Tianjian Lu1, Weiping Lu2, Chunyi Jia3, Shanguang Lou2, Yan Zhang4. 1. Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu, China. 2. Department of Thoracic Surgery, Changchun Tumor Hospital, China. 3. Department of Thoracic Surgery, Jilin Tumor Hospital, Changchun, China. 4. Department of Anesthesia, Nanhua University, Hengyang, China.
Abstract
BACKGROUND: Induction of acquired drug resistance occurs frequently with cisplatin-based therapy for non-small cell lung cancer (NSCLC). As recent studies have demonstrated that deregulation of microRNAs (miRNAs) is associated with drug resistance in cancers, correcting the deregulation of miRNAs represents a promising strategy to reverse acquired resistance in NSCLC. OBJECTIVES: This study investigated the functional role of miR-15b in cisplatin resistance in NSCLC. MATERIAL AND METHODS: Cisplatin-resistant PC9 and A549 NSCLC cell lines (PC9-R and A549-R) were established through long-term exposure to cisplatin. Differences in miR-15b expression between cisplatin-resistant NSCLC cell lines and their parental cell lines were identified through quantitative real-time polymerase chain reaction (qRT-PCR). The effect of anti-miR-15b on the sensitivity of PC9-R and A549-R to cisplatin-induced cytotoxicity was evaluated using Cell Counting Kit-8 (CCK-8) assays. Regulation of GSK-3β by miR-15b was confirmed with luciferase reporter assays. Cell apoptosis and mitochondrial membrane potential (MMP) were measured using flow cytometry analysis. RESULTS: In PC9-R and A549-R cells, miR-15b was significantly overexpressed. However, knockdown of miR-15b clearly reduced cisplatin resistance in PC9-R and A549-R cells. Researching the mechanism, we proved that GSK-3β was the target of miR-15b. Knockdown of miR-15b significantly increased the expression GSK-3β and thus promoted the degradation of MCL-1, which is a key anti-apoptosis protein. As a result, anti-miR-15b expanded the cisplatin-induced apoptosis in cisplatin-resistant NSCLC cells. CONCLUSIONS: Knockdown of miR-15b partially reversed cisplatin resistance in NSCLC cells through the GSK-3β/MCL-1 pathway.
BACKGROUND: Induction of acquired drug resistance occurs frequently with cisplatin-based therapy for non-small cell lung cancer (NSCLC). As recent studies have demonstrated that deregulation of microRNAs (miRNAs) is associated with drug resistance in cancers, correcting the deregulation of miRNAs represents a promising strategy to reverse acquired resistance in NSCLC. OBJECTIVES: This study investigated the functional role of miR-15b in cisplatin resistance in NSCLC. MATERIAL AND METHODS: Cisplatin-resistant PC9 and A549 NSCLC cell lines (PC9-R and A549-R) were established through long-term exposure to cisplatin. Differences in miR-15b expression between cisplatin-resistant NSCLC cell lines and their parental cell lines were identified through quantitative real-time polymerase chain reaction (qRT-PCR). The effect of anti-miR-15b on the sensitivity of PC9-R and A549-R to cisplatin-induced cytotoxicity was evaluated using Cell Counting Kit-8 (CCK-8) assays. Regulation of GSK-3β by miR-15b was confirmed with luciferase reporter assays. Cell apoptosis and mitochondrial membrane potential (MMP) were measured using flow cytometry analysis. RESULTS: In PC9-R and A549-R cells, miR-15b was significantly overexpressed. However, knockdown of miR-15b clearly reduced cisplatin resistance in PC9-R and A549-R cells. Researching the mechanism, we proved that GSK-3β was the target of miR-15b. Knockdown of miR-15b significantly increased the expression GSK-3β and thus promoted the degradation of MCL-1, which is a key anti-apoptosis protein. As a result, anti-miR-15b expanded the cisplatin-induced apoptosis in cisplatin-resistant NSCLC cells. CONCLUSIONS: Knockdown of miR-15b partially reversed cisplatin resistance in NSCLC cells through the GSK-3β/MCL-1 pathway.