Supplementary Material for: MicroRNA-372 Is Associated with Poor Prognosis in Colorectal Cancer

Objective: MicroRNA-372 (miR-372) is reportedly shown to be an oncogene in human testicular germ cell tumors and gastric cancers, but its expression in colorectal cancer (CRC) is not yet determined. This study investigated the clinical significance of miR-372 expression in CRC. Methods: qRT-PCR was used to evaluate miR-372 in 144 CRC patients, and large tumor suppressor 2 (LATS2) expression was also examined as the likely target gene of miR-372. In vitroassays were performed to evaluate the biological function of miR-372. Results: Multivariate analysis indicated that high miR-372 expression was an independent prognostic factor (p = 0.006). High miR-372 expression was associated with synchronous liver metastasis (p = 0.035). We found an inverse relationship between miR-372 and LATS2 by qRT-PCR (p = 0.007) and immunohistochemistry (p = 0.042) using CRC tissue samples. Furthermore, pre-miR-372 led to a decrease in the LATS2 protein and an increase in proliferative activity of LoVo cells. We also found a significant association between low LATS2 expression and liver metastasis (p = 0.042). Conclusions: This study suggested that miR-372 was a novel independent prognostic factor in CRC. Our data suggest that LATS2 may serve as one of the target genes of miR-372 in clinical CRC tissues.

研究目的：据报道，微小RNA-372（miR-372）在人类睾丸生殖细胞肿瘤及胃癌中属于致癌基因，但其在结直肠癌（colorectal cancer，CRC）中的表达情况尚未明确。本研究旨在探讨miR-372在CRC中的临床意义。
方法：采用实时定量逆转录聚合酶链反应（quantitative real-time polymerase chain reaction，qRT-PCR）检测144例CRC患者样本中的miR-372表达水平，同时检测其潜在靶基因大肿瘤抑制因子2（large tumor suppressor 2，LATS2）的表达。通过体外实验评估miR-372的生物学功能。
结果：多因素分析显示，高miR-372表达是独立预后因子（p=0.006）。高miR-372表达与同步肝转移显著相关（p=0.035）。通过CRC组织样本的qRT-PCR及免疫组织化学检测，我们发现miR-372与LATS2的表达呈负相关关系（分别为p=0.007和p=0.042）。进一步实验表明，转染前体miR-372可降低LoVo细胞中LATS2蛋白的表达水平，并增强细胞增殖活性。此外，我们还发现低LATS2表达与肝转移存在显著关联（p=0.042）。
结论：本研究证实，miR-372是CRC中一种新型独立预后因子。本研究数据提示，LATS2可能是miR-372在临床CRC组织中的靶基因之一。