外排型转运体与肿瘤多药耐药

肿瘤多药耐药（MDR）是导致肿瘤化疗失败的主要原因之一。肿瘤MDR的机制有多种,其中外排型转运体的过表达是导致MDR的主要机制,因此研究外排型转运体介导的肿瘤MDR机制和发现可以逆转肿瘤MDR的抑制剂成为国内外研究的热点。就目前研究的3种三磷酸腺苷结合盒转运体：P-糖蛋白、多药耐药相关蛋白、乳腺癌耐药蛋白介导的MDR及逆转MDR的机制进行综述,以期为提高肿瘤治疗疗效提供依据。     

中药逆转肿瘤多药耐药作用机制研究进展

多药耐药(multidrug resistance,MDR)是指肿瘤细胞对一种抗肿瘤药物出现耐药的同时,对其他结构不同、作用靶位不同的抗肿瘤药物也产生耐药现象。MDR产生的机制比较复杂,涉及到药物的外排增加和亚细胞分布改变,药物     

介导肿瘤多药耐药的ATP结合盒转运体的研究进展

多药耐药（MDR）是阻碍肿瘤化疗成功的一大障碍,其机制之一就是耐药的肿瘤细胞高表达三磷酸腺苷（ATP）结合盒（ABC）转运体。依据此机制提出克服肿瘤细胞耐药的策略即开发外排转运体抑制剂,以期逆转MDR。最近的研究发现肿瘤干细胞也可能是通过表达外排转运体天然耐药,这就提供了一个新的抗癌药物作用靶点。对介导肿瘤细胞多药耐药的ABC转运体及其抑制剂的开发作一综述。     

介导肿瘤多药耐药的ATP结合盒转运体的研究进展

多药耐药（MDR）是阻碍肿瘤化疗成功的一大障碍,其机制之一就是耐药的肿瘤细胞高表达三磷酸腺苷（ATP）结合盒（ABC）转运体。依据此机制提出克服肿瘤细胞耐药的策略即开发外排转运体抑制剂,以期逆转MDR。最近的研究发现肿瘤干细胞也可能是通过表达外排转运体天然耐药,这就提供了一个新的抗癌药物作用靶点。对介导肿瘤细胞多药耐药的ABC转运体及其抑制剂的开发作一综述。     

多药耐药糖蛋白p-糖蛋白研究进展

多药耐药糖蛋白介导的耐药机制是肿瘤细胞耐药机制非常常见的原因。多药耐药（multidrug resistance,MDR）是肿瘤细胞最重要的耐药形式之一,它是一种抗肿瘤药物出现耐药的同时,对其他许多结构不同、作用机制不同的抗肿瘤药物也产生耐药性,MDR包括天然性耐药和获得性耐药两种表型,天然性耐药是指首次使用化疗药物就产生耐药,而获得性耐药是指在化疗过程中产生耐药。     

急性白血病的多药耐药及逆转

多药耐药或多药抗性（MDR）系指肿瘤细胞或白血病细胞对结构和作用靶位不同的多种化疗药物有交叉耐药性,为化疗失败主要原因之一。按MDR发生机制有以下几点:（1）细胞膜上能量外排泵介导的 MDR,以 mdr-1/Pgp、MRP为代表;（2）胞质酶介导的MDR,以GST为代表;（3）胞核核孔蛋白介导的MDR,     

ATP结合盒转运蛋白介导的MDR逆转剂的实验研究现况

多药耐药性(mu ltidrug resistance,MDR)是指人肿瘤细胞对结构各异的化疗药物产生交叉耐药,是肿瘤化疗失败的主要原因之一。为了增强肿瘤细胞对化疗药物的敏感性,积极寻求有效逆转MDR的药物已成为研究重点。体外被证实具有逆转耐药活性的化合物很多,但由于体内要达到体外逆转试验的有效浓度所需剂量过大,毒副作用大,因此限制了临床应用。ATP结合盒转运蛋白家族(ATP-b ind ing cassette,ABC)介导的药物外排机制是目前MDR的主要机制,ABC转运蛋白家族中与多药耐药性相关的转运蛋有P-糖蛋白(P-gp)、多药耐药相关蛋白(MRP)和乳腺癌耐药蛋白(BCRP)。本文对ABC转运蛋白介导的MDR逆转剂的研究进展做一综述。     

