Wei Zeng1, Jin-Feng Zhu2, Jun-Yuan Liu3, Ying-Long Li3, Xiang Dong4, He Huang5, Li Shan6. 1. First Department of Lung Cancer Chemotherapy, Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, PR China; Department of Hematology and Oncology, Shenzhen University General Hospital, Shenzhen 518055, PR China. 2. Department of Gastrointestinal Surgery, Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, PR China. 3. First Department of Lung Cancer Chemotherapy, Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, PR China. 4. Institute of Cancer Prevention and Treatment, Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, PR China. 5. Department of Histology and Embryology, Xinjiang Medical University, Urumqi 830011, PR China; Department of Histology and Embryology, Xiangya School of Medicine, Central South University, Changsha 410013, PR China. Electronic address: huanghe@csu.edu.cn. 6. First Department of Lung Cancer Chemotherapy, Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, PR China. Electronic address: shanli0424@163.com.
Abstract
BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is an aggressive tumor entity characterized by early metastasis and late diagnosis. MicroRNA-133b (miR-133b) has been considered as a tumor suppressor in many human cancers by regulating epidermal growth factor receptor (EGFR). However, the specific effects of miR-133b and EGFR on ESCC remain unclear. METHODS: qRT-PCR and western blotting were applied for measuring expression of mRNA and protein. Flow cytometry was used for detecting cell cycle and apoptosis. Cell proliferation, migration and invasion were detected by colony formation and transwell assays. Luciferase reporter assay was used to confirm the interaction between miR-133b and EGFR. RESULTS: Low expression of miR-133b and high expression of EGFR were identified in ESCC cells and tissues. Overexpression of miR-133b or knockdown of EGFR suppressed the cell proliferation, migration, and invasion of ESCC cells, and raised the percentage of G1 phase cells. The apoptosis of ESCC cells were promoted by increasing miR-133b and decreasing EGFR expression. Luciferase reporter assay confirmed EGFR as the target of miR-133b in ESCC cells. Overexpression of miR-133b significantly decreased the phosphorylation of PI3K, ERK and AKT by directly down-regulating EGFR. Higher expression of E-cadherin and CK-18 and lower expression of Vimentin and N-cadherin were observed after the transfection of miR-133b mimics or shEGFR. CONCLUSION: Overexpression of miR-133b could suppress proliferation, migration and invasion of ESCC cells by inhibiting MAPK/ERK and PI3K/AKT signaling pathways through targeting EGFR, indicating that miR-133b might be a potential therapeutic target for the treatment of ESCC.
BACKGROUND:Esophageal squamous cell carcinoma (ESCC) is an aggressive tumor entity characterized by early metastasis and late diagnosis. MicroRNA-133b (miR-133b) has been considered as a tumor suppressor in many humancancers by regulating epidermal growth factor receptor (EGFR). However, the specific effects of miR-133b and EGFR on ESCC remain unclear. METHODS: qRT-PCR and western blotting were applied for measuring expression of mRNA and protein. Flow cytometry was used for detecting cell cycle and apoptosis. Cell proliferation, migration and invasion were detected by colony formation and transwell assays. Luciferase reporter assay was used to confirm the interaction between miR-133b and EGFR. RESULTS: Low expression of miR-133b and high expression of EGFR were identified in ESCC cells and tissues. Overexpression of miR-133b or knockdown of EGFR suppressed the cell proliferation, migration, and invasion of ESCC cells, and raised the percentage of G1 phase cells. The apoptosis of ESCC cells were promoted by increasing miR-133b and decreasing EGFR expression. Luciferase reporter assay confirmed EGFR as the target of miR-133b in ESCC cells. Overexpression of miR-133b significantly decreased the phosphorylation of PI3K, ERK and AKT by directly down-regulating EGFR. Higher expression of E-cadherin and CK-18 and lower expression of Vimentin and N-cadherin were observed after the transfection of miR-133b mimics or shEGFR. CONCLUSION: Overexpression of miR-133b could suppress proliferation, migration and invasion of ESCC cells by inhibiting MAPK/ERK and PI3K/AKT signaling pathways through targeting EGFR, indicating that miR-133b might be a potential therapeutic target for the treatment of ESCC.