Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, China.
Department of Obstetrics and Gynecology, Qilu Hospital of Shandong University, Shandong University, Jinan, China.
Kaohsiung J Med Sci. 2020 Mar;36(3):171-177. doi: 10.1002/kjm2.12149. Epub 2020 Jan 2.
Numb is a conserved protein plays important roles in the development of cancer. Two Numb isoforms have been found produced by alternative splicing and play contrast roles in regulating cellular functions. It is reported that the expression of Numb long isoform (Numb-L) was increased in various kinds of cancers, but in endometrial cancer, the condition is still unknown. The level of two Numb transcripts and protein isoforms were detected by semiquantitative polymerase chain reaction and immunoblotting in 47 paired endometrial tumor and adjacent non-tumor control tissues. The level of three alternative splicing related proteins: RBM5, RBM6, and RBM10 was determined by immunoblotting. MiRNAs targeting RBM10 were predicted by bioinformatics tools and their interaction with RBM10 was confirmed by luciferase assay and immunoblotting. The function of miR-335 in endometrial cancer was examined in xenograft mouse model. Numb-L level was increased in tumors and negatively correlated with RBM10 protein level. RBM10 mRNA level was not significantly altered in endometrial tumors suggesting its expression may regulated by post transcriptional regulators such as miRNAs. We identified miR-133a, miR-133b, and miR-335 directly target RBM10, but only miR-335 level increased in tumors and negatively correlated with RBM10 protein level. miR-335 overexpression promoted tumor growth by downregulating RBM10 and upregulating Numb-L level in xenograft mouse model. miR-335 overexpression promoted Numb-L expression via targeting RBM10 in endometrial cancer, which may provide new biomarkers for EC diagnosis.
Numb 是一种保守的蛋白质，在癌症的发展中发挥着重要作用。已经发现两种 Numb 异构体通过选择性剪接产生，并在调节细胞功能方面发挥着相反的作用。据报道，Numb 长异构体（Numb-L）的表达在各种癌症中增加，但在子宫内膜癌中，情况尚不清楚。通过半定量聚合酶链反应和免疫印迹法检测 47 对子宫内膜肿瘤和相邻非肿瘤对照组织中两种 Numb 转录本和蛋白异构体的水平。通过免疫印迹法测定三种选择性剪接相关蛋白：RBM5、RBM6 和 RBM10 的水平。通过生物信息学工具预测靶向 RBM10 的 miRNAs，并通过荧光素酶测定和免疫印迹法证实其与 RBM10 的相互作用。在异种移植小鼠模型中检查了 miR-335 在子宫内膜癌中的功能。Numb-L 水平在肿瘤中增加，并与 RBM10 蛋白水平呈负相关。子宫内膜肿瘤中 RBM10 mRNA 水平没有明显改变，提示其表达可能受 miRNA 等转录后调节因子的调节。我们鉴定了 miR-133a、miR-133b 和 miR-335 直接靶向 RBM10，但只有 miR-335 水平在肿瘤中增加并与 RBM10 蛋白水平呈负相关。miR-335 过表达通过下调 RBM10 和上调异种移植小鼠模型中的 Numb-L 水平促进肿瘤生长。miR-335 通过靶向 RBM10 过表达促进子宫内膜癌中的 Numb-L 表达，这可能为 EC 诊断提供新的生物标志物。
