热休克诱导人肝癌HepG2细胞HSP70和P-gp的表达及槲皮素对二者的抑制作用

背景与目的:研究提示热休克蛋白70(heatshockprotein70,HSP70)可抑制细胞凋亡,降低肿瘤热疗、化疗的疗效,但其与细胞化疗耐受性的内在关系尚不甚明确;P-糖蛋白(P-glycoprotein,P-gp)是一种耐药蛋白,在肿瘤耐药中起重要作用。本研究拟通过热休克诱导人肝癌HepG2细胞表达HSP70和P-gp,并观察槲皮素(quercetin,Qu)对二者表达的抑制效应。方法:恒温水浴法,42℃热休克HepG2细胞90min,分别采用免疫组化、流式细胞术检测热休克前及热休克后2h、4h、8h、12h、24h时HSP70和P-gp的表达情况;并于热休克前1h应用不同浓度槲皮素作用于HepG2细胞,观察其热休克后4h二者的表达。结果:(1)热休克诱导后,免疫组化显示细胞内HSP70表达增多,“核内迁移”;流式细胞术示HSP70阳性细胞数升高,4h达到最高(11.47%),较对照组(6.64%)升高近一倍(P<0.01),24h后回落到低值;P-gp阳性细胞数随HSP70升高后升高,12h达到最高值(96.31%),较对照组(33.95%)升高近两倍(P<0.01),24h后回落到低值。(2)热休克前应用槲皮素能有效抑制热休克诱导HSP70和P-gp的过量表达,以100～200μmol/L槲皮素作用明显(P<0.01),呈浓度依赖性。结论:热休克可诱导HepG2细胞HSP70和P-gp的过量表达,P-gp的表达可能与HSP70的表达有关;槲皮素可阻断热休克诱导HepG2细胞HSP7     

胰岛素抵抗的人肝癌细胞HepG2对多柔比星的敏感性

目的:观察胰岛素抵抗(insulin resistance, IR)的人肝癌细胞对抗癌药物多柔比星(adriamycin,ADM)的敏感性,并探讨其抗药机制.方法:采用5×10-6 moL/L胰岛素诱导(36和48 h)人肝癌细胞HepG2建立HepG2/IR细胞模型,并用盐酸吡格列酮(pioglitazone hydrochloride, PH)逆转HepG2/IR细胞的IR状态.MTT法检测HepG2/IR细胞对ADM的敏感性,FCM检测P糖蛋白(P-glycoprotein, P-gp)的表达水平,实时荧光定量RT-PCR检测多药耐药基因1(multiple drug resistance 1, MDR1)mRNA的表达.结果:HepG2/IR细胞对ADM的敏感性降低(P<0.05),MDR1 mRNA的表达量分别是HepG2细胞的1.62倍(胰岛素诱导36 h)和5.21倍(胰岛素诱导48 h),P-gp蛋白的阳性表达率分别提高了47.50%(胰岛素诱导36 h)和189.05%(胰岛素诱导48 h).PH可逆转HepG2/IR细胞MDR1/P-gp的表达增加以及逆转细胞对ADM的抗药性.结论:胰岛素诱导的人肝癌细胞HepG2/IR可通过增加MDR1/P-gp的表达,使细胞对抗癌药物产生抗药性.     

