mdr1介导的多药耐药及其逆转的研究进展

目的介绍mdr1介导的多药耐药及其逆转的研究进展。方法采用文献回顾的方式对国内外相关文献进行分析整理,对mdr1基因的结构功能、表达调控以及逆转多药耐药的方法进行综述。结果mdr1基因的过度表达是导致肿瘤多药耐药的重要原因,mdr1表达调控网络主要由转录、转录后水平和表观遗传调控构成,各种机制通常同时在细胞中起作用,逆转多药耐药的研究集中在药物和基因治疗两个方面。结论多种方法联合应用有助于逆转多药耐药。     

卵巢癌中多药耐药基因的表达及其意义

为探讨卵巢癌隐含的耐药机制及其对化疗的影响,用RT－PCR方法对7例正常卵巢组织及32例卵巢癌进行了多药耐药基因（mdr1)检测,结果表明：正常卵巢组织中,rdr1基因均无表达,32例卵巢癌中,mdr1表达阳性率为28．1％,mdr1基因表达与病理类型有关（P＜0．05）,而且mdr1表达阳性者耐药发生率（55．6％）显著高于阴性者（8．6％,P＜0．01）。结果提示：卵巢癌中隐含有由mdr1介导的多药耐药机制,mdr1的表达与卵巢癌的化疗耐药有一定的关系。     

DC-CIK细胞对K562/ADR细胞多药耐药的逆转作用

目的 探讨共培养树突状细胞(dendritic cell,DC)和细胞因子诱导的杀伤细胞(cytokine-induced killer cell,CIK),即DC-CIK逆转白血病细胞多药耐药的作用及相关机制.方法 采用RT-PCR方法检测DC-CIK处理后的耐药细胞株(K562/ADR细胞)中多药耐药基因(mdr1基因)的表达;利用MTT法检测DC-CIK细胞处理后的耐药细胞株对阿霉素敏感性的变化.结果 经DC-CIK作用后的K562/ADR细胞mdr1表达明显低于未经DC-CIK处理的K562/ADR细胞组(P<0.05),而且其对阿霉素的敏感性也明显高于未经DC-CIK处理的K562/ADR细胞(P<0.05).结论 DC-CIK可逆转耐药细胞的多药耐药,其作用机制可能与下调耐药细胞中mdr1的表达有关.     

32例肝癌组织中多药耐药基因及其产物P-糖蛋白的实验研究

探讨肝癌组织中mdr－1（多药耐药基因）mRNA及P－170（P－糖蛋白）的表达水平，采用RT－PCR及免疫组织化学SP法检测32例肝癌组织中mdr－1mRNA和P－糖蛋白的表达．发现不仅肝癌组织中mdr－1和P－糖蛋白的表达显著高于对照组，而且转移组中P－糖蛋白的表达高于非转移组．提示检测mdr－1／P－gp对肝癌制订治疗方案，判断疗效及MDR逆转剂的应用具有重要的临床意义；mdr－1mRNA／P－gp的过表达可能与肝肿瘤的转移预后有关．     

EGCG逆转人耐药肝癌细胞株多药耐药的体内实验研究

目的:研究表没食子儿茶素没食子酸酯(EGCG)体内逆转人肝癌细胞多药耐药性的作用及可能的机制.方法:MTT法检测肝癌耐药细胞株BEL-7404/ADR与其亲本细胞BEL-7404耐药倍数,采用BEL-7404/ADR种植于裸鼠皮下,建立肿瘤耐药模型,两周后EGCG灌胃,腹腔注射阿霉素(ADM),联合治疗两周;荧光分光光度法检测瘤体内ADM含量,HE染色观察形态学改变;RT-PCR检测瘤组织mdr1 mRNA的表达,免疫组化法检测瘤组织P糖蛋白(P-gp)的表达.结果:低、中、高EGCG联合ADM组肿瘤生长速度明显低于ADM组,瘤重明显低于阿霉素组;EGCG联合ADM可增加瘤体内ADM的含量 (P<0.01);三个EGCG联合 ADM组与阿霉素组相比HE病理图片显示肿瘤组织纤维包裹,炎细胞浸润; mdr1 mRNA和P-gp的表达明显低于对照组和阿霉素组 (P<0.01).结论:EGCG在体内具有逆转BEL-7404/ADR的耐药作用,机制可能是EGCG下调了肝癌细胞mdr1基因的表达,使P-gp的表达降低,瘤组织内药量增高.     

