鼠尾草酸逆转K562/A02细胞多药耐药的机制研究

Objective To investigate the effects of carnosic acid(CA)on reversal of the muhidrug resistance(MDR)of human leukemia cell line K562/A02 and its mechanism.Methods MTT assay was used to determine the sensitivity of K562/A02 cells to adriamycin(ADM)pre-and post-treated with CA.Flow cytometry(FCM)and laser scanning confocal microscopy(LSCM)were used to measure intracellular fluorescence intensity and concentration of ADM respectively.The expression level of mdr1 was detected by semi-quantitative RT-PCR.P-glycoprotein(P-gp)expression was detected by FCM and Western blot.Resuits CA decreased,IC50 of ADM in K562/A02 cells from 16.31 μg/mL to 1.35μg/mL,being a 12.08fold decrease.The intracellular ADM fluorescence intensity of K562/A02 was increased from 17.05 t0 60.53after treated with CA(P<0.01).In living K562/A02 ceils,after treated with CA,the diffuse distribution of intracellular ADM was recovered in both nuclear and cytoplasm,and the concentration of intracellular ADM increased from 4.93μg/mL to 15.43μg/mL.RT-PCR assay showed that CA inhibited the expressions of mdr1 mRNA in K562/A02 cells(P<0.01).Mean fluorescence intensity of P-gp detected by FCM in CA-treated K562/A02 was decreased to 22.80 as compared with that in untreated K562/A02 cells(44.40,P<0.05).Conclusion CA can reverse the MDR of K562/A02 cells in vitro.The mechanism may be associated with down-regulation of mdr1 and inhibition of P-gp function.     

鼠尾草酸逆转K562/A02细胞多药耐药的机制研究

Objective To investigate the effects of carnosic acid(CA)on reversal of the muhidrug resistance(MDR)of human leukemia cell line K562/A02 and its mechanism.Methods MTT assay was used to determine the sensitivity of K562/A02 cells to adriamycin(ADM)pre-and post-treated with CA.Flow cytometry(FCM)and laser scanning confocal microscopy(LSCM)were used to measure intracellular fluorescence intensity and concentration of ADM respectively.The expression level of mdr1 was detected by semi-quantitative RT-PCR.P-glycoprotein(P-gp)expression was detected by FCM and Western blot.Resuits CA decreased,IC50 of ADM in K562/A02 cells from 16.31 μg/mL to 1.35μg/mL,being a 12.08fold decrease.The intracellular ADM fluorescence intensity of K562/A02 was increased from 17.05 t0 60.53after treated with CA(P<0.01).In living K562/A02 ceils,after treated with CA,the diffuse distribution of intracellular ADM was recovered in both nuclear and cytoplasm,and the concentration of intracellular ADM increased from 4.93μg/mL to 15.43μg/mL.RT-PCR assay showed that CA inhibited the expressions of mdr1 mRNA in K562/A02 cells(P<0.01).Mean fluorescence intensity of P-gp detected by FCM in CA-treated K562/A02 was decreased to 22.80 as compared with that in untreated K562/A02 cells(44.40,P<0.05).Conclusion CA can reverse the MDR of K562/A02 cells in vitro.The mechanism may be associated with down-regulation of mdr1 and inhibition of P-gp function.     

Effect of hypoxia inducible factor1-α inhibitor on reversal of multidrug resistance of K562/A02 cell line

