AIM To investigate the local effect of phosphorus-32 glass microspheres (32 P-GMS) on hepatocellularcancer and its relation with chemoembolism.MVIETHODS (① Thirty-two BALB/c nu/nu nude mice were divided randomly into four groups, control groupand 3 treatment groups. Every mouse was implanted with human liver cancer cell line subset (H-CS). 32p-GMS amalgamated in iodine oil was injected directly into the tumor mass. After 2 wk, all animals but thosein the control group, were injected with 32p-GMS in the dosage of 880cGY, 1760cGY and 3520cGY formouce groups Ⅰ, Ⅱ and Ⅲ respectively. The histological reactions of tumor mass were observed; multidrugresistance (MDR) expressed p-glycoprotein was detected by flow cytometry. ②Forty-three patients withhepatocellular carcinoma based on the evidence from B sonography or CT and serum AFP >400 ng/mL orcytological and histological evidences in some cases with the negative AFP were divided randomly into twogroups, group Ⅰ treated with 32p-GMS (absorbed dose of 50Gy- 100Gy) alone, group Ⅱ treated with 32p-GMS and chemotherapeutics (half-dosage, doxorubicin 20mg/m2, cisplatin 30mg/m2). 32 P-GMS wasinjected through intra hepatic artery in these cases with single massive type and multi-nodular type. Everypatient was repeatedly treated with this method for 2 - 3 times. For evaluating the therapeutic results. Themodified WHO criteria for tumor therapy standard is the.RESULTS (①) Animal bearing tumors showed that the mass decreased markedly and the inhibitive ratesattained 66.53%, 83.06% and 91.53% in the absorbed doses ranged form 880GY, 1760Gy and 3520Gyrespectively (P<0.05, ANOVA). Flow cytometry detected MDR expressed p-glycoprotein decreased from68.2 ± 4.6 in control to 43.6 ± 3.4, 35.3 ± 4.3 and 33.2 ± 3.8 (P<0.05, compared with control, t-test) inthe cells from the tumors. (②) The foci in group Ⅰ revealed decreased in size dramatically with effective rate of71.43%, compared with 86.36% in the group Ⅱ (P<0.05, Chi-squaur test). The median survival period ofthe patients were 532 and 564 d in group Ⅰ and Ⅱ respectivcey (Kaplan-Meire method).CONCLUSION The enhanced effectiveness of the local treatment of 32 P-GMS conjugated withchemotherapeutics may be related to the local action on the MDR expressed p-glycoprotein.

绝望中寻找希望：肿瘤多药耐药的新选择

【据《J Med Chem》2014年9月报道】题：水溶性与可裂解的槲皮素氨基酸偶联物可作为以P糖蛋白为基础的肿瘤多药耐药调节剂（作者Kim MK等）肿瘤多药耐药（cancer multidrug resistance, MDR）始终是肿瘤治疗中的顽疾。在诸多作用机制中，ATP驱动的结构及功能上的跨膜转运的多为非特异性的细胞抑制剂，从而限制其在细胞内达到治疗浓度，这是当今广为接受的理论。ATP结合盒（ATP-binding cassette, ABC）超家族成员中的膜转运子在肿瘤细胞中过度表达，也是已知的通过ATP依赖性药物外排机制的MDR调节因子，包括P-糖蛋白（P-glycoprotein, Pgp）、多药耐药相关蛋白1（multidrug resistance associated protein 1, MRP1）及乳腺癌耐药蛋白（breast cancer resistance protein, BCRP）。以钙通道阻滞剂为代表的第一代Pgp抑制剂已被批准广泛应用于临床各种治疗，如免疫抑制剂（环孢素A）、抗生素（红霉素）、抗疟药（奎宁）、精神吩噻嗪（氟奋乃静）、吲哚生物碱（利血平）、类固醇激素（黄体酮）、抗激素类药物（三苯氧胺）及清洁剂（聚氧乙烯蓖麻油）。然而，在抑制MDR领域却未得到发展，缺乏灵敏度和特异性导致药物治疗无效或治疗剂量水平的毒性不良反应，被迫限制了Pgp应用。进一步研发毒性不良反应更低且更有效的Pgp抑制剂，从而孕育出伐司朴达、右维拉帕米、右尼古地平及比立考达等第二代MDR调节剂。然而，总体而言，MDR调节剂的发展始终受到缺乏敏感性，毒性较高及不可预知的药代动力学相互作用等问题困扰。类黄酮是一种广泛分布于多种植物的酚类抗氧化剂。众多食物中含有丰富的黄酮类物质，具有抗氧化、抗炎、抗癌和抗病毒活性，有益于人体健康，并被推荐为可食用的补充抗氧化剂并协同抗癌药物。来自韩国Konkuk大学及科技大学的Kim MK等研究希望将黄酮类化合物结合ABC转运蛋白的ATP结合位点，从而抑制细胞内抗肿瘤药物和（或）药物偶联物的流出。

拉莫三嗪对癫癎幼鼠海马中多药耐药基因表达的影响

癫癎是一种常见的神经系统疾病,约有25%的癫癎患者对大部分抗癫癎药物耐药,从而发展为难治性癫癎[1].越来越多的学者认为难治性癫癎的耐药机制可能与多种药物运输蛋白的过表达、抗癫癎药物不能有效地进入脑细胞有关,其中多药耐药基因(multidrug resistance gene,MDR)及其表达产物P-gp备受关注.