逆转mdr1引起的多药耐药性的策略

多药耐药基因1（mdr1）编码的P-糖蛋白表达的增加是肿瘤细胞多药耐药性最常见的发生机制之一。近年来以mdr1/P-糖蛋白为靶点,在蛋白质水平和基因水平上采用多种策略逆转MDR,这些研究均有较大进展,本文就目前逆转多药耐药性的研究状况进行综述。     

肿瘤多药耐药与癌基因的关系

近年来肿瘤耐药的机制主要集中在以下几个方面 :多药耐药基因 (multidrugresistancegene,mdr 1 )及其表达的P 糖蛋白 (P glycoprotein ,P gp)增强 ;多药耐药相关蛋白 (multidrugresistance asssociatedprotein ,MRP)表达增强 ;谷胱甘肽 S转移酶 (glutathioneS transferase,GST)表达增强 ;DNA拓扑异构酶表达下降 ;某些癌基因的活化 ;抗凋亡能力增强等等     

不同发育阶段豚鼠耳蜗外侧壁中mdr1/MRP1mRNA的表达及其意义

目的检测多药耐药基因1(multidrug resistance 1,mdr1)和多药耐药相关蛋白1(multidrug resistance-associated protein,MRP1)基因在不同发育阶段豚鼠耳蜗外侧壁细胞中的表达情况,并讨论其在血迷路屏障中的防护作用.方法利用原位杂交技术检测mdr1/MRP1mRNA的表达,采用MPLAS-500计算机图像处理系统进行图像分析.结果 (1)豚鼠耳蜗外侧壁中mdr1mRNA主要在微血管内皮细胞中表达,MRP1 mRNA主要在边缘细胞中表达.(2)mdr1/MRP1mRNA在不同发育阶段豚鼠耳蜗外侧壁中的表达强度存在差异:3周龄与4周龄豚鼠间mdr1mRNA表达强度差异无显著意义(P>0.05);但两者较1～2周龄豚鼠mdr1mRNA表达强,并有显著性意义(P<0.01);MRP1mRNA在1～2周龄耳蜗外侧壁中弱表达,与3周龄和4周龄间差异有显著意义(P<0.01).(3)在1～2周龄豚鼠耳蜗外侧壁中主要是mdr1mRNA表达,而MRP1mRNA表达较少,两者间差异有显著意义(P<0.01),而3周龄和4周龄豚鼠耳蜗外侧壁中两者表达差异无显著意义(P>0.05).结论 mdr1/MRP1mRNA存在于正常耳蜗外侧壁中,随着耳蜗外侧壁的发育其表达强度不同,并且两者的表达存在不同步性.     

人多药耐药基因1(mdr1)的克隆及重组腺病毒制备

目的:构建表达多药耐药基因1(MDR1)的重组腺病毒表达系统.方法:用基因工程技术将多药耐药基因1的cDNA亚克隆至穿梭质粒pAdTrack-CMV上,然后在细菌内与pAdEasy同源重组,经脂质体转染293细胞包装、扩增腺病毒颗粒.将重组腺病毒Ad5-mdr1感染小鼠单个核细胞,通过荧光显微镜及流式细胞仪进行检测.结果:酶切鉴定及PCR结果证明多药耐药基因重组腺病毒载体构建成功,构建的人多药耐药基因1(mdr1)重组腺病毒载体的效价达到8.3×1011 pfu/ml.对小鼠单个核细胞的感染效率可达10%～15%,转染小鼠单个核细胞细胞48h后,可检测到mdr1基因的表达.结论:成功构建了表达多药耐药基因1的重组腺病毒载体,为后续对mdr1的相关研究创造了条件.     

胃癌多药耐药基因1表达及其与生物学行为的关系

目的了解胃癌多药耐药基因1(mdr1)的表达及其与生物学行为的关系。方法应用现代信息技术,收集有关文献进行综合分析。结果正常和病理胃均可表达mdr1,胃癌的mdr1表达水平最高。胃癌的mdr1表达和胃癌对抗肿瘤药物敏感性及病人的生存期、生存率呈负相关,和组织分化、肿瘤浸润、分期及转移的关系不肯定,和肿瘤发生部位、大小、组织类型、患者年龄、性别之间无相关性。结论胃癌mdr1基因表达和生物学行为相关。     

Reversal of Multi-Drug Resistance by Vector-Based-ShRNA-Mdr1 In Vitro and In Vivo