Objective To study the reversal effect of the hypoxia inducible factor( HIF)-1α inhibitor,YC-1 ,on muitidrug resistance of K562/A02 cells and its mechanism. Methods Pre- and post- incubation with adriamycin (ADM) alone or in combination with YC-1 for 48 h, the proliferation capacity of K562/A02 and K562 cells were evaluated by MTT assay. The apoptosis rate of K562/A02 cells after treated with 0,5,10 and 20 μmol/L YC-1 alone or in combination with 1 mg/L ADM and intracellular ADM concentration were analyzed by flow cytometry(FCM). The mRNA levels of HIF-1α and mdr1 genes were determined by semi-quantitative RT-PCR. The protein levels of HIF-1α and P-glycoprotein (P-gp) were detected by Western blot. Results The IC50 of ADM for K562 and K562/A02 cells were ( 1.56 ± 0.07 ) mg/L and (42.98 ±3.15) mg/L respectively. The resistance of K562/A02 cells to ADM was 27.55- fold higher of that of K562cells. After treatment with YC-1 (5μmol/L, 10μmol/L, 20 μmol/L) for 48h, the resistances of K562/A02cells to ADM were 24.63-, 16.38- and 10.71- fold increase respectively. After treatment of K562/A02 cell with YC-1(0 μmol/L, 5 μmol/L, 10 μmol/L, 20 μmoL/L) alone or in combination with 1 mg/L ADM for 48 h, the apoptotic rates were ( 1.9 ± 0. 9) %, (4.9 ± 0. 9 ) %, ( 5.8 ± 1.1 ) %, and ( 9.3 ± 1.4 ) % and(2.3 ± 0.7 ) %, (8.2 ± 1.2) %, ( 19.0 ± 1.7 ) %, and ( 34.5 ± 2.4 ) % respectively. The intracellular flucorescence intensity of ADM were 232 ±33, 1300 ±219, 1961 ±240 and 3342 ±269 in the combined treatment group. With the increase in YC-1 concentration, the levels of mdr1 mRNA reduced, while that ofHIF-1α mRNA had no obvious change.Furthermore.the expressions of HIF-1α and P-gp were also decreased in K562/A02 cells.Conclusion YC-1,as a HIF-1 inhibitor,cau reverse multidrug resistance of K562/A02cells through down-regulating HIF-1α and p-gp.     

Effect of hypoxia inducible factor1-α inhibitor on reversal of multidrug resistance of K562/A02 cell line

Objective To study the reversal effect of the hypoxia inducible factor( HIF)-1α inhibitor,YC-1 ,on muitidrug resistance of K562/A02 cells and its mechanism. Methods Pre- and post- incubation with adriamycin (ADM) alone or in combination with YC-1 for 48 h, the proliferation capacity of K562/A02 and K562 cells were evaluated by MTT assay. The apoptosis rate of K562/A02 cells after treated with 0,5,10 and 20 μmol/L YC-1 alone or in combination with 1 mg/L ADM and intracellular ADM concentration were analyzed by flow cytometry(FCM). The mRNA levels of HIF-1α and mdr1 genes were determined by semi-quantitative RT-PCR. The protein levels of HIF-1α and P-glycoprotein (P-gp) were detected by Western blot. Results The IC50 of ADM for K562 and K562/A02 cells were ( 1.56 ± 0.07 ) mg/L and (42.98 ±3.15) mg/L respectively. The resistance of K562/A02 cells to ADM was 27.55- fold higher of that of K562cells. After treatment with YC-1 (5μmol/L, 10μmol/L, 20 μmol/L) for 48h, the resistances of K562/A02cells to ADM were 24.63-, 16.38- and 10.71- fold increase respectively. After treatment of K562/A02 cell with YC-1(0 μmol/L, 5 μmol/L, 10 μmol/L, 20 μmoL/L) alone or in combination with 1 mg/L ADM for 48 h, the apoptotic rates were ( 1.9 ± 0. 9) %, (4.9 ± 0. 9 ) %, ( 5.8 ± 1.1 ) %, and ( 9.3 ± 1.4 ) % and(2.3 ± 0.7 ) %, (8.2 ± 1.2) %, ( 19.0 ± 1.7 ) %, and ( 34.5 ± 2.4 ) % respectively. The intracellular flucorescence intensity of ADM were 232 ±33, 1300 ±219, 1961 ±240 and 3342 ±269 in the combined treatment group. With the increase in YC-1 concentration, the levels of mdr1 mRNA reduced, while that ofHIF-1α mRNA had no obvious change.Furthermore.the expressions of HIF-1α and P-gp were also decreased in K562/A02 cells.Conclusion YC-1,as a HIF-1 inhibitor,cau reverse multidrug resistance of K562/A02cells through down-regulating HIF-1α and p-gp.     

