A recent study, published in the Journal of Human Genetics, has analysed and identified a novel circRNA in pancreatic cancer that could serve as a potential biomarker.
Pancreatic cancer accounts for ~432,000 deaths annually, making it the seventh most common cause of cancer-related deaths worldwide. Despite advancements in cancer therapeutics, the 5-year survival rate of pancreatic cancer is still 9.3%. Pancreatic cancer has one of the worst prognoses among all cancer types. As a result, it is critical that experts develop early detection and novel knowledge-based therapeutics.
Circular RNAs (circRNAs) are single-stranded, covalently closed RNA molecules. They are generated from pre-mRNAs through a process known as back-splicing and are expressed under specific circumstances. Nevertheless, our understanding of their comprehensive expression status is still limited. Compared to linear RNAs, circRNAs are highly stable and tissue specific. Therefore, they may be a potentially useful biomarker for detection of cancer status. Advancements in high-throughput sequencing technologies have facilitated the detection of circRNAs.
In this study, researchers performed RNA sequencing on tissue samples from human pancreatic duct adenocarcinomas (PDACs) and normal pancreatic tissue. Researchers treated the samples with exoribonuclease RNase R to degrade the linear RNAs.
A novel circRNA
The researchers found more than 40,000 previously unknown circRNAs. Some were upregulated in PDAC tissues compared to normal pancreatic tissues. The team then determined the full-length sequences and features of a novel circRNA. The novel circRNA, named circPDAC RNA, was derived from two noncoding RNA loci on chromosome 12. The team found that circPDAC RNA was not expressed in normal human cells but was in PDAC and other carcinoma cells.
Next, the team sought to determine the possible function for circPDAC RNA. For example, evidence has shown that some circRNAs produce peptides or proteins. However, in this study, the team could not detect circPDAC RNA function. Nevertheless, they did confirm its aberrant expression in other PDAC tissues and in the serum of PDAC patients.
These findings demonstrate the potential biological role that circRNAs may play in human diseases, including cancer. The team were able to readily detect the expression of circPDAC RNA in PDAC tissues and other carcinoma cells; thereby, indicating its potential use as a novel biomarker for cancer.
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