DETECTION OF ALTERED MIRNA AND PIRNA EXPRESSION LEVELS IN RENAL CELL CARCINOMA BY NGS

Introduction:

MicroRNAs (miRNAs) are the class of small non-coding RNAs long 21-25 nucleotides. They 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 small non-coding RNA. They are single-stranded RNAs long 26-31 nucleotides. They are involved in silencing of transposable elements and also participate in sequence-specific chromatin modifications. Deregulation of piRNAs was observed in kidney, bladder, gastric, breast, pancreatic and liver cancers.

Patients and Methods:

In our study we used the tumor tissue and the paired adjacent non-tumor renal parenchyma of 12 patients (7 males and 5 females) with renal cell carcinoma (RCC) hospitalized in Masaryk Memorial Cancer Institute. 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 used to detect small RNAs.

Results:

In our 12 paired samples of tumor tissue and the paired adjacent non-tumor renal parenchyma we detected 283 miRNAs with > 1 read in at least 13 samples. 55 miRNAs were statistically significant different expressed (p < 0.05) in tumor tissue then in adjacent non-tumor parenchyma. MiRNAs with most significant altered expression (p < 0.01) were 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 piRNA sequences analysis we found 440 piRNAs with > 1 read in at least 13 samples. From these piRNAs were 38 piRNAs statistically significant deregulated (p < 0.01). Most statistically significant altered expression levels were observed in piR-1207, piR-2107, piR-2155, piR-12487, piR-12488, piR-21508, piR-23230, piR-26525, piR-26527 and piR-28131.

Conclusion:

In our pilot profiling study of miRNA and piRNA in RCC we found altered expression patterns in tumor tissue and paired adjacent non-tumor renal parenchyma. We successfully detected some miRNAs (e.q. miR-155, miR-210, miR-200b) described as deregulated in accordance with previous studies. However, further validation on a larger set of patients is needed for elucidation of role miRNAs and piRNAs in molecular pathology of RCC.

This work was supported by IGA MZCR No: NT/13860-4/2012, NT/13549-4/2012, NT/13547-4/2012, NT/13514-4/2012.