PHI逆转K562/A02细胞阿霉素耐药的机制

目的 探讨异硫氰酸苯乙酯(PHI)逆转K562/A102细胞株阿霉素(ADM)耐药的可能机制.方法 将耐ADM的人慢性粒细胞白血病K562/A02细胞株分别与不同浓度(0,5,10,20,30,40和50μM)的PHI共同孵育后,流式细胞术检测细胞周期、细胞内ADM浓度以及P-糖蛋白1(P-gp1)表达水平;逆转录聚合酶链反应(RT-PCR)检测PHI作用前后细胞内mdr1 mRNA的转录水平.结果 与对照组相比,联合作用48 h后,随着PHI浓度的增加G2期细胞逐渐减少,G1期细胞明显增多,而S期细胞无明显变化;K562/A02细胞内ADM平均荧光强度均高于对照组,K562/A02细胞mdrl mRNA表达下降和P-gp1表达下调(P＜0.05).结论 PHI逆转K562/A02细胞耐药机制可能与细胞G1期阻滞和P-gp1表达下调有关.     

姜黄素衍生物C15对白血病K562/A02细胞多药耐药的逆转作用

目的: 探讨姜黄素衍生物C15对人白血病K562/A02细胞多药耐药(multidrug resistance,MOR)的逆转作用及其作用机制。方法: 四甲基偶氮唑蓝(MTT)法检测细胞增殖;流式细胞术检测P-糖蛋白(P-gp)外排泵功能和细胞周期;免疫印迹法检测蛋白表达;P-gp-Glo^TM Assay System试剂盒检测P-gp ATP水解酶(ATPase)活性。结果: C15对K562/A02细胞半数抑制浓度(IC₅₀)大于50 μmol·L^-1。对K562/A02细胞无明显细胞毒的浓度为2.5,5.0,10.0 μmol·L^-1的C15逆转对K562/A02细胞对阿霉素(ADR)耐药的倍数分别为2.60,5.39,11.39,对长春新碱(vincristine, VCR)耐药的倍数分别为4.50,18.07,124.35,但是对非P-gp底物的化疗药物顺铂(cisplatin, CIS)和敏感细胞K562基本无逆转效果。2.5,5.0,10.0 μmol·L^-1 C15可以增加耐药细胞K562/A02胞内罗丹明123(Rh-123)的蓄积量分别为1.93,2.30,2.47倍。C15增加阿霉素(adriamycin, ADR)在K562/A02细胞中的蓄积水平,降低P-gp介导的Rh-123外排速率。2.5,10.0 μmol·L^-1 C15与300 nmol·L^-1VCR联合作用后,可使K562/A02细胞的G2/M期比例从9.36%增加到67.57%和69.38%。C15对P-gp蛋白和ATPase的活性没有抑制作用。结论: C15可能是P-gp的非衣物型抑制剂,且具有逆转K562/A02细胞MDR的作用,该作用与其抑制细胞P-gp的外排泵功能有关。     

鬼臼毒素衍生物LN-13诱导多药耐药细胞K562/A02凋亡及其机制

目的研究新型鬼臼毒素衍生物LN-13对多药耐药肿瘤细胞株K562/A02产生的凋亡作用及潜在机制。方法MTT法测定LN-13和阳性对照药VP-16抑制K562/A02细胞48 h后的生长情况及其IC50值,Hoechst 33342、PI双染色观察LN-13作用K562/A02细胞48 h后的形态变化,流式细胞术测定LN-13作用K562/A02细胞48 h的凋亡情况,RTPCR检测LN-13作用K562/A02细胞后Bcl-2、Bax、Caspase-3、mdr-1基因表达的影响,Western blot检测LN-13作用K562/A02细胞后P-gp的表达情况。结果 LN-13对K562/A02细胞生长有显著地抑制,IC50值3.32μmol·L~(-1),Hoechst 33342、PI双染色观察到LN-13作用后,K562/A02细胞发生明显凋亡形态。流式细胞术检测LN-13(2、4、8μmol·L~(-1))作用K562/A02细胞48 h后,出现剂量递增趋势的凋亡比例,分别达到15.0%、48.0%、68.96%。另外,随着LN-13剂量增加,K562/A02细胞的Bax、Caspase-3基因表达增加,mdr-1基因表达减少,另外也下调了P-gp表达,差异有统计学意义。结论 LN-13可诱导多药耐药肿瘤细胞K562/A02产生凋亡作用,其机制可能是通过抑制P-gp蛋白表达及凋亡相关基因表达。     

