阿霉素加热化疗对抗人肝癌耐药细胞多药耐药性的实验研究

 目的　观察比较阿霉素 ( ADM)化疗与 43℃加热化疗对耐药人肝癌细胞模型 - 772 1 /Adm(以下简称 772 1 /Adm细胞 )的敏感性及细胞内药物浓度的影响。方法　以人肝癌细胞模型 -772 1 /Adm为研究对象 ,采用水浴加温法、体外细胞毒试验 ( MTT法 )、流式细胞技术 ,观察阿霉素( ADM)化疗与加热化疗后细胞的存活率及细胞内阿霉素浓度的变化。结果　 ( 1 )阿霉素化疗、加热化疗 30、60 min后 772 1 /Adm细胞存活率分别为 70 .2 %、40 .8%和 60 .2 %、37.4% ;( 2 )流式细胞仪检测显示阿霉素化疗、加热化疗 30 min后细胞内阿霉素浓度分别为 41 .3%、92 .0 %。结论　加热可以显著对抗 772 1 /Adm的耐药性 ,提高其对阿霉素的敏感性 ,这与加热提高了细胞内药物浓度有关。     

肿瘤化疗多药耐药研究新进展

肿瘤化疗失败的主要原因是多药耐药（MDR）的产生。肿瘤多药耐药的机制十分广泛，其中以ATP结合盒式结构超家族成员研究较多。文章重点综述目前研究较多的多药耐药机制，并对肿瘤耐药逆转进展作简要介绍。     

胰腺癌化疗多药耐药研究进展

胰腺癌的化疗效果不理想主要原因与肿瘤细胞的多药耐药有关。胰腺癌细胞多药耐药产生的机制目前并未阐明,随着对多药耐药认识的不断深入,新的逆转剂已经产生。本文通过近5年文献资料的回顾复习,对胰腺癌耐药机制及其逆转剂的研究进展作一综述。     

恶性肿瘤多药耐药的基础与临床研究

化学治疗在肿瘤综合治疗中的地位和作用日益重要。近年来，新的细胞毒性药物的发展使许多肿瘤治疗效果有了明显改观。尽管如此，肿瘤细胞对多种化疗药物产生交叉耐药性，仍是造成化疗失败的主要原因，90％以上的肿瘤患者死因或多或少都与耐药有关。研究肿瘤的多药耐药性及其临床逆转已成为肿瘤治疗亟待解决的问题，亦是目前肿瘤研究的难点及热点领域。现就近年来国内外肿瘤多药耐药的发生机制及临床逆转研究作一综述。     

非霍奇金淋巴瘤多药耐药的实验研究

目的 探讨初发非霍奇金淋巴瘤(NHL)mdrl mRNA及多药耐药蛋白P糖蛋白(P-gp)、肺耐药蛋白(LRP)和多药耐药相关蛋白(MRP)的表达频率及临床意义.方法 采用逆转录多聚酶链反应(RT-PCR)半定量方法检测41例初治NHL患者淋巴结活组织中瘤细胞mdrl mRNA的表达,采用流式细胞仪免疫荧光法检测P-gP、LRP、MRP的表达,以13例反应性增生淋巴结患者作为对照组.并分析多药耐药蛋白表达与NHL临床特征的关系.结果 41例NHL患者中,11例mdrl mRNA表达阳性,8例P-gP表达阳性,7例MRP表达阳性,15例LRP表达阳性.NHL组与对照组比较,MRP阳性率差异无统计学意义(P=0.887),LRP阳性率明显增高(P=0.047).NHL患者淋巴结组织P-gP、MRP、LRP表达两两之间均不存在相关关系,P-gP表达与mdrl mRNA表达正相关(r=0.396,P=0.01).P-gP表达与临床分期、LDH水平有关(均P<0.05),而与恶性分级无关.MRP表达与临床分期、恶性分级、血清乳酸脱氢酶(LDH)水平均无关(均P>0.05),而LRP表达与三者均有关(均P<0.05).P-gP和LRP表达阳性患者的完全缓解(CR)率分别为37.5%和53.3%,低于阴性表达者(均P<0.05),化疗疗效较差,而MRP表达与化疗疗效无关.结论 P-gP、LRP可能是NHL原发耐药的主要因素,影响NHL患者的化疗疗效,而MBP与NHL原发耐药无关,不影响NHL患者的化疗疗效.     