细胞培养氨基酸稳定同位素标记-质谱技术测定槲皮素对人肝癌细胞热休克蛋白表达的影响

目的 观察槲皮素对人肝癌细胞HepG2中热休克蛋白(HSP)表达的影响,为其抗肿瘤活性探寻可能的靶点.方法 经过连续传代,充分氘化HepG2细胞中的亮氨酸,并鉴定其标记率.采用四甲基偶氮唑蓝(MTT)法检测槲皮素对HepG2细胞生长的抑制活性及有效浓度.以50 μmol/L槲皮素作用氘化HepG2细胞48 h后,与正常HepG2细胞按1:1等量混合电泳,提肽后进行质谱鉴定,将获得的肽片段数据进行Mascot检索.设定严格的可信区间,得出槲皮素作用前后HSP的定量信息.采用逆转录聚合酶链反应(RT-PCR)验证槲皮素作用前后HepG2细胞中HSP90和HSP70的表达差异.结果 连续传代10次以上,HepG2细胞中氘化亮氨酸已达95％以上.MT法检测结果表明,槲皮素对HepG2细胞的IC50接近50 μmol/L,且随着时间和浓度的增加,其对HepG2细胞的生长抑制作用更加明显.细胞培养氨基酸稳定同位素标记-质谱技术(SILAC-MS)获得了槲皮素作用前后HepG2细胞中HSP90、HSP70、HSP60和HSP20的定量信息.相对正常HepG2细胞而言,所有鉴定的HSP在50 μmol/L槲皮素作用48h后均有较大程度的表达下调,其中HSP90表达下调至正常HepG2细胞的49.3％,HSP70表达下调至正常HepG2细胞的43.6％.RT-PCR的检测结果支持SILAC-MS的鉴定结果.结论 SILAC-MS成熟可靠,能全面定量分析外因作用前后HepG2细胞中全系列蛋白谱的变化.槲皮素对HepG2细胞中HSP表现出强烈的抑制能力,并且这种作用可能是其发挥抗肿瘤活性的途径之一.     

阿霉素热化疗对肝癌细胞增殖和凋亡的影响

目的：探讨阿霉素（ADM）加热化疗对人肝癌细胞HHCC及HepG2的增殖抑制和凋亡诱导作用。方法：以体外培养的人肝癌细胞HHCC和HepG2为研究对象,采用水浴加温法,观察单纯热疗,ADM化疗和热化疗对细胞增殖和凋亡的影响。MTT法确定阿霉素的工作浓度并检测细胞增殖的抑制作用,流式细胞术检测细胞凋亡。结果：热化疗组细胞的抑制率显著高于单纯热疗、单纯化疗组[HHCC细胞：（65.77±2.54）%vs（23.18±0.81）%、（38.35±2.23）%,P〈0.05。HepG2细胞：（74.25±1.53）%vs（1 7.1 2±2.8 6）%、（30.35±5.90）%,P〈0.05]。热化疗组细胞凋亡率显著高于单纯热疗组、单纯化疗组[HHCC细胞：（76.1±2.33）%vs（23.83±1.76）%、（45.57±2.81）%,P〈0.05。HepG2细胞：（76.9±2.79）%vs（19.7±7.63）%、（37.43±1.88）%,P〈0.05]。结论：加热能增强ADM对HHCC及HepG2的增殖抑制和诱导凋亡作用。     

热疗联合阿霉素和TRAIL对肝癌HepG2细胞凋亡的影响

目的:观察热疗（hyperthermia,HT）联合亚浓度阿霉素(adriamycin,ADM)和肿瘤坏死因子相关凋亡诱导配体（tumor necrosis factor related apoptosis inducing ligand,TRAIL）对肝癌HepG2细胞凋亡的影响,以确定联合方案是否具有协同作用。方法:采用CCK8法检测细胞的活性;Hoechst 33258染色实验检测细胞的形态变化;流式细胞仪检测细胞的凋亡;Western blot实验检测细胞内蛋白的表达水平。结果:HT联合ADM和TRAIL可明显抑制肝癌HepG2细胞的活性（P＜0.05）,促进细胞染色质浓缩、核碎裂。流式细胞检测结果表明,HT联合ADM和TRAIL可促进细胞的早期凋亡（P＜0.001）和晚期凋亡（P＜0.01）。Western blot实验进一步证明,HT联合ADM和TRAIL通过上调DR4、DR5、caspase-3和caspase-8蛋白的表达来促进细胞的凋亡（P＜0.05）。结论:HT联合ADM和TRAIL具有协同作用,可明显增加细胞凋亡的敏感性,促进肝癌细胞的凋亡。     

