肺癌多药耐药生物逆转策略

肺癌的耐药性一直是影响其化疗效果的一大难题。耐药性的产生机制非常复杂，随着现代分子生物学技术的发展，不断有新的观点提出，并据此在逆转耐药方面提出许多新的干预方法，如生物逆转策略。这是解决肺癌耐药值得探究并有应用前景的策略。     

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。     

肺癌多药耐药及生物逆转

肺癌是人类最常见的恶性肿瘤之一,全身化疗在肺癌的治疗中仍占有相当重要的地位。近年来,随着抗肿瘤药物作用机理的深入研究,新的抗肿瘤药物不断发现,化疗方案不断改进,化疗的疗效也不断提高。但化疗药物的交叉耐药性即多药耐药性的存在是导致化疗失败的重要原因。多药耐药性(m     

红霉素逆转乳腺癌多药耐药的临床研究

目的：研究红霉素逆转乳腺癌多药耐药（MDR）的临床疗效，方法：采用免疫组化SP法检测乳腺癌P－糖蛋白（P-gp)表达，将P-gp表达阳性者随机分两组：红霉素加化疗组（试验组）28例，单纯化疗组（对照组）14例，采用CAF方案化疗，结果：试验组CR＋PR 19例（67．9％），对照组4例（28．6％），两组比较差异有显著性（P＜0．05），结论：红霉素对逆转乳腺癌MDR具有一定的作用。     

肿瘤的多药耐药及耐药逆转剂研究

目前 ,尽管不断有新的化疗药物和化疗方案推出 ,但肿瘤细胞对多种化疗药物产生的多药耐药性(ｍｕｌｔｉｄｒｕｇｒｅｓｉｓｔａｎｃｅ ,ＭＤＲ)仍是化疗失败的主要原因。所谓ＭＤＲ系指肿瘤对一种抗肿瘤药物出现耐药的同时 ,对其他许多结构各异、作用机制不同的抗肿瘤药物亦产生交叉耐药现象。ＭＤＲ现象可以原发性和继发性两种形式出现。原发性 (ｐｒｉｍａｒｙｒｅｓｉｓ ｔａｎｃｅ)是肿瘤细胞固有的对化疗药物不敏感 ,故首次使用化疗药物就产生耐药 ;继发性 (ｓｅｃｏｎｄａｒｙｒｅ ｓｉｓｔａｎｃｅ)则是初始对化疗药物敏感 ,但经过几…     

肿瘤多药耐药机制及逆转耐药研究进展北大核心

癌症化学治疗被视为旨在最小化和延迟肿瘤的发生、发展或复发的策略,但是肿瘤多药耐药是肿瘤患者治疗失败和复发的主要原因,是实现肿瘤患者治愈的主要限制因素。如何逆转化疗药物的耐药及耐药机制的研究成为肿瘤研究的挑战。为了解决肿瘤多药耐药问题,本文对传统化疗药物发生肿瘤多药耐药的机制、靶向治疗发生多药耐药的机制以及免疫治疗发生多药耐药的机制进行阐述;确定了癌症耐药性的实验室方法,如MTT测试法、药物敏感性测试、多药耐药基因和途径检测、高通量筛选技术、基因芯片技术等,为多药耐药的研究提供实验方法;并对多药耐药抑制剂或逆转剂的研究进展进行简单的综述,旨在为进一步发明逆转肿瘤多药耐药的药物提供研究基础。     

槲皮素对多药耐药细胞株KB-MRP的耐药逆转研究

目的:研究槲皮素(quercetin)对多药耐药细胞株KB-MRP的耐药逆转作用。方法:使用四甲基偶氮唑盐(MTT)法检测不同浓度槲皮素对细胞株KB-MRP的抑制率,确定其非细胞毒性浓度。用MTT法分别检测阿霉素(ADM)、依立替康(CPT-11)、长春新碱(VCR)、环磷酰胺(CTX)对细胞株KB-3-1、KB-MRP以及使用槲皮素处理后的KB-MRP的半数抑制浓度(IC50)。通过流式细胞术检测KB-3-1、加入槲皮素前后KB-MRP细胞内的化疗药物阿霉素(ADM)的荧光强度以及加入槲皮素前后多药耐药细胞株KB-MRP的MRP1蛋白表达。结果:终浓度为0~40μmol/L的槲皮素对KB-MRP无明显细胞毒作用。KB-MRP对ADM、VCR、CPT-11均有不同程度的耐药但对CTX不耐药。使用20μmol/L槲皮素处理后KB-MRP对上述ADM、CPT-11、VCR的敏感度均有不同程度的提高,胞内的化疗药物阿霉素(ADM)的荧光强度增强。槲皮素的浓度提高至40μmol/L时,KB-MRP对上述药物的敏感程度提高更明显。流式细胞仪结果显示经槲皮素处理后KB-MRP细胞MRP1表达明显下降。结论:槲皮素可以逆转KB-MRP的多药耐药,逆转效果与剂量相关,逆转机制可能与MRP1的表达下调有关。     

Estrone and 17beta-estradiol reverse breast cancer resistance protein-mediated multidrug resistance.