米哚妥林对P糖蛋白介导的多药耐药的逆转作用

目的评价新型激酶抑制剂类抗癌药米哚妥林逆转P糖蛋白(P-gp)介导肿瘤细胞多药耐药的作用,并探讨其可能机制。方法米哚妥林0.5,1和5μmol·L-1分别加入P-gp高表达的K562/A02和K562细胞中培养72 h,MTS法测定细胞存活率以检测细胞毒性。米哚妥林0.125,0.25和0.5μmol·L-1在K562/A02和K562细胞中与无毒剂量的P-gp底物多柔比星、紫杉醇或长春新碱共培养72 h,MTS法测定细胞存活率以检测逆转耐药作用。米哚妥林0.5和10μmol·L-1与P-gp荧光底物罗丹明123在耐药和敏感细胞中共同孵育30 min后用流式细胞术分析底物积累的变化。米哚妥林0.5μmol·L-1与耐药和敏感细胞共同孵育72 h,Western印迹法检测耐药蛋白和信号分子的表达,定量PCR检测MDR1基因表达的变化。将米哚妥林与P-gp膜蛋白共孵育,化学发光法测定剩余ATP的量,检测米哚妥林对P-gp ATP酶活性的影响。结果米哚妥林对P-gp高表达的K562/A02和亲本敏感细胞K562的细胞毒性无明显的差异,其中米哚妥林0.5μmol·L-1时2种细胞的存活率均达80%以上。米哚妥林0.5μmol·L-1在细胞水平即可有效逆转K562/A02对多种底物的耐药,而对敏感细胞无显著作用;米哚妥林能显著抑制P-gp的外排作用,增加底物Rh-123在K562/A02细胞中的积累,且效果好于阴性对照维拉帕米0.5和10μmol·L-1;米哚妥林对P-gp基因和蛋白表达以及AKT和ERK的表达与磷酸化水平均无影响;米哚妥林对P-gp的ATP酶活性具有明显的抑制作用。结论米哚妥林可抑制P-gp介导的药物外排并逆转P-gp介导的肿瘤多药耐药。     

桑皮苷A逆转K562/阿霉素耐药细胞化疗多药耐药的研究

目的 研究桑皮苷A对人白血病耐药细胞K562/阿霉素耐药细胞（K562/ADM）化疗耐药的影响。方法 实验分为溶媒（DMSO）对照组、阳性对照组(10μmol·L^-1维拉帕米处理48 h,再用5μg·mL^-1阿霉素孵育1 h或2μg·mL^-1罗丹明123孵育1.5 h)、阿霉素单用组(5μg·mL^-1阿霉素孵育1 h)、阿霉素合用桑皮苷A组(用5,10,20μmol·L^-1桑皮苷A处理48 h,再用5μg·mL^-1阿霉素孵育1 h)、罗丹明123合用桑皮苷A组(用5,10,20μmol·L^-1桑皮苷A处理48 h,再用2μg·mL^-1罗丹明123孵育1.5 h)。用噻唑蓝（MTT）实验初步确定桑皮苷A的逆转耐药作用;再以细胞内阿霉素蓄积实验,罗丹明123（Rho123）蓄积及外排实验进一步研究桑皮苷A的逆转耐药作用;分别用聚合酶链反应（PCR）和蛋白质印迹（Western blot）法检测桑皮苷A对K562/AD...     