二甲基亚砜(DMSO)对人肝癌HepG2 细胞的诱导分化作用的实验研究

目的:探讨二甲基亚砜(DMSO)对人肝癌HepG2细胞的诱导分化作用。方法:体外培养人肝癌HepG2细胞,用DMSO干预细胞,MTT法检测药物对细胞增殖活力的影响;倒置相差显微镜和瑞氏-姬姆萨染色观察细胞形态学的变化;放射免疫法检测细胞甲胎蛋白（AFP）和清蛋白(ALB)的分泌量;酶促反应试剂盒检测细胞中γ-谷胺酰转肽酶（γ-GT）、碱性磷酸酶（ALP）的活性。结果:用DMSO处理HepG2细胞72h后,能显著抑制细胞的增殖（P＜0.05）;细胞的形态向成熟细胞分化;细胞AFP的分泌量和γ-GT酶的活性明显降低,ALP活性和ALB含量则显著升高（P＜0.05）。结论:DMSO具有诱导人肝癌HepG2向正常细胞分化的作用并抑制细胞增殖。     

miR-490-3p逆转MCF-7／ADM细胞对阿霉素耐药性的影响

【摘 要】目的 探讨miR-490-3p在阿霉素（ADM）耐药乳腺癌细胞系MCF-7／ADM中的表达情况及其对MCF-7／ADM细胞增殖、凋亡和ADM耐药的影响。方法 以野生型人乳腺癌细胞系MCF-7及其耐药型细胞系MCF-7／ADM为研究对象,用实时荧光定量PCR（qPCR）比较两种细胞中miR-490-3p的表达水平,将miR-490-3p的过表达载体pcDNA1（+）miR-490-3p瞬时转染至MCF-7／ADM细胞（过表达组）后采用qPCR检测转染效果,同时设pcDNA3.1（-）空载体对照组和空白对照组;采用MTT法测定转染pcDNA3.1（+）miR-490-3p对各组MCF-7/ADM细胞增殖能力的影响,测定ADM对MCF-7／ADM细胞的增殖抑制率并计算半数抑制浓度（IC50）及逆转倍数以评价对ADM敏感性的变化;分别于瞬时转染48 h后用Annexin V／FITC流式细胞术检测各组MCF-7/ADM细胞的凋亡率,Western blotting检测耐药蛋白P-糖蛋白（P-gp）,乳腺癌耐药蛋白（BCRP）和多药耐药相关蛋白1（MRP1）的表达,荧光分光光度计检测胞内ADM药物浓度,流式细胞仪检测P-gp活性。结果 MCF-7／ADM细胞中miR-490-3p的表达水平为0.24±0.07,显著低于野生型MCF-7细胞的1.02±0.03（P＜0.05）;过表达组瞬时转染24～96 h的miR-490-3p水平持续升高,均高于空载体对照组和空白对照组（P＜0.05）;过表达组的增殖抑制率随转染时间的延长而增加,转染24、48、72和96 h的增殖抑制率依次为（17.52±1.87）％、（31.67±2.79）％、（45.09±1.88）％和（61.82±2.52）％,高于空载体对照组（P＜0.05）;ADM对过表达组的IC50值为（11.27±2.34）μg／ml,低于空白对照组的和空载体对照组（P＜0.05）,且过表达组相对于空白对照组和空载体对照组的逆转倍数分别为3.35倍和3.39倍;与其余两组相比,过表达组的MCF-7/ADM细胞早、晚期凋亡率和细胞内药物浓度均升高,P-gp、BCRP和MRP1表达及P-gp活性均降低,差异均有统计学意义（P＜0.05）。结论 上调miR-490-3p可逆转MCF-7／ADM细胞对ADM的耐药性,可能通过降低耐药蛋白表达及抑制P-gp活性有关,且升高其水平可抑制细胞增殖并诱导凋亡。     