肿瘤耐药机制研究进展

肿瘤的耐药又分为原发耐药（primary drug resistance,PDR）和多药耐药（mutidrug resistance,MDR）,PDR只对诱导药物产生耐药性,MDR则是指肿瘤细胞对一种抗肿瘤药产生耐药性后,对结构与作用机制不同的抗肿瘤药也产生交叉耐药性。肿瘤MDR是导致肿瘤化疗失败的最主要原因。本文就其耐药机制作一综述。     

透明质酸寡糖与肿瘤多药耐药相关性的研究进展

透明质酸寡糖(o-HA)对不同的肿瘤有不同的作用,其机制也不同。o-HA可以逆转肿瘤细胞的多药耐药性(MDR),抑制糖蛋白的表达,干扰糖蛋白介导的药物外排泵发挥作用,增加抗肿瘤药物在耐药细胞中的蓄积,从而增强疗效。o-HA可以诱导肿瘤细胞发生凋亡,从而使肿瘤细胞恢复对化疗剂的敏感性。o-HA与肿瘤及肿瘤细胞的MDR作用有一定的相关性,且可减弱肿瘤细胞的MDR,具有开发为增敏剂的可能。本文对o-HA肿瘤及肿瘤细胞MDR相关性的进展进行综述。     

中药逆转卵巢癌多药耐药的研究进展

多药耐药（muhidrug resistance，MDR）指肿瘤细胞对一种抗肿瘤药产生耐药性后，对结构与作用机制不同的抗肿瘤药产生交叉耐药的现象。这种现象可以是先天的，也可以是化疗诱导产生的。目前认为其共同的生物学基础是MDR1基因产物P2糖蛋白（P2gP）过量表达，与肿瘤内药物结合或直接从细胞膜上排除抗肿瘤药物，从而降低药物对肿瘤细胞的毒性所致。MDR是目前化疗的主要障碍，是肿瘤细胞产生耐药的重要原因。     

Investigational ABC transporter inhibitors

INTRODUCTION: Multidrug resistance (MDR) is the main cause of failure in cancer therapy. One mechanism responsible for MDR is the active efflux of drugs by ATP-binding cassette (ABC) transporters. Several agents have been developed to block transporter-mediated drug efflux and some of these compounds have entered Phase II/III clinical testing. Evidence is also emerging of the role played by ABC transporters in cancer cell signalling that is likely to be important in disease progression and which is distinct from MDR. AREAS COVERED: This article reviews current literature to analyse the rationale for targeting ABC transporters in cancer. Preclinical and clinical results of ABC transporter inhibitors in early clinical trials, as single agents or in combination with other drugs, are described. The development of new strategies to target MDR and the emerging roles of ABC transporters in cancer signalling are discussed. EXPERT OPINION: The intense active search for safe and effective inhibitors of ABC transporters has led to some success in MDR reversal in preclinical studies. However, there has been little impact on clinical outcome. The discovery of novel, potent and nontoxic inhibitors as well as new treatment strategies is therefore needed.     