热休克蛋白70与槲皮素在白血病耐药机制中的作用研究

热休克蛋白(heat shock protein,HSP)作为一种重要的分子伴侣,主要功能是在各种应激刺激下维持细胞的自身稳定性,保护细胞的生存和功能.

Objective: A single mechanistic pathway cannot explain the genesis of drug resistance in cancer. Drug resistance in cancer is a major obstacle to successful chemotherapy. KB cells provide a useful starting point for selection of the multidrug resistant (MDR) cell lines. Methods: We used cDNA microarrays containing 12,720 sequences of known genes, expressed sequence tags and unknown clones to monitor gene expression profiles in MDR KB cells. Results: Preliminary data analysis showed that 18 genes were up-regulated and 18 genes were down-regulated by comparison of expression patterns between KB 3-1 and MDR KB-V1 cells. Furthermore, the highly over-expressed CGA, CLU genes in MDR KB-V1 cell were verified with conventional Northern blot analysis. These genes contain information predictive of drug resistance of cancer cells. Conclusion: Our study demonstrates that genome-wide gene expression profiling by using cDNA microarray technique is a valuable approach in obtaining molecular mechanism of drug resistance in cancer cells.

Objective: To clone multidrug resistance (MDR) related genes in lung adenocarcinoma cell lines. Methods: The differentially expressed cDNA fragments between A549 and A549DDP cells were analyzed by mRNA differential display PCR(DD RT-PCR). The fragments thus obtained were further analyzed by DNA sequencing and Northern blotting. Results: Three differentially expressed cDNA fragments were obtained and confirmed by Northern blot. Sequence analysis revealed that two of them were novel and one was 100% identical with ICE gene. Conclusion: Analyzing differentially expressed fragment between A549 and A549DDP cells may be helpful for finding new MDR related genes. The drug resistance of A549DDP cells may be related to the inhibition or down-regulation of ICE gene.

Newly developed drugs invented to treat tuberculosis in clinical trial

Tuberculosis (TB) is a leading cause of morbidity and mortality in more than one-third of the world population.Its impact on global health is a result of decades of neglect for such an important infectious disease,lack of resources for national TB control programs,poor case detection,and inadequate/inappropriate therapy in high-burden countries.The worldwide dissemination of multidrug (MDR) and extensively drug resistant (XDR) Mycobacterium tuberculosis poses a serious threat to human health due to inadequacy of long and cumbersome tuberculosis (TB) therapy.Treatment regimens consist of at least four drugs with different mechanisms of action.Several new molecules in clinical development hasencouraged the scientific community to discover new drug targets and new drug candidates.Therefore,new drugs are urgently needed to shorten and improve the treatment course in drug resistant TB,and to minimize the occurrence of new infections and death.Nowadays,various new investigational drugs,such as bedaquine (TMC207),nitroimidazoles (PA-824,OPC-67683),diamines (SQ109),oxazolidinones (Linezolid,PNU-100480 (Sutezolid),ADZ5847),pyrroles (LL3858) and fluoroquinolones (moxifloxacin and gatifloxacin),have entered clinical trials and are in progress to be developed for the treatment of MDR-TB.In this perspectivearticle,an overview of the new anti-TB drugs with different structures that are either being clinically used or in advanced stages clinical stages as well as of preclinical development are presented.This review provides snapshots of the efforts that are being made in the development of new drugs as lead anti-TB agents.Finally,it is crucial to improve the connection between research and development institutes,industries,drug contro 1 authorities,and intemational policv-making bodies to deliver efficacious therapies for patients who are suffering from TB.

