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Updated: Dec 10, 2025
Use of Alu Element Containing Minigenes to Analyze Circular RNAs
Published on: March 10, 2020
Aberrant expression of a novel circular RNA in pancreatic cancer
Takahiro Seimiya1, Motoyuki Otsuka2, Takuma Iwata1
1Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-8655, Japan.
Abstract:
Circular RNAs (circRNAs) are single-stranded, covalently closed RNA molecules that are produced from pre-mRNAs through a process known as back-splicing. Although circRNAs are expressed under specific conditions, current understanding of their comprehensive expression status is still limited. Here, we performed a large-scale circRNA profiling analysis in human pancreatic ductal adenocarcinoma (PDAC) tissues, using circular RNA-specific RNA sequencing. We identified more than 40,000 previously unknown circRNAs, some of which were upregulated in PDAC tissues, compared with normal pancreatic tissues. We determined the full-length sequence of a circRNA upregulated in PDAC, which was derived from two noncoding RNA loci on chromosome 12. The novel circRNA, named circPDAC RNA, was not expressed in normal human cells, but was expressed in PDAC and other carcinoma cells. While postulated biological functions, such as peptide production from the circPDAC RNA, were not detected, its aberrant expression was confirmed in other PDAC tissues and in serum from a PDAC patient. These results demonstrate that comprehensive studies are necessary to reveal the expression status of circRNAs and that the circPDAC RNA identified here might serve as a novel biomarker for cancers, including PDAC.
Insights
Researchers discovered over 40,000 new circular RNAs (circRNAs) in pancreatic cancer. A novel circRNA, circPDAC RNA, was found to be highly expressed in cancer cells and may serve as a potential cancer biomarker.
Area of Science:
- Oncology
- Molecular Biology
- Genomics
Background:
- Circular RNAs (circRNAs) are a class of RNA molecules formed by back-splicing.
- The comprehensive expression profile and functional significance of circRNAs remain largely unexplored.
- Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with limited diagnostic markers.
Purpose of the Study:
- To conduct a large-scale profiling of circRNAs in human pancreatic ductal adenocarcinoma (PDAC).
- To identify novel circRNAs, including those aberrantly expressed in PDAC.
- To investigate the potential of a novel circRNA as a diagnostic biomarker for PDAC.
Main Methods:
- Utilized circular RNA-specific RNA sequencing for comprehensive circRNA profiling in PDAC tissues.
- Performed sequence determination for upregulated circRNAs.
- Validated the expression of the novel circRNA in various cancer cell lines, PDAC tissues, and patient serum.
Main Results:
- Identified over 40,000 previously unknown circRNAs in human PDAC.
- Discovered several circRNAs upregulated in PDAC compared to normal pancreatic tissues.
- Characterized a novel circRNA, circPDAC RNA, derived from noncoding RNA loci, which is specifically expressed in PDAC and other cancer cells but not in normal cells.
- Confirmed aberrant expression of circPDAC RNA in PDAC tissues and serum from a PDAC patient.
Conclusions:
- Large-scale circRNA profiling is essential for understanding their expression landscape.
- The novel circPDAC RNA exhibits aberrant expression in PDAC and holds potential as a novel biomarker for cancers, including PDAC.
- Further research is warranted to elucidate the biological functions and clinical utility of circPDAC RNA.
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