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??OBJECTIVE To investigate the effect of TiO₂ nanoparticles on overcoming cancer multidrug resistance(MDR). METHODS Doxorubicin-TiO₂ nanoparticles(DTN) were prepared, the K562/DOX cells were chosen as the model cells. And doxorubicin solution(F-DOX) and doxorubicin liposomes(DOX-L) were also prepared as the control. The MTT assay were measured, and the amount of doxorubicin in the K562/DOX cells at different time were determined by HPLC. The P-gp expression were detected by flow cytometry.RESULTS The MTT assay shows that IC₅₀ of group DTN were lower than that of group F-DOX. The uptake test shows that amount of doxorubicin in K562/DOX cells of group DTN was 1.23 times of group DOX-L when in 4 h, and the efflux test shows that amount of doxorubicin in K562/DOX cells was 1.18 times of group DOX-L. The flow cytometry result revealed that the effect of TiO₂ nanoparticles on overcoming MDR maybe through down-regulating the expression of P-gp in K562/DOX cells.CONCLUSION The TiO₂ nanoparticles are a new inorganic materials-based nanoparticles which promising approach to overcome MDR.     

Cariporide降低K562/DOX细胞株表达P-糖蛋白而逆转耐药的影响

 目的 探讨cariporide对耐药细胞株K562/DOX中P-糖蛋白（P-glycoprotein,P-gp）的影响,为抗白血病多药耐药（multidrug resistance, MDR）提供新方法。方法 应用cariporide对细胞进行酸化,应用激光共聚焦显微镜测定野生型细胞系K562及耐药细胞株K562/DOX细胞内pH值及细胞酸化对K562和K562/DOX细胞内阿霉素累积的影响。采用MTT法观察细胞酸化对细胞活力的影响。应用流式细胞术检测细胞酸化对K562/DOX细胞中P-gp功能的影响。采用实时定量RT-PCR技术检测MDR1基因在mRNA表达水平的变化。结果 Cariporide处理3 h对K562及K562/DOX细胞的活力影响较小。在K562/DOX细胞中,P-gp的外排药物能力随细胞内pH值的降低而减弱,cariporide明显增加了细胞对罗丹明123（rhodaminel 123,Rh123）和阿霉素的累积。细胞酸化还在mRNA水平抑制了K562/DOX细胞中P-gp的表达。结论 Cariporide能够抑制K562/DOX耐药细胞株中MDR1基因表达和P-gp的功能。     

小檗碱增强K562/DOX细胞对多柔比星敏感性的研究

 目的 探讨小檗碱增强耐药K562/DOX细胞对化疗药多柔比星的敏感性的作用。方法 四甲基偶氮唑蓝法检测小檗碱的细胞毒性及其对多柔比星抗肿瘤活性的增强作用;高内涵活细胞成像系统检测无毒剂量小檗碱作用后,多柔比星在K562/DOX细胞内的蓄积量;PI/Hoechst33342双染法检测小檗碱对多柔比星诱导的K562/DOX细胞凋亡的影响;罗丹明123蓄积实验检测小檗碱对P-糖蛋白外排功能的影响。结果 1 μmol·L^-1为小檗碱的无毒剂量,在此无毒剂量下,小檗碱使多柔比星对K562/DOX细胞的IC₅₀降低了1.5倍;1 μmol·L^-1小檗碱可使多柔比星在K562/DOX细胞内的蓄积量增加,增强多柔比星诱导的K562/DOX细胞凋亡, 增加K562/DOX细胞内罗丹明123的蓄积量,从而抑制P-糖蛋白的外排功能。结论 小檗碱可通过抑制K562/DOX细胞膜上P-糖蛋白的外排功能,增加K562/DOX细胞内多柔比星浓度,促进多柔比星对耐药细胞的诱导凋亡作用,逆转K562/DOX细胞的多药耐药性。     