肺癌化疗多药耐药与逆转策略

恶性肿瘤化疗失败的主要原因是多药耐药的发生。研究表明,多药耐药的机制十分复杂,P-gp、TopoⅡ、GST-π、金属硫蛋白(metallothionein,MT)及p53基因突变等是肺癌产生多药耐药的物质基础。本文重点介绍非小细胞肺癌耐药因子及耐药逆转的对策,以指导临床化疗药物的筛选及治疗方案的优化,有助于提高肺癌患者的生存期和生存率。     

胃癌多药耐药研究新进展

胃癌在我国是造成死亡人数最多的恶性肿瘤，手术是目前治疗胃癌的主要方法，但在我国胃癌的手术切除率仅为50％～70％，对失去手术机会、术后复发转移及发生残胃癌的患者，化疗是其主要治疗方法。另一方面，手术作为一种局部的治疗手段也有不足之处，如手术难以发现和处理潜在的亚临床转移灶、手术操作本身也有可能会促使癌细胞的扩散和转移等，     

潘生丁对KB细胞株对多药耐药逆转作用的实验研究

目的：观察了潘生丁对ＫＢ细胞株多药耐药的逆转作用并对其作用机制进行探讨。方法：使用ＭＴＴ法检测比较ＫＢ母细胞和耐药细胞株对长春新碱（ＶＣＲ）的药物敏感度并观察潘生丁对耐药的逆转程度;用＾３Ｈ标记的ＶＣＲ检测细胞内药物浓度的变化。结果：潘生丁作用下,ＫＢ母细胞和耐药细胞株的药物敏感度均有增高并呈剂量相关关系,有ＭＰＰ表达的耐药细胞株对ＭＲＰ表达的耐药细胞株对ＶＣＲ的敏感度比母细胞株高１７倍,母细胞株     

尼莫地平逆转胶质瘤多药耐药的实验研究

 目的　探讨胶质瘤细胞对化疗药物的敏感性及尼莫地平对化疗耐药的逆转作用。方法　将新鲜肿瘤组织标本进行短期原代培养 ,分别将BCNU、VCR、PCB单独或与尼莫地平联合作用于培养的瘤细胞 ,用MTT法检测细胞存活率。结果　联合应用尼莫地平的细胞存活率较单独应用BCNU、VCR、PCB的细胞存活率明显降低。结论　尼莫地平可明显增加化疗药物的肿瘤抑制作用 ,对于化疗耐药有较好的逆转效果。     

多药耐药功能实验对急性白血病化疗疗效的预测意义

背景与目的:多药耐药排药蛋白P-糖蛋白(P-glycoprotein,P-gp)在介导急性白血病多药耐药中的作用已得到公认。多项研究显示,P-gp及其编码基因MDR1mRNA的表达与白血病化疗疗效相关,但我们在临床实践中所获得的结果却并非如此。近年来多项研究发现,多药耐药功能实验结果比P-gp的表达水平对预测化疗疗效更有价值。为了解P-gp的表达和多药耐药功能实验对判断患者预后的价值,我们对24例初诊未治急性白血病患者白血病细胞膜P-gp的表达以及功能活性进行了检测,以探讨多药耐药功能试验对化疗疗效的预测价值。方法:用流式细胞仪测定24例急性白血病患者白血病细胞的P-gp表达率以及反映MDR功能的Rh123排出实验和细胞内柔红霉素蓄积实验的MIR值,并就患者的化疗疗效进行分组比较和相关分析。结果:CR患者初诊时白血病细胞P-gp表达率为(2.16±2.42)%,与NR患者犤(15.02±25.88)%犦差异无显著性(P=0.114)。CR患者初诊时白血病细胞Rh123排出实验的MIR值:MIR(RE)(1.16±0.38)明显低于NR患者(1.43±0.26)(P=0.045)。CR患者初诊时白血病细胞内柔红霉素积蓄实验的MIR值:MIR(IDA)(1.02±0.05)亦明显低于NR患者(1.47±0.44)(P=0.005)。MIR(RE)(r=0.590,P=0.006)和MIR(IDA)(r=0.867,P=0.000)与疗效间有显著相关性。P-gp表达率与疗     

DEVELOPMENT OF AN ADRIAMYCIN RESISTANT MURINE TUMOR S-180 CELL LINE IN VIVO

Adriamycin resistant cells were obtained from low dotage treated BABL/c mice Inoculated with S-180 cells. Resistance of these cells for adriamycin was 66-fold more than their parental cells. The resistance for a typical DNA topoisomerase Ⅱ inhibitor VP16 (Etopcaide) was increased 9 times. Overexpression of multidrug resistant gene (MDR gene) products, P-glycoproteins (P-1 70), was also demonstrated by immunohistochemistry. Furthermore, the ability of the resistant cells to reduce net cellular drug accumulation measured by flow fluorescence cytometry was 89-fold higher than their parental cells. These results support the hypothesis that the resistance of S-180R cells to adriamycin was mainly due to the overexpression of P-glycoproteins. The S-180R cells will be useful to select drugs or some other therapeutic strategies to overcome multidrug resistance in vivo.     

