Investigation of expression regulatory mechanisms of drug transporters with its possible application for circumventing anticancer drug resistance

药物转运蛋白表达调控机制的研究及其在规避抗癌耐药性方面的可能应用

基本信息

批准号：
18590379
负责人：
IMAI Yasuo
金额：
$ 1.54万
依托单位：
Dokkyo Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18590379/
关键词：
Cancer Chemotherapy

项目摘要

ABCG2/BCRP, a member of the ATP-binding cassette transporter G family, functions as an efflux pump that excludes such anticancer agents as mitoxantrone, SN-38 (an active metabolite of irinotecan), and topotecan, across cell membrane. Accordingly ABCG2 causes multidrug resistance when overexpressed in cancer cells. We have thus far clarified that estrogen markedly down-regulates ABCG2 expression in estrogen receptor-positive breast cancer cells in the post-transcriptional manner, but use of estrogen in the practical clinic seemed to be limited due to its original physiological function.We then transfected ABCG2 cDNA to breast cancer MCF-7 cells and gastric cancer MKN1 and NCI-N87 cells, which express endogenous ABCG2, in order to exploring small molecules that affects ABCG2 expression levels, and termed them MCF-7/ABCG2, MKN1/ABCG2, and NCI-N87/ABCG2 cells.Exogenous ABCG2 protein expression in MCF-7/ABCG2, MKN1/ABCG2, NCI-N87/ABCG2 cells was markedly repressed by p44/p42 mitogen-activat … More ed protein kinase (MAPK), PD98059 and U0126, in the dose-dependent manner. These compounds almost completely overcame mitoxantrone- or SN-38- resistance of MCF-7/ABCG2 and NCI-N87/ABCG2 cells. FACS analyses revealed that the reversal effects were due to increased intracellular uptake of anticancer agents. Quantitative RT-PCR analyses demonstrated that ABCG2 mRNA levels were not affected by the treatment with PD98059 or U0126. In addition, a half life of the ABCG2 protein was significantly short in the presence of PD98059 as compared with that in the control experiment.PD98059-mediated degradation of ABCG2 protein was not affected by MG132, an ubiquitin/endosome inhibitor, but was completely blocked by bafilomycin A1, an endosomal inhibitor. These data suggest that inhibition of p44/p42 MAPK pathway may accelerate endosomal degradation of ABCG2 protein and makes it possible to overcome ABCG2-mediated multidrug resistance. These data may also suggest that p44/p42 MAPK inhibitors may serve for establishment of safe and effective chemotherapeutic regimen. Less

ABCG2/BCRP 是 ATP 结合盒转运蛋白 G 家族的成员，充当外排泵，排除米托蒽醌、SN-38（伊立替康的活性代谢物）和拓扑替康等抗癌药物穿过细胞膜。迄今为止，我们已经阐明，雌激素在雌激素受体阳性细胞中显着下调 ABCG2 的表达。乳腺癌细胞以转录后方式表达，但雌激素由于其原有的生理功能，在实际临床中的使用似乎受到限制。然后我们将ABCG2 cDNA转染到乳腺癌MCF-7细胞和胃癌MKN1和NCI-N87细胞中，表达内源性ABCG2，以探索影响ABCG2表达水平的小分子，并将它们命名为MCF-7/ABCG2、MKN1/ABCG2和NCI-N87/ABCG2 细胞。MCF-7/ABCG2、MKN1/ABCG2、NCI-N87/ABCG2 细胞中的外源 ABCG2 蛋白表达受到 p44/p42 丝裂原激活蛋白激酶 (MAPK)、PD98059 和 U0126 的显着抑制，以剂量依赖性方式，这些化合物几乎完全克服了米托蒽醌或米托蒽醌。 MCF-7/ABCG2 和 NCI-N87/ABCG2 细胞的 SN-38 抗性表明，逆转效应是由于抗癌药物的细胞内摄取增加所致。定量 RT-PCR 分析表明，ABCG2 mRNA 水平不受此影响。用PD98059或U0126处理此外，与PD98059存在下相比，ABCG2蛋白的半衰期显着缩短。 PD98059介导的ABCG2蛋白降解不受泛素/内体抑制剂MG132影响，但被内体抑制剂巴弗洛霉素A1完全阻断。这些数据表明，抑制p44/p42 MAPK途径可能会加速内体降解。 ABCG2 蛋白并使得克服 ABCG2 介导的多药耐药性成为可能。这些数据也可能表明 p44/p42 MAPK。抑制剂可能有助于建立安全有效的化疗方案。