Breast cancer resistance protein (BCRP), an adenosine triphosphate-binding cassette transporter, confers resistance to a series of anticancer reagents, including mitoxantrone, SN-38 and topotecan. In the present study, we found that estrone and 17beta-estradiol potentiated the cytotoxicity of mitoxantrone, SN-38 and topotecan in BCRP-transduced K562 cells (K562 / BCRP). These estrogens showed only a marginal effect, or none, in parental K562 cells. Estrone and 17beta-estradiol increased the cellular accumulation of topotecan in K562 / BCRP cells, but not in K562 cells, suggesting that these estrogens inhibit the BCRP-mediated drug efflux and overcome drug resistance.     

托瑞米芬逆转乳腺癌耐药蛋白介导的多药耐药机制

目的 探讨托瑞米芬逆转乳腺癌耐药蛋白(BCRP)介导的多药耐药机制。方法 通过基因扩增,构建分别由BCRP启动子和巨细胞病毒(CMV)启动子启动表达BCRP的重组质粒pcDNA3-Promoter-BCRP和作为对照的质粒pcDNA3-CMV-BCRP,将其分别转染雌激素受体α（ERα）阳性的MCF-7和ERα阴性的MDA-MB-231乳腺癌细胞系,建立由BCRP启动子和CMV启动子启动表达BCRP的4种耐药细胞系MCF-7/Promoter-BCRP、MCF-7/CMV-BCRP、MDA-MB-231/PromoterBCRP和MDA-MB-231/CMV-BCRP。在耐药细胞培养基中加入托瑞米芬,通过逆转录聚合酶链反应(RT-PCR)、Western blot、外排实验以及细胞毒性实验观察托瑞米芬对不同细胞系的耐药逆转效果。结果与空白对照组（未加药物）相比,托瑞米芬以剂量依赖方式抑制BCRP mRNA的表达,0.1、1和10 μmol/L托瑞米芬处理组MCF-7/Promoter-BCRP细胞中BCRP mRNA的表达水平分别下调29.5％(P＜0.05)、68.1％ (P＜0.01)和97.4％(P＜0.01);MCF-7/Promoter-BCRP细胞经托瑞米芬和17β-雌二醇联合处理后,细胞中BCRP mRNA的相对表达水平为64.2％±1.3％,明显高于托瑞米芬单独处理组(3.8％±0.2％,P＜0.01)。托瑞米芬对各组细胞系中BCRP蛋白表达的调控作用与mRNA相似。经托瑞米芬处理后,MCF-7/Promoter-BCRP细胞内米托蒽醌的荧光强度显著增强,外排米托蒽醌的能力降低了 47.3％ (P ＜0.05);经托瑞米芬和17β-雌二醇联合处理后,MCF-7/Promoter-BCRP细胞内米托蒽醌的荧光强度明显低于托瑞米芬单独处理组,外排米托蒽醌的能力升高了61.5％。托瑞米芬可有效逆转MCF-7/Promoter-BCRP细胞对米托蒽醌的耐药性。上述作用在MCF-7/CMV-BCRP、MDA-MB-231/Promoter-BCRP和MDA-MB-231/CMV-BCRP细胞中未能体现。结论 托瑞米芬可能通过ERot的介导与BCRP启动子上游调控序列中的ERE结合,负性调节BCRP的表达,抑制BCRP蛋白的功能,在体外有效逆转BCRP介导的多药耐药。     

肺癌多药耐药性机制研究进展

多药耐药是肺癌药物治疗失败的重要原因。克服多药耐药障碍是肺癌基础和临床研究的重点。Pgp，多药耐药相关蛋白和肺耐药相关蛋白等药物外排泵机制，是目前研究最广泛深入的机制。     