In order to investigate the effects of vector-based hairpin small interference RNA (shRNA) on the reversal of multi-drug resistance (mdr) of A2780/Taxol cells, a novel vector pEGFP-H1/mdr1 containing mdr1-shRNA targeting at position 2943-2963 of mdr1 was designed and synthesized.Subsequently, A2780/Taxol cells were transfected with pEGFP-H1/mdrl, and the expression of mdr1 mRNA and P-gp was detected by using RT-PCR and Western blot respectively. MTT was used to measure the 50% inhibition concentration (1C50) of Taxol to A2780/Taxol cells. The results showed that at the 24th and 48th h after transfection, the expression of mdr1 mRNA was decreased to (52.1±1.0)% and (0.01+1.7)%, and that of P-gp decreased to (88.3±2.1)% and 0%, respectively. At the 48th h after transfection, the relative reversal rate of A2780/Taxol cells to Taxol was 69.54%. In vivo, the nude mice xenografts were injected with pEGFP-H1/mdrl, and then administrated Taxol.The tumor volume in pEGFP-H1/mdr1-transfected group was significantly reduced as compared with that in blank control group or pEGFP-H1-transfected group (807.20±103.16 vs 1563.78±210.54 or 1480.78±241.24 mm3, both P<0.01). These results suggested that transfection of pEGFP-H1/mdr1 could efficiently down-regulate the expression of mdr1 mRNA and P-gp in A2780/Taxol cells, and effectively restore the sensitivity of A2780/Taxol cells to Taxol both in vitro and in vivo.     

Reversal of multi-drug resistance by vector-based-ShRNA-Mdr1 <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">In Vivo</Emphasis>

In order to investigate the effects of vector-based hairpin small interference RNA （shRNA） on the reversal of multi-drug resistance （mdr） of A2780/Taxol cells, a novel vector pEGFP-HI/mdrl containing mdrl-shRNA targeting at position 2943-2963 of mdrl was designed and synthesized. Subsequently, A2780/Taxol cells were transfected with pEGFP-H1/rndrl, and the expression ofmdrl mRNA and P-gp was detected by using RT-PCR and Western blot respectively. MTT was used to measure the 50% inhibition concentration （IC50） of Taxol to A2780/Taxol cells. The results showed that at the 24th and 48th h after transfection, the expression of mdrl mRNA was decreased to （52.1±1.0）% and （0.01±1.7）%, and that of P-gp decreased to （88.3±2.1）% and 0%, respectively. At the 48th h after transfection, the relative reversal rate of A2780/Taxol cells to Taxol was 69.54%. In vivo, the nude mice xenografts were injected with pEGFP-H1/mdrl, and then administrated Taxol. The tumor volume in pEGFP-H1/mdrl-transfected group was significantly reduced as compared with that in blank control group or pEGFP-Hl-transfected group （807.20±103.16 vs 1563.78±210.54 or 1480.78±241.24 mm^3, both P〈0.01）. These results suggested that transfection of pEGFP-HI/mdrl could efficiently down-regulate the expression of mdrl mRNA and P-gp in A2780/Taxol cells, and effectively restore the sensitivity of A2780/Taxol ceils to Taxol both in vitro and in vivo.     

Retroviral-mediated transfer and functional expression of multidrug resistance gene in human placenta mesenchymal stem cells

Background Most of gynecologic malignancies are sensitive to chemotherapy. Myelosuppression is the main dose-related toxicity of many chemotherapeutic drugs. The human multidrug resistance （mdrl） gene is well known for its ability to confer drug resistance. This study aimed to explore the feasibility of expression and resistance of mdrl gene transduction into human placenta mesenchymal stem cells （P-MSCs） by retrovirus vector. Methods Human P-MSCs were isolated from trypsin-digested term placentas, and their immunophenotypes and differentiation potential were evaluated. Human P-MSCs were transduced by reconstructed retroviral vector containing the mdrl gene and green fluorescent protein （GFP） reporter gene. The integration and expression of the mdrl gene were observed indirectly by the expression of GFP, and fluorescence-activated cell sorter was used to evaluate the functional activity of permeability glycoprotein （P-gp） encoded by the mdrl gene. The stimulating test was made in vitro to show pleiotropic drug resistance of transfected cells. Results The isolated, cultured and expanded P-MSCs expressed stem cell markers such as CD29, CD44 and CD73, and showed osteogenic and adipogenic differentiation potentials under appropriate conditions. The expression of P-gp in the non-transfected P-MSCs cells was （0.4±0.1）%, but increased to （28.1±4.7）% after gene transfection （P〈0.01）. And positive staining of P-gp located mainly at cell membrane and cytoplasm. Accumulation and extrusion assays showed that P-gp expressed by the transfected cells had pump-functional activity and could efflux daunomycin out of cells. The analysis of cell survival confirmed that transfected P-MSCs had a characteristic of multidrug resistance with a significant increase in the resistance to anticancer agents. Conclusions Transfer and expression of human mdrl gene mediated by retrovirus vector conferred P-MSCs drug resistance. It might provide a new alternative to chemoprotection strategies.     

