AIM:To study the mechanism of 5-fluorouracil(5-FU)resistance in colon cancer cells and to develop strategies for overcoming such resistance by combination treatment.METHODS:We established and characterized a 5-FU resi...AIM:To study the mechanism of 5-fluorouracil(5-FU)resistance in colon cancer cells and to develop strategies for overcoming such resistance by combination treatment.METHODS:We established and characterized a 5-FU resistance(5-FU-R)cell line derived from continuous exposure(25μmol/L)to 5-FU for 20 wk in 5-FU sensitive HCT-116 cells.The proliferation and expression of different representative apoptosis and anti-apoptosis markers in 5-FU sensitive and 5-FU resistance cells were measured by the MTT assay and by Western blotting,respectively,after treatment with Resveratrol(Res)and/or 1,3-Bis(2-chloroethyl)-1-nitrosourea(BCNU).Apoptosis and cell cycle arrest was measured by 4',6'-diamidino-2-phenylindole hydrochloride staining and fluorescence-activated cell sorting analysis,respectively.The extent of DNA damage was measured by the Comet assay.We measured the visible changes in the DNA damage/repair cascade by Western blotting.RESULTS:The widely used chemotherapeutic agents BCNU and Res decreased the growth of 5-FU sensitive HCT-116 cells in a dose dependent manner.Combined application of BCNU and Res caused more apoptosis in5-FU sensitive cells in comparison to individual treatment.In addition,the combined application of BCNU and Res caused a significant decrease of major DNA base excision repair components in 5-FU sensitive cells.We established a 5-FU resistance cell line(5-FU-R)from 5-FU-sensitive HCT-116(mismatch repair deficient)cells that was not resistant to other chemotherapeutic agents(e.g.,BCNU,Res)except 5-FU.The 5-FU resistance of 5-FU-R cells was assessed by exposure to increasing concentrations of 5-FU followed by the MTT assay.There was no significant cell death noted in5-FU-R cells in comparison to 5-FU sensitive cells after5-FU treatment.This resistant cell line overexpressed anti-apoptotic[e.g.,AKT,nuclear factorκB,FLICE-like inhibitory protein),DNA repair(e.g.,DNA polymerase beta(POL-β),DNA polymerase eta(POLH),protein Flap endonuclease 1(FEN1),DNA damage-binding protein 2(DDB2)]and 5-FU-resistance proteins(thymidylate synthase)but under expressed pro-apoptotic proteins(e.g.,DAB2,CK1)in comparison to the parental cells.Increased genotoxicity and apoptosis were observed in resistant cells after combined application of BCNU and Res in comparison to untreated or parental cells.BCNU increased the sensitivity to Res of 5-FU resistant cells compared with parental cells.Fifty percent cell death were noted in parental cells when 18μmol/L of Res was associated with fixed concentration(20μmol/L)of BCNU,but a much lower concentration of Res(8μmol/L)was needed to achieve the same effect in 5-FU resistant cells.Interestingly,increased levels of adenomatous polyposis coli and decreased levels POL-β,POLH,FEN1 and DDB2 were noted after the same combined treatment in resistant cells.CONCLUSION:BCNU combined with Res exerts a synergistic effect that may prove useful for the treatment of colon cancer and to overcome drug resistance.展开更多
目的采用双侧海马注射Aβ25-35建模,观察反式白藜芦醇(TR)对模型大鼠海马诱导型一氧化氮合酶(i NOS)mRNA表达的影响。方法大鼠经莫式水迷宫(MWM)训练合格后,随机分为5组:假手术组,模型组,TR高、中、低剂量组。在大鼠海马内注射Aβ25-35...目的采用双侧海马注射Aβ25-35建模,观察反式白藜芦醇(TR)对模型大鼠海马诱导型一氧化氮合酶(i NOS)mRNA表达的影响。方法大鼠经莫式水迷宫(MWM)训练合格后,随机分为5组:假手术组,模型组,TR高、中、低剂量组。在大鼠海马内注射Aβ25-35制模,制模后用TR干预。采用逆转录实时定量荧光聚合酶链反应法(RT-PCR)检测5组大鼠海马i NOS mRNA表达。结果在MWM中模型组逃避潜伏期比TR高、中、低剂量组和假手术组明显延长,假手术组,模型组,TR高、中、低剂量组i NOS mRNA表达分别为0.23±0.90、1.23±0.91、0.34±0.18、0.48±0.12、0.87±0.49。原位末端标记(TUNEL)法检测假手术组,模型组,TR高、中、低剂量组间海马凋亡细胞百分比(术后第11天)分别为:(3.23±0.52)%、(21.32±5.02)%、(5.72±1.56)%、(7.21±1.22)%、(10.93±3.25)%;术后第17天分别为:(3.21±0.29)%、(16.31±4.27)%、(5.13±2.00)%、(7.12±1.78)%、(9.84±2.66)%。各组间凋亡细胞百分比差异有统计学意义(P<0.01)。结论 TR可减轻Aβ25-35诱导的大鼠记忆减退,其机制可能部分与下调海马i NOS mRNA表达从而减少海马细胞凋亡有关。展开更多
应用高效液相色谱(HPLC)及液相色谱 电喷雾离子化质谱(LC ESI MS)方法对反式白藜芦醇的长期热稳定性及光致顺反异构化反应进行了研究。色谱条件为:采用Hypersil ODS色谱柱分离,流动相为甲醇 0 05%三氟乙酸水溶液(体积比为60∶40)(用于H...应用高效液相色谱(HPLC)及液相色谱 电喷雾离子化质谱(LC ESI MS)方法对反式白藜芦醇的长期热稳定性及光致顺反异构化反应进行了研究。色谱条件为:采用Hypersil ODS色谱柱分离,流动相为甲醇 0 05%三氟乙酸水溶液(体积比为60∶40)(用于HPLC分析)及甲醇 5mmol/L甲酸铵水溶液(含0 1%甲酸)(体积比为60∶40)(用于LC ESI MS分析),检测波长300nm,进样量20μL(HPLC)或10μL(LC ESI MS);质谱检测中设定为负离子模式。在4～40℃条件下的热稳定性研究表明,反式白藜芦醇溶液在冷藏条件下避光保存600h后,浓度没有明显下降。通过测定254及365nm紫外光照条件下不同光照时间各个化合物浓度的变化,研究了反式白藜芦醇的异构化和其余几个副反应的机理。根据实验结果推测,白藜芦醇的顺反异构化是通过一个p 几何状态完成的,而另外几个副反应则是通过自由基历程完成的。展开更多
