title: RNAi-based knockdown of multidrug resistance-associated protein 1 is sufficient to reverse multidrug resistance of human lung cells.
abstract: Up-regulation of multidrug resistance-associated protein 1 (MRP1) is regarded as one of the main causes for multidrug resistance (MDR) of tumor cells, leading to failure of chemotherapy-based treatment for a multitude of cancers. However, whether silencing the overexpressed MRP1 is sufficient to reverse MDR has yet to be validated. This study demonstrated that RNAi-based knockdown of MRP1 reversed the increased efflux ability and MDR efficiently. Two different short haipin RNAs (shRNAs) targeting MRP1 were designed and inserted into pSilence- 2.1-neo. The shRNA recombinant plasmids were transfected into cis-dichlorodiamineplatinum-resistant A549 lung (A549/DDP) cells, and then shRNA expressing cell clones were collected and maintained. Real time PCR and immunofluorescence staining for MRP1 revealed a high silent efficiency of these two shRNAs. Functionally, shRNA-expressing cells showed increased rhodamine 123 retention in A549/DDP cells, indicating reduced efflux ability of tumor cells in the absence of MRP1. Consistently, MRP1-silent cells exhibited decreased resistance to 3- (4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and DDP, suggesting reversal of MDR in these tumor cells. Specifically, MRP1 knockdown increased the DDP-induced apoptosis of A549/DDP cells by increased trapping of their cell cycling in the G2 stage. Taken together, this study demonstrated that RNAi- based silencing of MRP1 is sufficient to reverse MDR in tumor cells, shedding light on possible novel clinical treatment of cancers.
authors.affiliation: College of Life Sciences and Agriculture and Forestry, Qiqihar University, Qiqihar, China E-mail : shshl32@163.com.
authors.forename: Shu-Li
authors.initials: SL
authors.lastname: Shao
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Cui
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Zhang
authors.forename: Zhen-Li
authors.initials: ZL
authors.lastname: Xie
authors.forename: Chang-He
authors.initials: CH
authors.lastname: Wang
authors.forename: Hong-Shuang
authors.initials: HS
authors.lastname: Jia
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology*; D018432:Drug Resistance, Multiple / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005455:Fluorescent Antibody Technique; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D002945:Cisplatin; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C421109:multidrug resistance-associated protein 1