尼洛替尼联合5-溴汉防己甲素逆转K562/A02细胞耐药的研究

Objective To investigate the reversible effect of nilotinib,BrTet(5-bromotetrandrine)and their combination on multidrug resistance cell line K562/A02 and its mechanism.Methods Cell proliferation inhibition wag assessed by MTT method and cell apoptosis by flow cytometry(FCM).The expression of mdr1 mRNA was determined by RT-PCR,and the expression of P-gp was assessed by Western blot.Results After 48 h 5 nmol/L nilotinib or 0.5μmol/L BrTet treatment,IC50 of daunorubicin(DNR)to K562/A02 was 4.52 mg/L or 5.41 mg/L respectively;While on combinative treatment,its IC50 decreased to 2.98mg/L.Nilotinib or BrTer alone was not able to increase the DNR induced apoptosis rate of K562/A02 cell (P>0.05),while on combination treatment the apoptosis rate increased remarkably.After 48 h 5 nmol/Lnilotinib or 0.5 μmol/L BrTet treatment alone,gray-scale value of mdr1 mRNA was 0.48±0.04 or 0.64±0.01,respectively;while on combinative treatment the value decreased to 0.35±0.04.The P-gp expression level in K562/A02 cells was 0.61±0.05.or 0.52±0.02 when treated with 5 nmol/L nilotinib or 0.5 μmol/L BrTet alone for 48 h.but on combination treatment,the level decreased to 0.44±0.03.Conclusion Nilotinib or BrTet alone can partially reverse drug resistance of K562/A02 cells.The mechanism may be associated with the decrease of mdr1 mRNA and P-gp expression and increase of the apoptosis rate.And there is a synergistic action with these two agants in combination.     

尼洛替尼联合5-溴汉防己甲素逆转K562/A02细胞耐药的研究

Objective To investigate the reversible effect of nilotinib,BrTet(5-bromotetrandrine)and their combination on multidrug resistance cell line K562/A02 and its mechanism.Methods Cell proliferation inhibition wag assessed by MTT method and cell apoptosis by flow cytometry(FCM).The expression of mdr1 mRNA was determined by RT-PCR,and the expression of P-gp was assessed by Western blot.Results After 48 h 5 nmol/L nilotinib or 0.5μmol/L BrTet treatment,IC50 of daunorubicin(DNR)to K562/A02 was 4.52 mg/L or 5.41 mg/L respectively;While on combinative treatment,its IC50 decreased to 2.98mg/L.Nilotinib or BrTer alone was not able to increase the DNR induced apoptosis rate of K562/A02 cell (P>0.05),while on combination treatment the apoptosis rate increased remarkably.After 48 h 5 nmol/Lnilotinib or 0.5 μmol/L BrTet treatment alone,gray-scale value of mdr1 mRNA was 0.48±0.04 or 0.64±0.01,respectively;while on combinative treatment the value decreased to 0.35±0.04.The P-gp expression level in K562/A02 cells was 0.61±0.05.or 0.52±0.02 when treated with 5 nmol/L nilotinib or 0.5 μmol/L BrTet alone for 48 h.but on combination treatment,the level decreased to 0.44±0.03.Conclusion Nilotinib or BrTet alone can partially reverse drug resistance of K562/A02 cells.The mechanism may be associated with the decrease of mdr1 mRNA and P-gp expression and increase of the apoptosis rate.And there is a synergistic action with these two agants in combination.     

