MicroRNAs (miRNAs), endogenous non-coding RNAs, are known gene regulators repressing messenger RNA (mRNA). Aberrant expression has been identified as a prognostic indicator in the development of a number of diseases including cancer. Thus, monitoring the dysregulation of miRNA in vivo is an effective option for evaluating tumor progression and can provide valuable information for therapeutic efficacy. However, measuring miRNA expression in vivo is still a challenge due to its low intracellular abundance.
To overcome this issue, a robust detection strategy is developed by Haojun Liang’s group (University of Science and Technology of China, Hefei, Anhui), published in Advanced Biosystems. A DNA molecular machine powered by double-stranded fuel (DSF) strands is constructed to visualize miRNA in living cancer cells and tumor tissues. In order to obtain a robust DNA probe without signal leakage, the nanostructure of DSF was systematically optimized.
Upon the transfection of the DNA probe into tumor cells, intracellular miRNA triggers the release of signal strands. Since the same miRNA is used a number of times, the signal is amplified to receive a clear signal and image within living cells. Moreover, the authors explored, for the first time, the visualization of miRNA expression in tumor-bearing mice.