阿霉素热化疗对肝癌细胞及其耐药株凋亡的影响与机制

目的探讨阿霉素(ADM)加热化疗对人肝癌细胞BEL7402(以下简称BEL7402细胞)及其耐药株BEL7402/ADM细胞(以下简称BEL7402/ADM细胞)的凋亡诱导作用。方法以体外培养的人肝癌细胞BEL7402和BEL7402/ADM细胞为研究对象,采用水浴加温法,观察单纯热疗、单纯ADM化疗与热化疗对细胞凋亡的影响。用AnnexinV-FITC和PI双染色流式细胞仪检测细胞凋亡;采用流式细胞技术检测加热对BEL7402细胞和BEL7402/ADM细胞胞内ADM浓度和细胞膜上P糖蛋白(P-gp),多药耐药性相关蛋白(MRP)的影响。结果热化疗组细胞凋亡率(%)显著高于单纯热疗、单纯ADM化疗组的同种细胞[BEL7402细胞:(79.21±0.54)vs(16.67±1.03),(48.91±0.05),P均<0.05;BEL7402/ADM细胞:(75.42±0.16)vs(14.79±0.61),(23.78±0.04),P均<0.05]。热化疗组细胞内ADM浓度显著高于单纯化疗组的同种细胞(P<0.05)。热化疗组和单纯热疗组细胞膜上P-gp、MRP的表达率显著低于单纯化疗组的同种细胞(P<0.05)。结论加热可能通过抑制细胞膜上P-gp、MRP的表达,从而提高BEL7402细胞及BEL7402/ADM细胞对ADM诱导凋亡作用的敏感性。     

三氧化二砷联合热疗对大鼠肝脏移植瘤模型凋亡相关基因表达的影响

目的 研究三氧化二砷(arsenic trioxide,As₂O₃)联合热疗对大鼠肝脏移植瘤细胞的凋亡、热休克蛋白70(Heat shock protein 70,HSP70)、p53和增殖细胞核抗原(Proliferation cell nuclear antigen,PCNA)表达的影响,探讨其诱导肿瘤细胞凋亡的可能机制。方法 建立大鼠肝脏移植瘤模型,分别对荷瘤大鼠给予生理盐水、As₂O₃、热疗及As₂O₃联合热疗,观察肿瘤生长情况,用免疫组化法检测肿瘤细胞凋亡及肿瘤组织中HSP70、p53及PCNA的表达。结果 As₂O₃ 联合热疗的抗肿瘤作用最明显,坏死及凋亡细胞数量增加。对照组HSP70、p53及PCNA阳性细胞表达率分别为30.12%±3.60%,27.64%±4.90%和74.23%±6.35%,三氧化二砷联合热疗组HSP70、p53及PCNA阳性细胞表达率分别为87.4%1±5.70%,90.06%±6.42%和22.10%±6.17%。与对照组(仅给予As₂O₃或热疗处理)比较,经As₂O₃联合热疗处理后,HSP70、p53表达显著升高(P=0.000＜ 0.05),PCNA表达则显著降低(P=0.000 ＜0.05)。结论 As₂O₃与热疗联合应用治疗大鼠肝癌有明显的协同作用;As₂O₃联合热疗通过诱导HSP70及p53的表达和降低PCNA的表达抑制肝癌细胞增殖并促进细胞凋亡。     