孤啡肽逆转人白血病K562/ADM细胞耐药性的研究

目的 探讨孤啡肽对人白血病K562/ADM细胞对阿霉素耐药性的逆转作用.方法 测定孤啡肽的细胞毒性及其对K562/ADM细胞药物敏感性的影响,计算耐药逆转倍数.瑞士染色观察药物作用后K562/ADM细胞形态的改变;流式细胞仪检测阿霉素单用或与孤啡肽联用K562/ADM细胞凋亡百分率;DNA琼脂糖凝胶电泳观察孤啡肽与阿霉素联用后K562/ADM细胞内DNA的损伤程度.结果 非细胞毒性剂量的孤啡肽(10-7mol/L)作用于K562/ADM细胞时,对阿霉素耐药起到了部分逆转作用,使K562/ADM细胞的IC50由原来的(46.99±0.25)μg/ml降低至(23.11±0.29)μg/ml,其逆转倍数为2.03倍;孤啡肽(10-7mol/L)和阿霉素(20μg/ml)联合处理K562/ADM细胞48h,K562/ADM细胞呈典型的凋亡形态改变;细胞的凋亡率达到(18.73±3.90)%,明显高于两种药物在相同条件下单独作用的效果,P＜0.01;结论 孤啡肽能诱导K562/ADM细胞凋亡,从而能逆转K562/ADM细胞的耐药性,提高阿霉素的敏感性.     

半夏水提取液逆转多药耐药细胞系K562/A02耐药性的研究

目的观察非细胞毒性浓度半夏水提取液对耐阿霉素的人白血病细胞系K562/A02多药耐药性的逆转作用,并探讨其逆转机制.方法采用MTT法测定半夏水提取液的细胞毒性及其对K562/A02细胞敏感性的影响,用流式细胞仪检测非细胞毒性浓度的半夏水提取液处理后K562/A02细胞膜表面糖蛋白P170表达的变化.结果半夏水提取液对K562/A02细胞有一定的细胞毒作用,非细胞毒性浓度半夏水提取液可显著降低阿霉素对K562/A02细胞的IC50,显著降低细胞膜糖蛋白P170的表达.结论半夏水提取液可部分逆转多药耐药细胞系K562/A02细胞对阿霉素的耐药性.     

屈洛昔芬对K562耐阿霉素细胞株耐药性的逆转作用(英文)

目的:研究屈洛昔芬(DRO)对耐阿霉素(ADR)K562细胞株(K562/A02)多药耐药性(MDR)的逆转作用及逆转机制。方法:用DRO分别处理K562/A02和K562敏感株。MTT法观察DRO影响K562/A02对ADR化学敏感性的变化。DRO 10μmol/L处理K562/A02前后,通过RT-PCR和免疫细胞化学染色,分析MDR1、GSTπ基因表达的变化,采用流式细胞技术测定细胞内ADR浓度的变化。结果:DRO显著逆转K562/A02的MDR,在20、10和5μmol/L浓度时,对ADR的化学敏感性分别增加到14、13和4倍,逆转活性与维拉帕米相当。MDR1和GSTπ的mRNA和蛋白表达在DRO 10μmol/L处理后第2天开始下降,第5天明显降低。用20、10和5μmol/L浓度的DRO处理两株细胞,K562/A02细胞内ADR积累分别增加到2.9、2.3和1.5倍。但DRO不能明显增加K562细胞内的ADR的浓度。结论:DRO对K562/A02的MDR有较强的逆转活性,逆转强度与维拉帕米相当,其逆转机制有多种不同的途径。     

