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。     

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。     

外排型转运体介导的抗肿瘤药物多药耐药的研究进展

多药耐药（MDR）是指肿瘤细胞接触一种抗肿瘤药物后,也对其他多种结构不同、功能不同的抗肿瘤药物产生耐药性,其中外排型转运体所介导的MDR是其中至关重要的一部分。外排型转运体是指位于肿瘤细胞生物膜上的具有将抗肿瘤药物从细胞内外排到细胞外的转运体。已知的具有外排作用的转运体有P糖蛋白（P-gp）、多药耐药相关蛋白（MRP）、乳腺癌耐药蛋白（BCRP）和肺耐药蛋白（LRP）。综述这几种外排型转运体的一般性质并着重于阐述逆转这些转运体介导的多药耐药的药物及方法。     

ABC转运蛋白与肿瘤多药耐药

目的 :介绍ABC转运蛋白与肿瘤多药耐药的研究进展 ,阐述ABC转运蛋白高表达是多药耐药的重要机制之一。方法 :检索国内外大量文献资料进行汇总、综述。结果 :ABC转运蛋白是具有ATP结合区的单向底物外排泵。P -糖蛋白高表达是肿瘤细胞产生多药耐药的经典路径 ,多药耐药相关蛋白高表达能导致非P -糖蛋白介导的多药耐药。结论 :开发多药耐药蛋白抑制剂有广阔的应用价值 ,但注重其药理作用的同时还应对其潜在的毒副作用保持高度警惕     

ATP结合盒转运体介导的肝癌多药耐药研究进展

ATP结合盒转运体(ABC转运体)介导的多药耐药(MDR)是肝癌化疗失败的主要原因,研究确定天然的及获得性MDR的产生机制,有利于提出更有效的治疗措施。针对ATP结合盒转运体的肿瘤MDR逆转策略,对于肝癌化疗效果的提高具有重要意义。此外,ATP结合盒转运体可能参与了肿瘤生物学的一些重要过程,发挥药物外排泵以外的作用,为肿瘤的治疗提供了新的研究方向。     

纳米药物载体抗肿瘤多药耐药机制的研究进展

肿瘤细胞对化疗药物产生多药耐药(multidrug resistance,MDR)是临床化疗失败的一个重要原因,而纳米技术的发展为肿瘤药物的靶向输送提供了新的研究机遇。纳米载体可以通过避免和降低MDR肿瘤细胞的药物外排泵,靶向肿瘤干细胞(cancer stem cells,CSC)克服其复发性,阻断肿瘤细胞的互调及其作用的微环境,以及改变免疫反应等增强细胞对化疗药物的敏感性。本文综述了肿瘤多药耐药的机制,纳米药物载体抗肿瘤多药耐药的机制研究的新进展。     

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。     

孕烷X受体与肿瘤多药耐药

多药耐药（MDR）是肿瘤化疗失败的主要原因之一。MDR的产生主要由ATP结合盒（ABC）转运蛋白超家族的跨膜蛋白所引起,其中P-糖蛋白及其编码基因mdr1的过表达是MDR产生的最主要机制。研究MDR的产生机制,寻找诱发mdr1表达的诱因并阻断其表达,是克服肿瘤多药耐药性行之有效的方法。近来研究发现,孕烷X受体（PXR）可介导mdr1的表达,活化的PXR诱导MDR1的表达。因此,特异性地阻断PXR的活化可抑制mdr1的表达,从而克服多药耐药性。现已发现多种物质可作为PXR抑制剂或拮抗剂。本文即对核受体PXR与MDR、PXR抑制剂及拮抗剂的研究现状做一介绍,以期为克服肿瘤多药耐药提供参考。     

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。     

P-糖蛋白介导的肿瘤多药耐药与逆转

最近数十年,一些ATP依赖的药物外排泵被证实与肿瘤的多药耐药（MDR）有关。ATP结合盒（ATP—binding cassette,ABC）蛋白是一个结合蛋白大家族,由ABC基因编码,在真核生物和原核生物中都有表达。     

Impact of ABC transporters, glutathione conjugates in MDR and their modulation by flavonoids: an overview

Overexpression of ATP-binding cassette (ABC) transporter and glutathione conjugates results in efflux of cytotoxic agent from tumor cells leading to multidrug resistance (MDR). Many MDR inhibitors have been identified but none of them have been proven clinically valuable without side effects. Efforts are continue to develop an ideal MDR inhibitor. Recently, herbal modulation of ABC transporter and glutathione conjugates by flavonoids is emerging as popular therapy in MDR. In this review, we have covered structure, function of different ABC transporters and glutathione-mediated MRP overexpression. This review also focuses on the problems with existing MDR inhibitors, modulation of ABC transporter and glutathione-S-transferase by flavonoids.     