CIK逆转K562/ADR细胞多药耐药作用及其机制探讨

目的 研究细胞因子诱导的杀伤细胞(CIK)体外逆转阿霉素(ADR)耐药细胞株K562/ADR细胞多药耐药(MDR)的作用,并探讨其机制.方法 健康人外周血单个核细胞经细胞因子体外诱导获得CIK,检测其表型和培养上清液细胞因子含量.实验组为CIK作用于K562/ADR细胞48 h后加入ADR;对照1组为CIK作用于K562/ADR细胞48 h,对照2组为ADR作用K562/ADR细胞48 h.采用MTT法检测各组细胞杀伤活性,用流式细胞术检测细胞膜P-糖蛋白(P-gp)含量、细胞内ADR浓度等.结果 实验组对K562/ADR细胞杀伤活性高于对照1组(P＜0.05);且随效靶比增大,杀伤活性增大(P＜0.05);随所加入的ADR浓度增大,杀伤活性无明显变化(P＞0.05).实验组和对照1组的P-gp含量均下降(P＞0.05).实验组细胞内ADR浓度高于仅经ADR作用的对照组2组(P＜0.05),但细胞内ADR浓度与加入的ADR浓度无明显关系(P＞0.05).结论 通过CIK与ADR对K562/ADR细胞的先后作用,降低了其细胞内P-gp的表达,提高了K562/ADR细胞内ADR浓度,增强了ADR对耐药细胞的杀伤活性.为应用生物活性细胞逆转MDR提供理论依据.

Abstract：

Objective To investigate the effects and mechanism of cytokine-induced killer(CIK) cells in reversing multidrug resistance(MDR) and increasing intracellular concentration of adriamycin(ADR)in the K562/ADR cells. Methods Peripheral mononuclear cells (MNCs) were isolated from healthy donors and cultured with combined cytokines to generate CIK. The changes of cell phenotype and cytokines secretion of CIK were determined. K562/ADR cells were divided into three groups: ADR in combination CIK (group Ⅰ ), CIK alone (group Ⅱ ) and ADR alone (groupⅢ) . The viability and proliferation of K562/ADR cells were assayed by MTT assay, the intracellular concentration of ADR and the expression of P-glycoproteins (P-gp) in K562/ADR cells by FCM. Results The cytotoxicity of ADR in group Ⅰ was higher than that in group Ⅱ ( P ＜0.05 ). The cytotoxicity was increased with the E/T ratio increasing( P ＜0.05 ) but had no relation with the concentration of ADR in group Ⅰ (P＞0.05). The expression of P-gp was declined in group Ⅰ and group Ⅱ (P ＞0.05 ). The intracellular concentration of ADR in group Ⅰ was higher than that in group Ⅱ ( P ＜ 0.05 ), and had no relation with the ADR concentration ( P ＞ 0.05 ). Conclusion Pre-treatment with CIK can increase the cytotoxicity and the intracellular concentration of ADR and decrease the expression of P-gp in K562/ADR cells in the ADR and CIK combination group. Acute leukemia patients would be most likely to benefit from the combination of chemotherapy and CIK therapy.     

AMN107联合血红素加氧酶-1抑制剂诱导慢性髓系白血病细胞凋亡

运用AMN107(尼洛替尼)联合血红素加氧酶-1(HO-1)抑制剂锌原卟啉Ⅸ(ZnPPⅨ)作用于慢性髓系白血病(CML)细胞株K562细胞,研究其对CML细胞增殖的影响并探讨其作用机制。采用MTT法和台盼蓝染色法检测AMN107(10μmol/L)及ZnPPⅨ(10μmol/L)单独或联合处理不同时间的细胞增殖率;半定量RT-PCR法和Westernblot法检测空白对照组、ZnPPⅨ(10μmol/L)组、AMN107(10μmol/L)组、AMN107(10μmol/L)联合ZnPPⅨ(10μmol/L)组48 h时细胞HO-1的表达;AnnexinⅤ/PI双染色法检测处理48 h时各组细胞凋亡情况。结果表明:联合用药对细胞的抑制作用最强,且呈时间依赖性;联合用药组HO-1的表达量最低;空白对照组、ZnPPⅨ(10μmol/L)组、AMN107(10μmol/L)组、AMN107(10μmol/L)联合ZnPPⅨ(10μmol/L)组48 h时细胞凋亡率分别为(11.38±0.02)%、(17.44±0.08)%、(39.81±0.07)%和(56.46±0.19)%。结论:第二代酪氨酸激酶抑制剂AMN107具有诱导CML细胞凋亡的作用;抑制HO-1表达能加强AMN107对CML细胞的杀伤作用,这为临床进一步提高CML的疗效提供实验依据。     

