Abstract
Numerous indirect and in silico produced evidences suggest circular RNAs (circRNA) in mammals while thorough experimental proofs of their existence have rarely been reported. Biological studies of circRNA, however, should be based on experimentally verified circRNAs. Here, we describe the identification of two circRNAs originating from the gene locus of the translocation associated membrane protein 1 (TRAM1). Linear and potentially circular TRAM1-specific transcripts were identified in a transcriptome analysis of urine RNA of bladder cancer (BCa) patients versus healthy donors. Thus, we first focused on the topology of TRAM1-specific transcripts. We describe conclusive experimental evidence for the existence of TRAM1-specific circRNAs in the human BCa cell lines ECV-304 and RT-4. PCR-based methodology followed by cloning and sequencing strongly indicated the circular topology of two TRAM1 RNAs. Further, studies with exon fusion sequence-specific antisense oligonucleotides (asON) and RNase H as well as studies in the use of RNase R contribute to conclusive set of experiments supporting the circular topology of TRAM1 transcripts. On the biological side, TRAM1-specific circRNAs showed low expression levels and minor differences in BCa cell lines while linear TRAM1 transcripts displayed down-regulated expression in the higher cancer stage model ECV-304 versus more differentiated RT-4 cells.
Highlights
Numerous indirect and in silico produced evidences suggest circular RNAs in mammals while thorough experimental proofs of their existence have rarely been reported
It is important to note that this study focuses on the biogenesis and characterization of circular RNA derived from the translocation associated membrane protein 1 (TRAM1) gene locus which was identified by transcriptome analyses in the use of urine RNA from patients of bladder cancer versus healthy donors[37]
In order to study RNA-based markers for non-invasive diagnosis of bladder carcinoma (BCa), we performed a systematic, whole transcriptome analysis of urine RNA collected from healthy donors (C) and patients with high risk of bladder cancer (BCa) (HR) as described recently[37]
Summary
Numerous indirect and in silico produced evidences suggest circular RNAs (circRNA) in mammals while thorough experimental proofs of their existence have rarely been reported. Linear and potentially circular TRAM1-specific transcripts were identified in a transcriptome analysis of urine RNA of bladder cancer (BCa) patients versus healthy donors. Beside initial diagnostic data the correct classification of BCa is a major goal of future non-invasive approaches This objective can conceivably be approached by RNA markers for staging and grading of BCa. On a deeper level, more insights are expected from transcriptome analyses of patient RNAs. Examples for transcriptome analyses in the area of BCa already exist for single c ells[14], tissue samples[15] and u rine[16]. There is increasing evidence for circular transcripts in serum27, saliva[28], and urine[29] This suggests a high potential of circRNAs as biomarkers for a non-invasive detection in tumor diagnostics. Packaging into exosomes can increase the stability of circRNAs in liquid biopsies and may function as nuclease-resistant environment for transportation to distant tissues and organs[27]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