MDR1调控的信号传导机制研究进展

多药耐药(multidrug resistance,MDR)是肿瘤化疗失败的主要原因。MDR的产生与P-糖蛋白(P-glycoprotein,P-gp)的过度表达相关。P-gp是由MDR1基因编码的膜转运蛋白,属于转运蛋白超家族,即ABC家族(ATP binding cassette family),具有能量依赖性药泵功能。过度表达的P-gp导致细胞内药物外排增加是MDR发生的主要机制。细胞内外的许多信号物质(包括化疗药物,紫外线、组织缺氧、化学致癌物质等)都能诱导MDR1基因的表达。本文主要介绍了MDR1调控的信号传导机制研究进展。     

Role of ABC transporters in the chemoresistance of human gliomas

Malignant gliomas are frequently chemoresistant and this resistance seems to depend on at least two mechanisms. First, the poor penetration of many anticancer drugs across the blood-brain barrier (BBB), the blood-cerebrospinal fluid barrier (BCSFB) and blood-tumor barrier (BTB), due to their interaction with several ATP-binding cassette (ABC) drug efflux transporters that are overexpressed by the endothelial or epithelial cells of these barriers. Second, resistance may involve the tumor cells themselves. Although ABC drug efflux transporters in tumor cells confer multidrug resistance (MDR) on several other solid tumors, their role in gliomas is unclear. This review focuses on astrocytes and summarizes the current state of knowledge about the expression, distribution and function of ABC transporters in normal and tumor astroglial cells. The recognition of anticancer drugs by ABC transporters in astroglial cells and their participation in the multidrug resistance phenotype of human gliomas is discussed.     

Revisiting the ABCs of multidrug resistance in cancer chemotherapy

The adenosine tri-phosphate binding cassette (ABC) transporters are one of the largest transmembrane gene families in humans. The ABC transporters are present in a number of tissues, providing protection against xenobiotics and certain endogenous molecules. Unfortunately, their presence produces suboptimal chemotherapeutic outcomes in cancer patient tumor cells. It is well established that they actively efflux antineoplastic agents from cancer cells, producing the multidrug resistance (MDR) phenotype. The inadequate response to chemotherapy and subsequent poor prognosis in cancer patients can be in part the result of the clinical overexpression of ABC transporters. In fact, one of the targeted approaches for overcoming MDR in cancer cells is that directed towards blocking or inhibiting ABC transporters. Indeed, for almost three decades, research has been conducted to overcome MDR through pharmacological inhibition of ABC transporters with limited clinical success. Therefore, contemporary strategies to identify or to synthesize selective "resensitizers" of ABC transporters with limited nonspecific toxicity have been undertaken. Innovative approaches en route to understanding specific biochemical role of ABC transporters in MDR and tumorigenesis will prove essential to direct our knowledge towards more effective targeted therapies. This review briefly discusses the current knowledge regarding the clinical involvement of ABC transporters in MDR to antineoplastic drugs and highlights approaches undertaken so far to overcome ABC transporter-mediated MDR in cancer.     

Reversal of antifungal resistance mediated by ABC efflux pumps from Candida albicans functionally expressed in yeast

The enhanced efflux of antifungal drugs through ATP-binding cassette (ABC) transporters constitutes a major cause of clinical multidrug resistance (MDR). The inhibition of drug efflux pumps by specific compounds is considered to be a feasible strategy to overcome clinical antifungal resistance. Therefore, several blockers of mammalian and yeast ABC drug pumps, including FK506, propafenones, as well as the antifungal drug terbinafine were tested for their capacity to reverse CDR-mediated azole resistance in bakers yeast and in clinical isolates of Candida albicans. We have functionally expressed the C. albicans Cdr1p and Cdr2p transporters in hypersensitive Saccharomyces cerevisiae recipient strains lacking several endogenous ABC pumps. Cdr1p and Cdr2p were functional in yeast, as they conferred pronounced drug resistance to known antifungal drugs, including azoles and terbinafine. We employ two functional assays to demonstrate that ABC pump inhibitors reverse CDR-mediated antifungal resistance, thereby restoring drug susceptibility of yeast cells and resistant clinical isolates. Our results suggest that reversal of antifungal resistance can be achieved through ABC pump-dependent and independent mechanisms.     

P-糖蛋白及其逆转肿瘤细胞多药耐药性的研究进展

随着化疗药物的广泛使用,肿瘤多药耐药性是导致化疗失败的主要原因之一。而p-糖蛋白（P-gp）介导的多药耐药性已成为目前的研究热点,本文就P—gp的结构、组织分布、P—gp介导的肿瘤细胞的多药耐药性及其逆转的研究现状作一综述。     

P-glycoprotein inhibition: the past, the present and the future

The multidrug resistant phenotype of cancer cells can often result from the over-production of a number of ATP binding cassette (ABC) transporters, including P-glycoprotein (P-gp). These multidrug efflux transporters expel administered anti-cancer drugs from the cancer cell, preventing sufficient intracellular drug accumulation and ultimately, drug efficacy. The co-administration of compounds that can impede the efflux of chemotherapeutic agents by these ABC transporters can concomitantly modulate various cytochrome P450 (CYP450) enzymes, consequently impacting upon anti-cancer drug metabolism. This can further result in unfavourable drug-drug interactions and altered pharmacokinetic properties of the administered anti-cancer drugs with knock-on adverse cytotoxic side effects. This review will discuss some of the P-gp inhibitors designed and employed to date, as well as expressing our views of the shortcomings of their design strategy. We present a medicinal chemist's wish list for the paradigmatic P-gp inhibitor molecule and examine the possible future strategies that could be implemented to achieve its design.     

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.