去铁胺对白血病细胞K562/A02的影响及机制研究

本研究旨在探讨铁螯合剂去铁胺对人白血病耐阿霉素细胞K562/A02的影响及其作用机制。采用四甲基偶氮唑蓝法(MTT)检测不同浓度去铁胺作用48小时对K562/A02细胞增殖的抑制效应;流式细胞术检测去铁胺25、50、100和200μmol/L作用K562/A02细胞48小时后细胞的凋亡率;半定量RT-PCR检测各组细胞凋亡基因BAX、BCL-2以及多药耐药基因1(MDR1)mRNA表达变化;Western blot检测各组细胞P-糖蛋白(P-gp)表达变化。结果显示,随着去铁胺药物浓度的增加,细胞活力逐渐下降,凋亡率明显增加,呈剂量依赖性;随着去铁胺浓度增加,BAX表达水平逐渐升高,但MDR1 mRNA与P-gp的表达受到显著抑制。结论:去铁胺可以通过螯合细胞内铁,影响细胞DNA的合成;同时去铁胺可抑制阿霉素诱导的MDR1、P-gp表达,增加白血病细胞对化疗药物的敏感性,进而诱导凋亡。     

尼洛替尼联合5-溴汉防己甲素逆转K562/A02细胞耐药的研究

目的 探讨尼洛替尼、5-溴汉防己甲素(BrTet)及其联合应用对K562/A02细胞多药耐药的逆转作用及其机制.方法 尼洛替尼、BrTet单独或联合作用于K562/A02细胞,应用MTY法检测细胞增殖抑制率、流式细胞术检测细胞凋亡率、RT-PCR检测mdr1 mRNA的表达及Western blot分析P糖蛋白(P-gp)的表达的情况.结果 5 nmol/L尼洛替尼和0.5μmol/L BrTet单独使用48 h后,柔红霉素(DNR)对K562/A02细胞的IC50分别为4.52 mg/L和5.41 mg/L,联合使用后,DNR对K562/A02细胞的IC50降为2.98 mg/L.单用DNR、尼洛替尼和BrTet均不能增加K562/A02细胞凋亡率(P>0.05),DNR联合尼洛替尼和BrTet后细胞凋亡率明显增高.单用5 nmol/L尼洛替尼和0.5μmol/L BrTet 48 h后,K562/A02细胞mdr1 mRNA灰度值为0.48±0.04、0.64±0.01,两者合用K562/A02细胞mdr1 mRNA灰度值下降为0.35±0.04.单用5 nmol/L尼洛替尼作用48 h,P-gp的表达水平为0.61±0.05;单用0.5μmoL/L BrTet作用48 h,P-gp的表达水平为0.52 ±0.02;两者合用K562/A02细胞P-gp的表达水平降为0.44±0.03.结论 单独应用尼洛替尼和BrTet均可部分逆转K562/A02细胞的耐药,机制可能与降低mdr1 mRNA和P-gp的表达及增加K562/A02细胞凋亡有关,并且两药联用具有明显的协同作用.     

