Hongmei Yuan1, Hongge Wu2, Jing Cheng2, Jie Xiong3. 1. Department of Pathology, Wuhan Jinyintan Hospital, Wuhan City, Hubei province, China. 2. Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei province, China. 3. Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan City, Hubei province, China. xiongjie_whuh@163.com.
Abstract
BACKGROUND: The involvement of circular RNAs (circRNAs) in the development of cancers has attracted much interest. This study aimed to determine the role of circ_0000376 in non-small cell lung cancer (NSCLC) and provide a new mechanism. METHODS: The expression of circ_0000376, miR-488-3p and bromodomain containing 4 (BRD4) mRNA was measured by quantitative real-time PCR (qPCR). Cell behaviors, including cell proliferation, invasion, migration, apoptosis and cell cycle progression were investigated using cell counting kit-8 (CCK-8) assay and colony formation assay, transwell assay, wound healing assay and flow cytometry assay, respectively. The putative relationship between miR-488-3p and circ_0000376 or BRD4 was verified by dual-luciferase reporter assay. The protein levels of BRD4 and phosphorylated PI3K/PKB were detected by western blot. Xenograft model was constructed to determine the role of circ_0000376 in vivo. RESULTS: Circ_0000376 was highly expressed in NSCLC tissues and cells. Circ_0000376 downregulation inhibited NSCLC cell proliferation, invasion and migration, promoted cell apoptosis and cell cycle arrest and slowed tumor growth in vivo. Circ_0000376 competitively bound to miR-488-3p to regulate the expression of BRD4. Rescue experiments showed that miR-488-3p deficiency reversed the effects of circ_0000376 downregulation, and miR-488-3p restoration-suppressed cell proliferation, migration and invasion were recovered by BRD4 overexpression. Moreover, circ_0000376 downregulation weakened the levels of phosphorylated PI3K and PKB, thus reducing the activity of the PI3K/PKB pathway. CONCLUSION: Circ_0000376 downregulation blocked the development of NSCLC by targeting the miR-488-3p/BRD4 network and suppressing the PI3K/PKB pathway, which broadens knowledge into the understanding of the role of circ_0000376 in NSCLC.
BACKGROUND: The involvement of circular RNAs (circRNAs) in the development of cancers has attracted much interest. This study aimed to determine the role of circ_0000376 in non-small cell lung cancer (NSCLC) and provide a new mechanism. METHODS: The expression of circ_0000376, miR-488-3p and bromodomain containing 4 (BRD4) mRNA was measured by quantitative real-time PCR (qPCR). Cell behaviors, including cell proliferation, invasion, migration, apoptosis and cell cycle progression were investigated using cell counting kit-8 (CCK-8) assay and colony formation assay, transwell assay, wound healing assay and flow cytometry assay, respectively. The putative relationship between miR-488-3p and circ_0000376 or BRD4 was verified by dual-luciferase reporter assay. The protein levels of BRD4 and phosphorylated PI3K/PKB were detected by western blot. Xenograft model was constructed to determine the role of circ_0000376 in vivo. RESULTS: Circ_0000376 was highly expressed in NSCLC tissues and cells. Circ_0000376 downregulation inhibited NSCLC cell proliferation, invasion and migration, promoted cell apoptosis and cell cycle arrest and slowed tumor growth in vivo. Circ_0000376 competitively bound to miR-488-3p to regulate the expression of BRD4. Rescue experiments showed that miR-488-3p deficiency reversed the effects of circ_0000376 downregulation, and miR-488-3p restoration-suppressed cell proliferation, migration and invasion were recovered by BRD4 overexpression. Moreover, circ_0000376 downregulation weakened the levels of phosphorylated PI3K and PKB, thus reducing the activity of the PI3K/PKB pathway. CONCLUSION: Circ_0000376 downregulation blocked the development of NSCLC by targeting the miR-488-3p/BRD4 network and suppressing the PI3K/PKB pathway, which broadens knowledge into the understanding of the role of circ_0000376 in NSCLC.