槲皮素对乳腺癌MCF-7细胞热休克蛋白表达的影响

目的:探讨槲皮素对乳腺癌MCF-7细胞株热休克蛋白70(HSP70)、HSP27和HSP90的表达的影响。方法:对体外培养的乳腺癌MCF-7细胞,恒温42℃热处理2h,分别于4、8、12和24h后荧光定量PCR检测HSP70、HSP27和HSP90的基因表达变化并用蛋白质印迹检测蛋白表达量的变化。观察热处理前使用150μmol/L槲皮素对乳腺癌MCF-7细胞HSP70、HSP27和HSP90的基因表达变化、蛋白表达量的影响。结果:42℃热处理后乳腺癌MCF-7细胞HSP70、HSP27和HSP90表达在基因及蛋白水平上均有明显升高,4h达到高峰,8h后开始减少,24h接近正常值。槲皮素能抑制HSP70、HSP27表达,但导致HSP90表达水平先升高,4～8h表达仍处于高峰值,8h后才开始下降。结论:HSP70、HSP27和HSP90在MCF-7细胞内的基因和蛋白表达均在热处理后迅速升高,在热处理前使用槲皮素可以抑制HSP70、HSP27的表达,HSP90水平升高及下降延迟。     

The synergistic reversal effect of multidrug resistance by quercetin and hyperthermia in doxorubicin-resistant human myelogenous leukemia cells

PURPOSE: This study aimed to evaluate the multidrug resistance (MDR) reversal activity of quercetin (Que) in combination with hyperthermia (HT) in human myelogenous leukemia cells K562/A. METHODS: The cytotoxicity of Que alone and the effect of Que and HT to doxorubicin (Dox) cytotoxicity were determined using MTT assay in K562 and K562/A cells. K562/A cells was heated with or without Que pretreatment, and the protein and mRNA levels of heat shock protein 70 (HSP70) and P-glycoprotein (P-gp) were determined by flow cytometry (FCM) and RT-PCR, respectively. Intracellular accumulation of Dox, cell cycle and apoptosis were monitored with FCM. RESULTS: Que alone inhibited cell growth in a dose-dependent manner in K562 and K562/A cells. Either Que or HT alone had a weak reversal effect on Dox resistance, however, combination HT and Que showed a much more significant reversal effect on Dox resistance (reverse fold 9.49). The elevated protein expression and mRNA level of HSP70 and P-gp in response to HT were inhibited by Que. Pretreatment with Que caused the cells to accumulate Dox 8.3-fold higher than in control cells. In addition, Que induced apoptosis and G2/M arrest in a dose-dependent manner, and the combination of Que and HT was found to have a synergistic effect on apoptosis. CONCLUSIONS: Que pretreatment could significantly enhance the MDR reversal activity of HT in resistant cell line, by sensitizing the cell to reversing MDR activity of HT.     

Quercetin sensitizes cells in a tumour-like low pH environment to hyperthermia

Quercetin has been shown to act as a hyperthermia sensitizer by inhibiting the synthesis of heat shock protein 70 (HSP70) in a variety of tumour cell lines. It is most effective under conditions of low pH. This study was designed to test the hypothesis that quercetin suppresses thermotolerance development in cells adapted to growth at low pH and renders them as responsive as acutely acidified cells to hyperthermia-induced cytotoxicity. Chinese hamster ovarian carcinoma cells (OvCa) were exposed to 42°C hyperthermia and/or quercetin (50-200 mm) at their growth pH of either 7.3 or 6.7 or after acute acidification from 7.3 to 6.7. Thermotolerance development was measured by colony survival. HSP70 synthesis and total protein synthesis were measured by radioactive precursor pulse labelling techniques. Quercetin, in a concentration-dependent manner, reduced the rate of total protein synthesis and increased cytotoxicity equally after acute acidification to pH 6.7 or growth at pH 6.7 at 37°C, and to a greater extent than it did in cells at pH 7.3. At 42°C, 100 mm quercetin inhibited total protein synthesis, HSP70 synthesis and thermotolerance development to a similar extent in cells grown at pH 6.7 or acutely acidified to pH 6.7. In contrast, quercetin reduced but did not completely inhibit HSP70 synthesis and thermotolerance development in cells grown and heated at pH 7.3. These results support the hypothesis that quercetin can specifically reduce thermotolerance development in tumour cells adapted to growth at pH e 6.7 so that they respond similarly to acutely acidified cells. Since many tumours are adapted to growth at low pH and may resist a wide variety of therapeutic modalities, inhibition of thermotolerance expression by quercetin may not only enhance the response to hyperthermia but the response to commonly used therapies such as chemotherapy and radiation.     