低氧诱导因子-1α抑制剂逆转K562/A02细胞多药耐药机制研究

目的 探讨低氧诱导因子抑制剂3-(5'-Hydroxymethyl-2'-furyl)-1-benzylindazoh(YC-1)对人白血病耐阿霉素细胞K562/A02的耐药逆转作用,并探讨逆转机制.方法 采用MTT法检测不同浓度YC-1和阿霉素(ADM)单独或联合使用48 h对K562/A02细胞和K562细胞增值抑制效应及耐药逆转效应;用流式细胞术检测0、5、10和20 μmol/L YC-1单独或联合1 mg/L阿霉素作用K562/A02细胞48 h后细胞凋亡率及联合应用后细胞内阿霉素浓度;半定量RT-PCR检测各组细胞低氧诱导因子-1α(HIF-1α)、mdr1基因mRNA表达变化;Western blot方法检测各组细胞HIF-1α、P-糖蛋白(P-gp)表达变化.结果 K562与K562/A02细胞对阿霉素的IC50值分别为(1.56±0.07)mg/L和(42.98±3.15)mg/L,耐药倍数为27.55倍.予5、10和20μmol/L YC-1作用后,K562/A02细胞对阿霉素的耐药倍数分别为24.63、16.38和10.71倍;0、5、10和20μmol/L YC-1单独或联合1 mg/L阿霉素处理K562/A02细胞48 h后,凋亡率分别为(1.9±0.9)%、(4.9±0.9)%、(5.8±1.1)%和(9.3±1.4)%与(2.3±0.7)%、(8.2±1.2)%、(19.0±1.7)%和(34.5 ±2.4)%.0、5、10和20 μmol/L YC1联合1 mg/L阿霉素处理K562/A02细胞48 h后细胞内阿霉素荧光强度分别为232±33、1300±219、1961±240和3342±269;随着YC-1浓度增加,HIF-1α mRNA表达没有明显差异,mdr1 mRNA逐渐下调,HIF-1±和P-gp表达均下调.结论 YC-1可以通过抑制HIF-1α蛋白表达,下调mdr1 mRNA水平和P-gp水平,增加细胞内阿霉素药物浓度,部分逆转K562/A02细胞耐药.     

藤黄酸对白血病K562/A02细胞的耐药逆转作用

本研究旨在探讨藤黄酸(gambogic acid,GA)对K562/A02细胞株的耐药逆转作用及其逆转机制。采用MTT法检测GA对K562和K562/A02细胞的增殖抑制作用及对K562/A02细胞阿霉素(ADM)耐药逆转效应;用流式细胞术检测GA联合ADM对K562及K562/A02细胞凋亡率的影响;DAPI荧光染色观察ADM联合GA作用后细胞的形态学改变;Western blot法检测K562及K562/A02细胞P-糖蛋白(P-gp)、存活蛋白(Survivin)基因的表达。结果表明:ADM作用48 h抑制K562和K562/A02细胞增殖的IC50值分别为(1.42±0.07)μg/ml和(28.42±1.40)μg/ml。GA≤0.0625μmol/L时,对K562及K562/A02细胞株无明显增殖抑制作用;0.0625μmol/L GA联合ADM作用于K562/A02细胞能增加其对ADM的敏感性,耐药逆转倍数为1.53。0.0625μmol/L GA联合ADM作用于K562/A02细胞48 h能提高细胞的凋亡率(P<0.05),下调Survivin及P-gp蛋白的表达(P<0.05)。结论:GA可以逆转K562/A02细胞的耐药性,增强耐药细胞对ADM的敏感性,其机制可能与提高K562/A02细胞凋亡、下调Survivin和P-gp蛋白的表达有关。     

