Exosomal miR-126 as a circulating biomarker in non-small-cell lung cancer regulating cancer progression

Franco Grimolizzi,Monica Amati,Cristiana Bersaglieri,Marco Tomasetti,Franca Saccucci,Corrado Rubini,Lory Santarelli,Simona Gaetani,Jiri Neuzil,Federica Monaco,Matteo Valentino,Francesca Leoni,Massimo Bracci,Sara Staffolani

doi:10.1038/s41598-017-15475-6

Abstract

Lung cancer is one of the leading causes of cancer-related deaths. It is diagnosed mostly at the locally advanced or metastatic stage. Recently, micro RNAs (miRs) and their distribution in circulation have been implicated in physiological and pathological processes. In this study, miR-126 was evaluated in serum, exosome and exosome-free serum fractions in non-small cell lung cancer (NSCLC) patients at early and advanced stages, and compared with healthy controls. Down-regulation of miR-126 was found in serum of advanced stage NSCLC patients. In healthy controls, circulating miR-126 was equally distributed between exosomes and exosome-free serum fractions. Conversely, in both early and advanced stage NSCLC patients, miR-126 was mainly present in exosomes. Different fractions of miR-126 in circulation may reflect different conditions during tumour formation. Incubation of exosomes from early and advanced NSCLC patients induced blood vessel formation and malignant transformation in human bronchial epithelial cells. On the other hand, exosome-enriched miR-126 from normal endothelial cells inhibited cell growth and induces loss of malignancy of NSCLC cells. These findings suggest a role of exo-miRs in the modulation of the NSCLC microenvironmental niche. Exosome-delivered miRs thus hold a substantial promise as a diagnostics biomarker as well as a personalized therapeutic modality.

Highlights

Lung cancer is one of the leading causes of cancer-related deaths
Exosomes were isolated from serum of the subjects and their level in the circulation of patients of various tumour stages evaluated by several methods
Isolated exosomes were visualized by transmission electron microscopy (TEM), their size distribution was evaluated using nanoparticle tracking analysis (NTA) technology, and the concentration was estimated by the number of particles and exosomal protein level

Summary

Introduction

Lung cancer is one of the leading causes of cancer-related deaths. It is diagnosed mostly at the locally advanced or metastatic stage. MiR-126 was evaluated in serum, exosome and exosome-free serum fractions in non-small cell lung cancer (NSCLC) patients at early and advanced stages, and compared with healthy controls. In healthy controls, circulating miR-126 was distributed between exosomes and exosome-free serum fractions In both early and advanced stage NSCLC patients, miR-126 was mainly present in exosomes. MiR-126 is an endothelial-specific miR, which is expressed at low levels in NSCLC patients[12,16,17], and its re-expression inhibits cell proliferation in vitro and tumour growth in vivo by targeting EGFL718. Given that circulating miRs are differentially regulated and selectively packaged in exosomes, we evaluated the distribution of miR-126 in the circulation of NSCLC patients at early and advanced stages of the disease, and compared the level of the miR with healthy subjects. We examined the possibility that exo-miR-126 discriminates NSCLC patients at different stages from controls, as well as that it affects tumour formation and progression

Methods

Results

Conclusion