OncoTargets and Therapy (Nov 2020)
Let-7c-5p Inhibits Cell Proliferation and Migration and Promotes Apoptosis via the CTHRC1/AKT/ERK Pathway in Esophageal Squamous Cell Carcinoma
Abstract
Yaxin Zheng,1,2,* Mao Luo,3,* Muhan Lü,1,2 Tiejun Zhou,4 Fang Liu,1,2 Xiaoni Guo,5 Jian Zhang,1,2 Min Kang1,2 1Department of Gastroenterology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan, People’s Republic of China; 2Nuclear Medicine and Molecular Imaging Key Laboratory of Sichuan Province, Luzhou, Sichuan, People’s Republic of China; 3Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Drug Discovery Research Center, Southwest Medical University, Luzhou, Sichuan, People’s Republic of China; 4Department of Pathology, The Affiliated Hospital of Southwest Medical University, Luzhou, Sichaun, People’s Republic of China; 5School of Public Health and Management, Chongqing Medical University, Chongqing, People’s Republic of China*These authors contributed equally to this workCorrespondence: Min KangDepartment of Gastroenterology, The Affiliated Hospital of Southwest Medical University, No. 23 Taiping Street, Luzhou, Sichuan 646000, People’s Republic of ChinaTel/Fax +86 18989131773Email [email protected]: Let-7c-5p has been identified as a tumor suppressor in various malignancies; however, its function and mechanism in esophageal squamous cell carcinoma (ESCC) remain unclear. Here, we explored the role and potential molecular mechanism of let-7c-5p in ESCC.Materials and Methods: mRNA and protein expression levels were detected by quantitative real time-polymerase chain reaction (qRT-PCR) and Western blotting. The cell counting kit-8 (CCK-8) assay was used to assess cell proliferation. Flow cytometry analysis was used to detect cell apoptosis, and cell migration was measured by wound healing assay and Transwell assays. The dual-luciferase reporter assay was used to verify the targeting relationship between let-7c-5p and CTHRC1. The tumor xenograft model was constructed to further verify the effect of let-7c-5p on the growth of ESCC in vivo.Results: We found that let-7c-5p expression was downregulated in ESCC tissue and cell lines, and its reduced expression was correlated with TNM staging and lymph node metastasis. Next, we found that let-7c-5p can be used to discriminate ESCC patients from normal control subjects by receiver operating characteristic (ROC) curve analysis. Subsequently, we observed that let-7c-5p overexpression inhibited proliferation and migration and promoted apoptosis, while let-7c-5p down-regulation promoted proliferation and migration and inhibited apoptosis of TE-1 and KYSE150 cells. Furthermore, let-7c-5p overexpression inhibited tumor growth, while let-7c-5p inhibition promoted tumor growth in xenograft models. In addition, we confirmed that CTHRC1 was a direct target gene of let-7c-5p. Then, we found that let-7c-5p level was negatively correlated with CTHRC1 and negatively regulated expression of CTHRC1 in ESCC. Moreover, we confirmed that let-7c-5p upregulation significantly reduced the phosphorylation of AKT and ERK by directly inhibiting CTHRC1, while let-7c-5p downregulation showed the opposite effect.Conclusion: Our findings indicate that let-7c-5p is markedly downregulated in ESCC and suppresses proliferation and migration and promotes apoptosis of ESCC cells by inhibiting the AKT and ERK signaling pathways through negatively regulating CTHRC1. Therefore, these results suggest that let-7c-5p may represent a novel biomarker and therapeutic target for ESCC.Keywords: let-7c-5p, ESCC, CTHRC1, proliferation, migration, apoptosis