AGEs与其受体相互作用与K562及K562/A02细胞耐药性

目的观察晚期糖基化终末产物(AGEs)与其受体相互作用是否与K562及K562/A02细胞对阿霉素(ADM)耐药性相关。方法用流式细胞术检测K562及K562/A02细胞晚期糖基化终末产物受体(RAGE)及P-糖蛋白(P-gp)的表达和细胞凋亡率,CCK-8法观察AGEs对K562及K562/A02细胞增殖的影响,计算AGEs作用下两种细胞对ADM的半抑制浓度(IC50)值,用半定量RT-PCR检测mdr1mRNA相对表达水平。结果 K562与K562/A02细胞RAGE表达比较差异无统计学意义。AGEs可呈浓度和依赖性促进K562及K562/A02细胞增殖(P<0.05);AGEs作用K562及K562/A02细胞48h后,K562细胞mdr1mRNA及P-gp的表达均为阴性,K562/A02细胞mdr1mRNA及P-gp的表达与不加AGEs组比较差异均无统计学意义。结论 AGEs不能改变K562细胞对ADM的敏感性,同时亦不能改变K562/A02细胞对ADM的耐药性;AGEs与其受体相互作用与K562及K562/A02细胞耐药性无关。     

屈洛苷芬对K562耐阿霉素细胞株耐药性的逆转作用

目的：研究屈洛昔芬（DRO）对耐阿霉素（ADR）K562细胞株（K562／A02)多药耐药性（MDR）的逆转作用及逆转机制。方法：用DRO分别处理K562／A02和K562敏感株。MTT法观察DRO影响K562／A02对ADR化学敏感性的变化。DRO 10μmol/L处理K562／A02前后,通过RT－PCR和免疫细胞化学染色,分析MDR1、GSTπ基因表达的变化,采用流式细胞技术测定细胞内ADR浓度的变化。结果：DRO显著逆转K562／A02的MDR,在20,10和5μmol/L浓度时,对ADR的化学敏感性分别增加到14、13和4倍,逆转活性与维拉帕米相当。MDR1和GSTπ的mRNA和蛋白表达在DRO 10μmol/L处理后第2天开始下降,第5天明显降低。用20、10和5μmol/L浓度的DRO处理两株细胞,K562／A02细胞内ADR积累分别增加到2．9、2．3和1．5倍。但DRO不能明显增加K562细胞内的ADR的浓度。结论：DRO对K562／A02的MDR有较强的逆转活性,逆转强度与维拉帕米相当,其逆转机制有多种不同的途径。     

FAT对K562/A02细胞内GSH含量的影响

目的：探讨FAT对K562/A02细胞内谷胱甘肽（GSH）含量的影响,及其对白血病细胞代谢解毒系统介导的多药耐药（MDR）的逆转效果。方法：采用生化DTNB法测定细胞内谷胱甘肽水平。结果：K562/A02细胞内GSH含量（231.54μmol/106细胞）高于K562细胞内GSH含量（58.03μmol/106细胞）,为K562细胞的3.99倍;VRP（10μmol/L）、FAT（0.01、0.02、0.04、0.08mg/ml）作用48h后,K562/A02细胞内GSH含量从231.54μmol/106细胞分别减少到96.95μmol/106细胞、212.89μmol/106细胞、161.00μmol/106细胞、122.35μmol/106细胞。结论：细胞内GSH含量增加是K562/A02细胞产生MDR的机制之一;FAT降低K562/A02细胞内GSH的含量是FAT逆转MDR的机制之一。     

Modulation of P-glycoprotein activity by the substituted quinoxalinone compound QA3 in adriamycin-resistant K562/A02 cells

QA3 is a derivative of the substituted 1,3-dimethyl-1H-quinoxalin-2-ones, which are compounds that may selectively antagonize P-glycoprotein (P-gp) in multidrug resistance (MDR) cancer cells. Our previous work identified QA3 as a candidate compound for reversing MDR in cancer cells. In the present study, we found that QA3 significantly decreases the intracellular level of ATP, stimulates ATPase activity in membrane microsomes and decreases protein kinase C (PKC) activity. These results indicated that QA3 inhibits P-gp activity by blocking ATP hydrolysis and ATP regeneration. Furthermore, QA3 triggered and increased adriamycin-induced K562/A02 cell apoptosis as evidenced by Annexin V-FITC plus PI staining. Western blot analysis showed that the levels of cleaved caspase-9 and cleaved caspase-3 proteins increased, and similarly, the levels of procaspase-9 and procaspase-3 decreased after QA3 treatment. Consequently, poly ADP-ribose polymerase (PARP) activity increased as evidenced by the presence of the PARP cleavage product in K562/A02 cells. QA3 also enhanced the potency of adriamycin against K562/A02 cells as demonstrated by increased apoptosis and activation of caspase-9,-3 and PARP. These data support the observation that P-gp activity is inhibited after QA3 treatment. Moreover, these results indicate that QA3 is a novel MDR reversal agent with potent inhibitory action against P-gp MDR cancer cells.     

