The Influence of Radical Prostatectomy on the Expression of Cell-Free MiRNA

Abstract

MiRNAs of blood and urine have been shown to represent a convenient source of biomarkers for prostate cancer (PCa) diagnosis and assessment of the therapy effectiveness due to their high stability and representation and the low invasiveness of sample collection. Here, we studied the influence of radical prostatectomy (RP) on the expression of 12 cell-free miRNAs previously shown as potential markers of PCa (i.e., miR-19b, miR-22, miR-92a, miR-378, miR-425, miR-30e, miR-31, miR-125b, miR-200b, miR-205, miR-375 and miR-660). The relative expression of the miRNAs combined into 31 paired ratios was evaluated in the urine extracellular vesicles (EVs), clarified urine (CU) and blood plasma of healthy donors, pre- and post-RP samples of PCa patients. Nineteen miRNA ratios based on combinations of ten of the miRNAs (miR-19b, miR-30e, miR-31, miR-125b, miR-200b, miR-205, miR-375, miR-378, miR-425, and miR-660) were altered by RP. The comparative expression analysis of the cell-free miRNA ratios between healthy donors and PCa patients revealed miR-125b/miR-30e and miR-375/miR-30e as potential markers for evaluating therapeutic efficacy. MiR-378/miR-19b, miR-425/miR-19b, miR-200/miR-30e, miR-660/miR-30e, and miR-205/miR-30e had minor prognostic value but could be used to increase the steadiness of the diagnostic system. The urine EVs had the highest potential as a source of markers.

Keywords: blood plasma; cancer; cell-free miRNA; extracellular vesicles; miRNA; prostate cancer; radical prostatectomy; urine.

Figure 1

Examples of the miRNA ratios (dCt) whose expression was altered after RP of prostate cancer (PCa) patients. Wilcoxon signed-rank test, p < 0.01. EVs—extracellular vesicles; RP—radical prostatectomy. Different colored lines represent different donors.

Figure 2

Euler–Venn diagram of the relative expression of the miRNAs in urine EVs, clarified urine (CU) and blood plasma. Arrows represent the ratio of the relative expression of the miRNA pairs before and after RP. Wilcoxon signed-rank test for different samples: Urine EVs, ** p < 0.01 and * p < 0.05; CU, ^oo p < 0.01 and ^o p < 0.05; blood plasma, ^xx p < 0.01 and ^x p < 0.05.

Figure 3

Involvement of the 12 cell-free miRNAs in tumor-related processes. The research papers were available in PubMed and were found by searching the following keywords: prostate, cancer, miR-19b, miR-22, miR-92a, miR-378, miR-425, miR-30e, miR-31, miR-125b, miR-200b, miR-205, miR-375, miR-660. * according to DIANA-mirPath v.3.0.

Figure 4

Target genes for miR-660, miR-30e, miR-125b, miR-205, miR-375, miR-378, miR-19b and miR-425, which are involved in prostate cancerogenesis. PANTHER data: GO-Slim Biologic Process.

Figure 5

STRING data: Interactional network of the nine genes responsible for “cellular proliferation”.

Figure 6

STRING data: Interactional network of the 27 genes responsible for “biologic regulation”. Genes involved in cell cycle regulation indicated in gray, in the regulation of the immune system process in light gray and in kinase activity regulation in dark gray.

Figure 7

The altered expression of the miRNAs after RP and their target genes responsible for “cellular proliferation” and “biologic regulation” (according to the PANTHER database) visualized using the miRnet database.