MicroRNA-31 Predicts the Presence of Lymph Node Metastases and Survival in Patients with Lung Adenocarcinoma

Abstract

Purpose We performed genome-wide microRNA-sequencing (miRNA-seq) in primary cancer tissue from lung adenocarcinoma patients to identify markers for the presence of lymph node metastasis. Experimental Design Markers for lymph node metastasis identified by sequencing were validated in a separate cohort using QPCR. After additional validation in the TCGA dataset, functional characterization studies were performed in vitro. Results MiR-31 was upregulated in lung adenocarcinoma tissues from patients with lymph node metastases compared to those without lymph node metastases. We confirmed miR-31 to be up-regulated in lymph node positive patients in a separate patient cohort (p=0.009, t-test), and to be expressed higher in adenocarcinoma tissue than in matched normal adjacent lung tissues (p<0.0001, paired t-test). MiR-31 was then validated as a marker for lymph node metastasis in an external validation cohort of 233 lung adenocarcinoma cases of the TCGA (p=0.031, t-test). In vitro functional assays showed that miR-31 increases cell migration, invasion, and proliferation in an ERK1/2 signaling dependent manner. Of note, miR-31 was a significant predictor of survival in a multivariate cox regression model even when controlling for cancer staging. Exploratory in silico analysis showed that low expression of miR-31 is associated with excellent survival for T2N0 patients. Conclusions We applied microRNA-seq to study microRNomes in lung adenocarcinoma tissue samples for the first time and identified potentially a microRNA predicting the presence of lymph node metastasis and survival outcomes in lung adenocarcinoma patients.

MicroRNA-31 initiates lung tumorigenesis and promotes mutant KRAS-driven lung cancer

“…However, miR-31 was recently shown to be upregulated in lymph node metastases of patients with lung adenocarcinoma and in lung tumors of cyclin E transgenic mice (21,22). These conflicting ation in the miR-31-overexpressing cells was completely inhibited with expression of RASA1, SPRED2, SPRY1, or SPRY4, whereas SPRED1 expression partially inhibited proliferation ( Figure 7F).…”

“…This KRAS mouse model is known for not producing distant metastases, despite developing a large lung tumor burden with high-grade carcinoma (33). Consequently, we cannot exclude the possibility that miR-31 also contributes to lung cancer metastasis, as elevated levels of miR-31 were associated with patients with lung adenocarcinoma with lymph node metastasis, and this correlated with decreased survival (22). Increased miR-31 levels are also associated with advanced colorectal cancer and lung squamous cell carcinoma and correlated with decreased survival of patients with lung squamous cell carcinoma (18,19).…”

“…In the lung, miR-31 overexpression was observed in lung cancers from cyclin E transgenic mice and in 2 of 3 human lung adenocarcinomas and all 3 lung squamous cell carcinomas analyzed (21). Inhibition of miR-31 resulted in reduced numbers of lung adenocarcinoma cells (21), whereas elevated miR-31 expression was shown to correlate with lymph node metastasis in patients with lung adenocarcinoma (22). Despite these reports, the contribution and mechanism of miR-31 function in lung adenocarcinoma remain unclear.…”

Decreased microRNA-132 and its function in human non-small cell lung cancer

“…miRNAs may act as either oncogenes or tumor suppressors according to the function of the target gene. In terms of NSCLC, in vitro functional assays have shown that miR-31 and miR-196 promote the proliferation, invasion and migration of cancer cells (10,11). Clinical analysis demonstrated that decreased miR-375 and increased miR-21 expression in NSCLC tissues are associated with advanced clinical stage and poor prognosis (12,13).…”

miRNA Detection Methods and Clinical Implications in Lung Cancer

“…With this approach they detected 76 previously unknown miRNAs and 41 novel mature forms of known precursors, as well as 39 miRNAs significantly altered in cancer patients. Recently, a miRNA-sequencing (miRNA-Seq) study was conducted using SOLiD platform in ten fresh-frozen tumor samples from lung ADC patients [72]. The investigators found that miR-31 was up-regulated in patients with lymph node metastasis, compared with those without lymph node metastasis.…”