Abstract 3990: Identification of microRNAs from exosomes of bulk and stem cells from prostate cancer by next generation sequencing

Abstract

Abstract Cancer stem cells (CSCs) are related with cancer initiation, metastasis, resistance and recurrence, by regulating their environment in different ways, including the release of exosomes that modify surrounding and distant cells. Exosomes contain, among other molecules, miRNAs. By identifying the entire spectrum of miRNAs included in exosomes from prostate cancer (PCa) cells by next generation sequencing (NGS), is possible to identify miRNAs specifically released by CSCs, and those related with microenvironment regulation. We stablished adherent primary cell cultures (bulk cells) from PCa tissue from 5 patients. Later, from these cells we obtained CSCs enriched prostatospheres. From bulk and CSCs cultures we purified exosomes by precipitation (ExoQuick-TC, SBI) for miRNAs extraction (mirVana, Ambion). Quality of miRNAs was assessed by Bioanalizer (Agilent Technologies). NGS was performed in the Illumina platform (MiSeq, Illumina) according to manufacturer instructions. Bioinformatic analyses were carried out by Sistemas Genómicos. Overexpressed miRNAs were detected in plasma exosomes by TaqMan miRNA Assays (Lifetechnologies). We identified 1839 miRNAs in exosomes, and 223 species were differentially expressed between bulk and CSCs, but only 26 significantly. Nineteen of them were known species including 6 that were overexpressed in CSCs respect to bulk cells. These miRNAs target genes related with cell differentiation, matrix remodeling and genic expression. From all miRNA detected, 3 were highly overexpressed among all, and were detected in exosomes isolated from plasma of men with prostatic disease. Our study extensively characterizes the miRNA from exosomes of PCa cells. Exosomes contain high diversity of miRNAs, different in CSCs and bulk cells, suggesting differential regulation of their microenvironment. From these, CSCs exosome-related miRNAs could be released to bloodstream and play a role in PCa progression and metastasis (FONDECYT 11121525/1140417). Citation Format: Catherine A. Sanchez, Eliana Andahur, Rodrigo Valenzuela, Enrique Castellon, Christian Ramos, Juan Carlos Triviño. Identification of microRNAs from exosomes of bulk and stem cells from prostate cancer by next generation sequencing. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3990. doi:10.1158/1538-7445.AM2015-3990