CA916798 regulates multidrug resistance of lung cancer cells

Objectives: Multidrug resistance (MDR) significantly reduces the efficacy of chemotherapy for lung cancer. In this study, we characterized the significance of CA916798, a gene up-regulated in cis-dichlorodiamine platinum (CDDP)-resistant lung adenocarcinoma cells, in mediating MDR in lung cancer cells. Methods: CA916798 was stably transfected into H446 cells with low endogenous expression of CA916798, and knocked down in A549/CDDP cells with high endogenous level of CA916798. Expression was confirmed by real-time PCR, Western immunoblotting and immunocytochemistry. Subsequent effects were examined on cellular growth, apoptosis and cell cycle progression. Results: Ectopic expression of CA916798 in H446 cells confered enhanced resistance to multiple chemotherapeutic agents, while its reduction rendered A549/CDDP cells less resistant to chemotherapeutic agents tested. Further analysis revealed that CA916798 regulates CDDP-induced cell growth, apoptosis and cell cycle progression. Conclusion: CA916798 may be a novel MDR-related target for lung cancer therapy.     

Effect of natural flavonoids to reverse P-glycoprotein-related multidrug resistance in breast cancer cell cultures

The aim of the research was to evaluate the influence of two P-glycoprotein (P-gp) inhibitors silymarin and quercetin on anticancer drug doxorubicin (DOX) and pegylated liposomal doxorubicin (PLD) delivery into breast cancer cells (2D cultures) and cancer cell spheroids (3D cultures) at different pH. The cytotoxicity of the compounds was assessed using MTT assay. Spheroids were generated using magnetic 3D Bioprinting method. The uptake of DOX and PLD into monolayer-cultured cells and spheroids was assessed by fluorescence microscopy. Both tested flavonoids did not increase DOX and PLD levels into monolayer-cultured 4T1 cells and 4T1 cell spheroids. However, both silymarin and quercetin enhanced DOX and PLD uptake into JC cell cultures. Silymarin and quercetin may modulate DOX and PLD transport into monolayer-cultured cells and three-dimensional cancer cell cultures depending on P-gp activity.     

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.     

Molecular and pharmacological strategies to overcome multidrug resistance

Multidrug resistance is a major obstacle to the effective treatment of cancer. Despite vast improvements in our understanding of the mechanisms of drug resistance, relatively few significant advances have been made towards effectively circumventing it in a clinical setting. The ability to modulate multidrug resistance has been complicated by the fact that many human tumors simultaneously exhibit multiple resistance mechanisms. In order to effectively overcome multidrug resistance it will be necessary to design new strategies that combine multiple modulating agents and approaches. This review provides an overview of the major causes of multidrug resistance and summarizes many of the current approaches being taken to overcome it. We also describe how liposomal drug delivery systems can be utilized to aid in achieving these goals.     

Molecular and pharmacological strategies to overcome multidrug resistance

Multidrug resistance is a major obstacle to the effective treatment of cancer. Despite vast improvements in our understanding of the mechanisms of drug resistance, relatively few significant advances have been made towards effectively circumventing it in a clinical setting. The ability to modulate multidrug resistance has been complicated by the fact that many human tumors simultaneously exhibit multiple resistance mechanisms. In order to effectively overcome multidrug resistance it will be necessary to design new strategies that combine multiple modulating agents and approaches. This review provides an overview of the major causes of multidrug resistance and summarizes many of the current approaches being taken to overcome it. We also describe how liposomal drug delivery systems can be utilized to aid in achieving these goals.     

Resistance to anticancer immunity in cancer patients: potential strategies to reverse resistance

In the 1990s, the application of immunotherapy approaches to target cancer cells resulted in significant clinical responses in patients with advanced malignancies who were refractory to conventional therapies. While early immunotherapeutics were focused on T cell-mediated cytotoxic activity, subsequent efforts were centered on targeted antibody-mediated anticancer therapy. The initial success with antibody therapy encouraged further studies and, consequently, there are now more than 25 FDA-approved antibodies directed against a range of targets. Although both T cell and antibody therapies continue to result in significant clinical responses with minimal toxicity, a significant subset of patients does not respond to immunotherapy and another subset develops resistance following an initial response. This review is focused on describing examples showing that cancer resistance to immunotherapies indeed occurs. In addition, it reviews the mechanisms being used to overcome the resistance to immunotherapies by targeting the tumor cell directly and/or the tumor microenvironment.     

乳腺癌内分泌治疗的耐药机制及对策

内分泌治疗是激素敏感型乳腺癌患者的重要治疗手段,临床实践及基础研究均发现内分泌治疗存在原发或继发耐药,导致内分泌治疗失败,本文主要介绍内分泌治疗代表药物选择性雌激素受体和芳香化酶抑制剂的耐药机制及相应对策.