce ALI model in both TLR4 mutant (TLR4~(-/-)) and wild type (WT,TLR4~+(/+)) mice.Lung tissues were collected for gross and micrographic histological injury analysis and for assessment of lung edema.Meanwhile,the levels of myeloperoxidase (MPO) in lung tissues in both strains were assessed to evaluate the extent of polymorphological neutrophils (PMN) infiltration.Results The gross and micrographic injury of lung was milder in TLR4 mutant mice than that in wild type mice.The extent of lung edema (W/D) was also reduced compared with wild type mice,especially in 5 mg?kg~(-1) group [(4.08?0.1)vs.(4.55+0.2),n=10,t=12.71,P＜0.01].With high dosage of LPS,the value of W/D in both mice strains was higher than that in sham operation group (P＜0.01).The extent of PMN infiltration in lung tissues in TLR4 mutant mice was reduced compared with wild type mice.But they were higher than sham operated mice (P＜0.01).Conclusion TLR4 May involve in the development of ALI,by sequestration of PMN into lung tissues.