HMGB1基因沉默对阿霉素诱导K562/A02细胞凋亡增敏作用的研究

目的 探讨高迁移率族蛋白1(HMGB1)基因沉默对白血病细胞耐药逆转的作用.方法 将HMGB1基因特异性干扰RNA(HMGB1 siRNA)导入K562/A02细胞中,通过Western blot和RTPCR方法检测HMGB1基因在转染前后的表达;WST8法检测阿霉素(ADM)对转染前后K562/A02细胞的半数抑制浓度(IC50);流式细胞术检测凋亡细胞百分率;Western blot检测线粒体促凋亡蛋白Smac/DIABLO的释放;采用caspase活性定量检测试剂盒分析caspase-3的活性.结果 ①与未经处理的K562/A02细胞组相比,转染HMGB1 siRNA的K562/A02细胞组HMGB1 mRNA和蛋白水平分别下降86%和71%;②HMGB1基因沉默使K562/A02细胞对ADM的药物敏感性增强,其IC50值从转染前的(4.83±0.08)μg/ml降低到(1.33±0.10)μg/ml,并在ADM浓度为1μg/ml和5μg/ml时,细胞凋亡百分率分别增加27%、32%;③HMGB1基因沉默可促进ADM所致Smac/DIABLO从线粒体向胞浆释放,并增加caspase-3的活性.结论 HMGB1基因沉默能明显增加K562/A02细胞对ADM的敏感性,逆转K562/A02细胞对ADM耐药.     

达沙替尼联合氟达拉滨对慢粒K562细胞的抑制作用研究

目的探讨达沙替尼联合氟达拉滨对慢粒K562细胞的抑制作用。方法选取慢粒K562细胞株进行研究,采用MTT法分别测定单独使用达沙替尼和氟达拉滨对慢粒K562细胞的抑制率,以及达沙替尼联合氟达拉滨对诱导K562细胞的抑制率。根据金氏方程计算2种药物联合的抑制率及凋亡情况的协同作用及治疗效果。金氏公式为:q=D1+2/(D1+D2-D1×D2),q表示2种药物联合作用的抑制率,D1和D2是单独用药作用的抑制率。当q值＞1.15表示为协同作用。经过不同浓度的达沙替尼(1,5,10 μg/L)和氟达拉滨(1,2.5,5 ng/L)单独处理后或联合处理(1 μg/L达沙替尼+1 ng/L氟达拉滨),(5 μg/L达沙替尼+2.5 ng/L氟达拉滨),(10 μg/L达沙替尼+5 ng/L氟达拉滨)24 h后,K562细胞的增殖受到明显的抑制,且达沙替尼和氟达拉滨具有协同效应。结果在相同的时间范围内,氟达拉滨和达沙替尼对K562细胞的抑制作用呈剂量依赖性,由于5 μg/L达沙替尼和2.5 ng/L氟达拉滨均能明显抑制K562细胞的增殖作用,因此在后续的实验过程中,选择该浓度作为细胞处理的终浓度。实验组和对照组的抑制率,差异均有统计学意义(t＝39.998,P<0.05)。达沙替尼联合氟达拉滨存在协同抑制慢粒K562细胞的作用(q＞1.15,P＜0.05);低浓度(1 μg/L)达沙替尼对慢粒K562细胞p-BCR/ABL水平的下调作用(31.8％±1.9％)明显优于高浓度(10 ng/L)氟达拉滨(15.2％±2.1％),联合药物更明显下调慢粒K562细胞p-BCR/ABL水平的表达(49.8％±1.1％),差异具有统计学意义(t＝6.754,P＜0.05)。达沙替尼联合氟达拉滨能改善白血病,提高凋亡细胞的数量。结论达沙替尼联合氟达拉滨作用于白血病慢粒K562细胞具有协同抑制作用,加速慢粒K562细胞的凋亡,具有重要的临床意义。     

Heme oxygenase-1 contributes to imatinib resistance by promoting autophagy in chronic myeloid leukemia through disrupting the mTOR signaling pathway

