miR-138-5p contributes to cell proliferation and invasion by targeting Survivin in bladder cancer cells

Molecular Cancer, Dec 2016

Background Survivin (encoded by the gene BIRC5) plays an important role in the carcinogenesis of bladder cancer. Identifying miRNAs that target Survivin in the setting of bladder cancer will help to develop Survivin-based therapies for bladder cancer. Methods The expression levels of miR-138-5p and Survivin protein were measured in 12 resected bladder cancer specimens. The correlation between miR-138-5p and Survivin was further examined by evaluating Survivin expression in human bladder cancer cell lines that either overexpressed or knocked down miR-138-5p. A luciferase reporter assay was performed to test the direct binding of miR-138-5p to the target gene BIRC5. We also investigated the biological role of miR-138-5p targeting to Survivin in bladder cancer cell lines both in vivo and in vitro. Results In this study, we found that the Survivin protein was either absent or weakly expressed in normal adjacent tissues and consistently up-regulated in bladder cancer tissues; however, the mRNA levels did not vary as much, suggesting that a post-transcriptional mechanism was involved. Because microRNAs are powerful post-transcriptional regulators of gene expression, we used bioinformatic analyses to search for microRNAs that could potentially target BIRC5 in the setting of bladder cancer. We identified 2 specific targeting sites for miR-138-5p in the 3′ untranslated region (3′-UTR) of BIRC5. We further identified an inverse correlation between miR-138-5p and Survivin protein levels in bladder cancer tissue samples. By overexpressing or knocking down miR-138-5p in bladder cancer cells, we experimentally confirmed that miR-138-5p directly recognizes the 3′-UTR of the BIRC5 transcript and regulates Survivin expression. Furthermore, the biological consequences of the targeting of BIRC5 by miR-138-5p were examined in vitro via cell proliferation and invasion assays and in vivo using a mouse xenograft tumor model. We demonstrated that BIRC5 repression by miR-138-5p suppressed the proliferative and invasive characteristics of bladder cancer cells and that miR-138-5p exerted an anti-tumor effect by negatively regulating BIRC5 in a xenograft mouse model. Conclusions Taken together, our findings provide the first clues regarding the role of miR-138-5p as a tumor suppressor in bladder cancer by inhibiting BIRC5 translation.

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miR-138-5p contributes to cell proliferation and invasion by targeting Survivin in bladder cancer cells

Yang et al. Molecular Cancer miR-138-5p contributes to cell proliferation and invasion by targeting Survivin in bladder cancer cells Rong Yang 1 2 Minghui Liu 1 Hongwei Liang 1 Suhan Guo Xu Guo 1 Min Yuan 1 Huibo Lian 2 Xiang Yan 2 Shiwei Zhang 2 Xi Chen 1 Feng Fang 0 Hongqian Guo 2 Chenyu Zhang 1 0 Department of Pharmacology, Nanjing Medical University , 101 longmian Avenue, Nanjing, Jiangsu 211166 , China 1 Jiangsu Engineering Research Center for microRNA Biology and Biotechnology, State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University , Nanjing 210093 , China 2 Department of Urology, The Affiliated Drum Tower Hospital of Nanjing University Medical School , 321 Zhongshan Road, Nanjing, Jiangsu 210008 , China Background: Survivin (encoded by the gene BIRC5) plays an important role in the carcinogenesis of bladder cancer. Identifying miRNAs that target Survivin in the setting of bladder cancer will help to develop Survivin-based therapies for bladder cancer. Methods: The expression levels of miR-138-5p and Survivin protein were measured in 12 resected bladder cancer specimens. The correlation between miR-138-5p and Survivin was further examined by evaluating Survivin expression in human bladder cancer cell lines that either overexpressed or knocked down miR-138-5p. A luciferase reporter assay was performed to test the direct binding of miR-138-5p to the target gene BIRC5. We also investigated the biological role of miR-138-5p targeting to Survivin in bladder cancer cell lines both in vivo and in vitro. Results: In this study, we found that the Survivin protein was either absent or weakly expressed in normal adjacent tissues and consistently up-regulated in bladder cancer tissues; however, the mRNA levels did not vary as much, suggesting that a post-transcriptional mechanism was involved. Because microRNAs are powerful posttranscriptional regulators of gene expression, we used bioinformatic analyses to search for microRNAs that could potentially target BIRC5 in the setting of bladder cancer. We identified 2 specific targeting sites for miR-138-5p in the 3′ untranslated region (3′-UTR) of BIRC5. We further identified an inverse correlation between miR-138-5p and Survivin protein levels in bladder cancer tissue samples. By overexpressing or knocking down miR-138-5p in bladder cancer cells, we experimentally confirmed that miR-138-5p directly recognizes the 3′-UTR of the BIRC5 transcript and regulates Survivin expression. Furthermore, the biological consequences of the targeting of BIRC5 by miR-1385p were examined in vitro via cell proliferation and invasion assays and in vivo using a mouse xenograft tumor model. We demonstrated that BIRC5 repression by miR-138-5p suppressed the proliferative and invasive characteristics of bladder cancer cells and that miR-138-5p exerted an anti-tumor effect by negatively regulating BIRC5 in a xenograft mouse model. (Continued on next page) © The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. - (Continued from previous page) Conclusions: Taken together, our findings provide the first clues regarding the role of miR-138-5p as a tumor suppressor in bladder cancer by inhibiting BIRC5 translation. Background Bladder cancer is the most common malignancy of the urogenital system and is one of the major causes of cancer-related death among Chinese patients. Based on statistics by Chen et al., an estimated 80,500 new cases of urinary bladder cancer would be diagnosed and approximately 32,900 deaths from bladder cancer were anticipated in China in 2015 [1]. Bladder cancer can be classified into two types according to the tumor invasion depth: non-muscle invasive tumor (70 ~ 80%) and muscle-invasive tumor (20 ~ 30%) [2]. Compared with non-muscle invasive tumors, muscle-invasive tumors are a highly aggressive disease. The 5-year survival rate for patients with non-muscle invasive bladder cancer is nearly 90%, whereas that for patients with muscleinvasive bladder cancer is approximately 60% [3]. Therefore, it is of great clinical significance to clarify the mechanisms underlying the aggressive progression of bladder cancer, which will help to identify specific molecular targets and develop more effective therapies for this disease. Survivin (encoded by the gene BIRC5) is a key member of the inhibitor of apoptosis protein (IAP) family [4]. Dysregulation of Survivin is a typical signature of man (...truncated)


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Rong Yang, Minghui Liu, Hongwei Liang, Suhan Guo, Xu Guo, Min Yuan, Huibo Lian, Xiang Yan, Shiwei Zhang, Xi Chen, Feng Fang, Hongqian Guo, Chenyu Zhang. miR-138-5p contributes to cell proliferation and invasion by targeting Survivin in bladder cancer cells, Molecular Cancer, 2016, pp. 82, 15, DOI: 10.1186/s12943-016-0569-4