六神丸逆转K562/DOX细胞阿霉素耐药的研究

目的:探讨六神丸对阿霉素耐药细胞株K562/DOX的耐药逆转作用。方法:MTT法检测单独应用阿霉素或阿霉素联合六神丸含药血清对K562/DOX细胞的生存率的影响;RT-PCR检测MDR1 mRNA表达;Western blot检测MDR1蛋白的表达。结果:阿霉素与六神丸含药血清联合作用:①细胞抑制率最高,最高值出现在72h(49.4%),且与对照组和单独应用阿霉素组相比有显著性差异;②48h细胞MDR1 mRNA表达明显降低,与单独应用阿霉素组相比有显著性差异;③48h细胞MDR1蛋白表达下降,且与对照组和单独应用阿霉素组相比有显著性差异。结论:六神丸可能通过下调MDR1表达水平进而逆转K562/DOX细胞对阿霉素的耐药性,增加肿瘤耐药细胞对化疗药物的敏感性。     

复方三根制剂对MDR细胞株K562/ADR和K562/VCR逆转作用的研究

目的：研究复方中药——复方三根制剂对多药耐药(MDR)细胞株的逆转作用。方法：应用MTT比色法，观察复方三根制剂对MDR细胞的逆转作用。运用流式细胞仪(FCM)，测定其对耐药细胞积聚和外排阿霉素(ADR)的影响，以及对耐药株细胞表达P=gp的影响。结果：复方三根制剂可部分恢复K562／ADR和K562／VCR耐药细胞对ADR的敏感性，而对VCR抗药性的逆转作用不明显；可增加K562／ADR和K562／VCR耐药细胞内ADR的积聚，并对外排ADR有一定影响；可部分下调p-gp的表达。结论：复方三根制剂可部分逆转耐药细胞的抗药性。     

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??OBJECTIVE To investigate the synergetic antibacterial effects of chitosan-modified polymyxin B liposomes(c-PMB-Lip) combined with ultrasound microbubbles on biofilm-producing Acinetobacter baumannii(AB) in vitro. METHODS c-PMB-Lip was prepared by an injection method. The minimum biofilm inhibition concentrations (MBIC) of the AB clinical isolates treated with different preparations of polymyxin B were determined. The antibacterial effects and the dose-effect relationship of chitosan-modified polymyxin B liposome group (c-PMB-Lip), ultrasound microbubble + polymyxin B group (USMB+PMB) and ultrasound microbubble + chitosan modified polymyxin B liposome group (USMB+c-PMB-Lip) were further revealed. RESULTS The MBIC of c-PMB-Lip was (8.0??2.0)??g??mL^-1 against biofilm-producing AB. USMB could enhance the inhibitory effects of polymyxin B on biofilm-producing AB. Moreover, USMB combined with lipid agents could obtain the most significant inhibitory effects and even completely remove the biofilm-producing AB. With the drug concentration increasing, the antibacterial effects of each group showed a dose-effect relationship within a certain range. Compared with the sterile blank group, USMB+c-PMB-Lip could completely remove the bacterial biofilm and achieve a maximum antibacterial effects at 2 ??g??mL^-1(P>0.05). CONCLUSION c-PMB-Lip combined with USMB have significant synergistic antibacterial effect on biofilm-producing AB.     

欧白芷素对K562/A02细胞阿霉素耐药的逆转作用(英文)

目的:探讨欧白芷素对耐药细胞株K562/A02中P-糖蛋白(P-glycoprotein,P-gp)的影响,为抗白血病多药耐药(multi-drug resistance,MDR)提供新方法。方法:采用MTT法观察阿霉素对细胞活力的影响。应用流式细胞术检测欧白芷素对K562和K562/A02细胞内阿霉素累积和细胞中P-gp功能的影响。采用实时定量RT-PCR技术检测MDR1基因在mRNA表达水平的变化。结果:欧白芷素对耐药细胞株K562/A02有显著的逆转耐药活性,最大逆转倍数为7.36。在K562/A02细胞中,欧白芷素明显增加阿霉素的累积,增加了罗丹明123(rhodaminel123,Rh123)蓄积,抑制了Rh123的外排,同时欧白芷素还在mRNA水平抑制了K562/A02细胞中P-gp的表达。结论:欧白芷素能够抑制K562/A02耐药细胞株中MDR1基因表达和P-gp的功能。     

