Abstract 1953: MiRNA and piRNA expression profiles in renal cell carcinoma tissue detected by next generation sequencing

MicroRNAs (miRNAs) are the class of small non-coding RNAs, about 21-25 nucleotides in length, that play an important role in regulation of transcription. They affect gene expression at post-transcriptional levels through binding to complementary mRNAs and mediate their degradation in RISC complex. Piwi-interacting RNAs (piRNAs) is newly discovered class of non-coding RNA. PiRNAs are short single-stranded RNAs with 26-31 nucleotides in length. They are involved in silencing of transposable elements and it is assumed that also participate in sequence-specific chromatin modifications. It was repeatedly shown that piRNAs are present also in somatic cells and are dysregulated in kidney, bladder, gastric, breast, pancreatic and liver cancers. According to small non-coding RNA databases there are about 2600 mature miRNAs and more than 24 000 piRNAs in humans. There were extensive studies aiming to discover miRNAs and to analyze their functions. However, there are only few published studies of miRNA and piRNA profiles in renal cell carcinoma (RCC) using next generation sequencing (NGS) technology. In our study we used the tumor tissue and the paired adjacent non-tumor renal parenchyma of 12 patients (8 males and 4 females) with RCC treated in Masaryk Memorial Cancer Institute (Brno, Czech Republic). RNA was isolated with mirVana™ miRNA Isolation Kit. For preparing RNA library was used TruSeq Small RNA Sample Preparation Kit from Illumina and then the miSeq sequencing technology was employed to detect small RNAs. In our 12 paired samples of tumor tissue and the paired adjacent non-tumor renal parenchyma we detected 283 miRNAs with over 1 read in at least 7 samples. Expression levels of 55 miRNAs were significantly different expressed (p < 0.05) in tumor tissue and adjacent non-tumor parenchyma. Among miRNAs with the most significantly altered expression (p < 0.01) were for example, miR-129, miR-138, miR-142, miR-149, miR-154, miR-155, miR-200b, miR-210, miR-218, miR-340, miR-584, miR-885, miR-891a, miR-1270, miR-3690 and miR-7641. After analyzing piRNA sequences we found 440 piRNAs with over 1 read in at least 7 samples. From these piRNAs were 38 piRNAs significantly deregulated (p