MicroRNAs as Potential Liquid Biopsy Biomarker for Patients with Castration-Resistant Prostate Cancer

Purpose: To identify micro-RNAs (miRNAs) expression profiles in peripheral blood plasma that could play a role as potential biomarkers in patients who progressed to castration-resistant prostate cancer (CRPC). Liquid biopsy analysis of miRNAs is a fast-developing field with a considerable likelihood to predict tumor progression and metastasis by targeting genes involved in oncogenesis. Patients and Methods: Differential expression analysis of miRNAs profile in CRPC patients was performed by creating small RNA libraries of circulating miRNAs using HiSeq2500 Illumina platform. A secondary analysis of aligned reads with miRNA identification and quantification was performed using miARmaSeq. Using the Bowtie algorithm, the selected variants were compared to reference nucleotide sequence GRCh38 and miRbase. Novel miRNA sequences were structurally analyzed using mirDeep2®. Results: A total of 16 patients with CRPC were included for analysis. Identified circulating miRNAs were hsa-miR-885-3p, hsa-miR-4467, hsa-miR-4686, hsa-miR-146a-3p, hsa-miR-6514-5p. Genes identified as regulated by these miRNAs were GPR56, BDNF, CTNND1, C17orf62, and DTNA. Conclusion: We explored the miRNA expression profile in patients with CRPC, identifying five miRNAs implicated in the regulation of genes involved in prostate cancer (PCa) oncogenesis and progression. We also found miRNA 855–3p in peripheral blood for the first time, which has a critical role in tumor growth mechanisms and higher expression profile than in healthy individuals.