Department of Radiotherapy, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China.
Department of Oncology, The First Affiliated Hospital, Xi'an Medical University, Xi'an, Shaanxi 710077, P.R. China.
Oncol Rep. 2021 Apr;45(4). doi: 10.3892/or.2021.7955. Epub 2021 Mar 2.
The development of multidrug resistance is the major obstacle to successful lung cancer chemotherapy. Cancer cells gain resistance through increased levels of P‑glycoprotein (P‑gp), which is encoded by the multidrug resistance‑associated protein 1 () gene. Leucine‑rich PPR motif‑containing protein (LRPPRC), a member of the PPR family, has been verified to regulate the transcription of . This regulation is influenced by the methylation status of the GC ‑100 box in the promoter. The present study aimed to investigate the effect of LRPPRC on cisplatin (DDP) resistance in lung cancer cells and explore the underlying mechanism. DDP‑resistant non‑small cell lung cancer cell lines (A549/DDP, H1299/DDP) were generated. The expression levels of LRPPRC and P‑gp/, investigated by qPCR and western blot analysis, were increased in the A549/DDP and H1299/DDP cells compared with that in the parental cells. LRPPRC silencing with shRNA increased DDP sensitivity and . LRPPRC silencing inhibited the level of LRPPRC binding with the MDR1 promoter, investigated by chromatin immunoprecipitation‑qPCR, and the corresponding expression. Demethylation treatment rescued the decrease in the level of LRPPRC binding with and the corresponding expression of and the increase in DDP sensitivity due to LRPPRC silencing. Our study suggests that LRPPRC contributes to DDP resistance in lung cancer cells by regulating transcription. Thus, LRPPRC may serve as a potential molecular target for chemo‑resistance reversal in lung cancer.
多药耐药的发展是肺癌化疗成功的主要障碍。癌细胞通过增加 P-糖蛋白(P-gp)的水平获得耐药性,P-gp 由多药耐药相关蛋白 1(MDR1)基因编码。富含亮氨酸的 PPR 基序蛋白(LRPPRC)是 PPR 家族的一员,已被证实可调节 MDR1 基因的转录。这种调节受 MDR1 启动子中 GC-100 盒的甲基化状态影响。本研究旨在探讨 LRPPRC 对肺癌细胞顺铂(DDP)耐药性的影响,并探讨其潜在机制。通过 qPCR 和 Western blot 分析,在 A549/DDP 和 H1299/DDP 细胞中,LRPPRC 和 P-gp/MDR1 的表达水平均高于亲本细胞。用 shRNA 沉默 LRPPRC 可增加 DDP 敏感性和 MDR1 表达。通过染色质免疫沉淀-qPCR 研究发现,LRPPRC 沉默抑制了 LRPPRC 与 MDR1 启动子的结合水平,相应的 MDR1 表达也受到抑制。去甲基化处理可挽救因 LRPPRC 沉默导致的 MDR1 启动子与 LRPPRC 结合水平降低和 MDR1 及其下游靶基因表达增加,以及 DDP 敏感性增加。本研究表明,LRPPRC 通过调节 MDR1 转录参与肺癌细胞的 DDP 耐药。因此,LRPPRC 可能成为逆转肺癌化疗耐药的潜在分子靶点。