Objective To evaluate toxicity and safety of trans-resveratrol(t-RSV).Methods For assays of acute toxicity,genetic toxicity,and sub-chronic toxicity,Ames test,mice bone marrow erythrocyte micronucleus,and mice sperm a...Objective To evaluate toxicity and safety of trans-resveratrol(t-RSV).Methods For assays of acute toxicity,genetic toxicity,and sub-chronic toxicity,Ames test,mice bone marrow erythrocyte micronucleus,and mice sperm abnormality were performed.Results In the acute oral toxicity tests,maximum tolerable dose(15g/kg) in male and female Kunming mice showed no toxicological signs.For 90-d feeding of t-RSV at dosage range of 167–500 mg/(kg·d) in both male and female Sprague-Dawley rats,no noticeable toxicological effects were observed.Conclusion T-RSV has no acute toxicity and no genotoxicity,no harmful effects on the human body at the tested dosage range and thus resveratrol is safe for human consumption.展开更多
The efficient hydrolytic kinetic separation of trans/cis-（R）-（＋）-limonene oxides was realized in a 1 ： 1 mixed solvent of water and 1,4-dioxane without additional catalyst. Optically pure trans-（R）-（＋）-limo...The efficient hydrolytic kinetic separation of trans/cis-（R）-（＋）-limonene oxides was realized in a 1 ： 1 mixed solvent of water and 1,4-dioxane without additional catalyst. Optically pure trans-（R）-（＋）-limonene oxide was recovered in high yield （77%）.展开更多
基金Supported by Indian Council of Medical Research and Department of Biotechnology,Government of India
文摘AIM:To study the mechanism of 5-fluorouracil(5-FU)resistance in colon cancer cells and to develop strategies for overcoming such resistance by combination treatment.METHODS:We established and characterized a 5-FU resistance(5-FU-R)cell line derived from continuous exposure(25μmol/L)to 5-FU for 20 wk in 5-FU sensitive HCT-116 cells.The proliferation and expression of different representative apoptosis and anti-apoptosis markers in 5-FU sensitive and 5-FU resistance cells were measured by the MTT assay and by Western blotting,respectively,after treatment with Resveratrol(Res)and/or 1,3-Bis(2-chloroethyl)-1-nitrosourea(BCNU).Apoptosis and cell cycle arrest was measured by 4',6'-diamidino-2-phenylindole hydrochloride staining and fluorescence-activated cell sorting analysis,respectively.The extent of DNA damage was measured by the Comet assay.We measured the visible changes in the DNA damage/repair cascade by Western blotting.RESULTS:The widely used chemotherapeutic agents BCNU and Res decreased the growth of 5-FU sensitive HCT-116 cells in a dose dependent manner.Combined application of BCNU and Res caused more apoptosis in5-FU sensitive cells in comparison to individual treatment.In addition,the combined application of BCNU and Res caused a significant decrease of major DNA base excision repair components in 5-FU sensitive cells.We established a 5-FU resistance cell line(5-FU-R)from 5-FU-sensitive HCT-116(mismatch repair deficient)cells that was not resistant to other chemotherapeutic agents(e.g.,BCNU,Res)except 5-FU.The 5-FU resistance of 5-FU-R cells was assessed by exposure to increasing concentrations of 5-FU followed by the MTT assay.There was no significant cell death noted in5-FU-R cells in comparison to 5-FU sensitive cells after5-FU treatment.This resistant cell line overexpressed anti-apoptotic[e.g.,AKT,nuclear factorκB,FLICE-like inhibitory protein),DNA repair(e.g.,DNA polymerase beta(POL-β),DNA polymerase eta(POLH),protein Flap endonuclease 1(FEN1),DNA damage-binding protein 2(DDB2)]and 5-FU-resistance proteins(thymidylate synthase)but under expressed pro-apoptotic proteins(e.g.,DAB2,CK1)in comparison to the parental cells.Increased genotoxicity and apoptosis were observed in resistant cells after combined application of BCNU and Res in comparison to untreated or parental cells.BCNU increased the sensitivity to Res of 5-FU resistant cells compared with parental cells.Fifty percent cell death were noted in parental cells when 18μmol/L of Res was associated with fixed concentration(20μmol/L)of BCNU,but a much lower concentration of Res(8μmol/L)was needed to achieve the same effect in 5-FU resistant cells.Interestingly,increased levels of adenomatous polyposis coli and decreased levels POL-β,POLH,FEN1 and DDB2 were noted after the same combined treatment in resistant cells.CONCLUSION:BCNU combined with Res exerts a synergistic effect that may prove useful for the treatment of colon cancer and to overcome drug resistance.
