Ligation-mediated circuit-driven cascade amplification with high utilization rate of template for lncRNA MALAT1...

Long non-coding RNAs (lncRNAs) are essential in the regulation of gene expression and the abnormal expression of them are considered as one of the driving forces for the development and progression of cancers including apoptosis regulation, migration and invasion of cancer cells. Especially, it has been confirmed the diagnostic and prognostic significance of long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in breast, cervical, lung and other cancers. Thus, lncRNA MALAT1 has emerged as significant biomarker and therapeutic target.

Here, we devised a highly sensitive method for detecting lncRNA MALAT1 by utilizing the ligation-mediated circuit-driven cascade amplification with high utilization rate of template. A special template was designed to initiate the ligation reaction occurring within and between templates in the presence of MALAT1, generating circle template for rolling circle amplification (RCA) and linear template for dual exponential amplification (EXPAR). Subsequently, the primer hybridized with the ligated templates to initiate the RCA and dual EXPAR simultaneously, generating three different products for producing enhanced fluorescent signal. Moreover, the method could be operated by a simple "mixing" procedure for highly selective and sensitive detection of lncRNA MALAT1 with a detection limit of 0.81 aM, and it has been successfully validated for detecting MALAT1 in the extract of cancer mice tissues, demonstrating its potential for practical implementation in MALAT1-related diagnosis and prognosis response.

Furthermore, the method provides a new way for transforming lncRNA MALAT1 into multiple short DNAs by isothermal amplification with only three DNA reactants, holding the promise for ultrasensitive, selective and cost-effective detection of other long non-coding RNAs.