Quercetin sensitizes cells in a tumour-like low pH environment to hyperthermia.

Quercetin has been shown to act as a hyperthermia sensitizer by inhibiting the synthesis of heat shock protein 70 (HSP70) in a variety of tumour cell lines. It is most effective under conditions of low pH. This study was designed to test the hypothesis that quercetin suppresses thermotolerance development in cells adapted to growth at low pH and renders them as responsive as acutely acidified cells to hyperthermia-induced cytotoxicity. Chinese hamster ovarian carcinoma cells (OvCa) were exposed to 42 degrees C hyperthermia and/or quercetin (50-200 mm) at their growth pH of either 7.3 or 6.7 or after acute acidification from 7.3 to 6.7. Thermotolerance development was measured by colony survival. HSP70 synthesis and total protein synthesis were measured by radioactive precursor pulse labelling techniques. Quercetin, in a concentration-dependent manner, reduced the rate of total protein synthesis and increased cytotoxicity equally after acute acidification to pH 6.7 or growth at pH 6.7 at 37 degrees C, and to a greater extent than it did in cells at pH 7.3. At 42 degrees C, 100 mm quercetin inhibited total protein synthesis, HSP70 synthesis and thermotolerance development to a similar extent in cells grown at pH 6.7 or acutely acidified to pH 6.7. In contrast, quercetin reduced but did not completely inhibit HSP70 synthesis and thermotolerance development in cells grown and heated at pH 7.3. These results support the hypothesis that quercetin can specifically reduce thermotolerance development in tumour cells adapted to growth at pHe 6.7 so that they respond similarly to acutely acidified cells. Since many tumours are adapted to growth at low pH and may resist a wide variety of therapeutic modalities, inhibition of thermotolerance expression by quercetin may not only enhance the response to hyperthermia but the response to commonly used therapies such as chemotherapy and radiation.     

The synergistic reversal effect of multidrug resistance by quercetin and hyperthermia in doxorubicin-resistant human myelogenous leukemia cells

Purpose: This study aimed to evaluate the multidrug resistance (MDR) reversal activity of quercetin (Que) in combination with hyperthermia (HT) in human myelogenous leukemia cells K562/A.

Methods: The cytotoxicity of Que alone and the effect of Que and HT to doxorubicin (Dox) cytotoxicity were determined using MTT assay in K562 and K562/A cells. K562/A cells was heated with or without Que pretreatment, and the protein and mRNA levels of heat shock protein 70 (HSP70) and P-glycoprotein (P-gp) were determined by flow cytometry (FCM) and RT-PCR, respectively. Intracellular accumulation of Dox, cell cycle and apoptosis were monitored with FCM.

Results: Que alone inhibited cell growth in a dose-dependent manner in K562 and K562/A cells. Either Que or HT alone had a weak reversal effect on Dox resistance, however, combination HT and Que showed a much more significant reversal effect on Dox resistance (reverse fold 9.49). The elevated protein expression and mRNA level of HSP70 and P-gp in response to HT were inhibited by Que. Pretreatment with Que caused the cells to accumulate Dox 8.3-fold higher than in control cells. In addition, Que induced apoptosis and G2/M arrest in a dose-dependent manner, and the combination of Que and HT was found to have a synergistic efeect on apoptosis.

Conclusions: Que pretreatment could significantly inhance the MDR reversal activity of HT in resistant cell line, by sensitizing the cell to reversing MDR activity of HT.     

