Qian Liu1, Wei Yu1, Shujuan Zhu1, Ke Cheng1, Hong Xu2, Yalan Lv3, Xuan Long4, Lan Ma1, Juan Huang1, Shanquan Sun1, Kejian Wang1. 1. Department of Anatomy, Institute of Neuroscience, Chongqing Medical University, Chongqing, China. 2. Department of Epidemiology, School of Public Health and Management, Chongqing Medical University, Chongqing, China. 3. Department of Medical Information Management and Decision Making, School of Medical Informatics, Chongqing Medical University, Chongqing, China. 4. Department of Orthopedics, Renmin Hospital of Wuhan University, Wuhan, China.
Abstract
INTENTION: Long noncoding RNAs, transcribed from a recently discovered class of noncoding genes, may play a critical role in regulating cellular processes, such as cell proliferation and apoptosis, as well as in cancer progression and metastasis. We previously detected the induction of growth arrest-specific 5 (GAS5) during glioma cell death. However, the function and underlying mechanism of GAS5 in human gliomas remain to be elucidated. METHODS: Cell proliferation was detected using CellTiter 96® AQueous Non-Radioactive Cell Proliferation Assay (MTS) and tumorigenicity assay in nude mice. Wound-healing assay and transwell assay were utilized to examine the effects of GAS5 expression on glioma cells migration and invasion. In situ hybridization (ISH) was performed to evaluate GAS5 and microRNA (miR)-18a-5p levels in tissue microarrays. The relationship between GAS5 and miR-18a-5p was evaluated by quantitative reverse-transcription polymerase chain reaction and RNA precipitation. RESULTS: In this study, we demonstrated that overexpression of GAS5 inhibits malignant phenotypes in glioma cells, including proliferation, migration, and invasion, whereas GAS5 knockdown enhances these phenotypes. We further observed Argonaute 2-dependent reciprocal repression between GAS5 and miR-18a-5p in glioma cells. Downregulation of GAS5 and upregulation of miR-18a-5p were observed in glioma tissue microarrays relative to normal brain tissue by ISH. By deletion analysis, we identified one miR-18a-5p-binding site within exon 2 of GAS5 that is partially responsible for the tumor-suppressor functions of GAS5. CONCLUSION: Taken together, our findings suggest that GAS5 is a tumor suppressor in human gliomas that acts in part by repressing miR-18a-5p.
INTENTION: Long noncoding RNAs, transcribed from a recently discovered class of noncoding genes, may play a critical role in regulating cellular processes, such as cell proliferation and apoptosis, as well as in cancer progression and metastasis. We previously detected the induction of growth arrest-specific 5 (GAS5) during glioma cell death. However, the function and underlying mechanism of GAS5 in humangliomas remain to be elucidated. METHODS: Cell proliferation was detected using CellTiter 96® AQueous Non-Radioactive Cell Proliferation Assay (MTS) and tumorigenicity assay in nude mice. Wound-healing assay and transwell assay were utilized to examine the effects of GAS5 expression on glioma cells migration and invasion. In situ hybridization (ISH) was performed to evaluate GAS5 and microRNA (miR)-18a-5p levels in tissue microarrays. The relationship between GAS5 and miR-18a-5p was evaluated by quantitative reverse-transcription polymerase chain reaction and RNA precipitation. RESULTS: In this study, we demonstrated that overexpression of GAS5 inhibits malignant phenotypes in glioma cells, including proliferation, migration, and invasion, whereas GAS5 knockdown enhances these phenotypes. We further observed Argonaute 2-dependent reciprocal repression between GAS5 and miR-18a-5p in glioma cells. Downregulation of GAS5 and upregulation of miR-18a-5p were observed in glioma tissue microarrays relative to normal brain tissue by ISH. By deletion analysis, we identified one miR-18a-5p-binding site within exon 2 of GAS5 that is partially responsible for the tumor-suppressor functions of GAS5. CONCLUSION: Taken together, our findings suggest that GAS5 is a tumor suppressor in humangliomas that acts in part by repressing miR-18a-5p.