miR-21-5p is a Biomarker for Predicting Prognosis of Lung Adenocarcinoma by Regulating PIK3R1 Expression

Jianting Du,1,2 Jiekun Qian,1,2 Bin Zheng,1,2 Guobing Xu,1,2 Hao Chen,1,2 Chun Chen1,2 1Department of Thoracic Surgery, Fujian Medical University Union Hospital, Fuzhou, Fujian, People’s Republic of China; 2Key Laboratory of Cardio-Thoracic Surgery (Fujian Medical University), Fujian Province University, Fuzhou, Fujian, People’s Republic of ChinaCorrespondence: Chun ChenDepartment of Thoracic Surgery, Fujian Medical University Union Hospital, 29 Xinquan Road, Fuzhou, Fujian, 350000, People’s Republic of ChinaTel +86 13805069983Fax +86 591-87113828Email dujt1220@fjmu.edu.cnBackground: Lung cancer (LUCA) is one of the most prevalent human malignancies, and the leading cause of cancer-related deaths worldwide. Previous reports have shown that miR-21-5p plays a vital role in development of various tumors. Here, we explored the relationship between miR-21-5p/PIK3R1 axis and prognosis of patients with lung adenocarcinoma (LUAD).Methods: MiRNAseq data, deposited in The Cancer Genome Atlas (TCGA) database, was downloaded and used to determine patterns of miR-21-5p expression in both LUAD and normal lung tissues. Statistical analyses and data visualization were performed using dbDEMC v3.0 platform, starBase v3.0 database and packages implemented in R software. Next, we employed TargetScan Human, miRDB and DIANA Tools databases to predict miR-21-5p target genes, then analyzed their expression patterns as well as prognostic value in LUAD.Findings: Most human cancers overexpressed miR-21-5p. Specifically, miR-21-5p was significantly upregulated in LUAD tissues relative to normal lung tissues (P < 0.001), and this high expression was significantly correlated with poor patient prognosis (hazard ratio [HR]=1.45, P = 0.014). PIK3R1 was predicted as a miR-21-5p target gene, and both were negatively correlated (r=− 0.218, P < 0.01). Notably, PIK3R1 was significantly downregulated in LUAD, relative to normal lung tissues (P < 0.01), with its overexpression significantly associated with poor prognosis of LUAD patients (HR = 0.62, P = 0.0014).Conclusion: miR-21-5p is a potential prognostic biomarker for LUAD patients. Moreover, it might be playing a role in LUAD progression by regulating PIK3R1 expression.Keywords: lung adenocarcinoma, miR-21-5p, PIK3R1, surviva