两型肾癌的共同标志物筛选及机制研究

The Identification of Common Potential Biomarkers and Mechanism for Two Types of Renal Cancer

目的肾细胞癌是一种源发于肾小管上皮系统的恶性肿瘤。在已有肾癌相关mi RNA标志物的研究中,大都忽略了不同亚型肾癌之间样本数据量差距对筛选结果的影响,这会导致mi RNA生物标志物对不同亚型肾癌患者的诊断能力存在较大差异,进而发生漏诊误诊。因此本课题考虑了两种亚型肾癌共同标志物进行研究。方法对透明肾细胞癌(KIRC)和乳头状肾细胞癌(KIRP)的表达谱数据分别进行统计学和两种机器学习方法筛选并对结果取交集获得两型肾癌共同mi RNA标志物。接着,用ROC方法验证了这些标志物的诊断能力。用机器学习方法对外部数据集KICH进行了验证,进一步证明这些标志物的诊断能力以及避免过拟合。还用已有实验文献验证了这些标志物的合理性。用生物信息学方法对mi RNA标志物分子机制进行研究。结果获得了6个两型肾癌共同mi RNA标志物(mi R-21、mir-210、mir-185、mir-188、mir-362、mir-199a-2),其中有4个已有实验报道和肾癌密切相关,而mir-188和mir-199a-2尚未见文献报道其与肾癌相关,可能是新的肾癌相关mi RNA标志物。之后对6个两型肾癌共同mi RNA标志物进行了生物信息学分析,其结果表明新发现的两型肾癌共同标志物mir-188和mir-199a-2参与调控了肾癌相关的MAPK信号通路和TGF-β信号通路。对mi RNA及其在通路中的靶基因进行了差异表达的验证,进一步证明了mi RNA作为标志物的可靠性及其对靶基因的调控作用。本文还发现,标志物mir-185的下游靶基因中同属于UGT1A基因家族的9个靶基因可能参与肾癌的机制,而在肾癌相关研究领域中尚未见到此种机制研究的文献。结论本研究发现了两型肾癌可能的新的共同mi RNA标志物,揭示了肾癌相关领域中尚未见到的肾癌发生机制。

Objective Renal cell carcinoma is a malignant tumor originating from the renal tubular epithelial system.In the field of mi RNA biomarkers for renal cancer,many previous researches had ignored the large gap in the amounts of samples between different subtypes of renal cancer,this may lead to differences in the diagnostic ability of selected mi RNA biomarkers among patients with different subtypes of renal cancer,and may cause missed diagnosis and misdiagnosis.Therefore,we considered two subtypes of kidney cancer common markers for the study.Methods Statistics and two machine learning methods were performed to screen the expression profile data of clear renal cell carcinoma(cc RCC,KIRC)and papillary renal cell carcinoma(p RCC,KIRP)respectively and the results were intersected to obtain common mi RNA markers for both types of kidney cancer.Then,ROC curve was used to verify the diagnostic ability of these biomarkers,machine learning methods using external data set(KICH)were also conformed to these biomarkers,the two methods further proved that these mi RNA biomarkers’diagnostic ability and avoided overfitting.The rationality of these biomarkers was also verified by existing experimental literature.The molecular mechanisms of mi RNA markers were investigated using bioinformatics methods.Results A total of 6 common mi RNA markers for both types of kidney cancer were obtained(mi R-21,mir-210,mir-185,mir-188,mir-362,mir-199a-2),4 of them have been reported to be associated with renal cancer.Mir-188 and mir-199a-2 have not been reported to be associated with renal cancer,and maybe novel mi RNA biomarkers of renal cancer.Then,we performed bioinformatic analysis on these 6 mi RNA biomarkers,the results showed that the newly discovered biomarkers(mir-188 and mir-199a-2),were involved in the regulation of two renal cancer related pathway,MAPK signaling pathway and TGF-βsignaling pathway.The differential expression of mi RNA and its target genes in the pathway was verified,which further proved the reliability of mi RNA as a marker and its regulatory effect on target genes.Also a possible mechanism of how 9 target genes of mir-185(all belonging to the UGT1A gene family)participate in renal cancer was found,and there was no related literature.Conclusion The present study identifies possible new common mi RNA markers for both types of kidney cancer and discovers a mechanism of kidney carcinogenesis that has not been seen in kidney cancer-related fields.