Heme oxygenase-1 (HO-1) has been verified to play an important role in imatinib (IM)-resistant chronic myeloid leukemia (CML) cells, but the mechanism remains unclear. In drug resistant CML cells, HO-1 expression abnormally increased and that of autophagy-related protein LC-3I/II also increased, so we herein postulated HO-1 was associated with autophagy. HO-1 expressions in IM-sensitive/resistant K562/K562R cells were regulated through lentiviral mediation. K562 cells transfected with HO-1 resisted IM and underwent obvious autophagy. After HO-1 expression was silenced in K562R cells, autophagy was inhibited and the sensitivity to IM was increased. The findings were related with the inhibitory effects of high HO-1 expression on the mTOR signaling pathway that negatively regulated autophagy. High HO-1 expression promoted autophagy by inhibiting mTOR. Similar to the cell line results, mononuclear cells of IM-resistant CML patients became significantly sensitive to IM when HO-1 expression was inhibited. In summary, HO-1, which is involved in the development of chemoresistance in leukemia cells by regulating autophagy, may be a novel target for improving leukemia therapy.     

二硫化二砷联合伊马替尼诱导慢性髓细胞白血病细胞凋亡机制探讨

目的：观察二硫化二砷（As2S2）和伊马替尼（STI571）联合用药对慢性髓细胞白血病（chronic myeloid leukemia,CML）细胞株的作用机制。方法：应用MTT增殖抑制实验、锥虫蓝拒染细胞计数、瑞氏染色细胞形态观察、Annexin V流式细胞仪检测凋亡细胞,RT-PCR检测bcr-abl mRNA的表达及蛋白印迹（Western blot）分析BCR-ABL的表达、细胞色素C（cytoC）和天冬氨酸特异性半胱氨酸蛋白酶（caspase）蛋白表达,观察As2S2、STI571联合或单独作用于STI571敏感细胞株K562S及耐药细胞株K562R的情况。结果：2.5μmol/LAs2S2＋0.25μmol/LSTI571或4μmol/LAs2S2＋8μmol/LSTI571联合用药对K562S或K562R有明显生长抑制协同作用和促凋亡协同作用;联合用药对K562S或K562R的bcr-abl mRNA的表达无明显影响,但K562S细胞BCR-ABL表达明显减少,K562R细胞BCR-ABL表达略有减少。且联合用药可促进凋亡诱导蛋白cytoC释放增多及caspase9和caspase3前体下调。结论：STI571与As2S2联合用药对K562S和K562R细胞有明显的生长抑制和促凋亡的协同作用,这一作用可能通过减少BCR-ABL表达及凋亡相关蛋白cytoC释放,并下调caspase9和caspase3前体的表达以促进细胞凋亡。     

COX-2抑制剂塞来昔布对FLT3-ITD突变阳性急性髓系白血病细胞体外增殖的影响及其机制研究

本研究旨在探讨塞来昔布（Celecoxib）对FLT3-ITD突变阳性急性髓系白血病细胞增殖、凋亡的影响及其机制.以不同浓度Celecoxib作用于MV4-11（FLT3-ITD＋）,K562（FLT3-ITD-）细胞,通过CCK-8法检测白血病细胞增殖抑制率,流式细胞术检测白血病细胞凋亡,Western blot法检测MEK,Mcl-1,pAkt蛋白的表达.结果表明,Celecoxib对白血病细胞MV4-11,K562细胞的增殖均有抑制作用,其对MV4-11细胞增殖抑制的IC50为（29.14±2.4）μmol/L,显著低于K562细胞的IC50浓度（39.84±1.0） μmol/L,两者差异有统计学意义（P＜0.05）;以20-80μmol/L浓度范围的Celecoxib作用于MV4-11细胞未观察到细胞发生明显凋亡,而同等浓度范围的Celecoxib作用于K562细胞可见凋亡率随药物浓度的增加而增高;Westem blot结果显示,IC50浓度的Celecoxib作用MV4-11细胞后可明显下调MEK,Mcl-1的表达,对pAKT的表达未见明显影响,而作用K562细胞后对Mcl-1的表达轻微下调,对MEK,pAkt未见明显影响.结论：Celecoxib能够显著抑制FLT3-ITD突变阳性AML细胞的增殖,其作用机制可能与抑制MEK/Mcl-1信号通路有关.