抗肿瘤多药耐药的研究进展

肿瘤多药耐药(multidrug resistance,MDR)逆转剂通过抑制药物转运泵功能,逆转耐药;与此不同,抗肿瘤MDR药物则通过直接抑制或杀伤MDR肿瘤克服肿瘤MDR。近年来,抗肿瘤MDR药物的研究越来越受到重视。本文在总结以P-糖蛋白(P-glycoprotein,P—gp)与凋亡调控以及神经酰胺信号系统与MDR的关系为代表的MDR机制研究新进展基础上,首次将抗肿瘤MDR药物分为MDR相关抗肿瘤药物的结构修饰物、破坏MDR机制的抗MDR药、诱导caspase非依赖型凋亡的抗MDR药、干扰神经酰胺代谢的抗MDR药和机制未明的抗MDR药五类,并讨论它们的主要特点和作用机理。     

Induction of apoptosis in S-180 and S-180R tumor cells by adriamycinin vivo

Apoptosis of tumor cells have become a new standard for chemotherapy. It is useful to demonstrate induction of apoptosis in tumor cells by anti-cancer drugsin vivo. We reported the results of apoptosis induction in murine tumor cell line S-180 and it’s resistant cell line S-180R by adriamycin in different dose and different time. We found that apoptosis in S-180 cells could be induced by low dose of adriamycin, the apoptosis was started at 24 h. after the administration, and reached to 62.5% of the cells to apptosis until 72 h. Comparison with the parental cell line, only 13% of S-180R cells were apoptosed. At high dose, 20% of S-180R cells were apoptosed, whereas, almost all S-180 cells were killed in the same time. The lymphocytes were appeared in abdominal cavity of the mice after treatment of adriamycin for 24 h. It was very interested to find out that there was no lymphocyte left in the abdominal cavity of the mice with S-180R cells treated at high dose of adriamycin.     

Molecular biological evidences for the genetic stability of doxorubicin resistant cell line S-180Rin vivo

Objective: In order to assess the genetic stability of doxorubicin resistance sarcoma S-180R cell linein vivo. Methods: The drug resistant genes and molecules were examined by flow cytometry, Southern blot, Northern blot and RT-PCR. Results: The results showed that drug-efflux in S-180R increased nearly 100-folds, as compared with its parent cells, the rate of half peak width resistant cell/peak high decreased from 0.56 to 0.23 measured by flow cytometry after two years. The mdr1 gene amplified and overexpressed significantly in S-180R and the expression of topoisomerase II α gene decreased remarkably in S-180R. There was no significant different of the MRP expression between S-180R and S-180. Conclusion: These results indicated that drug resistance of S-180R was maintained and also increased. The major mechanism of drug resistance is the amplification and overexpression of mdr1 gene, the decreased expression of topoisomerase II α also contributed to it. So, S-180R is an ideal experimental model for the study of doxorubicin resistance and its reversionin vivo.     

Targeting protein kinases to reverse multidrug resistance in sarcoma

Sarcomas are a group of cancers that arise from transformed cells of mesenchymal origin. They can be classified into over 50 subtypes, accounting for approximately 1% of adult and 15% of pediatric cancers. Wide surgical resection, radiotherapy, and chemotherapy are the most common treatments for the majority of sarcomas. Among these therapies, chemotherapy can palliate symptoms and prolong life for some sarcoma patients. However, sarcoma cells can have intrinsic or acquired resistance after treatment with chemotherapeutics drugs, leading to the development of multidrug resistance (MDR). MDR attenuates the efficacy of anticancer drugs and results in treatment failure for sarcomas. Therefore, overcoming MDR is an unmet need for sarcoma therapy. Certain protein kinases demonstrate aberrant expression and/or activity in sarcoma cells, which have been found to be involved in the regulation of sarcoma cell progression, such as cell cycle, apoptosis, and survival. Inhibiting these protein kinases may not only decrease the proliferation and growth of sarcoma cells, but also reverse their resistance to chemotherapeutic drugs to subsequently reduce the doses of anticancer drugs and decrease drug side-effects. The discovery of novel strategies targeting protein kinases opens a door to a new area of sarcoma research and provides insight into the mechanisms of MDR in chemotherapy. This review will focus on the recent studies in targeting protein kinase to reverse chemotherapeutic drug resistance in sarcoma.     