Substituted tetrahydroisoquinoline compound B3 inhibited P-glycoprotein-mediated multidrug resistance in-vitro and in-vivo

P-glycoprotein (P-gp) mediated multidrug resistance (MDR) is one of the main obstacles in tumour chemotherapy. A promising approach to reverse MDR is the combined use of nontoxic and potent P-gp inhibitor with conventional anticancer drugs. We have examined the potential of a newly synthesized tetrahydroisoquinoline derivative B3 as a MDR-reversing agent. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to examine the effect of B3 on the cytotoxicity in K562/A02 and MCF-7/ADM cells caused by doxorubicin (adriamycin). Accumulation and efflux of P-gp substrate rhodamine123 in K562/A02 and primary cultured rat brain microvessel endothelial cells (RBMECs) were measured to evaluate the inhibitory effect of B3 on P-gp. The K562/A02 xenograft model in nude mice was established to examine MDR-reversing efficacy of B3 in-vivo. The results indicated that co-administration of B3 resulted in an increase on chemosensitivity of K562/A02 and MCF-7/ADM cells to doxorubicin in a dose-dependent manner. Rhodamine123 accumulation in K562/A02 cells and RBMECs were significantly enhanced after the incubation with various concentrations of B3. Furthermore, B3 inhibited the efflux of rhodamine123 from RBMECs. Co-administration of B3 with doxorubicin significantly decreased weight and volume of tumour in nude mice. In conclusion, B3 is a novel and potent MDR reversal agent with the potential to be an adjunctive agent for tumour chemotherapy.     

苦瓜蛋白逆转K562／AO2细胞多药耐药性的研究

目的：研究非细胞毒性质量浓度苦瓜蛋白对耐阿霉素的人红白血病细胞株K562／AO2多药耐药性的逆转作用和促凋亡作用。方法：采用CCK-8法测定苦瓜蛋白的细胞毒性及其对K562／AO2细胞敏感性的影响,用流式细胞仪检测K562／AO2细胞经不同药物处理后细胞的凋亡情况。结果：苦瓜蛋白对K562／AO2细胞有一定的细胞毒作用,其非细胞毒性质量浓度为5μg／mL,非细胞毒性质量浓度苦瓜蛋白对K562／AO2细胞对阿霉素、长春新碱（VCR）和柔红霉素的耐药性都有部分逆转作用（分别为5．4、6．5和4．0倍）;5μg／mL苦瓜蛋白联合VCR诱导K562／AO2细胞凋亡,凋亡率为（19．38±1．06）％,而对照组为（1．64±0．27）％,单一苦瓜蛋白组为（3．79±0．82）％,单一VCR组为（9．83±0．98）％。结论：苦瓜蛋白能部分逆转人红白血病K562／AO2细胞对阿霉素、VCR和柔红霉素的耐药,一定剂量的苦瓜蛋白与VCR联合应用可增加肿瘤细胞凋亡率。     

