Monitoring Exosomal Non-coding RNA in Lung Cancers

In this chapter, we present information about the biogenesis of exosomes and their content. We focus on non-coding RNAs (ncRNAs) in exosomes that may be important in the early diagnosis of lung cancer and monitoring the course of treatment. Accumulative evidence suggests that the ncRNA molecules, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), may have significant diagnostic and therapeutic potential. Both types of ncRNAs can be packed and transported in exosomes – the extracellular vesicles of endosomal origin. Exosomes are produced and released by different cell types, and due to the small dimensions of 40–100 nm, they can reach distant organs. Exosomes can be found in saliva, blood, bronchoalveolar lavage (BAL) fluid, sputum, and other body fluids. Exosomal cargo can alter the gene expression locally and in distant organs, thus playing an essential role in cancer development. Firstly, they act on the extracellular matrix facilitating local changes and enabling the proliferation of the cancer cells. Cancer cell-originated miRNAs mediate gene silencing, leading to vascularisation of the tumour and epithelial to mesenchymal transition. Exosomes can establish a premetastatic niche, leading to lung cancer cells’ metastasis. Some miRNAs present in exosomes are also associated with the development of chemoresistance. Identifying new circulating miRNAs as putative non-invasive biomarkers unlocks new opportunities in diagnostics, leading to the creation of an early screening program or identification of patients at risk of recurrence. The cancer-derived exosomes present in circulating peripheral blood can be assessed in an inexpensive and patient-friendly way, which is a significant advantage of future diagnostic solutions.