Objective To investigate the anti-tumor effect of ZM-66 on multidrug-resistant leukemic cell line K562/ADM.
Methods The K562/ADM cells were treated with varying concentrations (0, 1, 2, 4×10-3 mmol/L) of ZM-66 or etoposide for 24 hours. The proliferation was detected by Sulforhodamine B Sodium Salt (SRB) assay and apoptosis was detected by flow cytometry analysis and fluorescent staining. In addition, the expression levels of p53 and bax genes in K562/ADM cells were detected by RT-PCR analysis. The level of P-glycoprotein (P-gp), P53 and Bax protein in K562/ADM cells were detected by Western blot assay.
Results SRB assay demonstrated that etoposide had little inhibitory effect on K562/ADM cells, whereas ZM-66 (1, 2, 4×10-3 mmol/L) had significantly inhibitory effect on K562/ADM cells (all P<0.01). The acridine orange/propidium iodide dual staining showed that there were typical condensation of chromatin and nuclear fragmentation nuclei with red color in ZM-66 treated cells. Flow cytometric analysis showed that there was a significantly increase of apoptotic cells in K562/ADM cells after treated with ZM-66. RT-PCR showed that the p53 and bax mRNA expression levels in K562/ADM cells treated with ZM-66 at 1, 2, 4×10-3 mmol/L were higher than those in the cell without treatment. Western blot showed that the P53 and Bax protein expression levels in K562/ADM cells treated with ZM-66 at 2, 4×10-3 mmol/L were higher than those in the cell without treatment. But the P-gp protein expression level in K562/ADM cells treated with ZM-66 at 2, 4×10-3 mmol/L was gradually lower than those in the cell without treatment.
Conclusion ZM-66 is able to induce cell death by apoptosis in vitro, as a result of the reverse of the apoptosis resistance in drug-resistant K562/ADM cells by modulating expression of key factors associated with apoptosis induction.

多药耐药与肝细胞保护的研究进展

正常细胞表达多药耐药转运蛋白,从而表现出多药耐药的特性.细胞保护是指在不利因素下细胞对自身的保护能力.细胞保护除了需要增加有利因素外,减少细胞内的有害因素也是一个有效手段,多药耐药就是其中一个重要的因素.引起多药耐药的ABC转运蛋白在正常细胞中存在广泛的表达,尤其是排泄器官如肝、肾、肠道等,表明其作为防止药物渗透的屏障及在药物消除机制中的重要作用;肝细胞主要表达ABC(ATP-binding cassette)转运蛋白超家族中的P-糖蛋白(P-gp)及多药耐药相关蛋白(MRP)1,2,3,6.本文通过对相关研究进展的分析,从多个方面阐述了多药耐药与细胞保护,尤其是肝细胞保护的关系,从而为疾病的预防和治疗提供新的思路.

辐射诱导多药耐药肝癌细胞HepG2/ADM凋亡的实验研究

目的研究联合应用放、化疗对多药耐药肝癌细胞HepG2/ADM凋亡的影响并探讨诱导凋的机制.方法比较放化疗、单纯放疗、单纯化疗的诱导凋亡作用,将HepG2/ADM分为6组,比较各组凋亡率;应用RT-PCR法检测各组HepG2/ADM细胞p53、bcl-2和bax的表达.结果经处理因素作用后,组1～6HepG2/ADM细胞凋亡率分别为2.8±0.3%,5.2±0.5%,10.9±2.3%,31.7±4.1%,11.7±2.8%,35.2±4.5%.放化疗与单纯化疗相比诱导HepG2/ADM凋亡率明显增高(P＜0.05).RT-PCR检测组1～6 p53表达分别为:0.22±0.04、0.23±0.02、0.31±0.04、0.55±0.02、0.35±0.04、0.57±0.05;bcl-2表达分别为:0.34±0.03、0.3l±0.04、0.25±0.02、0.14±0.02、0.26±0.03、0.10±0.03;bax表达分别为:0.21±0.02、0.25±0.02、0.29±0.03、0.38±0.03、0.29±0.03、0.41±0.06.结论放化疗联合应用能够显著增加耐药细胞HepG2/ADM凋亡率,这种作用与p53、bax、bcl-2表达调节有关.

ABCC10, also known as multidrug-resistant protein 7 (MRP7), is the tenth member of the C subfamily of the ATP-binding cassette (ABC) superfamily. ABCC10 mediates multidrug resistance (MDR) in cancer cells by preventing the intracellular accumulation of certain antitumor drugs. The ABCC10 transporter is a 171-kDa protein that is localized on the basolateral cell membrane. ABCC10 is a broad-specificity transporter of xenobiotics, including antitumor drugs, such as taxanes, epothilone B, vinca alkaloids, and cytarabine, as wel as modulators of the estrogen pathway, such as tamoxifen. In recent years, ABCC10 inhibitors, including cepharanthine, lapatinib, erlotinib, nilotinib, imatinib, sildenafil, and vardenafil, have been reported to overcome ABCC10-mediated MDR. This review discusses some recent and clinically relevant aspects of the ABCC10 drug efflux transporter from the perspective of current chemotherapy, particularly its inhibition by tyrosine kinase inhibitors and phosphodiesterase type 5 inhibitors.