The medicinal chemistry of multidrug resistance (MDR) reversing drugs

Multidrug resistance (MDR) is a kind of resistance of cancer cells to multiple classes of chemotherapic drugs that can be structurally and mechanistically unrelated. Classical MDR regards altered membrane transport that results in lower cell concentrations of cytotoxic drug and is related to the over expression of a variety of proteins that act as ATP-dependent extrusion pumps. P-glycoprotein (Pgp) and multidrug resistance protein (MRP1) are the most important and widely studied members of the family that belongs to the ABC superfamily of transporters. It is apparent that, besides their role in cancer cell resistance, these proteins have multiple physiological functions as well, since they are expressed also in many important non-tumoural tissues and are largely present in prokaryotic organisms. A number of drugs have been identified which are able to reverse the effects of Pgp, MRPI and sister proteins, on multidrug resistance. The first MDR modulators discovered and studied in clinical trials were endowed with definite pharmacological actions so that the doses required to overcome MDR were associated with unacceptably high side effects. As a consequence, much attention has been focused on developing more potent and selective modulators with proper potency, selectivity and pharmacokinetics that can be used at lower doses. Several novel MDR reversing agents (also known as chemosensitisers) are currently undergoing clinical evaluation for the treatment of resistant tumours. This review is concerned with the medicinal chemistry of MDR reversers, with particular attention to the drugs that are presently in development.     

多药耐药相关蛋白及其在肿瘤耐药中的作用

多药耐药(multidrug resistance,MDR)是导致肿瘤患者化疗失败的主要原因。介导多药耐药的重要机制之一是多药耐药相关蛋白(multidrug resistance-associated proteins,MRPs)的表达增加。MRPs是一类ATP能量依赖型跨膜转运蛋白,是具有选择性和特异性的药物外排泵。本文主要针对MRPs的生理特征、结构特点、耐药谱特征及其逆转进行综述。     

Overcoming multidrug resistance in human cancer cells by natural compounds

Multidrug resistance is a phenomenon whereby tumors become resistant to structurally unrelated anticancer drugs. P-glycoprotein belongs to the large ATP-binding cassette (ABC) transporter superfamily of membrane transport proteins. P-glycoprotein mediates resistance to various classes of anticancer drugs including vinblastine, daunorubicin, and paclitaxel, by actively extruding the drugs from the cells. The quest for inhibitors of anticancer drug efflux transporters has uncovered natural compounds, including (-)-epigallocatechin gallate, curcumin, capsaicin, and guggulsterone, as promising candidates. In this review, studies on the effects of natural compounds on P-glycoprotein and anticancer drug efflux transporters are summarized.     

Multidrug resistance: retrospect and prospects in anti-cancer drug treatment

Conventional cancer chemotherapy is seriously limited by the multidrug resistance (MDR) commonly exhibited by tumour cells. One mechanism by which a living cell can achieve multiple resistances is via the active efflux of a broad range of anticancer drugs through the cellular membrane by MDR proteins. Such drugs are exported in both ATP-dependent and -independent manners, and can occur despite considerable concentration gradients. To the ATP-dependent group belongs the ATP-binding cassette (ABC) transporter family, which includes P-gp, MRP, BCRP, etc. Another protein related to MDR, though not belonging to the ABC transporter family, is lung resistance-related protein (LRP). All of these proteins are involved in diverse physiological processes, and are responsible for the uptake and efflux of a multitude of substances from cancer cells. Many inhibitors of MDR transporters have been identified over the years. Firstly, MDR drugs were not specifically developed for inhibiting MDR; in fact, they had other pharmacological properties, as well as a relatively low affinity for MDR transporters. They included compounds of diverse structure and function, such as verapamil and cyclosporine, and caused side effects. Secondly, the new drugs were more inhibitor-specific, in terms of MDR transport, and were designed to reduce such side effects (e.g., R-verapamil, dexniguldipine, etc.). Unfortunately, they displayed poor response in clinical studies. Recently, new compounds obtained from drug development programs conducted by the pharmaceutical industry are characterized by a high affinity to MDR transporters and are efficient at nanomolar concentrations. Some of these compounds (e.g., MS-209) are currently under clinical trials for specific forms of advanced cancers. We aim to provide an overview of the properties associated with those mammalian MDR transporters known to mediate significant transport of relevant drugs in cancer treatments. We also summarize recent advances concerning resistance to cancer drug therapies with respect to the function and overexpression of ABC and LRP multidrug transporters.