原发性肝癌中HIF-1α、P-gp的表达及相关性的研究

目的：观察HIF-1α和P-gp在原发性肝癌（HCC）中的表达，探讨两者相互作用的关系。方法：采用免疫组织化学法检测36例HCC及20例非肿瘤肝组织中P-gp和HIF-1α的表达，对两者均表达阳性的病例，进行免疫组织化学双标记染色。结果：36例HCC中HIF-1α和P-gp高表达，阳性率分别为58.33%和77.78%，明显高于非肿瘤肝组织（P＜0.001）。两者表达呈正相关（r=0.388，P＜0.05）。18例两者均表达阳性的病例中，免疫双标共表达率为61.1%。结论：HCC中HIF-1α和P-gp的表达密切相关，HIF-1α可通过上调P-gp的表达实现对化疗药物的耐受，HIF-1α有望成为评价及逆转肿瘤多药耐药的新指标。     

RNA干扰逆转白血病细胞耐药性的研究

目的 用RNA干扰技术下调白血病耐药细胞系K562/A02多药耐药基因mdr1的表达以逆转白血病对化学药物的耐药性.方法 针对mdr1基因已知mRNA序列不同位点,选择两条靶序列,构建靶向mdr1 shRNA真核表达载体,脂质体介导转染白血病耐药细胞株K562/A02.实时荧光定量RT-PCR检测mRNA表达,Western blot检测细胞膜P-gp表达,柔红霉素泵出试验检测P-gp外排泵功能,MTT法检测细胞对阿霉素的敏感性.结果 构建了二条针对mdr1基因的shRNA真核表达载体,分别下调mdr1 mRNA的表达89.74%和87.18%,降低细胞膜P-gp表达,使膜外泵功能明显下降,柔红霉素在细胞内贮留明显增多,60min 时柔红泵出率为13.16%、22.02%,对照组为40.44%、45.31%,对阿霉素药物敏感性的相对逆转率为84.36%和76.69%.结论 RNA干扰技术可有效逆转mdr1所致耐药.     

靶向抑制肝癌耐药细胞多药耐药基因表达的实验研究

目的：构建含多药耐药基因MDR1的短发夹状RNA（shorthairp in RNA,shRNA）表达质粒,并观察其对肝癌耐药细胞Bel-7402/R的MDR1 mRNA的抑制作用。方法：利用分子克隆技术,将含MDR1的双链DNA,与经双酶切后的载体PGE-1连接,构建pshRNA-MDR1重组质粒,在脂质体的介导下转染肝癌耐药细胞株BEL-7402/R,RT-PCR分析MDR1mRNA的表达,流式细胞仪检测细胞P-gp的表达。结果：PCR和DNA测序证实了表达质粒构建成功,并能明显地抑制MDR1mRNA的表达;P-gp的表达阳性率降低了57.3%,P〈0.05。结论：构建的pshRNA-MDR1表达质粒能靶向抵制肝癌耐药细胞MDR1mRNA和P-gp的表达。     

X射线照射后鼻咽癌细胞多药耐药基因的表达

目的 通过检测射线照射前后鼻咽癌CNE1细胞多药耐药基因(mdr1基因)及其编码产物P糖蛋白(P-gp)的表达和功能为临床鼻咽癌放化疗顺序提供参考。方法 利用RT-PCR、Western blotting和流式细胞仪检测射线照射前后CNE1细胞的mdr1基因和P-gp的表达及对柔红霉素的外排功能。结果 鼻咽癌CNE1细胞射线照射前mdr1基因、P-gp不表达;照射后较长时间内mdr1基因、P-gp均明显表达;对柔红霉素的摄取较射线照射前低。结论 鼻咽癌CNE1细胞射线照射后化疗敏感性降低,提示临床对于中晚期鼻咽癌的治疗应考虑先化疗再放疗即诱导化疗的治疗方案。     

X射线照射后鼻咽癌细胞多药耐药基因的表达

目的 通过检测射线照射前后鼻咽癌CNE1细胞多药耐药基因(mdr1基因)及其编码产物P糖蛋白(P-gp)的表达和功能为临床鼻咽癌放化疗顺序提供参考。方法 利用RT-PCR、Western blotting和流式细胞仪检测射线照射前后CNE1细胞的mdr1基因和P-gp的表达及对柔红霉素的外排功能。结果 鼻咽癌CNE1细胞射线照射前mdr1基因、P-gp不表达；照射后较长时间内mdr1基因、P-gp均明显表达；对柔红霉素的摄取较射线照射前低。结论 鼻咽癌CNE1细胞射线照射后化疗敏感性降低，提示临床对于中晚期鼻咽癌的治疗应考虑先化疗再放疗即诱导化疗的治疗方案。