Low-intensity ultrasound enhanced the antitumor effects of cisplatin in non-small cell lung cancer cells via inhibiting miR-124/STAT3 signaling
Creators: name: Peng, Liqing
name: Luo, Zhijian
name: Liu, Dan
name: Feng, Gang
name: Li, Mingxing
Publisher: name: IfADo - Leibniz Research Centre for Working Environment and Human Factors, Dortmund
Year: 2018
Subjects: low-intensity ultrasound
cisplatin
non-small cell lung cancer
reactive oxygen species
microRNA-124
STAT3

description: Cisplatin (CDDP) is one of the most widely employed first-line chemotherapeutic agent against human non-small cell lung cancer (NSCLC). However, most NSCLC patients are eventually resistant to chemotherapy. Recently, the combined effects of low-intensity ultrasound (US) and several anti-cancer drugs have often been reported, but the underlying mechanism remains largely unknown. This study aimed to test whether low-intensity ultrasound could enhance the anti-tumor effects of cisplatin in NSCLC cells and reveal its underlying molecular mechanism. First, the effects of low-intensity US on cisplatin mediated cell viability, induction of apoptosis and reactive oxygen species (ROS) production were determined by CCK-8 assay, flow cytometry analysis and fluorescent probe (DCFH-DA), respectively. To profile the expression of miRNAs that are involved in the combined effects of cisplatin and low-intensity US, miRNA microarray was applied and the result was verified by quantitative reverse transcription PCR (qRT-PCR). Loss-of-function study was performed to determine the role of miR-124 in the combined effect of cisplatin and low-intensity US exposure. A luciferase reporter assay was performed to validate the interaction between miR-124 and signal transducer and activator of transcription 3 (STAT3) followed by qRT-PCR and Western blot confirmation. Afterward, we further explored whether the effects of miR-124 on the anti-tumor activity of US combined with cisplatin are mediated by STAT3 signaling pathway. Our study showed that low-intensity US enhanced the anti-tumor effects of cisplatin in A549 cells, as evidence by the reduction of cell viability and the induction of apoptosis and ROS levels compared with cisplatin alone treatment. Subsequently, blockade of ROS generation by NAC significantly reversed low-intensity US induced the expression of miR-124, suggesting that cisplatin combined with low-intensity US up-regulated the expression of miR-124 through generation of ROS. Knockdown of miR-124 inhibited the synergistic effects of cisplatin combined with low-intensity US in A549 cells. STAT3, an oncogene, was identified as a direct target of miR-124 and its expression was negatively regulated by miR-124 at mRNA and protein levels. Furthermore, cisplatin combined with low-intensity US decreased the expressions of STAT3 and its downstream genes, phosphorylated STAT3 (p-STAT3), B-cell lymphoma 2 (Bcl-2) and Bcl-xL, whereas knockdown miR-214 reversed the inhibitory effects of cisplatin combined with low-intensity US in A549 cells. In conclusion, our study unraveled low-intensity US enhanced the anti-tumor effects of cisplatin on NSCLC cells and elucidated the participation of miR-124/STAT3 signaling pathway in the synergistic effects of cisplatin combined with low-intensity US. Our findings suggest that low-intensity US can be considered to be a potential strategy for overcoming cisplatin resistance in NSCLC.
description: EXCLI Journal; 17:Doc113; ISSN 1611-2156