环孢素A诱导多药耐药细胞HR20和HT9凋亡的方式

背景与目的：诱导细胞凋亡是许多化疗药物的作用机制,多药耐药细胞常可以抵抗药物诱导的凋亡,有必要从分子机理上探索其抗凋亡机制。但正是由于耐药细胞的抗凋亡特性,难以在凋亡通路中展开相关研究,本研究用环孢素A(Cyclosporin A,CsA)诱导药物敏感的人急性白血病细胞HL-60,及其多药耐药细胞HR20和HT9凋亡,通过对二者凋亡通路中的关键分子进行比较,分析耐约细胞与敏感细胞凋亡途径的差别。方法：用10、20mg／L CsA分别处理HL-60、HR20和HT9细胞,用细胞核形态观察、DNA凝胶电泳以及流式细胞术方法答定调亡,通过分光光度法和免疫印迹法检测捌亡过程中相关因子的变化：结果：10、20mg／L CsA处理HL-60、HR20和HT9细胞,能够诱导细胞都发生明显的凋亡,包括染色质凝集、DNA片断化因子(DNA fragmentation factor、DFF)裂解激活以及DNA断裂,然而仅在HL-60凋亡细胞中检测到Caspase-3活化,而在HR20和HT9凋亡细胞中Caspase-3没有活化。结论：CsA诱导HR20和HT9细胞凋亡的通路可能不依帧于Caspase-3,其凋亡通路中可能存在除Caspase-3以外的DFF活化因子。推测Caspase-3不容易活化可能是HR20和HT9多药耐药的原因之一。     

Fluoxetine and reversal of multidrug resistance

This review centers on recent findings with respect to modulating cancer multidrug resistance (MDR) with the well-known antidepressant fluoxetine (prozac). The MDR phenomena and mechanisms are discussed, including the roles of ABC transporters as MDR-pumps and the potential involvement of cancer stem cells. The three generations of MDR reversal agents (chemosensitizers) are reviewed, introducing the concept of single-pump and multi-pump agents. The current status of chemosensitization is summarized, pointing-out the need for additional agents and outlining experimental criteria for testing novel candidates. Major in vitro and in vivo findings are summarized showing that fluoxetine is a chemosensitizer of the multi-pump type, and proposing it be considered a fourth-generation chemosensitizer. In concluding, we contemplate future prospects of modulating MDR in the clinic.     

Vitamin E reverses multidrug resistance in vitro and in vivo

Multidrug resistance (MDR) is a major obstacle to successful and effective chemotherapeutic treatments of cancers. This study explored the reversal effects of vitamin E on MDR tumor cells in vitro and in vivo, elucidating the potential mechanism of this reversal. VE at a concentration of 50 μM exhibited a significant reversal of the MDR effect (compared to only PTX in DMSO, p < 0.05) in two human MDR cell lines (H460/taxR and KB-8-5). The MDR cell xenograft model was established to investigate the effect of VE on reversing MDR in vivo. Mice intravenously injected with Taxol (10 mg/kg) with VE (500 mg/kg, IP) showed an ability to overcome the MDR. VE and its derivatives can significantly increase intracellular accumulation of rhodamine 123 and doxorubicin (P-gp substrate), but not alter the levels of P-gp expression. These treatments also did not decrease the levels of intracellular ATP, but were still able to inhibit the verapamil-induced ATPase activity of P-gp. The new application of VE as an MDR sensitizer will be attractive due to the safety of this treatment.     

乳腺肿瘤摄取99Tcm-甲氧基异丁基异睛与耐多药蛋白表达的关系

目的研究乳腺肿瘤摄取99Tcm-甲氧基异丁基异睛 (99Tcm-MIBI)与耐多药蛋白表达水平间的相关性.方法 30例经病理证实的原发性浸润性导管癌患者,均行99Tcm-MIBI早期显像和延迟显像.对显像阳性的肿块计算感兴趣区与对侧正常相应部位的放射性计数比值,以早期摄取比值(EUR)和延迟摄取比值(DUR)计算滞留指数(RI).以免疫组织化学法检测手术切除标本肿瘤组织的P-糖蛋白(P-gp)和多药耐药相关蛋白(MRP)的表达水平.数据分别进行配对t检验、Pearson相关分析及偏相关分析.结果 P-gp的平均表达水平为0.1183±0.0700,MRP的平均表达水平为0.1195±0.0522.P-gp和MRP的表达水平在RI≥0和RI＜0的组中,差异有显著性.P-gp的表达与RI(r=-0.919,P=0.001)、DUR(r=-0.675,P=0.001)和MRP(r=0.549,P=0.002)有相关性,与EUR(r=-0.097,P=0.610)无相关性.MRP的表达与RI(r=-0.547,P=0.002)有相关性,与EUR(r=0.292,P=0.117)、DUR(r=-0.173,P=0.361)无相关性.P-gp与MRP的表达有相关性(r=0.549,P=0.001).偏相关分析则显示,P-gp的表达与RI(r=-0.8847,P=0.001)有显著相关性,MRP的表达与RI(r=-0.1296,P=0.512)无相关性.结论 99Tcm-MIBI乳腺显像与P-gp的表达呈负相关关系,与MRP未见有相关性.