人肝癌原发性耐药细胞亚系的建立及耐药机制的初步探讨

目的从人肝癌细胞系HeFG2中筛选出原发性耐药株,建立相应的细胞亚系并探讨其耐药机制.方法采用阿霉素(adriamycin,ADM)大剂量冲击法筛选原发性耐药细胞株,倒置显微镜下观察其形态学变化,细胞计数法绘制生长曲线,MTT法检测药物敏感性,流式细胞术分析细胞周期和检测耐药蛋白的表达.结果随冲击次数的增加,筛选出细胞的耐药指数(resistance index, RI)逐渐升高,筛选3次后对ADM的RI可达30.5;其形态学特点、生长特性及细胞周期分布与亲本细胞有明显差异,同时发现耐药蛋白P-gp、MRPt LRP表达增强.结论肝癌细胞系HepG2是个非均质的群体,其中存在着原发性耐药细胞株.     

Sensitization of human Ewing's tumor cells to chemotherapy and heat treatment by the bioflavonoid quercetin

BACKGROUND: The bioflavonoid quercetin, a polyphenolic compound widely distributed in the plant kingdom, has been demonstrated to exert cytostatic activity against a variety of tumor cells in vitro and in vivo. It may be useful in cancer therapy as a thermosensitizer by increasing the cell killing effect of hyperthermia and chemotherapy because of its ability to suppress heat-shock protein expression. MATERIALS AND METHODS: We investigated the effect of quercetin combined with two cytotoxic agents, cDDP (cis-diamminedichloroplatinum II) and VP-16 (etoposide), under various heat-shock conditions in two Ewing's tumor cell lines SK-ES-1 and RD-ES, using XTT-assay and Western blot analysis. RESULTS: Induction of thermotolerance by a sublethal heat-shock (42 degrees C, 1 hour) led to a transient resistance against subsequent heat treatment alone or combined thermochemotherapy with the crosslinking agent cDDP or the topoisomerase II inhibitor VP-16. Quercetin (> or = 50 microM) applied for 24 hours inhibited cell proliferation, increased the cytotoxic activity of cDDP or VP-16 alone or combined with simultaneous hyperthermia and suppressed the development of thermotolerance. Hyperthermia (43 degrees C, 45 degrees C for 1 hour) induced high expression of the inducible form of HSP70, whereas HSP27, which is constitutively expressed at normothermic conditions, is only slightly induced by 43 degrees C and nearly completely suppressed at 45 degrees C. Induction of thermotolerance is accompanied by an elevated expression of both HSP70 and HSP27. Quercetin (> or = 50 microM), alone as well as in combination with thermochemotherapy, inhibited the expression of both HSP70 and HSP27. CONCLUSION: These data suggest that the bioflavonoid quercetin potentially may be useful in clinical trials for optimizing the efficacy of hyperthermia in combination with chemotherapy.     

HIFU逆转人肝癌细胞HepG2/Adm多药耐药的实验研究

背景与目的：超声波能够改变细胞膜通透性,增强化疗药物对肿瘤细胞的杀伤作用。本研究评价高强度聚焦超声及其联合阿霉素(Adriamycin,ADM)对人肝癌多药耐药细胞株HepG2／Adm的效应,并探讨其作用机制。方法：取对数生长期的HepG2、HepG2／Adm细胞进行实验,分为HepG2、HepG2(超声波照射5s)、HepG2／Adm、HepG2／Adm(超声波照射5s)4组。用MTT法检测处理前后耐药细胞对抗癌药物的敏感性;用流式细胞仪检测肿瘤细胞表面mdr1基因表达产物P170的表达及细胞内阿霉素浓度;利用SP免疫组化法观察细胞膜及核膜上P-糖蛋白(P-glycoprotein,P-gp)的表达。结果：频率0.8MHz、焦域声强460W／(cm^2连续照射5s,能够部分逆转HepG2／Adm细胞的耐药性,HepG2／Adm细胞P-gp的表达活性下降83．1％,耐药细胞内ADM浓度增加88％,对ADM、cDDP、MMc、5-FU和MTX相对逆转效率分别为66．4％、63．4％、89．4％、72．4％和75．0％。结论：高强度聚焦超声可提高人肝癌细胞HepG2／Adm内药物浓度,降低细胞膜及核膜表面P-gp表达,从而部分逆转肿瘤细胞多药耐药。