AUTHOR=Zhao Ya jing , Song Xingguo , Niu Limin , Tang Youyong , Song Xianrang , Xie Li 

TITLE=Circulating Exosomal miR-150-5p and miR-99b-5p as Diagnostic Biomarkers for Colorectal Cancer

JOURNAL=Frontiers in Oncology

VOLUME=9

YEAR=2019

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2019.01129

DOI=10.3389/fonc.2019.01129

ISSN=2234-943X

ABSTRACT=<p><bold>Background:</bold> Circulating exosomal miRNAs are potential non-invasive biomarkers for colorectal cancer. The present study aimed to validate the novel sensitive and specific exosomal miRNA biomarkers for diagnosing colorectal cancer (CRC).</p><p><bold>Patients and Methods:</bold> Exosomes isolated from the serum of CRC patients and healthy donors by ultracentrifugation were characterized using TEM, qNano, and immunoblotting. The exosomes from 2 healthy donors and 4 CRC patients were subjected to RNA isolation and miRNA sequencing. The differently expressed miRNAs from 165 primary CRC patients and 153 healthy donors were substantiated by RT-qPCR.</p><p><bold>Results:</bold> The RNA-sequence data analysis revealed that 29 exosomal miRNAs (20 downregulated and 9 upregulated) with &gt;1.5-fold difference between CRC patients and healthy donors were selected. The serum exosomal miR-99b-5p and miR-150-5p levels were significantly downregulated in CRC patients as compared to healthy donors (<italic>p</italic> &lt; 0.0001 and <italic>p</italic> &lt; 0.0001, respectively) and benign disease (<italic>p</italic> = 0.009 and <italic>p</italic> &lt; 0.0001, respectively). The expression levels of exosomal miR-99b-5p and miR-150-5p were significantly decreased in early CRC patients as compared to healthy donors (<italic>p</italic> &lt; 0.0001 and <italic>p</italic> &lt; 0.0001, respectively). The expression levels of exosomal miR-99b-5p and miR-150-5p were significantly increased postoperatively (<italic>p</italic> = 0.0058 and <italic>p</italic> &lt; 0.0001, respectively).</p><p><bold>Conclusions:</bold> The present study demonstrated that serum exosomal miRNAs are promising, sensitive, specific, and non-invasive diagnostic biomarkers for CRC.</p><p><bold>Impact:</bold> This is the first study to specifically identify exosomal miR-99b-5p and miR-150-5p associated with CRC. This study, therefore, might deepen the understanding of tumor-derived exosomes for CRC diagnosis.</p>