木犀草素对K562细胞增殖与凋亡的影响及其机制

目的　探讨木犀草素对K562细胞增殖、凋亡的影响及其作用机制。方法　取对数生长期K562细胞分别加入0、10、25、50、100 μmol/L木犀草素培养24 h、48 h、72 h,采用CCK-8法检测细胞增殖抑制率;K562细胞分别加入0、25、50 μmol/L木犀草素培养48 h,采用流式细胞术检测细胞凋亡情况;K562细胞分别加入0、10、50、100 μmol/L木犀草素培养48 h,采用Westem blot检测B细胞淋巴瘤2蛋白（Bcl-2）、Bcl-2相关X蛋白（Bax）、多聚ADP核糖聚合酶（PARP）、Cleaved-PARP、半胱氨酸天冬氨酸蛋白水解酶3（Caspase3）、Cleaved-Caspase3、蛋白激酶B（AKT）、磷酸化AKT（p-AKT）、断裂点簇集区蛋白（BCR）、c-abl癌基因1（c-ABL）BCR-ABL蛋白表达。结果　CCK-8检测结果显示,随木犀草素浓度增加及作用时间的延长,K562细胞增殖抑制率均呈增长趋势（P＜0.05）。流式细胞仪检测结果显示,木犀草素0、25、50 μmol/L组K562细胞的凋亡率依次升高（分别为8.21%±0.55%、23.43%±1.50%和40.47%±2.97%）。Western blot结果显示,Bax、Cleaved-PARP、Cleaved-Caspase3表达水平随木犀草素浓度的增加而升高（P＜0.05）。木犀草素0、10、50 μmol/L组PARP蛋白表达水平依次升高（P＜0.05）,100 μmol/L组与50 μmol/L组差异无统计学意义。100 μmol/L组Caspase3、Bcl-2蛋白表达水平均低于其余组（P＜0.05）。50、100 μmol/L组p-AKT蛋白表达水平低于0、10 μmol/L组,100 μmol/L组低于50 μmol/L组。50 μmol/L组BCR-ABL融合蛋白表达水平高于0 μmol/L组,100 μmol/L组低于0、50 μmol/L组（P＜0.05）。结论　木犀草素可抑制K562细胞增殖,促进细胞凋亡,其机制可能与调控BCR-ABL蛋白表达及PI3K/AKT信号通路有关。     

抗多药耐药基因肽核酸与反义寡脱氧核苷酸增强K562／ADM细胞的敏感性和促进凋亡

AIM: To investigate the reversal effect and apoptosis enhancement of peptide nucleic acid (PNA) and antisenseoligodeoxyribonucleotide (ASODN) targeted to multidrug resistance gene (mdrl) on human multidrug resistantleukemia K562/ADM cells. METHODS: A 15-mer PNA and the same sequence of ASODN, complementary to the5' end of the AUG initiator codon-containing region of mdrl messenger RNA (MDR1-PNA, MDR1-ASODN), weredesigned and synthesized. Proliferation and sensitivity to adriamycin of K562/ADM cells treated with MDRI-PNAand MDR1-ASODN were analyzed with a MTT colorimetric assay. Apoptotic morphologies, P-glycoprotein (P-gp)expression, intracellular adriamycin accumulation, and cell cycle were measured. RESULTS: MDRI-PNA 1 to 10μmol/L and MDR1-ASODN 2 to 20 μmol/L alone had no inhibitory effects on the proliferation of K562/ADM cells,but significantly inhibited the growth of K562/ADM cells cultured in adriamycin-containing medium. After treatment with MDRI-PNA and MDRI-ASODN, intracellular adriamycin accumulation in K562/ADM cells increasedgreatly and P-gp synthesis was strikingly reduced. The resistance to adriamycin of the drug-resistant cells waspartly reversed and the cells were induced to apoptosis by adriamycin. The reversal efficacy of MDR1-PNA was3.1-fold higher than that of the same sequence of MDR-ASODN, but neither MDRI-PNA nor MDRI-ASODNcould completely block the mdrllP-gp expression. CONCLUSION: Sequence-special PNA targeted to mdr1 genemore effectively than the same sequence of MDR1-ASODN inhibited the expression of P-glycoprotein to overcomethe drug-resistance.     