文摘目的采用双侧海马注射Aβ25-35建模,观察反式白藜芦醇(TR)对模型大鼠海马诱导型一氧化氮合酶(i NOS)mRNA表达的影响。方法大鼠经莫式水迷宫(MWM)训练合格后,随机分为5组:假手术组,模型组,TR高、中、低剂量组。在大鼠海马内注射Aβ25-35制模,制模后用TR干预。采用逆转录实时定量荧光聚合酶链反应法(RT-PCR)检测5组大鼠海马i NOS mRNA表达。结果在MWM中模型组逃避潜伏期比TR高、中、低剂量组和假手术组明显延长,假手术组,模型组,TR高、中、低剂量组i NOS mRNA表达分别为0.23±0.90、1.23±0.91、0.34±0.18、0.48±0.12、0.87±0.49。原位末端标记(TUNEL)法检测假手术组,模型组,TR高、中、低剂量组间海马凋亡细胞百分比(术后第11天)分别为:(3.23±0.52)%、(21.32±5.02)%、(5.72±1.56)%、(7.21±1.22)%、(10.93±3.25)%;术后第17天分别为:(3.21±0.29)%、(16.31±4.27)%、(5.13±2.00)%、(7.12±1.78)%、(9.84±2.66)%。各组间凋亡细胞百分比差异有统计学意义(P<0.01)。结论 TR可减轻Aβ25-35诱导的大鼠记忆减退,其机制可能部分与下调海马i NOS mRNA表达从而减少海马细胞凋亡有关。
文摘应用高效液相色谱(HPLC)及液相色谱 电喷雾离子化质谱(LC ESI MS)方法对反式白藜芦醇的长期热稳定性及光致顺反异构化反应进行了研究。色谱条件为:采用Hypersil ODS色谱柱分离,流动相为甲醇 0 05%三氟乙酸水溶液(体积比为60∶40)(用于HPLC分析)及甲醇 5mmol/L甲酸铵水溶液(含0 1%甲酸)(体积比为60∶40)(用于LC ESI MS分析),检测波长300nm,进样量20μL(HPLC)或10μL(LC ESI MS);质谱检测中设定为负离子模式。在4～40℃条件下的热稳定性研究表明,反式白藜芦醇溶液在冷藏条件下避光保存600h后,浓度没有明显下降。通过测定254及365nm紫外光照条件下不同光照时间各个化合物浓度的变化,研究了反式白藜芦醇的异构化和其余几个副反应的机理。根据实验结果推测,白藜芦醇的顺反异构化是通过一个p 几何状态完成的,而另外几个副反应则是通过自由基历程完成的。
文摘Objective To evaluate toxicity and safety of trans-resveratrol(t-RSV).Methods For assays of acute toxicity,genetic toxicity,and sub-chronic toxicity,Ames test,mice bone marrow erythrocyte micronucleus,and mice sperm abnormality were performed.Results In the acute oral toxicity tests,maximum tolerable dose(15g/kg) in male and female Kunming mice showed no toxicological signs.For 90-d feeding of t-RSV at dosage range of 167–500 mg/(kg·d) in both male and female Sprague-Dawley rats,no noticeable toxicological effects were observed.Conclusion T-RSV has no acute toxicity and no genotoxicity,no harmful effects on the human body at the tested dosage range and thus resveratrol is safe for human consumption.
文摘The efficient hydrolytic kinetic separation of trans/cis-（R）-（＋）-limonene oxides was realized in a 1 ： 1 mixed solvent of water and 1,4-dioxane without additional catalyst. Optically pure trans-（R）-（＋）-limonene oxide was recovered in high yield （77%）.
