Wang Xiao-Xu, Liu Jue, Tang Yi-Min, Hong Liang, Zeng Zhi, Tan Guang-Hua
Department of Joint Surgery, the Second Affiliated Hospital, University of South China, 35 Jiefang Road, Hengyang, Hunan, People's Republic of China.
Department of Dobstertics and Gynecology, the Second Affiliated Hospital, University of South China, Hengyang, Hunan, People's Republic of China.
Tumour Biol. 2016 Dec;37:16367–16375. doi: 10.1007/s13277-016-5379-1. Epub 2017 Jan 3.
MicroRNAs (miRNAs) are a type of small noncoding RNAs that often play important roles in carcinogenesis, but the carcinogenic mechanism of miRNAs is still unclear. This study will investigate the functions and the mechanism of miR-638 in osteosarcoma (OS). The expression of miR-638 in OS and the DNA copy number of miR-638 were detected by real-time PCR. The effect of miR-638 on cell proliferation was measured by CCK8 assay. Different assays, including bioinformatics algorithms, luciferase report assay, and Western blotting, were used to identify the target gene proviral integration site for Moloney murine leukemia virus 1 (PIM1) of miR-638 in OS. The expression of PIM1 in clinical OS tissues was also validated by immunohistochemical assay. From this research, we found that miR-638 was downregulated in OS tissues compared with corresponding noncancerous tissues (NCTs), and the DNA copy number of miR-638 was lower in OS than in NCTs, which may induce the corresponding downregulation of miR-638 in OS. Ectopic expression of miR-638 inhibited OS cell growth in vitro. Subsequently, we identified that PIM1 is the downstream target gene of miR-638 in OS cells, and silencing PIM1 expression phenocopied the inhibitory effect of miR-638 on OS cell proliferation. Furthermore, we observed that PIM1 was overexpressed in OS tissues, and high expression of PIM1 in OS predicted poor overall survival. In summary, we revealed that miR-638 functions as a tumor suppressor through inhibiting PIM1 expression in OS.
微小RNA（miRNA）是一类小的非编码RNA，其在癌症发生过程中常常发挥重要作用，但其致癌机制仍不清楚。本研究将探讨miR-638在骨肉瘤（OS）中的功能及机制。通过实时PCR检测OS中miR-638的表达及miR-638的DNA拷贝数。采用CCK8法检测miR-638对细胞增殖的影响。运用包括生物信息学算法、荧光素酶报告基因检测及蛋白质免疫印迹法等不同检测方法，鉴定OS中miR-638的靶基因莫洛尼鼠白血病病毒1前病毒整合位点（PIM1）。通过免疫组织化学检测验证PIM1在临床OS组织中的表达。通过本研究，我们发现与相应的非癌组织（NCT）相比，OS组织中miR-638表达下调，且OS中miR-638的DNA拷贝数低于NCT，这可能导致OS中miR-638相应下调。miR-638的异位表达在体外抑制OS细胞生长。随后，我们鉴定出PIM1是OS细胞中miR-638的下游靶基因，沉默PIM1表达可模拟miR-638对OS细胞增殖的抑制作用。此外，我们观察到PIM1在OS组织中过表达，且OS中PIM1的高表达预示总体生存率较差。总之，我们揭示了miR-638在OS中通过抑制PIM1表达发挥肿瘤抑制作用。