K562/A细胞阿霉素转运动力学参数与逆转倍数的相关性

 目的研究K562/A细胞中阿霉素转运动力学参数与多药耐药逆转剂逆转能力之间的相关性。方法将维拉帕米等7种多药耐药逆转剂作用于耐药的肿瘤细胞,用高效液相色谱-荧光检测法检测细胞内外阿霉素浓度变化,建立K562/A细胞药物转运动力学模型;同时应用MTT法测定阿霉素的细胞毒性作用得到逆转倍数RI,进而研究RI与转运动力学参数R的相关性。结果RI与1/(R+1)之间具有良好的线性相关性,r²=0.9545。结论动力学参数可以用来筛选MDR逆转剂和评价逆转剂的逆转效果。     

盐酸小檗碱通过上调SIRT1的表达发挥对多柔比星心脏毒性的保护作用

目的 通过建立多柔比星(doxorubicin,DOX)大鼠急性心脏毒性模型和大鼠心肌细胞模型来验证盐酸小檗碱(Ber)对心脏毒性的保护作用并阐明相关的作用机制。方法 采用一次性腹腔注射DOX 20 mg·kg^-1致大鼠急性心脏损伤模型。大鼠随机分为5组:空白对照(Con)组,DOX组,DOX+Ber 5、10及20 mg·kg^-1组。Ber组均采用灌胃给药,每天1次,连续10 d。Con组及DOX组均给予等容积的蒸馏水,每日1次,连续10 d。于第8天除对照组外,其余各组均i.p. DOX 20 mg·kg^-1。10 d后观察大鼠生存率的变化并将大鼠麻醉,剖开动物的胸腔,取一部分心脏组织用于组织病理学检查,一部分制成匀浆备心肌组织中谷胱甘肽过氧化物酶(GSH-PX)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和丙二醛(MDA)的检测。另取急性分离的心肌细胞建立DOX心肌细胞氧化损伤模型,MTT法检测生存率;双氯荧光素(DCFH-DA)探针检测细胞活性氧(ROS)水平从而明确Ber对DOX所致心脏损伤是否有保护作用,并从氧化应激的角度对其机制进行探讨。在心肌组织及心肌细胞水平用Western blot检测沉默信息调节因子2同源蛋白1(SIRT1)蛋白表达。罗丹明123(Rh123)染色荧光显微镜照像测定线粒体膜电位(ΔΨ_m)、荧光染料rhod-2-AM(分子探针)测定线粒体Ca²⁺浓度([Ca²⁺]_m)以评价线粒体损伤。结果 Ber预处理能显著改善DOX引起的病理学改变并提高DOX大鼠心肌组织CAT、SOD和GSH-PX活性,降低MDA水平。Western blot结果显示Ber可上调心肌组织及心肌细胞中SIRT1蛋白表达,并且这种上调可被SIRT1的抑制剂EX527所取消。此外,Ber通过调节心肌细胞内ROS、ΔΨ_m和[Ca²⁺]_m水平,显著改善DOX诱导的心肌细胞氧化损伤和线粒体损伤。而这种保护作用可被EX527所取消。结论 Ber可减轻DOX引起的心肌氧化损伤,这种保护作用可能是通过上调SIRT1来实现的。     

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??OBJECTIVE To study the changes of VEGF signaling pathway in colon cancer patients and the effect of schisandrin B on SW620 cells and to analyze its possible mechanism. METHODS The protein expression of VEGFA, VEGF-R2, PI3K, Akt and p-Akt in human cancerous colon samples and adjacent normal samples were detected by Western blotting. The proliferation of SW620 cells was detected by CCK-8 method. The mRNA expression of VEGFA, VEGF-R2, PI3K and Akt in SW620 cells were detected by real-time PCR. The protein expression of VEGFA, VEGF-R2, PI3K, Akt and p-Akt in SW620 cells were detected by Western blotting. RESULTS The protein expression of VEGF-R2, PI3K, Akt and p-Akt in human cancerous colon samples was significantly higher than that in the adjacent normal samples(P<0.05). Compared with the control group, schisandrin B could significantly inhibit the proliferation and migration of SW620 cells, the mRNA expression of VEGFA, VEGF-R2, PI3K and Akt(P<0.01) and the protein expression of VEGFA, VEGF-R2, PI3K, Akt and p-Akt(P<0.05) in SW620 cells also were significantly decreased by schisandrin B. CONCLUSION The VEGF/PI3K/Akt signaling pathway is activated in colon cancer patients. Schisandrin B could inhibit the activity and migration of SW620 cells and inhibit the VEGF/PI3K/Akt signaling pathway.