咯萘啶逆转肿瘤多药耐药及其作用机制

目的:利用mdr1~ 的人白血病和乳腺癌多药耐药(MDR)细胞系K562/A02和MCF-7/ADR研究咯萘啶(pyronaridine,PND)对MDR的逆转作用及其机制.方法:采用MTT法、荧光分光光度法、荧光显微镜法、流式细胞仪法和RT-PCR法分别测定PND单独或与阿霉素(DOX)合用,对肿瘤细胞的生长抑制、诱导凋亡、细胞内药物浓度、mdr1基因表达的影响.结果:PND对敏感及耐药细胞均具有生长抑制作用,半数抑制剂量(IC_(50))根据不同细胞在5.10-18.66μmol/L之间;低毒剂量PND显著增强DOX对耐药细胞的细胞毒和诱导凋亡作用,且增加DOX在耐药细胞内的蓄积及减少罗丹明(Rh123)的外排.RT-PCR结果显示,PND对mdr1基因无下调作用.结论:PND可作为第三代P-糖蛋白(P-gp)抑制剂,通过下调P-gp药物外排泵功能而产生强大的逆转MDR效应.     

Triptolide modulates the sensitivity of K562/A02 cells to adriamycin by regulating miR-21 expression

Context: Multidrug-resistance is a serious obstacle encountered in leukemia treatment. Recent studies have shown microRNA-21 (miR-21) is overexpressed in several types of cancer and contributes to tumor resistance to chemotherapy. In our previous studies, we found triptolide (TPL) could enhance adriamycin-induced cytotoxicity and apoptosis in K562/A02 cells. Objective: In the present study, we investigated the mechanism of TPL on the sensitivity of K562/A02 cells to adriamycin. Materials and methods: Cell viability was assessed by methyl thiazolyl tetrazolium (MTT) assay. Expression of mature miR-21 was determined by SYBER green PCR. The miR-21 mimics and inhibitors were chemically synthesized and transfected into K562 cells or K562/A02 cells. PTEN protein levels was determined by western blots. PTEN promoter activity was measured by luciferase assays. Results: TPL (5 nmol/L) increased the sensitivity of K562/A02 to adriamycin. When adriamycin was combined with 5 nmol/L TPL, the mean apoptotic population of K562/A02 cells was increased from 4.3 to 18.5%, respectively. K562/A02 cells showed a significant reduction in miR-21 and phosphatase and tensin homolog deleted on chromosome ten (PTEN) expressions after TPL treatment. K562/A02 cells that were transfected with the miR-21 inhibitor had a significantly higher PTEN protein level than the control. K562 cells that were pre-treated with PTEN siRNA had increased survival rate compared to the control group. Discussion and conclusion: Our findings indicated that triptolide modulates the sensitivity of K562/A02 cells to adriamycin by regulating miR-21 expression. Triptolide inhibited miR-21 expression and enhanced PTEN levels in K562/A02 cells.     

2-氯脱氧腺苷对多药耐药白血病细胞的毒性实验研究

目的　探讨 2 -氯脱氧腺苷 (2 - CDA)对多药耐药白血病细胞 (K5 6 2 / A0 2 )的毒性作用。方法　细胞毒实验采用 MTT法 ,二药合用时细胞毒性作用采用 Chou- Talalay联合指数法分析。结果　 2 - CDA对 K5 6 2和K5 6 2 / A0 2的 IC50 分别为 (2 3.9± 2 .4) nmol/ L 和 (137.6± 12 .7) nm ol/ L(P<0 .0 5 )。 2 - CDA与柔红霉素 (DNR)联合应用时 ,对 K5 6 2细胞的联合指数分别是 1.0 ,对 K5 6 2 / A0 2细胞为 5 .1。结论　 2 - CDA对敏感白血病细胞具有明显细胞毒性作用。多药耐药白血病细胞对 2 - CDA不敏感。2 - CDA与 DNR联合应用时 ,对敏感白血病细胞的毒性为相加作用 ,对多药耐药白血病细胞的毒性为拮抗作用。